# Electric Porsche



## Joey (Oct 12, 2007)

After 10 years, I'm finally able to begin my electric car conversion. My goals are 0-60 MPH in < 8 seconds, 100 mile range (60 is an absolute min) at 80% dod, >80 mph top speed, and 4 seats.

I've narrowed the donor car decision down to two: Porsche 944 or Porsche 911/912. I would prefer the 911, but not at the price they seem to be selling for in my area, $14 -20 k USD (1978-1989). The 944 goes for between $1,000 - $5,000 (1983-1987).

For components I don't think I will stray too far from what a lot of people have been doing:
9 inch Warp - keeping the clutch and flywheel
Soliton Jr, or Soliton1
56 cells at 130 aH CALB or 48 cells at 180 aH
Manzanita 20 - The idea of long recharging times (12 hours) doesn't bother me
Battery monitoring and instrumentation - not selected yet

I'm thinking that the batteries will be the system bottleneck and any money I can squeeze from the bugdet should go there. Not sure how many will fit without messing up the weight distribution too much.


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## steven4601 (Nov 11, 2010)

Top tip, wait until a Porsche boxter engine blows. They are driven usually quite hard and failure rate is high enough to find them. This could help with keeping donor costs low.


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## Rational (Nov 26, 2011)

Joey said:


> 100 mile range


Using the method here,
http://physics.ucsd.edu/do-the-math/2011/07/100-mpg-on-gasoline/
and just accounting for air drag, to go 100 miles at 33 mph using the vehicle cross section and drag coefficient in the link you'll need 2200 w-h.
At 67 mph you'll need 8800.

0.3	=Cd
3	=A, cross sectional area, m^2
1.3	=p, air density in kg/m^3
30	=v, velocity, m/s
60000	=D, distance traveled, meters
E=0.5(Cd)pAD(v^2)
31590000	=calc'd E, energy, in joules
8775	=calc'd E, energy in w-h

The energy used to cancel out rolling resistance is another calculation, as is your accel requirement, as is your top speed.


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## DavidDymaxion (Dec 1, 2008)

The 911 is a great choice of car! I'll admit my bias, I have one that I have converted (actually am converting). The 2.7 motor had issues, so you can get those a bit cheaper. I found one with a blown motor but very good condition otherwise. The rear seats are pretty small and don't have seat belts (at least for my old one). 1977+ is nice because they were fully galvanized and much less rust prone. The 912 is basically the same car and much cheaper.

Here are a few details on mine:

http://ExplodingDinosaurs.com



Joey said:


> After 10 years, I'm finally able to begin my electric car conversion. My goals are 0-60 MPH in < 8 seconds, 100 mile range (60 is an absolute min) at 80% dod, >80 mph top speed, and 4 seats.
> 
> I've narrowed the donor car decision down to two: Porsche 944 or Porsche 911/912. I would prefer the 911, but not at the price they seem to be selling for in my area, $14 -20 k USD (1978-1989). The 944 goes for between $1,000 - $5,000 (1983-1987).
> 
> ...


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## Joey (Oct 12, 2007)

Rational said:


> Using the method here,
> http://physics.ucsd.edu/do-the-math/2011/07/100-mpg-on-gasoline/
> and just accounting for air drag, to go 100 miles at 33 mph using the vehicle cross section and drag coefficient in the link you'll need 2200 w-h.
> At 67 mph you'll need 8800.
> ...


Thanks for the link. I think D should be 160000 meters (= 100 miles). Then the needed energy is 23500 for 100 miles, or 235 watt hours / mile.

I was estimating 250 watt hours / mile based on results for other porsches posted in the garage and on EVAlbum.

For a series pack:
Energy = S*C*V

with S = 48 cells
C = 180 amp hr cell capacity
and V = 3.2

I get 27650 watt hours.

If I multiply pack energy by 80% dod, and divide by 250 watt hours/mile, I estimate 88 mile range.

This safely meets my minimum range requirement of 60 mile, and my goal of 100 miles could be feasible at lower speeds (62 MPH) or with more cells (55).

These calculations assume a lot (like level terrain, constant velocity without starts and stops, low friction losses, etc) and I'm only considering then as a general guideline.


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## Joey (Oct 12, 2007)

steven4601 said:


> Top tip, wait until a Porsche boxter engine blows. They are driven usually quite hard and failure rate is high enough to find them. This could help with keeping donor costs low.


I've waited 10 years already. I can wait a little longer to get a good deal. I do need 4 seats though, so the boxter and 914 are out.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> The 911 is a great choice of car! I'll admit my bias, I have one that I have converted (actually am converting). The 2.7 motor had issues, so you can get those a bit cheaper. I found one with a blown motor but very good condition otherwise. The rear seats are pretty small and don't have seat belts (at least for my old one). 1977+ is nice because they were fully galvanized and much less rust prone. The 912 is basically the same car and much cheaper.
> 
> Here are a few details on mine:
> 
> http://ExplodingDinosaurs.com


I love the shape and style of the 911, and I agree on the rust protection. The plan is to be a daily driver, and while we don't have salt on the road, we do get 37 inches of rain a year. If I could get one for $10,000 in good shape I would have to do it.


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## rwaudio (May 22, 2008)

I'd love a 911, but budget gave me a 944. If you go that way get the 85.5+ the interior is just so much nicer. The 944 is still a nice car, and nice to work on (once the gas stuff is gone) not a single rusted bolt, many lightweight parts. Plenty of original and after market support for parts/upgrades. The transmission from a Turbo gives you nicer ratio's to use the high torque of an electric motor (assuming 1000A controller), as well as being a bit beefier to handle that torque long term. I'm using an A123 pack and it will all be in the rear, but there is plenty of room up front if you went with a larger prismatic pack and had to split it front/rear.


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## Rational (Nov 26, 2011)

Joey said:


> Thanks for the link. I think D should be 160000 meters (= 100 miles). Then the needed energy is 23500 for 100 miles, or 235 watt hours / mile.


My bad.  I used to know this stuff! 

Fixed it

0.3	=Cd
3	=A, cross sectional area, m^2
1.3	=p, air density in kg/m^3
30	=v, velocity, m/s
161000	=D, distance traveled, meters
E=0.5(Cd)pAD(v^2)
84766500	=calc'd E, energy, in joules
23546.25	=calc'd E, energy in w-h
235.4625	=calc'd E in w-h/mile


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## Joey (Oct 12, 2007)

It will be a 911 afterall. I put a deposit on one today after work. I'll pick it up tomorrow. It is a 1983 SC and the condition was very nice. Service records going back over the last 40,000 miles.


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## Rational (Nov 26, 2011)

Joey said:


> It will be a 911 afterall. I put a deposit on one today after work. I'll pick it up tomorrow. It is a 1983 SC and the condition was very nice. Service records going back over the last 40,000 miles.


On the 100 mile range, you have a good chance of getting better than 0.13 w-h/mile per pound of vehicle weight so for a 2200 lb vehicle you'd need 280 w-h.
Does that sound plausible?

And I can always use more [valid] data like that below\/

four wheeled electric vehicles 
w-h/mile	lbs	w-h/mile-lb..	notes
217	.......2723	0.080	............tesla roadster
275	.......4800	0.057	...............truck
225 
240 
265 
290	.......2020	0.144	
300 
310 
320	.......3000	0.107	
325 
161	.......1250	0.129	
400 

3/4ths of the vehicles sampled did better than 
312.5	w-h/mile	
and better than 
0.129	w-h/mile-lb

half the vehicles weighed between 
3000 
and 
2020


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## Rational (Nov 26, 2011)

Make that 28 kwh.
0.13*2200*100.

Seems I can't do arithmetic at this hour of the morning.


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## dtbaker (Jan 5, 2008)

Joey said:


> It will be a 911 afterall. I put a deposit on one today after work. I'll pick it up tomorrow. It is a 1983 SC and the condition was very nice. Service records going back over the last 40,000 miles.


SWEET!

Your spec/expectations look about right. Lots of variables, and *your mileage may vary*  But, I'd say you are safe with Warp9, Soliton, 156v worth of 180ah CALB to get well over 60 miles and probably closer to 80 depending on conditions and speed.

Was the engine blown, or still running? Did you get a good deal? how much?


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## tomofreno (Mar 3, 2009)

100 mile range at what speed? I would guess to get that range at 60 mph and 80% DoD, no heater, no AC, you would need around a 32kWh pack. If you use the motor/controller dt suggested, you could use a 178V pack of 180Ah CALB to get the required kWh (the Soliton1 takes up to 340V I think) and limit the MOTOR voltage in the controller sw to about 160 - 170V (limit suggested by Jim Husted: http://www.diyelectriccar.com/forums/showpost.php?p=19666&postcount=4) to protect against arcing brushes etc. Provided of course you can find room for 55 cells in the car and the money to pay for them.


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## Joey (Oct 12, 2007)

Rational said:


> On the 100 mile range, you have a good chance of getting better than 0.13 w-h/mile per pound of vehicle weight so for a 2200 lb vehicle you'd need 280 w-h.
> Does that sound plausible?
> 
> And I can always use more [valid] data like that below\/


280 w-h/mile does seem reasonable. I would expect anything between 200 and 325. I am hoping for 250. The car is probably closer to 2700 lbs. The weight creeps up the later you go in a car generation. The AC was removed, which saves a few lbs.



dtbaker said:


> SWEET!
> 
> Your spec/expectations look about right. Lots of variables, and *your mileage may vary*  But, I'd say you are safe with Warp9, Soliton, 156v worth of 180ah CALB to get well over 60 miles and probably closer to 80 depending on conditions and speed.
> 
> Was the engine blown, or still running? Did you get a good deal? how much?


Thanks. The engine is in good working order. It car was in very good condition, inside and out. I paid $11,000. While not a steal, it was a good price. The cars I looked at in this condition, in my area, were listed as high as $16,000. I plan to sell the motor to offset some of the cost. I would have loved to find a deal on a 911 with a blown motor, but it seems motor condition and car condition are stronly correlated (at least over the 3 months I searched). Also, buying a car that doesn't drive adds risk in assessing the condition of the transmission, which I want to keep.

If a 100 mile range becomes an obsession (it allows me to get to the beach, and it sounds better - which is a consideration if promoting electric is a goal), I think adding 5 or 6 cells to the pack would do it. I will have to see how my budget is looking when the time comes to buy the batteries.


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## Joey (Oct 12, 2007)

tomofreno said:


> 100 mile range at what speed? I would guess to get that range at 60 mph and 80% DoD, no heater, no AC, you would need around a 32kWh pack. If you use the motor/controller dt suggested, you could use a 178V pack of 180Ah CALB to get the required kWh (the Soliton1 takes up to 340V I think) and limit the MOTOR voltage in the controller sw to about 160 - 170V (limit suggested by Jim Husted: http://www.diyelectriccar.com/forums/showpost.php?p=19666&postcount=4) to protect against arcing brushes etc. Provided of course you can find room for 55 cells in the car and the money to pay for them.


Yes, I agree. Not sure if space or money will be limiting factor. 60 mile is the need. 100 miles is the want.

My 4 year old daughter loves the car, too. She asked Mommy if we now need to wear helmets when we drop her off at school. Sound like someone has been watching too many episodes of "Top Gear" on Netflix.


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## PThompson509 (Jul 9, 2009)

Something you will seriously want to do before doing ANYTHING to the car is to fix ALL of the 12v systems so they work perfectly. Since this is a relatively new car (unlike my 1975 914), you *shouldn't* have rust issues, but that should be looked for as well.

Take it to a Preferred Porsche Specialist for a very thorough checkout. You will find things you don't really want to know, but should.

As for the batteries, I second the recommendation to go higher in voltage - but keep it below 200v - there aren't many parts available to handle higher voltage (I'm all too aware of that - my pack is 370v).

Cheers,
Peter


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## Rational (Nov 26, 2011)

xxxxxxxxxxxxxxxxxx


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## cruisin (Jun 3, 2009)

Joey said:


> After 10 years, I'm finally able to begin my electric car conversion. My goals are 0-60 MPH in < 8 seconds, 100 mile range (60 is an absolute min) at 80% dod, >80 mph top speed, and 4 seats.
> 
> I've narrowed the donor car decision down to two: Porsche 944 or Porsche 911/912. I would prefer the 911, but not at the price they seem to be selling for in my area, $14 -20 k USD (1978-1989). The 944 goes for between $1,000 - $5,000 (1983-1987).
> 
> ...


Having to charge on the road for a long time will bother you I am sure. BAD decision on the charger. A 914 would be a much better donor car and a lot cheaoer than a 912/911.


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## rwaudio (May 22, 2008)

cruisin said:


> Having to charge on the road for a long time will bother you I am sure. BAD decision on the charger. A 914 would be a much better donor car and a lot cheaoer than a 912/911.


How is the charger a bad choice if you don't know what charging station/electrical outlets are available? The PFC20 can max out a normal plug, if that is all that is available bigger helps how??

And for the car how is a 914 better than a 911? I can't stand the look of a 914, so I would never convert one, it's personal choice. Others don't like the 944 so they would never convert one. The best car for "you" is the car you will enjoy driving for the next decade or so, it could be a Bug, 911, 914, hummer or anything that fits you needs and wants.

If you have constructive input, like the transmission of a 911/912 won't last or shift or something related to an EV conversion then it may be useful to suggest one car over another, but it is very clear that the "dream car" is a 911 and unsupported comments about a 914 being better just don't seem to provide worthwhile input. 

You may have valid points, but back them up and explain your reasoning, why is the charger a bad choice? What's wrong with a 911?


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## cruisin (Jun 3, 2009)

rwaudio said:


> How is the charger a bad choice if you don't know what charging station/electrical outlets are available? The PFC20 can max out a normal plug, if that is all that is available bigger helps how??
> 
> And for the car how is a 914 better than a 911? I can't stand the look of a 914, so I would never convert one, it's personal choice. Others don't like the 944 so they would never convert one. The best car for "you" is the car you will enjoy driving for the next decade or so, it could be a Bug, 911, 914, hummer or anything that fits you needs and wants.
> 
> ...


As the developer of the first EV on the road with 18650 Li-ion cells in 2003 and a part of the Tesla design team, a EV Conversion instructor since 2000, I thought you would see some benefit in my comments and others on this forum. You appear to be too hostile and non receptive to suggestions for me to feel good about helping you.
Why is a PFC a bad choice when out on the road needing power from a public charger that requires a 5-20 110v plug that will take forever or a J1772 that will take a couple of hours on 220v. I think you should be able to answer your own question.


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## frodus (Apr 12, 2008)

Why such the negative chip on your shoulder all the time! You seriously need to lighten up. You take everything as if someone is assaulting you, you're always ready to attack.

He asked some fairly simple questions on WHY you made the comments you did so the poster and others in this threat know why you made those comments.


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## dtbaker (Jan 5, 2008)

cruisin said:


> Why is a PFC a bad choice when out on the road needing power from a public charger that requires a 5-20 110v plug that will take forever or a J1772 that will take a couple of hours on 220v.



lets just stick to this....

I would argue that a simple PFC with 'normal' 110v plug is 'better' for several reasons:

- a properly sized battery pack won't leave you stranded in your daily travels, so the whole concept of quick charge on a public plug is a red herring benefitting only the manufacturers of the charging stations.

- a regular 110v plug allows a (slow) charge ANYWHERE

- most people's garages and outside outlets have only 15 amp 110v service anyway, so why pay double to put in a 220v high amp charger? The overnight charge will get ya a good 15kwhr.... enough to get *most* people their sub-50 mile daily needs.


....ok, ok, if you are driving OVER 50 miles a day, you probably need a higher capacity charger to get enough kWhr on board overnight. But I would still maintain that you'd be more likely to find a 110v outlet *somewhere* for an emergency charge than you are to have a J charge station handy.


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## cruisin (Jun 3, 2009)

frodus said:


> Why such the negative chip on your shoulder all the time! You seriously need to lighten up. You take everything as if someone is assaulting you, you're always ready to attack.
> 
> He asked some fairly simple questions on WHY you made the comments you did so the poster and others in this threat know why you made those comments.


I think YOU need to look in the mirror at yourself, your postings have a lot to be desired. Always looking to get one up on somebody.Your reputation up there with scammers doesnt do well for you either.


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## StanSimmons (Sep 3, 2011)

dtbaker said:


> - a regular 110v plug allows a (slow) charge ANYWHERE
> 
> - most people's garages and outside outlets have only 15 amp 110v service anyway, so why pay double to put in a 220v high amp charger? The overnight charge will get ya a good 15kwhr.... enough to get *most* people their sub-50 mile daily needs.


I've read about a few people using the Quick220 adapter to combine two opposite phase 110V 15A outlets into a 220V 15A for faster charging. It looks like it has some active electronics in it to make it safe. I'm thinking it might be useful when out on the road and charging at hotels. 









http://www.quick220.com/220_volt.htm

My plan for my summer trip next year is to camp at RV parks and use their 220V 30A or 50A outlets to charge.


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## frodus (Apr 12, 2008)

cruisin said:


> I think YOU need to look in the mirror at yourself, your postings have a lot to be desired. Always looking to get one up on somebody.Your reputation up there with scammers doesnt do well for you either.


You just made my point! Relax, you're gonna have a heart attack!

People aren't going to believe someone because of their credentials. People will believe you because you support your comments with fact, which is all he wanted you to do. 




P.S. Not sure what scammers you're talking about.


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## rwaudio (May 22, 2008)

frodus said:


> Why such the negative chip on your shoulder all the time! You seriously need to lighten up. You take everything as if someone is assaulting you, you're always ready to attack.
> 
> He asked some fairly simple questions on WHY you made the comments you did so the poster and others in this threat know why you made those comments.


I think what I said was clear and to the point without being "mean". I believe that frodus saw this from my point of view as well. I don't really care who you are if you don't take the time to fully explain your answers cruisin. All I ever see you do on here is push what you are selling and seldom contribute constructively. It's nice to see you provide input to this thread, I'm sure the builder and many more of us can benefit from what you have learned. Hell, I even watch Jack R's show and even though he is far from the most competent teacher, he doesn't hide his mistakes and we can all learn from them.



cruisin said:


> I think YOU need to look in the mirror at yourself, your postings have a lot to be desired. Always looking to get one up on somebody.Your reputation up there with scammers doesnt do well for you either.


cruisin, I'm not trying to start anything, and I don't think frodus was either, please just respond to my first post with constructive answers that can help this thread.

From my point of view dtbaker nailed it on why I think the PFC-20 is a good choice. If you disagree please suggest an alternative product and why. I personally live in a city with ZERO public charging stations (and it's a city of well over a million people) so for me and many others making the best use of a 120v outlet is not only the best, but the only way to go.


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## DavidDymaxion (Dec 1, 2008)

Agreed the 914 is alot cheaper -- but there are reasons for that! Here are some goods and bads:


Both cars have a surprising amount of room for batteries
Both cars can put the battery weight low for good handling
You can buy a kit for the 914
There are race parts and an enthusiastic community for both cars
Both cars have stronger brakes and transmissions than an economy car
The 914s were not galvanized and much more rust prone (911s were galvanized 1977+)
You can get a 911 with a roof -- this makes the car stronger
You can cram 4 people into a 911 if you have to -- there is no hope of that in a 914
911 is a better looking car 



cruisin said:


> ... A 914 would be a much better donor car and a lot cheaoer than a 912/911.


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## tomofreno (Mar 3, 2009)

> I would argue that a simple PFC with 'normal' 110v plug is 'better' for several reasons:
> 
> - a properly sized battery pack won't leave you stranded in your daily travels, so the whole concept of quick charge on a public plug is a red herring benefitting only the manufacturers of the charging stations.
> 
> ...


 I think, like many things, this depends on how/where you drive. Myself I think a 110V charger is useless anywhere but charging at home over night, or maybe at someone's house if you are staying there for a couple hours or more and just need to add 10 miles worth or so. If you only have an hour or so to charge it isn't going to help you much. I sometimes drive to a nearby town 60 miles round trip, return home in the afternoon then charge to drive another 30 miles a bit later. Or, drive to that town, charge in an RV park for 1 1/2 hr from a 240VAC/50A outlet while I walk to a nearby restaurant and eat breakfast, then continue on to my destination and have enough to get back home with about 30% SoC. Most of the time I charge at home over night at 7 to 10A, so a 120V charger would work fine, but the other times it would not.

I am thinking of upgrading to the new Curtis controller next year that is supposed to be about 160-170V max, so I can add 12-13 more cells and have about 100 mile range at 60 mph. If I do, I also plan to go to a 8 or 10kW charger - maybe valerun's. I could then charge at say 45A for an hour at the RV park adding 45Ah and drive to South Lake Tahoe to hike or mountain bike, and back home. So depends on how/where you drive.


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## Joey (Oct 12, 2007)

Generally, you can't say one choice is better than another without considering the use case. If you need to quick charge, then the PFC 20 is a bad choice. I don't think I will need to, but I will think it over again before making a purchase. I will almost always have 12 hours of charge time per day and I have a 240 volt outlet already in the garage. So I need to select a charger that can charge a 180 V, 180 amp-hr pack in 12 hours. I may move up to the PFC30, but first I will have to do some math.

As for the 914, I have seen many nice conversions, and they make great donors. I need 4 seats, so it wouldn't work for me. The 911 is more attractive to me. My second choice was a 944, which would have been a lot less costly. I would have been happy with the 944, but the 911 is the right car for me once I found one in my budget. I think I can make it into a decent electric car that will make me very happy.

I want comments, criticisms, design reviews, opinions on my planning for this project. I don't want to buy too many components more than once. That's why I'm posting here. The most useful posts for me give an explaination of why something may be a problem.


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## Overlander23 (Jun 15, 2009)

Elcon PFC2500 to PFC5000 ($650-1600). Dual voltage. For instance, the PFC5000 will output the full 5kw on 230VAC, or 2200kw on 115VAC. Of course, the 5kw charger is bigger than pure 2kw charger. Just a possible alternative...


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## cruisin (Jun 3, 2009)

Joey said:


> Generally, you can't say one choice is better than another without considering the use case. If you need to quick charge, then the PFC 20 is a bad choice. I don't think I will need to, but I will think it over again before making a purchase. I will almost always have 12 hours of charge time per day and I have a 240 volt outlet already in the garage. So I need to select a charger that can charge a 180 V, 180 amp-hr pack in 12 hours. I may move up to the PFC30, but first I will have to do some math.
> 
> As for the 914, I have seen many nice conversions, and they make great donors. I need 4 seats, so it wouldn't work for me. The 911 is more attractive to me. My second choice was a 944, which would have been a lot less costly. I would have been happy with the 944, but the 911 is the right car for me once I found one in my budget. I think I can make it into a decent electric car that will make me very happy.
> 
> ...


You didnt tell me you needed 4 seats. I wouldnt do the 944, resale value is real bad, and motor goes in front. Stick with a 912 which will be more reasonable and will be re sellable. I have done many of most Porsche models as well as VW's. My students did a 944 and cant sell it. One suggestion is, when selecting chargers,etc. always try to design the car to resemble the production cars in every aspect. The more corners you cut due to price will bite you on the ass. A 220v charger with a L1772 recepticle would be a good choice as you will be able to use a public charging station if needed without a bunch of cable adaptyers. Install a 220vac charging station in your garage, either designing your own, or buy one off the shelf from Home depot with additional features. Within time, houses with the charging stations will become standard, have more value for reasale and work a lot better at charging than the retrofits some are using today. We should look to the future when designing a EV and selecting components with less regard to cost.


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## Rational (Nov 26, 2011)

Whatever your vehicle ends up weighing, every thousand pounds of vehicle weight will cost you ~37 w-h/mile. 
With a correlation coefficient of only +0.6 the relationship is not too strong but as I get more data this should improve. 
The formula is 
wh/mile = [(veh wt in lbs) x .0369] + 151 
and it's based on the few data points below.

wh/m...veh wt....notes
217	2723	tesla roadster
275	4800	truck
340	3354	Nissan Leaf
320	3000	ptcruisin
161	1250	

0.0369	=slope	
151	=intercept	
0.64	=correlation coefficient

Some of these data points may be 'outliers' and so should be discarded but time will tell. I did graph them and the scatter didn't look too bad.


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## Joey (Oct 12, 2007)

cruisin said:


> One suggestion is, when selecting chargers,etc. always try to design the car to resemble the production cars in every aspect. The more corners you cut due to price will bite you on the ass. 220v charger with L1772 recepticle.


Thanks. I won't cut corners. I do have a budget, but I think it will allow me to achieve a reasonably good conversion. I will research your suggestions further.

I purchased an '83 911 a couple days ago. The rust I saw on the 912's was a major concern. The rust protection on Porsche improved a lot after 1978, but by then the 912 was out of production. 

While I'm not planning on selling it, you bring up a very good point that resale should be a consideration. Things change, and I may HAVE to sell (that would be a sad day). 



Rational said:


> Whatever your vehicle ends up weighing, every thousand pounds of vehicle weight will cost you ~37 w-h/mile.
> With a correlation coefficient of only +0.6 the relationship is not too strong but as I get more data this should improve.
> The formula is
> wh/mile = (veh wt in lbs) x .0369 + 151
> ...


The biggest effect mass has is on acceleration. Driving profile then becomes a factor and may explain some of the variation. For constant velocity on the flat, mass should have only a small impact on friction losses. When I get this thing on the road under electric power, I would be happy to share any data I collect with you. We should figure out if there is any valuable data to be had running it on gas before ripping out the engine.


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## Rational (Nov 26, 2011)

Joey said:


> The biggest effect mass has is on acceleration. Driving profile then becomes a factor and may explain some of the variation. For constant velocity on the flat, mass should have only a small impact on friction losses. When I get this thing on the road under electric power, I would be happy to share any data I collect with you. We should figure out if there is any valuable data to be had running it on gas before ripping out the engine.


I should soon have a working spreadsheet that translates f=mA and several other formulas into a second by second account in order to predict 0 to 60 time/distance and 1/4 mile time. For the time being I will assume torque is inversely related to RPM in a straight line fashion, but I think it was the Tesla info that talked about a constant torque motor.
A popular rolling resistance coefficient seems to be 0.01 so a 3000 lb veh would need 30 lbs to move it and the speed vs. drag vs. force vs. torque calcs seem pretty straightforward. 
A dynamometer or Prony Brake would come in handy for before/after benchmark measurements.


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## frodus (Apr 12, 2008)

Rational said:


> Whatever your vehicle ends up weighing, every thousand pounds of vehicle weight will cost you ~37 w-h/mile.


1000lbs = 37Wh/mile eh?

Not even close to accurate. My motorcycle, about 110wh/mile and it was ~400lbs , which is about average for most motorcycles. I think it's not just y = mx. There's energy lost in transmission, energy to overcome static friction and a bit of kinetic friction via tires.....vehicle speed..... motor efficiency.... all of those vary widely based on vehicle type.

It's not as simple as you want to make it. 

Many people have done the calcs before, including myself. Look up EVCalculator and put some info in there. It's straightforward, but it's not only weight, it's cross sectional area, drag coeff, etc. Maybe look at those some more before you release your theories.


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## Joey (Oct 12, 2007)

frodus said:


> 1000lbs = 37Wh/mile eh?
> 
> Not even close to accurate. My motorcycle, about 110wh/mile and it was ~400lbs , which is about average for most motorcycles. I think it's not just y = mx. There's energy lost in transmission, energy to overcome static friction and a bit of kinetic friction via tires.....vehicle speed..... motor efficiency.... all of those vary widely based on vehicle type.
> 
> ...


The 37 w-h/mile is only the slope of a linear fit taken from some emperical data that relates mass to energy use. He also gave the intercept of 151 w-h/mile. So, the predicted consumsion of a 400 lbs vehicle would be 166 w-h/mile. But nobody is suggestting that this is a complete description.

Rational understands drag and the other parameters you mentioned, (see the equations he posted earlier in this thread). The 37 w-h/mile per 1000 lbs of mass was only a correction factor when I mentioned my car was actually 2700 lbs instead of 2200 lbs.


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## frodus (Apr 12, 2008)

Ok, misunderstood. His wording was confusing.

But maybe don't make the assumption that it works with all "vehicles" because the equation doesn't work for light vehicles very well. 

It just can't be a blanket equation.

Sent from my SGH-I897 using Tapatalk


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## tomofreno (Mar 3, 2009)

> I should soon have a working spreadsheet that translates f=mA and several other formulas into a second by second account in order to predict 0 to 60 time/distance and 1/4 mile time.


 Something like this one (see zip file at bottom of first post)?

http://www.diyelectriccar.com/forum...-charts-ev-performance-spreadsheet-41565.html


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## EVfun (Mar 14, 2010)

Joey said:


> The 37 w-h/mile is only the slope of a linear fit taken from some emperical data that relates mass to energy use. He also gave the intercept of 151 w-h/mile. So, the predicted consumsion of a 400 lbs vehicle would be 166 w-h/mile. But nobody is suggestting that this is a complete description.
> 
> Rational understands drag and the other parameters you mentioned, (see the equations he posted earlier in this thread). The 37 w-h/mile per 1000 lbs of mass was only a correction factor when I mentioned my car was actually 2700 lbs instead of 2200 lbs.


Wow, that even fits my Buggy pretty well, putting it at 192 watt hours per mile. I could easily do that in city traffic if I enjoyed the Zilla a little less. Usually the Buggy is a terminal outlier on any energy use figures because at 1100 lb. it just doesn't fit any normal definition of a car. 

However, that good number isn't going to happen on the freeway unless someone gets out and pushes. The body shape sucks wind with a couple of parachutes for front fenders and a tall steep windshield.


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## tomofreno (Mar 3, 2009)

> Wow, that even fits my Buggy pretty well, putting it at 192 watt hours per mile. I could easily do that in city traffic if I enjoyed the Zilla a little less. Usually the Buggy is a terminal outlier on any energy use figures because at 1100 lb. it just doesn't fit any normal definition of a car.
> 
> However, that good number isn't going to happen on the freeway unless someone gets out and pushes.


 Yes, the data will fit any car at some speed since energy/mile varies so greatly with vehicle speed. The correlation coefficient is low because it is a sample from a population with large variance, consisting of a wide range of speeds, drag coeff/area, weight, and measurement method/accuracy. Means of small samples from such a population will vary considerably. If you take many small samples from such a population you can find one that gives the result you want to "prove" your point and throw the rest out. Larger samples will have lower standard error, and their means will have less variability.


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## Rational (Nov 26, 2011)

tomofreno said:


> Something like this one (see zip file at bottom of first post)?
> 
> http://www.diyelectriccar.com/forum...-charts-ev-performance-spreadsheet-41565.html


Man, that thing goes down to the level of individual molecules! 

I was going to have more of a summary: how much hp to move a car at walking speed and to achieve top speed and what accel curve is expected with a constant torque and an inverse torque speed curve, using the '5252' equation.
Assuming a default drive wheel radius of 11" I'll try to fit my results to published data and I'll certainly check my results against this worksheet. 
Maybe I can get some of my numbers within 10% of other data, some of the time.

Muchas gracias. . .


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## bonewibb (Aug 30, 2009)

Nice looking ride. Looks like it will make great conversion.


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## Anaerin (Feb 4, 2009)

Joey said:


> My 4 year old daughter loves the car, too. She asked Mommy if we now need to wear helmets when we drop her off at school. Sound like someone has been watching too many episodes of "Top Gear" on Netflix.


Some say that she never gets detention, and when she does, she spends the whole time making race car noises. All we know is... she's called The STIG!

Or maybe not.


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## Rational (Nov 26, 2011)

Does this prelim calc. contradict anything you have in mind so far?

80.00	>Enter min top speed in mph
117.33	=calc'd speed, ft/sec
11.00	>Enter drive wheel radius in inches
2.88	=calc'd wheel circumference in feet
2444.62	=calc'd max wheel rpm
5000.00	>Enter top speed of motor in rpm
2.05	=calc'd max gear reduction

8.00	>Enter max seconds for 0-60 mph
88.00	=calc'd accel, ft/sec
2700.00	>Enter vehicle mass in lbs.
83.85	=calc'd mass in slugs
11.00	=calc'd avg min acceleration, ft/sec^2
922.36	=calc'd min force on ground to achieve this, lbs
845.50	=calc'd total wheel torque, lb-ft
422.75	=calc'd per wheel torque, lb-ft
1833.46	=calc'd wheel rpm at 60 mph
295.16	=calc'd total hp at the wheels

I have a formula for almost any speed torque curve so you can input any values at any point and get any outputs. The idea is to work backward from the specs to a speed/torque of some existing motor.
Basically I can model graphs like this
http://www.thunderstruck-ev.com/Manuals/AC15_Torque.png
With formulas you can see what needs to be changed and how much effect a change will have, as opposed to a spreadsheet clunking through values.
Since the max hp for this type of curve is reached at below 5000 rpm the 295 hp is understated for the motor's rated hp.


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## Mark C (Jun 25, 2010)

I have a question that will likely advertise my ignorance, but here goes anyway. I'm reading a drive wheel radius of 11.00 inches. Is that correct? 

The best I can tell, the radius is from the center of the hub to the outer edge of the tire. Using my tire sizing calculator and entering the tire size for a stock 1990 Miata {185/60-14}, that diameter works out to be 22.74", so the radius is 11.37". I would've thought the Porsche tire would've been bigger than that.


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## Joey (Oct 12, 2007)

Mark C said:


> I have a question that will likely advertise my ignorance, but here goes anyway. I'm reading a drive wheel radius of 11.00 inches. Is that correct?
> 
> The best I can tell, the radius is from the center of the hub to the outer edge of the tire. Using my tire sizing calculator and entering the tire size for a stock 1990 Miata {185/60-14}, that diameter works out to be 22.74", so the radius is 11.37". I would've thought the Porsche tire would've been bigger than that.


My Porsche has 225/50R16 tires on the drive wheels. That works out to 12.4 inch radius. I probably should measure to see if this is close. I'm still working on the math for the rest of the calcs Rational posted, but the gear ratio is going to be different. The fifth gear ratio is 0.8214 and the final drive ratio is 3.875, so ratio of input to output on the gearbox is 3.183.

From the link tomofreno provided - http://www.diyelectriccar.com/forum...-charts-ev-performance-spreadsheet-41565.html (zip at the bottom of the first post)- the 0-60 time is estimated to be 6.5 seconds. Seems rather quick.


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## maxvtol (Nov 11, 2009)

Joey said:


> the 0-60 time is estimated to be 6.5 seconds. Seems rather quick.


Yes it does. If you post your info, weight, tire radius, motor, batteries, gear ratios, etc., maybe I could help out. Even though it's a rough approximation, it seems to fairly close. Using Jack Rickards rather detailed dyno info on the Speedster, it seems to be within 10% or better on 0-60mph.


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## Joey (Oct 12, 2007)

Maxvtol, I posted the file here. The wheels are forged aluminum. I estimated 15 lbs wheels + 22 for the tire, times 4 wheels = 148 lbs. I got the gear ratios out of the owners manual. I didn't change too many of the other values. Perhaps I was too optimistic with the total mass of the conversion. Adding just 200 lbs predicts a 0-60 time of 7.3 seconds. I would be curious to see if you would recommend any changes to the parameters.


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## Joey (Oct 12, 2007)

Rational said:


> Does this prelim calc. contradict anything you have in mind so far?
> 
> 80.00 >Enter min top speed in mph
> 117.33 =calc'd speed, ft/sec
> ...


The circumference of an 11 inch radius wheel is 5.76 feet (2*pi*R = C). This increases the max gear reduction to 4.6:1. In 5th I have a ratio of 3.18, and a wheel radius of 12.43 inches, so at 5000 motor RPM I would be doing 116 MPH (if the system were capable).

And then in the second grouping of calculations, the second line should be "calc'd *velocity*." This one is just an error in the label, the math is OK.

The 11 ft/sec^2 acceleration is what would be required for constant acceleration. Not sure how the rest of the calculations are computed, or how the motor torque/power curves are applied. Do you have the formulae for the last 4 calculated expressions? I don't think the acceleration is constant, or that you want to use this as a minimum over the run. I think you would need to do some kind of integration. I'm not saying this is what you have done, I just don't follow yet.


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## Duncan (Dec 8, 2008)

_*calc'd mass in slugs

*Cummon guys join the 20th century!!!
(then you can work on the 21st)_*

Everything gets so much easier if you use sensible units!*


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## maxvtol (Nov 11, 2009)

Joey said:


> Maxvtol, I posted the file here. The wheels are forged aluminum. I estimated 15 lbs wheels + 22 for the tire, times 4 wheels = 148 lbs. I got the gear ratios out of the owners manual. I didn't change too many of the other values. Perhaps I was too optimistic with the total mass of the conversion. Adding just 200 lbs predicts a 0-60 time of 7.3 seconds. I would be curious to see if you would recommend any changes to the parameters.


Parameters look pretty good. I think you might have too much wheel spin in 1st to get the ET that low. I've toyed improvements to the spreadsheet that take into account wheelspin and voltage drop under load. I've also put in dropdown boxes in a couple of spots and included where the drive wheels are, and F/R weight ratio to help with figuring out wheelspin. 

I've put in your values with the new attached spreadsheet and come up with about 8.45 sec 0-60 starting in second gear, which is pretty good, I think. You could toy around with the F/R weight ratios and throttle settings if you start in 1st and see what happens. 

You going to be able to get 56 batteries in there?


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## Rational (Nov 26, 2011)

Joey said:


> The circumference of an 11 inch radius wheel is 5.76 feet (2*pi*R = C). This increases the max gear reduction to 4.6:1. In 5th I have a ratio of 3.18, and a wheel radius of 12.43 inches, so at 5000 motor RPM I would be doing 116 MPH (if the system were capable).
> 
> And then in the second grouping of calculations, the second line should be "calc'd *velocity*." This one is just an error in the label, the math is OK.
> 
> The 11 ft/sec^2 acceleration is what would be required for constant acceleration. Not sure how the rest of the calculations are computed, or how the motor torque/power curves are applied. Do you have the formulae for the last 4 calculated expressions? I don't think the acceleration is constant, or that you want to use this as a minimum over the run. I think you would need to do some kind of integration. I'm not saying this is what you have done, I just don't follow yet.


I'll post back with the formulas and assumptions when I have more time. Half the problem is keeping the formulas dimensionally correct.
http://en.wikipedia.org/wiki/Dimensional_analysis
I'm too lazy to use differential equations so I'll do the second by second spreadsheet thing for some of it.


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## tomofreno (Mar 3, 2009)

> I don't think the acceleration is constant...


 It's usually not. Even if you can maintain the motor at its peak torque throughout the acceleration by shifting, the wheel torque drops when you shift up. It would only be about constant if you could maintain peak motor torque all the way through, 0 to 60 mph, without shifting. Even then, the drag force is increasing with speed and the applied force is constant with constant torque, so acceleration will still decrease some.

Hey Joe, thanks for the updated spreadsheet!


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## Rational (Nov 26, 2011)

Building a spreadsheet, part 1 

starting with a vehicle with drive wheel radius r and with drive wheel torque TQ 
you calc. the force f that the wheel exerts on the ground 
TQ = r(f) so f=TQ/r 
0.5	>Enter r in feet 
30	>Enter TQ in lb-ft 
60	=calc'd f in pounds 

you already have f so given the vehicle mass m you can calc. a. 
f=ma, so a = f/m 
100	>Enter m in slugs 
60	>Enter f in lbs 
0.6	=calc'd a in ft/sec^2

taking your rolling resistance as 1% of the vehicle weight	
the force opposing the f from above is 
1	>Enter 'slugs of rolling resistance'
32.2	=calc'd pounds of rolling resistance
so your new f is	
27.8	=calc'd new, net f
so your new a is	
0.278	=calc'd new a

right off the bat, v = at so t = v/a	
for this vehicle, the t to reach a speed can be calc'd	
0.3	>Enter a in ft/sec^2
88	>Enter desired v in ft/sec
293.3333333	=calc'd t in sec

since x [distance] = 0.5at^2	


This is lousy and will not get better so a redesign is in order.	

0.9	>Enter r in feet
60	>Enter TQ in lb-ft
66.66666667	=calc'd f in pounds

30	>Enter m in slugs
67	>Enter f in lbs
2.233333333	=calc'd a in ft/sec^2

0.3	>Enter 'slugs of rolling resistance'
9.66	=calc'd pounds of rolling resistance
so your new f is	
57.00666667	=calc'd new, net f
so your new a is	
1.900222222	=calc'd new a

1.9	>Enter a in ft/sec^2
88	>Enter desired v in ft/sec
46.31578947	=calc'd t in sec

1.9	>Enter a
46	>Enter t
2010.2	=calc'd distance in feet

How many seconds for this mythical vehicle to 
go 1320 feet?	
how fast will it be going at this point?	

Since I make mistakes it would be wise of me at this point to ask forum members for their take on this.

Except
for the one member who is on my ignore list. Regrettably, nothing you have to say to me is welcome. The bad news is that if he/she ever becomes a moderator then the ignore list becomes moot for me and I'll have to come up with a more permanent solution.

BTW, this forum bolds my stuff for no reason that I can see.

MKS is superior but the US uses English. BTW, a spacecraft failed because some engineer didn't make the conversion.

In the interest of squeezing as much info out of what you have at the moment, here's some more.

For a constant TQ the hp curve will be a ramp	
that goes up linearly with RPM.	

For TQ = 60 lb-ft and RPM = 3000
the peak hp is 
34.27265804
This looks like a triangle with height h
34 and base b of 3000.
The average hp would be the height of a rectangle
with the same area.
So 0.5bh equals an 'area' of 51000 so h of the rectangle is 17 hp 
17 hp for 46 seconds is 430,000 ft-lbs
is 162 w-h.

You've gone about 0.4 miles so you can now figure w-h/mile at about 400
Your veh weighs about 1000 lbs so you've got 0.4 w-h/mile-lb

I'm not to motivated to check this yet because it's basic physics, and I'd like to debug my eventual incremental spreadsheet at the very end. It's probably the "not invented here" factor that is governing my motivation at the moment. That, and the programming experience I've had.


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## drgrieve (Apr 14, 2011)

maxvtol said:


> You going to be able to get 56 batteries in there?


OP specified 48 * 180ah or 56 *130ah.

I have a better plan. 80 * 100ah. Which is ~25kWh at nominal.

Unfortunately I can't input this into your spreadsheet as it thinks the voltage is too high - but

80*3.3= 264v
@ 25% sag (at 8C) = 211V
@ Increasing Motor amps to 1000 vs battery amps 800 = 170V

This gives 170kW input to the motor.

It's this last step I can't figure on how to enter into the spreadsheet. Increasing motor amps by reducing voltage.


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## maxvtol (Nov 11, 2009)

tomofreno said:


> Hey Joe, thanks for the updated spreadsheet!


Your welcome, Tom. I hope it can be useful. Joey's car seemed to be close to mine, so I thought I'd post here. 



drgrieve said:


> OP specified 48 * 180ah or 56 *130ah.
> 
> I have a better plan. 80 * 100ah. Which is ~25kWh at nominal.
> 
> Unfortunately I can't input this into your spreadsheet as it thinks the voltage is too high


48 of the 180ah appears to be better, which would make sense since it's ~ 27kWh at nominal and the 56 of the 130ah is ~23kWh nominal. (If you maintain similar C rating between the batteries choices durning acceleration). And yes, the spreadsheet can't handle higher battery voltages than motor voltages. 

My 2c would be 48 of the 180ah. Fewer connections, more range, better acceleration. 

I put more battery choices in the attached spreadsheet.


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## drgrieve (Apr 14, 2011)

I'd disagree the 80*100ah would give much better accerlation due to the fact they can used at 8C whereas the 180ah tops out at 6C for bursts.

The 48*180 = at max 130 kW whereas 80*100 gives 170 kW

Of course more connections, but they could also fit easier depending on space restrictions.


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## Yabert (Feb 7, 2010)

I'm forced to agree with Drgrieve about number of cells.

48 cells is a bit low to used the full potential of most "large" DC motor.
The voltage under load of 48 cells can be as low than 130-135v... 

Assuming 1000A controller, it's almost 20-30 hp in less than you will let behind in comparison with 150-160v under load.

If I had to restart my battrery pack, I will go for 64S 6P instead of 48S 8P...


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## drgrieve (Apr 14, 2011)

maxvtol said:


> I put more battery choices in the attached spreadsheet.


Sorry for the hijack joey.

Hi maxvtol are you able to insert the warp 11 hv into your spreadsheet? Entering batteries I figured out but I couldn't work out the motor terminology.

Also if it's possible the ability to have pack voltage over motor voltage using the controller to trade motor voltage for motor amp.

It would be interesting to play around with these different setups.

I don't have results for calb 130ah but the 180ah cells saggs to 2.7v @ 4.5C and the 100ah sags to 2.7v @ 6.5C in a pack configuration. See this thread for the data behind this (http://www.diyelectriccar.com/forums/showthread.php?t=62326). Also manufacturer rates max c for these cells at 5.6C and 8C respectively.

Thanks


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## maxvtol (Nov 11, 2009)

drgrieve said:


> Sorry for the hijack joey.
> 
> Hi maxvtol are you able to insert the warp 11 hv into your spreadsheet? Entering batteries I figured out but I couldn't work out the motor terminology.
> 
> ...


 If you can find a different motor chart (torque curve or table) for the HV than the WarP 11, post a link in my thread here so we won't be hijacking Joey's thread. I can walk you through whatever you want to know there. I'll play around with pack over motor voltages too.


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## Joey (Oct 12, 2007)

Maxvtol, your spread sheet is great. I'm not sure if 56 cells will fit, but I will try. Once the gas parts are removed I can try to fit some cardboard mock ups and see what is possible.

Quick update on the conversion. Today I put the first wrench to the car. I replaced the four shift linkage bushings. 3 of the 4 were in good shape and probably not original, but one appeared to be original and in pretty rough shape. It tightened up the feel of the shift motion.

I'm also getting ready to order the motor (Warp 9) and an adapter plate. I'm keeping the flywheel and clutch. Progress will be slow during the holidays.


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## Joey (Oct 12, 2007)

I started a blog to document the build. I also added an entry for the car in the garage. Links are below in my signature.

I'm working on fixing up the car. I replaced the shift linkage bushings. This tighened up the shifting pattern. The bushing to the left (on the orange background) was the only one in poor condition, but it made a significant improvement.

Next I'm working on getting the door locks re-pinned so that they match the ignition switch. The car came with replacement keys only. I order some porsche blanks from Pelican Parts, and the locksmith was able to figure out my key code from the worn key. This way a new key can be cut with the proper cut, instead of just making a new key with the same wear pattern as old key.

As long as I've got the door apart, I might as well fix a few minor details. The stock interior door handles are really thin plastic. I've ordered some replacements in aluminum. Also, the door panels are damaged due to what looks like an oversized speaker that was installed at some point. I can only get replacements at a reasonable price in black. I think black will look good, as a lot of door trim and the dash is black.


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## PThompson509 (Jul 9, 2009)

Nice choices for the car. I tried to post on your blog, but blogger.com is having "issues". Oh well, not your problem.

Some suggestions: come up with a diagram to document how your controller and charger are hooked up. Lots of examples on the web for that. Manzanita has some good diagrams I seem to recall. 

Do you have a BMS selected yet? If not, I can highly recommend the miniBMS (minimal functionality, rock-solid reliability).

Cheers,
Peter


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## Joey (Oct 12, 2007)

PThompson509 said:


> Nice choices for the car. I tried to post on your blog, but blogger.com is having "issues". Oh well, not your problem.
> 
> Some suggestions: come up with a diagram to document how your controller and charger are hooked up. Lots of examples on the web for that. Manzanita has some good diagrams I seem to recall.
> 
> ...


Thanks for your comments. I will be sure to include an interconnect diagram in future posts.

The miniBMS is on my short list. It has a good reputation and is affordable. 

I really like the Manzanita Micro Display. The bar graphs on the display are super cool. It integrates with the Rudman regs, but it is on the expensive side.

The charger should have primary responsability for terminating the charge. With a balanced pack and a conservative voltage cutoff, the charger alone should be sufficient. I would like a BMS to be a cell monitor (low cell voltage warning), cell balancer, and act only as a back-up to terminate the charge. 

The miniBMS will do balancing, low cell warning, and high cell cutoff. I see there is an option for SOC display. The manzanita display gives cell level data. I'll have to see how my budget holds and if anyone has any other suggestions.


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## CrazyAl (May 9, 2011)

Hi,

Just wondering if you have considered getting a motor and controller combination that enables you to have regenerative braking?

Regenerative braking may assist in increasing your range if your trips includes going down hills and/or there is a lot of stopping involved.

Regards


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## Joey (Oct 12, 2007)

CrazyAl said:


> Hi,
> 
> Just wondering if you have considered getting a motor and controller combination that enables you to have regenerative braking?
> 
> ...


When I first started researching, I thought regen would be very cool. I still think it has a place in vehicle design. I don't know of many combos that have regen that can compete with series wound DC in terms of torque, reliability, availability to DIYers, and cost. If you do a lot of start and stop driving, and have significant downhill portions on your route, then regen might make more sense. For now I'm going to stick with the series DC.


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## cruisin (Jun 3, 2009)

Joey said:


> When I first started researching, I thought regen would be very cool. I still think it has a place in vehicle design. I don't know of many combos that have regen that can compete with series wound DC in terms of torque, reliability, availability to DIYers, and cost. If you do a lot of start and stop driving, and have significant downhill portions on your route, then regen might make more sense. For now I'm going to stick with the series DC.


I just wanted to correct a couple of your assumptions about a AC system.
1) AC will provide more torque in the upper usable RPM's than DC.
2) AC has been proven much more reliable than DC. All production cars use AC.
3) AC is as available as DC.
4) AC allows a lower voltage than DC, less costly battery purchase.
5) Cost is about the same when you account for the price of a controller, wiring harness, guages and the motor.
Dont want to hijack here, just want you to compare the differances before making a decision.


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## Joey (Oct 12, 2007)

cruisin said:


> Dont want to hijack here, just want you to compare the differances before making a decision.


This is on topic. No worries about a hijack.



cruisin said:


> I just wanted to correct a couple of your assumptions about a AC system.


I wasn't specifically talking AC vs DC. I know most AC setups include regen, but there are some DC setups that have regen too.



cruisin said:


> I just wanted to correct a couple of your assumptions about a AC system.
> 1) AC will provide more torque in the upper usable RPM's than DC.
> 2) AC has been proven much more reliable than DC. All production cars use AC.
> 3) AC is as available as DC.


I think that AC does beat DC in a lot of aspects, and for the most part I agree with your first 3 points. My reliability comment was specific to regen on DC controllers vs. DC without regen.



cruisin said:


> 4) AC allows a lower voltage than DC, less costly battery purchase.


I'm not sure I follow. I thought most AC setups go with higher voltage (since you don't have to worry about the brushes flashing), and for the same power, draw less current, so you can get away with lower energy capacity per cell. High voltage, low current for a given power will have less line loss and be more efficient.

With lower pack voltage, you will have to draw more current to get the same power, and I'm already at the limit of current draw for my proposed pack and desired performance. Lower voltage would mean that AC would have to be significantly more efficient, or I would have to step up to a bigger cell capacity.



cruisin said:


> 5) Cost is about the same when you account for the price of a controller, wiring harness, guages and the motor.


The last point is counter to what I've seen so far. If I could find an AC setup that could deliver the acceleration and performance of my proposed DC system, at a price that is within 10% of my build budget, I would be very interested. I followed this build, http://914ev.blogspot.com, and the owner noted that a similar DC build had better performance. I saw some seimens controllers and motors available that would perform quite nicely, but the price was around 80% more. At the upper price range, AC may outperform, but at my price range, DC seems the better choice. I'm not trying to be combative, I'm just relating my conclusion from what I've seen. I'm not rigid in my position and could be pursuaded.


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## cruisin (Jun 3, 2009)

Joey said:


> This is on topic. No worries about a hijack.
> 
> 
> 
> ...


If you research this forum you will find a lot of discussion of AC vs. DC pro's and con's. I have been doing conversions for 8 years using 914's, 912's, 911's boxsters and VW's. I have done everything with both DC and AC and teach EV conversion classes as well as sell AC, CALB and MinBMS.
Your question regarding voltage. The AC-50 requires a maximum of 130v which is 36 CALB cells. Most DC systems will use aboyt 144v+ requiring expensive controllers of $2k plus. Also require a few supporting parts I will not go into. Cost will come about the same unless you are buying used stuff at somebody elses expense. A AC system will run about $4400 plus your batteries and BMS. I just wanted to fill in some voids you may have regarding your options.


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## dladd (Jun 1, 2011)

cruisin said:


> I
> Your question regarding voltage. The AC-50 requires a maximum of 130v which is 36 CALB cells. Most DC systems will use aboyt 144v+ requiring expensive controllers of $2k plus. Also require a few supporting parts I will not go into. Cost will come about the same unless you are buying used stuff at somebody elses expense. A AC system will run about $4400 plus your batteries and BMS. I just wanted to fill in some voids you may have regarding your options.


If you read his first post, he wants a 0-60 of 8 seconds. No way you are getting anywhere close to that with an AC-50. No way.

But with a DC/Soliton 1 it's possible.

It seems like an incredibly backwards argument to say that the low voltage limit of the AC-50 is a 'feature' that lowers the cost of batteries...


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## cruisin (Jun 3, 2009)

dladd said:


> If you read his first post, he wants a 0-60 of 8 seconds. No way you are getting anywhere close to that with an AC-50. No way.
> 
> But with a DC/Soliton 1 it's possible.
> 
> It seems like an incredibly backwards argument to say that the low voltage limit of the AC-50 is a 'feature' that lowers the cost of batteries...


 
And if you read his post you will see he wants a system more readily avaiulable at a lower cost. A DC systems 0-60 in 8 seconds for less than the cost of AC. What are you smoking?


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## cruisin (Jun 3, 2009)

dladd said:


> If you read his first post, he wants a 0-60 of 8 seconds. No way you are getting anywhere close to that with an AC-50. No way.
> 
> But with a DC/Soliton 1 it's possible.
> 
> It seems like an incredibly backwards argument to say that the low voltage limit of the AC-50 is a 'feature' that lowers the cost of batteries...


I have a better idea, bring your lower cost DC system you are talking about from Novato over to Livermore and lets match up your quote with my AC systems. Is it a deal, or we just quoting.


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## dladd (Jun 1, 2011)

cruisin said:


> I have a better idea, bring your lower cost DC system you are talking about from Novato over to Livermore and lets match up your quote with my AC systems. Is it a deal, or we just quoting.


Are you really challenging me to a race? what are you 15? Anyway, the Porsche in this thread is not mine. I drive a modest 4 door sedan pushing 400 battery amps through a 750a DC controller. I'm not winning many races. Fwiw, my performance data is out there for anyone to see on my evalbum page, http://www.evalbum.com/4021 0-60 around 16 seconds. 

my point is simply that a) the only lowish cost AC system is not performance oriented. And b) being limited to 130v is not a 'feature' it is a limitation.


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## EVfun (Mar 14, 2010)

cruisin said:


> And if you read his post you will see he wants a system more readily avaiulable at a lower cost. A DC systems 0-60 in 8 seconds for less than the cost of AC. What are you smoking?


Perhaps the Zilla Z1k-LV controller for $1800, a WarP 9 motor for $1700, a contactor, pot box, main pack fuse, and liquid cooling system to complete the controller package for $550, for a total of $4050. That package will make about 130 shaft horsepower with a suitable battery pack. The prices come from EVsource.


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## Joey (Oct 12, 2007)

cruisin said:


> The AC-50 requires a maximum of 130v which is 36 CALB cells. Most DC systems will use aboyt 144v+ requiring expensive controllers of $2k plus. Also require a few supporting parts I will not go into. Cost will come about the same unless you are buying used stuff at somebody elses expense. A AC system will run about $4400 plus your batteries and BMS. I just wanted to fill in some voids you may have regarding your options.


I don't think the AC-50 is up to the task in my application. I used a model created by Maxvtol that uses motor torque curves and parameters about the car and battery to compute acceleration performance. The predicted 0-60 time of the Warp9 with 56 calb cells is 7.6 seconds. Keeping the model parameters constant, except for the AC50 motor and the limit of 36 cells the 0-60 time is 15.8 seconds. I don't think this is the fault of the motor. You just can't get around the drop in pack voltage and produce the same power by switching to AC. Is there an AC option that can handle higher voltage? What is the price range?


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## Joey (Oct 12, 2007)

dladd said:


> I drive a modest 4 door sedan pushing 400 battery amps through a 750a DC controller. I'm not winning many races. Fwiw, my performance data is out there for anyone to see on my evalbum page, http://www.evalbum.com/4021 0-60 around 16 seconds.
> 
> my point is simply that a) the only lowish cost AC system is not performance oriented. And b) being limited to 130v is not a 'feature' it is a limitation.


dladd, I looked at your album page. My planned setup is similar - same motor and battery brand. Your switch in controller, and resulting improvement in 0-60 time shows that the motor was not the limiting factor. Looks like you are limited by the battery current, and maybe the wheel spin in second gear .


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## dladd (Jun 1, 2011)

Joey said:


> dladd, I looked at your album page. My planned setup is similar - same motor and battery brand. Your switch in controller, and resulting improvement in 0-60 time shows that the motor was not the limiting factor. Looks like you are limited by the battery current, and maybe the wheel spin in second gear .


My limiter is definately battery current right now. It launches plenty hard, just once I get above 2000 or so RPM's it mellows way out. Even at 400 battery amps I pull the full 750a to the motor for a brief moment off the line. 

I'm chasing some battery sag issues, but even at it's current state it's very drivable and fun so I've not been in a big hurry to figure it out. If I could maintain 750a (which is 5.8c so theoretically I should be able to for a short period of time) I'm sure 10 seconds would be within my grasp.

Anyway, I love your build! Sweet car to start out with, and some solid component choices. I look forward to following your progress!


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## Bowser330 (Jun 15, 2008)

Joey said:


> I don't think the AC-50 is up to the task in my application. I used a model created by Maxvtol that uses motor torque curves and parameters about the car and battery to compute acceleration performance. The predicted 0-60 time of the Warp9 with 56 calb cells is 7.6 seconds. Keeping the model parameters constant, except for the AC50 motor and the limit of 36 cells the 0-60 time is 15.8 seconds. I don't think this is the fault of the motor. You just can't get around the drop in pack voltage and produce the same power by switching to AC. Is there an AC option that can handle higher voltage? What is the price range?


Netgain has upgraded the Warp line of motors to now withstand up to 192V before arching; a great enhancement for an increased peak power rpm.

The Soliton-1 or Netgain Controls controller would be great for your application. Either can limit the motor voltage while accepting higher battery voltage.

If the Calb cells sag ~25% when under 1000A load, the 3.2V will sag to ~2.5V. So to ensure you have 192V at your disposal your pack could contain ~77cells, 246V nominal, 192V sagged.

192V * 1000A = 192kw = 258hp, with 200ftlbs of tq from 0 to ~4000rpm

130AH cells weigh 9.7lbs ~10lbs with straps, so 77 = 770lbs

77 130AH cells for 1$/AH = ~10K$

246V * 130AH = 32kwh pack ~ 100 mile range @ 320wh/mile

sounds like a nice setup to me, if you can find the place for 77 130AH cells...


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## Joey (Oct 12, 2007)

Joey said:


> I don't think the AC-50 is up to the task in my application. I used a model created by Maxvtol that uses motor torque curves and parameters about the car and battery to compute acceleration performance. The predicted 0-60 time of the Warp9 with 56 calb cells is 7.6 seconds. Keeping the model parameters constant, except for the AC50 motor and the limit of 36 cells the 0-60 time is 15.8 seconds. I don't think this is the fault of the motor. You just can't get around the drop in pack voltage and produce the same power by switching to AC. Is there an AC option that can handle higher voltage? What is the price range?


I found some AC motors that would meet my performance requirements. The MES 200-250 is a 30 kW continuous motor that produces 240 ft-lbs of torque. The inverter (AC controller) accepts up to 400 VDC, and 100 amps from the battery. The modeled 0-60 time is 6.6 seconds. Everything about this combo looks good except the price - I found a reputable site that quotes $11,400 USD. I love the idea of AC, but not at that price.

I placed an order for the Warp9 and transmission adaptor yesterday. After I get the motor mounted, I will play the cardboard mock up game, and see how much room I have for batteries. My preference is for 56 cells of 180 aHr Calb, but we will have to see what fits.


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## Coulomb (Apr 22, 2009)

Joey said:


> The MES 200-250 is a 30 kW continuous motor that produces 240 ft-lbs of torque.


Good for continuous output.


> The inverter (AC controller) accepts up to 400 VDC, and 100 amps from the battery. The modeled 0-60 time is 6.6 seconds.


I don't think you will get 6.6 seconds 0-60 time with 40 kW going into the controller. Either that's a typo, or the AC output current will start dropping when the input current hits around 100 A.

Otherwise, you'll need one of those power amplifiers from www.overunity.com 

Edit: Oops - I didn't realise that there is an actual crackpot web site with that URL, and I didn't realise that the system would automatically link the URL. In case anyone doesn't get it, I don't believe in overunity, and there is no such thing as a "power amplifier".


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## EVfun (Mar 14, 2010)

Coulomb said:


> Otherwise, you'll need one of those power amplifiers from www.overunity.com
> 
> Edit: Oops - I didn't realise that there is an actual crackpot web site with that URL, and I didn't realise that the system would automatically link the URL. In case anyone doesn't get it, I don't believe in overunity, and there is no such thing as a "power amplifier".


Wow, surely that web site is for humor, right? There is a whole Payday bar just on the home page!


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## tomofreno (Mar 3, 2009)

> Edit: Oops - I didn't realise that there is an actual crackpot web site with that URL, and I didn't realise that the system would automatically link the URL. In case anyone doesn't get it, I don't believe in overunity, and there is no such thing as a "power amplifier".


 Yes there is:
http://www.empowerrf.com/
I've used some the size of a refrigerator. Not the kind you meant though.


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## Joey (Oct 12, 2007)

Coulomb said:


> Good for continuous output.
> I don't think you will get 6.6 seconds 0-60 time with 40 kW going into the controller. Either that's a typo, or the AC output current will start dropping when the input current hits around 100 A.
> 
> Otherwise, you'll need one of those power amplifiers from www.overunity.com
> ...


Wow, thanks for the reality check. I didn't enter the torque curve data correctly, and ended up with max torque at all RPM. The 0-60 time is more like 15 seconds. The MES 200-250 is closer to the AC-50, and both are more expensive than the WarP9 I ordered yesterday. 

I'm not an over unity optimist. I tend to think of 0.5 as the limit in real world systems.


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## Joey (Oct 12, 2007)

Interior door panels and handles have been replaced. The handles are anodized aluminum, a definite improvement over the stock plastic. Black was my only choice (at a reasonable price) for door panel color, but I think it looks good.







Before








After


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## powerhouse (Apr 1, 2011)

Looking great Joey! Keep up the good work, I can't wait to see the finished project


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## Joey (Oct 12, 2007)

I'm waiting for my motor and adaptor plate to arrive. It's time to get some design ideas figured out on the motor mount. I'm going to use the factory rubber mounts - two on the transmission cross member, and two in the back corners of the engine compartment. I'm learning how to use google sketchup. The black parts are going to be re-used from the original car. The yellow bits are the proposed new parts for the engine mount. Any comments or suggestions? For a scale reference, the motor is a Warp9. I don't have final dimensions for how low the motor will sit, or how far forward the motor will sit relative to the black engine mount cross brace, but this should be close.


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## DavidDymaxion (Dec 1, 2008)

I like your project and the diagrams.

I'm not a mechanical engineer! This is totally uninformed opinion! Your mount looks to me to be similar in strength up and down and fore-and-aft to the original mount. It looks to me to be much weaker side-to-side than the original. The motor and tranny put around 300 lbs of force sideways during hard cornering, or momentarily even more with bumps. I'd be afraid the little flat plates would tend to be bent back and forth, and there would be tremendous force put on those welds -- you have about an inch of plate lever trying to bend about 1/8 inch of weld -- that's a huge force multiplication.

I'd humbly suggest welding in some triangles of metal at right angles to the little flat plates and the round motor end plate. Another option would be to box in the little plates with plates on the top and bottom of them. 

I did a custom mount for my Porsche, and my son did a similar one for another 911. So far they have worked great:

http://explodingdinosaurs.com/9electric/motormount

I burned up my brushes so I'm taking the motor out. I think part of the problem is the cooling air doesn't really flow around the brushes very well. I'm considering (thanks to another great discussion here at diyelectriccar) putting some holes in the motor end bell to blow air right on the brush gear. I'm also considering putting the fan right in my motor mount, it would be a handy use for that space.


Joey said:


> I'm waiting for my motor and adaptor plate to arrive. It's time to get some design ideas figured out on the motor mount. I'm going to use the factory rubber mounts - two on the transmission cross member, and two in the back corners of the engine compartment. I'm learning how to use google sketchup. The black parts are going to be re-used from the original car. The yellow bits are the proposed new parts for the engine mount. Any comments or suggestions? For a scale reference, the motor is a Warp9. I don't have final dimensions for how low the motor will sit, or how far forward the motor will sit relative to the black engine mount cross brace, but this should be close.
> View attachment 12000
> View attachment 12001
> 
> View attachment 12002


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## Duncan (Dec 8, 2008)

Hi Joey

I agree with Davids comments,

How about getting a bigger piece of 3mm (1/8) steel plate
Cut a hole for the motor shaft - do a double bend to line up with the mount (or even a spacer) bolt it to the motor and the mounting 

That will be much stronger in every direction except fore-aft and I would expect the rear mount to handle that


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## Joey (Oct 12, 2007)

Thanks for the feedback guys. I'm not a mechanical engineer either. I agree that the plates are the weak point. The torque is going to try to twist them, and the stress will be greater closer to the rotation axis of the motor. 

I could see going one of two ways - switch the plates in the existing drawings to angle stock and add gussets, or do it in one piece with 2 bends as Duncan suggested. The bends could be reinforced with plates on the sides. I'll come back with some new drawings soon.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> I did a custom mount for my Porsche, and my son did a similar one for another 911. So far they have worked great:
> 
> http://explodingdinosaurs.com/9electric/motormount
> 
> I burned up my brushes so I'm taking the motor out. I think part of the problem is the cooling air doesn't really flow around the brushes very well. I'm considering (thanks to another great discussion here at diyelectriccar) putting some holes in the motor end bell to blow air right on the brush gear. I'm also considering putting the fan right in my motor mount, it would be a handy use for that space.


That mount looks nice and sturdy.

Did you have any forced air cooling on the motor when the brushes burned? I'm trying to figure out if I need to add forced air to the motor.


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## Joey (Oct 12, 2007)

Here is a beefed up version. The square tubing is directly on the motor plate - where the stress from torque will be greatest, with gussets added (I could add more gussets). The plates that were the weak part of the previous design have been replaced with u channel.

I like this better than the single bent plate, because the tolerances of the motor rotational position, and fore/aft position would have to be known exactly before making the part. With seperate parts, I can line everything up with the transmission and motor in the car, and tack the parts together, before pulling it out to fully weld up.


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## DavidDymaxion (Dec 1, 2008)

Thanks.

I burned up my brushes on the Salt Flats, running 1000 A for possibly as long as 30 seconds. That was with forced air cooling in addition to the internal fan. It likely would be fine for more sedate street driving. I would recommend an electric fan in addition to the internal fan in any case. I'm going for overkill cooling. BTW I have a Kostov, the brush gear looks beefier to me on the Warp motors (but the Kostovs are supposed to be beefier in voltage).


Joey said:


> That mount looks nice and sturdy.
> 
> Did you have any forced air cooling on the motor when the brushes burned? I'm trying to figure out if I need to add forced air to the motor.


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## Joey (Oct 12, 2007)

My adaptor plate supplier needs my flywheel to make the taper lock hub. This adaptor will allow me to keep the clutch. They have 6 bolt designs on hand, but all 911’s after 1978 use a nine bolt pattern on the flywheel. So I will need to begin the process of removing the gas motor this weekend. I will measure ride height, take measurements so that I can get the transmission back in the same position, and coast down times on a level road. Is there anything else I’m forgetting before removing the gas engine?


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## coulombKid (Jan 10, 2009)

StanSimmons said:


> I've read about a few people using the Quick220 adapter to combine two opposite phase 110V 15A outlets into a 220V 15A for faster charging. It looks like it has some active electronics in it to make it safe. I'm thinking it might be useful when out on the road and charging at hotels.
> 
> 
> 
> ...


 And as the old snow birds die off without replacement the RV parks will expand the restaurant/mini mall and pick up business with out spending a mint on new buried conduit. Your next android ap will point out their locations.


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## StanSimmons (Sep 3, 2011)

coulombKid said:


> And as the old snow birds die off without replacement the RV parks will expand the restaurant/mini mall and pick up business with out spending a mint on new buried conduit. Your next android ap will point out their locations.


Your prose is pretty, but I'm not quite getting what you are trying to say here.


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## coulombKid (Jan 10, 2009)

Who is left among those of us that are still paying into social security that will be willing to blow down the road in a 12,000 pound RV getting 6 miles per gallon. Times they are a changin'. RV parks will cater to EV cross country travelers as a survival tactic and add attractive amenities on site. Like wise you will see filling stations with excess parking start to add charging stations. Hell, eventually Wall Drug will have them. Merchandising plans and a free market economy make enough charging stations an eventual certainty


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## StanSimmons (Sep 3, 2011)

coulombKid said:


> Who is left among those of us that are still paying into social security that will be willing to blow down the road in a 12,000 pound RV getting 6 miles per gallon. Times they are a changin'. RV parks will cater to EV cross country travelers as a survival tactic and add attractive amenities on site. Like wise you will see filling stations with excess parking start to add charging stations. Hell, eventually Wall Drug will have them. Merchandising plans and a free market economy make enough charging stations an eventual certainty


Ah, now I get it. 

RV parks are already getting squeezed by people that can't afford the gas to travel... but it is getting somewhat offset by people like my folks who refuse to fly since the TSA has gotten to be such a pain. They haven't spent a penny on airfare in the last 5-6 years, but they have replaced their old RV with a newer one and have put over 70,000 miles on it in that time.


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## Dan Frederiksen (Jul 26, 2007)

Joey, if you haven't started the conversion, have you considered a 2000 911 which you can get from 15000$ on autotrader?
if you're going to spend a lot on doing a conversion isn't it worth the 4000 more to get a 17 year younger model?
if you have to go on a road trip to bring it back that still seems like a nobrainer to me.


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## PThompson509 (Jul 9, 2009)

Hi Dan,

The conversion is a lot harder with 2000 onward - more electronics to interface with. I seem to recall (but could be wrong) that CANBus started in Porsche then too. Since I converted a 1975 914, I have no such headache (different ones - rust primarily).

In general I agree that going with a newer model does give you some nice features (ABS for one), it also gives headaches. 

Fortunately, the newer motor controllers have CANBus built in, so hopefully they can emulate the engines they are replacing.

Cheers,
Peter



Dan Frederiksen said:


> Joey, if you haven't started the conversion, have you considered a 2000 911 which you can get from 15000$ on autotrader?
> if you're going to spend a lot on doing a conversion isn't it worth the 4000 more to get a 17 year younger model?
> if you have to go on a road trip to bring it back that still seems like a nobrainer to me.


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## Dan Frederiksen (Jul 26, 2007)

I very much doubt that a 2000 is too digital to get moving.
I don't care about ABS but I do care about the look and feel and a 996 is worlds apart from a 1983


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## DavidDymaxion (Dec 1, 2008)

Drain the gas
Drain the oil
make a mark on the shifter so it can be realigned
Check tire pressures before measuring ride height
This would be an extra credit kind of thing: Weigh each corner of the car so you can preserve the front/rear weight balance, and see the weight before and after.

You have to lift the rear of the Porsche very high to get the motor out from underneath. Some folks remove some of the rear bodywork. I was so high in the rear the motor kept falling forward, making it hard to lift uphill to pull the shifter rod out of its hole. Removing bodywork, or putting the front wheels on wheel stands would have made that easier. My electric motor is so much smaller than the gasser that won't be a problem in the future.

Some folks remove stuff from the top of the gas motor to make removal easier. That makes sense if you are rebuilding the motor. I didn't do that, since I want the motor whole to make it easier to sell. Don't get rid of your gas motor too soon. There were a couple of times I was glad I kept mine, for measurements.

You might consider putting in a lighter flywheel and a stronger clutch. The lighter flywheel would give slightly better acceleration and maybe 1/2 percent more range. The stronger pressure plate (or grippier clutch disk) will keep your high torque motor from slipping the clutch, you could easily have double the torque of the gas motor.

I'd suggest having the engine compartment cleaned before you remove the engine -- it'll be totally worth it! Once everything is out, that's a great chance to paint the motor compartment (mine had a tiny bit of surface rust).

It might be easier to do a compression test with the motor in the car. Take a video of that with a newspaper (to prove the date), and of the motor running and the car driving. That'll make it easier to sell the motor for top dollar.


Joey said:


> My adaptor plate supplier needs my flywheel to make the taper lock hub. This adaptor will allow me to keep the clutch. They have 6 bolt designs on hand, but all 911’s after 1978 use a nine bolt pattern on the flywheel. So I will need to begin the process of removing the gas motor this weekend. I will measure ride height, take measurements so that I can get the transmission back in the same position, and coast down times on a level road. Is there anything else I’m forgetting before removing the gas engine?


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## Tesseract (Sep 27, 2008)

PThompson509 said:


> ...
> Fortunately, the newer motor controllers have CANBus built in, so hopefully they can emulate the engines they are replacing.


Just because a motor controller has a CAN bus interface doesn't mean it can be used to "spoof" the missing engine sensors for the car's ECU. The controller software would need to be customized to generate properly formatted CAN data for each car, something which is clearly impractical for a general purpose motor controller.


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## Joey (Oct 12, 2007)

Dan Frederiksen said:


> Joey, if you haven't started the conversion, have you considered a 2000 911 which you can get from 15000$ on autotrader?
> if you're going to spend a lot on doing a conversion isn't it worth the 4000 more to get a 17 year younger model?
> if you have to go on a road trip to bring it back that still seems like a nobrainer to me.


I actually like the style of the '78-'83 911s the best. For me, it has to have round headlights. I don't care for the style that bends around to pick up the turn signals. I'm sure there are deals out there, but to get one in good shape, and non salvage title, the newer models I was seeing were closer to $18,000. The '83 I picked up was in very good condition, with service records. I'm very comfortable with my donor choice. But if I liked the style better, I think your suggestion would be a good one.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> Drain the gas
> Drain the oil
> make a mark on the shifter so it can be realigned
> Check tire pressures before measuring ride height
> ...


Great tips, David. I'll follow the procedure in my service manual, which include draining the fluids. I am glad to hear about your tip of putting the front end up a bit to start. Is 12 to 18 inches about right? 

My service manual gives a method of measuring ride height that is independent of tire pressure. Measure distance from ground to the wheel center. Measure from ground to the suspension arm pivot. The difference is called ride height. My manual gives tolerance for this measurement, and I’m in the good range. I also measured floor to fender, and that would depend on tire pressure.

I did think of taking a video of the running engine. I didn't think of the compression test. I have a gauge, but I'm not sure how difficult it is to reach the spark plugs. I'll look into it.

I am thinking of going with a stronger clutch and lighter pressure plate - aluminum instead of cast iron. Pelican parts has a complete clutch rebuild kit that they call a power kit that they say is good for autocross. The price is a little steep at $1200, but it includes the throw out bearing, throw out fork, pilot bearing, clutch cables and springs. Just about everything but the flywheel and the 12 point bit for removing the flywheel. I’m not spending the extra money on an aluminum flywheel. I’ll have to see if there is room to remove material on the existing flywheel once I get it out.

I'm not sure if I will find a place to weigh the corners of the car. Would be nice though.


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## Joey (Oct 12, 2007)

My vacuum pump for the brakes arrived. I have a VBS-EV-12. Pictures are posted in my blog (link is in my signature at the bottom of my post).


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## Joey (Oct 12, 2007)

The engine is out. Feels like my conversion project has REALLY started. David's tip to jack the front of the car a bit worked really well. The gear selector shaft on the transmission cleared the opening to the tunnel very easily.


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## DavidDymaxion (Dec 1, 2008)

Love the pics, that's a great looking car. I'll be curious to hear how much your motor sells for.


Joey said:


> The engine is out. Feels like my conversion project has REALLY started. David's tip to jack the front of the car a bit worked really well. The gear selector shaft on the transmission cleared the opening to the tunnel very easily.


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## powerhouse (Apr 1, 2011)

Wow not much space to work with 

Can't wait to see how you overcome all the obstacles!


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## Joey (Oct 12, 2007)

powerhouse said:


> Wow not much space to work with
> 
> Can't wait to see how you overcome all the obstacles!


I know. 56 cells may be too much. We'll see. I'm going to do a lot of planning with google sketchup, and then with cardboard mock-ups before placing the battery order. 

These guys managed to fit 12 on each side of the motor of the 160 Ahr size. They have an 11 inch Warp and I'm going with the 9 inch. There seems to still be a lot of room above the first layer of batteries and motor.









Removing the 20 gallon gas tank up front frees up a lot of space too. Weight distribution is going to be a factor. I don't want to go anymore tail heavy than stock (in terms of percentage) and hopefully be within 200 lbs of stock on overall weight.


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## PThompson509 (Jul 9, 2009)

To be honest (having a 964), you might do yourself a favor and go for more of a 50/50 weight ratio. That will give you a VERY nice handling 911. 

That's how a 914 with a larger motor can beat a 911. 

Cheers,
Peter


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## DavidDymaxion (Dec 1, 2008)

I have been impressed how fast the older Porsches can be on the racetrack -- they were significantly lighter than the newer ones. It does take a very good driver to get the most out of them, though.


Joey said:


> I actually like the style of the '78-'83 911s the best. For me, it has to have round headlights. I don't care for the style that bends around to pick up the turn signals. I'm sure there are deals out there, but to get one in good shape, and non salvage title, the newer models I was seeing were closer to $18,000. The '83 I picked up was in very good condition, with service records. I'm very comfortable with my donor choice. But if I liked the style better, I think your suggestion would be a good one.


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## DavidDymaxion (Dec 1, 2008)

A 911 is bigger than it looks. I could have fit about 16 Optima batteries at floor level in mine (3 each side of the motor, the rest where the gas tank used to be). With torsion bars, you don't have the huge spring towers intruding into the space. The steering rack is behind the front axle line, so the steering gear is out of the way.

I hope I'm enough of a driver for the original weight balance (I have done autocross and the road racing track for years and plan to do it in the electric). If I'm not up to it, then I can move some battery weight forward. We'll see. The car will accelerate and brake harder with the rear weight bias, but be a handful in hard cornering.


powerhouse said:


> Wow not much space to work with  ...


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## Yorkist (Aug 31, 2011)

Great thread -- I am shopping Porsches right now looking for a 911 to drive for a year or two and then convert. I'd love any specifics people have on an idea posted earlier in this thread:

_"have you considered a 2000 911 which you can get from 15000$ on autotrader?"_

For whatever reason the market value for 1999-2001 911's (996 model) is suprisingly low, maybe $16,000 to $20,000. Just saw one go by on ebay for under $15,000! Everything either newer or older seems less cost effective until you get back to the '78-'83 911sc, which can be had for $11,000 to maybe $14,000. Great cars, but you're talking about a 30 year old vehcile at this point with the inevitable tradeoffs. 

Has anyone tried to convert a 911/996, like a 1999 or a 2000? Are the issues with integrating the electronics/engine computer/CAN Bus, etc, just too much to deal with?

Any wisdom would be greatly appreciated!


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## Bowser330 (Jun 15, 2008)

Yorkist said:


> Great thread -- I am shopping Porsches right now looking for a 911 to drive for a year or two and then convert. I'd love any specifics people have on an idea posted earlier in this thread:
> 
> _"have you considered a 2000 911 which you can get from 15000$ on autotrader?"_
> 
> ...


yes they have been converted before you should search EVALBUM.COM to find who did them and see if you can contact the builders/owners for your questions, you should probably create a new thread for your questions...just an idea...


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## cruisin (Jun 3, 2009)

Yorkist said:


> Great thread -- I am shopping Porsches right now looking for a 911 to drive for a year or two and then convert. I'd love any specifics people have on an idea posted earlier in this thread:
> 
> _"have you considered a 2000 911 which you can get from 15000$ on autotrader?"_
> 
> ...


 
I have done a 2001 Boxster and a 2000 911, and can tell you that they make nice conversions, but is not the top of my list of favorites. Yes, the electronics causes a lot of hurdles to jump over and has alot of challanges to deal with like power brakes, steering, AC, heating etc. Also, people tend to enjoy the noise and speed of a Porsche with a ICE in it rather than a EV. So, I tend to go back to the cars without those hurdles and have some value, like the 914, 912, VW Beetle, etc. They will turn a lot more heads than the later cars that have been converted.


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## Joey (Oct 12, 2007)

Yorkist said:


> Great thread -- I am shopping Porsches right now looking for a 911 to drive for a year or two and then convert. I'd love any specifics people have on an idea posted earlier in this thread:
> 
> _"have you considered a 2000 911 which you can get from 15000$ on autotrader?"_
> 
> ...


Pick a car that is in your budget and that you would like to drive. Then you can figure out if there are issues you would need to address - like airbags, abs brakes, missing engine to ECU signals.

I picked the '83 because it was only $1000 above my budget (I can sell unused parts to get back under) and it met the following requirements: 4 seats, 1978 and newer have rust protection, round headlamp lenses, manual steering (I've heard that Porsche power steering pumps tend to leak), not white, and the car was in really good shape.

I would have preferred manual brakes, to avoid needing a vacuum pump, but I can live with it.

You can find good porsche information on the Pelican Parts forum and the Rennlist forum. Try to find a blog of someone converting your car model, and you can decide if you want to or are able to overcome the issues.

I don't mind discussing the suitability of various 911s for conversion on this thread, but if you start your own thread, you may get a broader response.


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## Joey (Oct 12, 2007)

Yorkist said:


> For whatever reason the market value for 1999-2001 911's (996 model) is suprisingly low, maybe $16,000 to $20,000.


I just came accross this link. The reliability concern will not be a factor if you are converting to electric. http://grassrootsmotorsports.com/fo...d-porsches-911-c2-so-low-priced-/15898/page1/


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## DavidDymaxion (Dec 1, 2008)

1977+ were fully galvanized and much less rust prone.

The 2.7L motors had problems, these cars can often be had for less money.

Older ones are lighter.

If you get an older one, in some states you don't have to have it smogged. Your converting it to an EV improves the air more than converting a newer car.

Wild card idea: Get one used for racing. You might find one minus a motor, with lots of lightweight parts.


Yorkist said:


> Great thread -- I am shopping Porsches right now looking for a 911 to drive for a year or two and then convert. I'd love any specifics people have on an idea posted earlier in this thread:
> 
> _"have you considered a 2000 911 which you can get from 15000$ on autotrader?"_
> 
> ...


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## Joey (Oct 12, 2007)

WarP9 was delivered today. It is so beautiful. More so than I ever imagined. The serial number had a couple letters, a long string of zeroes and a 6. Did the WarP9 design change recently? The manual does not specify.

I've been modeling the car with google sketchup and I have found a home for 45 batteries - 12 on each side of the motor and 21 in front where the 20 gallon fuel tank currently resides. I want to keep the batteries vertical, be as accessable as possible, feature the Soliton1 in the rear compartment, and only cover 50% of the view of the motor. I'm not sure if all of that is achievable, but the top priority is to get 56 cells in there.


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## DavidDymaxion (Dec 1, 2008)

I'm away from my pics, I'll have to post some. Anyway, consider hanging the controller from above. The 911 is one of the few cars that can do that. What I did with mine is rest the rear of a huge heat sink on the frame rail at the back (actually front in the driver's orientation) of the motor compartment. The other end I suspended by plates riveted to the rear shelf and metal flat bars. The controller sits on the heat sink. The underside of the heat sink has a car radiator fan. You want the controller to motor leads to be short -- this did that and got the wiring up out of the way.


Joey said:


> WarP9 was delivered today. It is so beautiful. More so than I ever imagined. The serial number had a couple letters, a long string of zeroes and a 6. Did the WarP9 design change recently? The manual does not specify.
> 
> I've been modeling the car with google sketchup and I have found a home for 45 batteries - 12 on each side of the motor and 21 in front where the 20 gallon fuel tank currently resides. I want to keep the batteries vertical, be as accessable as possible, feature the Soliton1 in the rear compartment, and only cover 50% of the view of the motor. I'm not sure if all of that is achievable, but the top priority is to get 56 cells in there.
> 
> ...


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## drgrieve (Apr 14, 2011)

Hi Joey are you trying to fit 56 180ah or 130ah Calb cells?

Also are you going for range or acceleration?

I might be able to suggest some alternative configurations still using large format prismatic cells.


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## PThompson509 (Jul 9, 2009)

Another observation - if you are going to attach BMS boards to the batteries, you will need to allow space for a battery box to protect the boards. Since you will get splash up in the engine compartment, you should do this anyways to keep the dirt off of the battery cables. 

Nice sketchup work. 

Cheers,
Peter


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> Consider hanging the controller from above. The 911 is one of the few cars that can do that.


I'm jealous I didn't think of that. I would love to see a picture, but your description was pretty clear.



drgrieve said:


> Hi Joey are you trying to fit 56 180ah or 130ah Calb cells?
> 
> Also are you going for range or acceleration?
> 
> I might be able to suggest some alternative configurations still using large format prismatic cells.


I'm trying for 56 of the 180 aHr Calb. Range is primary. I figured I needed about 32 kWhr for 100 miles at 50 MPH. It don't want it to be too much slower than stock however. If I go with 130 Ahr cells, I would need to up the voltage to keep my pack current near 3C, and still use the upper end of the 1000 amp range of the Soliton1 on the motor side. Until I pay for my cells, I'm open to any and all suggestions.



PThompson509 said:


> Another observation - if you are going to attach BMS boards to the batteries, you will need to allow space for a battery box to protect the boards. Since you will get splash up in the engine compartment, you should do this anyways to keep the dirt off of the battery cables.
> 
> Nice sketchup work.
> 
> ...


Peter, I agree. I'm thinking about a platic pan on the bottom of the engine compartment - I want to keep my beautiful WarP looking good. For battery boxes, I'm thinking of a structural frame, and non structural thin sheets of gavlanized steel or aluminum for the sides and bottom. The tops might be acrylic or polycarbonate.

As for BMS, my thought is that the charger should be able to handle the charge termination. I will pick a conservative cutoff voltage. The BMS should only be used in a back up role - to cut off the charger IF a single cell goes too high, or to cutback the controller (or warn the driver) IF a cell goes too low. From a reliability perspective it is a nightmare to have 56 circuits all in a primary role protecting the pack. [56 items in series with a 99.9% reliability each will have a 94.6% reliability as a system. 0.999^56 = 0.946] But a charger that is 98% reliable, backed up by a monitor that is 99.9% reliable would have a system reliability of 99.998% [failure occurs if charger fails, 2%, and monitor fails, 0.1%. 0.02*0.001 = 0.00002 chance of failure or 1-0.00002 = 99.998% reliable.] These examples are a bit simplistic, but in general I try to avoid critical components in series, wherever possible.

The shunt functionality of some BMS products concerns me a little, too. I prefer a monitor mode for everyday use, and a balance mode that I initiate when I can keep a close eye on the operation.


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## PThompson509 (Jul 9, 2009)

There are some nice after-market belly pans for the 911s you should look into. That'll help keep the road dust and such off, but not completely.

Your idea for the battery box sounds good. Probably better to go for the aluminum for rust reasons. 

Your thoughts on the BMS coincide with mine. I ended up using the miniBMS, as I just want the system to protect the batteries and to tell me if "something has gone wrong". I'm good at diagnostics, and I tried a fancy BMS but ended up ignoring all of the data. 

Cheers,
Peter



> Peter, I agree. I'm thinking about a platic pan on the bottom of the engine compartment - I want to keep my beautiful WarP looking good. For battery boxes, I'm thinking of a structural frame, and non structural thin sheets of gavlanized steel or aluminum for the sides and bottom. The tops might be acrylic or polycarbonate.
> 
> As for BMS, my thought is that the charger should be able to handle the charge termination. I will pick a conservative cutoff voltage. The BMS should only be used in a back up role - to cut off the charger IF a single cell goes too high, or to cutback the controller (or warn the driver) IF a cell goes too low. From a reliability perspective it is a nightmare to have 56 circuits all in a primary role protecting the pack. [56 items in series with a 99.9% reliability each will have a 94.6% reliability as a system. 0.999^56 = 0.946] But a charger that is 98% reliable, backed up by a monitor that is 99.9% reliable would have a system reliability of 99.998% [failure occurs if charger fails, 2%, and monitor fails, 0.1%. 0.02*0.001 = 0.00002 chance of failure or 1-0.00002 = 99.998% reliable.] These examples are a bit simplistic, but in general I try to avoid critical components in series, wherever possible.
> 
> The shunt functionality of some BMS products concerns me a little, too. I prefer a monitor mode for everyday use, and a balance mode that I initiate when I can keep a close eye on the operation.


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## drgrieve (Apr 14, 2011)

Joey said:


> I'm trying for 56 of the 180 aHr Calb. Range is primary. I figured I needed about 32 kWhr for 100 miles at 50 MPH. It don't want it to be too much slower than stock however. If I go with 130 Ahr cells, I would need to up the voltage to keep my pack current near 3C, and still use the upper end of the 1000 amp range of the Soliton1 on the motor side. Until I pay for my cells, I'm open to any and all suggestions.


I looked up the 911 stats. Better than I thought for an old car. 180kw peak but that is @ 7000 RPM and 0-60 in 5 seconds. That is a fast car!

With the warp 9 I think you could come close to 140kw if you changed to Calb 100ah cells instead of the 125kw you'd get with the 180ah and still with the same range. As you say higher voltage. Your effective RPM range would also be higher, meaning you can stay in each gear for longer.

The pack building is more complicated with 100 cells (this is the new upper limit for the Soliton 1 version 1.5), but the better performance for the same $$ is a no brainer I think. You also might find the smaller cells easier to find room for. I leave that up to you!

However looking at range then consider swapping over to Sinopoly 200ah. Same weight @ 5.6Kg but 190 wh/litre instead of the 160 wh/litre you get with the Calb cells. You should be able to fit more cells into the same space with a bonus 20ah as well. 

However the voltage sag under hard acceleration is not known so I don't know if you'd make the equivalent 125kw.

Lastly when you order the cells, ask the supplier to match the cells for you. If each cell has roughly the same ah it makes your pack much more balanced at both ends, instead of choosing which end to balance.

http://sinopoly.todayir.com/attachment/201110101246483_en.pdf


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## Joey (Oct 12, 2007)

I seperated the engine and transmission. I need to send the flywheel out to get the adaptor hub made. The cluch didn't have much lining left. There is oil in the bell housing. The gear selector input shaft also leaks. I ordered new seals. While I wait for the adaptor, there are a lot of battery configuration details to work out.


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## Joey (Oct 12, 2007)

PThompson509 said:


> Some suggestions: come up with a diagram to document how your controller and charger are hooked up. Lots of examples on the web for that. Manzanita has some good diagrams I seem to recall.
> Cheers,
> Peter


I started on the system interconnect diagram. I borrowed heavily from the soliton1 user's manual and my 911 service manual. I still need to finish the heater/defroster and vacuum pump circuits. 

On this car heating and defrost is a little unconventional. With the air cooled motor, there is no heater core, but a heat exchanger in the exhaust system to heat incoming air with exhaust. There are three blowers in the car - one for the AC, heat, and fresh air -with independent duct systems for heat, defrost, and AC. I'm thinking of a ceramic heater, in a new metal box, with a single blower. The AC compressor was already removed before I got the car. I might as well get rid of the blowers to save weight and make room of EV gear (batteries).


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## Joey (Oct 12, 2007)

Today I worked on removing the old fuel system: tank, pump, filler tube. There was three gallons left in the beast of a tank (20 gallons). The good news is there is a lot of room to mount batteries up front. The bad news is I don't think I want to add more than 200 pounds or so over the front wheels. The plan for now remains 20 batteries up front.


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## drgrieve (Apr 14, 2011)

Hi Joey, some nice looking progress there.

Looking forward to seeing your progress / thoughts on battery configuration. Are you still planing on the 180ah? Interested in hearing your reasons on that decision.


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## DavidDymaxion (Dec 1, 2008)

200 lbs is about right to keep it at stock weight (here are some weights from my car: http://explodingdinosaurs.com/9electric/weight ).

I have 400 lbs of batteries in the front of mine. It actually seems to ride and drive OK, but the front looks low to me. When I get my lithiums in it'll be closer to 250 lbs up front.

Don't forget the 911 suspension is adjustable, so you could crank on those torsion bars a bit. Be sure you know what you are doing or have it done professionally, as they are under very high tension and could kill you if the tension was relieved incorrectly. There are also stiffer racing torsion bars you can get. I might fiddle with such things to improve the handling, as it looks like I'll have a bit more forward of a weight bias than stock.

I had originally cut my gas tank in 1/2, thinking to use the lower 1/2 as a floor (I blew compressed air though it for a long time to dry the gas, and then filled it with inert gas, and then used a nibbler rather than a die grinder, to avoid sparks. Anyway, I wasn't happy how the floor wasn't flat, so I ditched the tank entirely and welded in a flat piece of metal. Play with a piece of cardboard and you'll find it's pretty flat if you do it right. If I get ambitious I might cut out the platform the orginal car battery sits upon.



Joey said:


> Today I worked on removing the old fuel system: tank, pump, filler tube. There was three gallons left in the beast of a tank (20 gallons). The good news is there is a lot of room to mount batteries up front. The bad news is I don't think I want to add more than 200 pounds or s o over the front wheels. The plan for now remains 20 batteries up front.
> 
> View attachment 12293
> View attachment 12294
> ...


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## Joey (Oct 12, 2007)

drgrieve said:


> With the warp 9 I think you could come close to 140kw if you changed to Calb 100ah cells instead of the 125kw you'd get with the 180ah and still with the same range. As you say higher voltage. Your effective RPM range would also be higher, meaning you can stay in each gear for longer.
> 
> The pack building is more complicated with 100 cells (this is the new upper limit for the Soliton 1 version 1.5), but the better performance for the same $$ is a no brainer I think. You also might find the smaller cells easier to find room for. I leave that up to you!
> 
> However the voltage sag under hard acceleration is not known so I don't know if you'd make the equivalent 125kw.





drgrieve said:


> Hi Joey, some nice looking progress there.
> 
> Looking forward to seeing your progress / thoughts on battery configuration. Are you still planing on the 180ah? Interested in hearing your reasons on that decision.


Thanks. I’ve been thinking about this battery issue. I’m not an expert at all. But it seems to me that the effective RPM range may not be all that different because while current draw from the pack will be lower, the C rating of the higher voltage pack will also be lower. I’m hoping someone may be able to tell me where/if I’ve gone wrong in this example:


Consider pack 1: A pack of 56 cells at 180 AHr has a pack voltage of 179 V and 32.3 kWHr of energy. Pack 2: For a similar energy pack, you would need 100.8 cells of 100 AHr cells, for a pack voltage of 322 V. (You would have to choose a whole number of cells in an actual pack.)

Assume both packs have a 3C discharge rating and can burst 5C for up to 10 seconds. That is, the voltage sag will be similar for either packs when normalized in terms of C rating. 

With a static motor load of 125 V and 1000 Amps, the controller for pack 1 will have a duty cycle of 67% and draw 670 amps from the pack, for a 3.7C discharge rate. The controller for pack 2 will have a duty cycle of 37% and draw 372 amps from the pack, or 3.7C.
Both packs seem to be working equally hard to drive the same load. I do not know if the controller efficiency varies significantly over a range of pack voltage. I do know that line losses will be higher for Pack 1 because of the higher pack current draw. I don’t know if it is valid to use a static load in this type of example.

Luckily battery vendors price the cells so that for a given pack energy you can trade voltage for capacity (A Hr) so you can go with a higher pack voltage without a price penalty for purchase of the cells, but the BMS and interconnects do have a per cell cost that I estimate at $20 per cell (miniBMS and braided jumpers with Nordlock washers is one option I’m considering), so if you wanted to keep the price between pack 1 and pack 2 equal, you would have to give up 5 cells from pack 2 and 1.5 kW Hrs of energy storage.

Once you get the pack voltage (under load with sag) above the motor limit and have enough pack capacity for range, I don’t see a compelling reason to trade cell amp-hours for higher voltages. I’m still favoring the 56 cell, 180 A Hr configuration. But I can be swayed by fact or a good argument.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> 200 lbs is about right to keep it at stock weight (here are some weights from my car: http://explodingdinosaurs.com/9electric/weight ).
> 
> When I get my lithiums in it'll be closer to 250 lbs up front.
> 
> ...


I'm probably going to be at 250 lbs in front. The suspension is adjustable. My service manual says that the adjustment will affect toe-in.

I thought about cutting the tank too, or doing a fiberglass layup off the bottom of the tank. I'll probably go the welding route, too. 

Funny you should mention cardboard. I spent part of the day making a cardboard mock up of 12 cells, and coming up with this configuration: 12 cells on each side of the motor. 10 cells on a shelf, as far back into the motor bay as possible. 22 batteries up front. The hole left by the tank and the 45 degree rotation of the 12 volt battery sure do complicate things.


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## corbin (Apr 6, 2010)

Joey said:


> I'm probably going to be at 250 lbs in front. The suspension is adjustable. My service manual says that the adjustment will affect toe-in.
> 
> I thought about cutting the tank too, or doing a fiberglass layup off the bottom of the tank. I'll probably go the welding route, too.
> 
> ...


Use a smaller 12v battery, and not the stock size!

corbin


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## DavidDymaxion (Dec 1, 2008)

I like the drawings.

I'm not sure you'd have room to put those shelf batteries in there vertically, you might have to put them on their sides.


Joey said:


> I'm probably going to be at 250 lbs in front. The suspension is adjustable. My service manual says that the adjustment will affect toe-in.
> 
> I thought about cutting the tank too, or doing a fiberglass layup off the bottom of the tank. I'll probably go the welding route, too.
> 
> ...


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## DavidDymaxion (Dec 1, 2008)

One advantage to the fewer 180 Ahr cells is if the controller fails shorted, you are less likely to fry the motor due to high voltage.

One assumption is the motor can't take more than 170 Volts.

You would be a bit faster with the 100 Ahr cells for 2 reasons. One is voltage sag:

180 Ahr cell has 0.6 milliohms of internal resistance. 

56 cells * ( 3.3V - 1000A * 0.6e-3ohm) = 151 Volts

You'll lose about 1 - 151V / 170V = 11% less power

100 Ahr cell has 0.9 milliohms of internal resistance.

100 cells * ( 3.3V - 1000A * 0.9e-3ohm) = 240 Volts

This is well above a motor limit of 170V. It gets better, since the controller acts like a transformer, trading volts for Amps, it would actually only have to do about 600 battery Amps to do 170 Volts at 1000A out.

The other benefit is the 100 Ahr battery has less internal resistance per kilogram, making it a bit more powerful per kg of battery.

So if you care about having 11% more power, go for the 100 Ahr. Another option would be to put in 63 of the 180 Ahr cells, to be able to keep the motor at max voltage.

Obviously you'd need a controller that could handle higher voltage, and could control voltage to the motor.



Joey said:


> Thanks. I’ve been thinking about this battery issue. I’m not an expert at all. But it seems to me that the effective RPM range may not be all that different because while current draw from the pack will be lower, the C rating of the higher voltage pack will also be lower. I’m hoping someone may be able to tell me where/if I’ve gone wrong in this example:
> 
> 
> Consider pack 1: A pack of 56 cells at 180 AHr has a pack voltage of 179 V and 32.3 kWHr of energy. Pack 2: For a similar energy pack, you would need 100.8 cells of 100 AHr cells, for a pack voltage of 322 V. (You would have to choose a whole number of cells in an actual pack.)
> ...


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## Joey (Oct 12, 2007)

corbin said:


> Use a smaller 12v battery, and not the stock size!
> 
> corbin


 I'll probably go with a SLA for the 12 V system. I'm not sure of the size yet, I need to add up all of my expected loads (vacuum pump, headlights, and blowers are the big ones that come to mind), size-up the DC-DC, and have some safety margin - maybe 20-40 AHrs. 

It is hard to see in the picture, but the space for the starting battery platform is raised several inches from the area vacated by the gas tank. To use some of the starting battery space for traction batteries, the raised platform would need some metal work modifications.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> One advantage to the fewer 180 Ahr cells is if the controller fails shorted, you are less likely to fry the motor due to high voltage.
> 
> One assumption is the motor can't take more than 170 Volts.
> 
> ...


David, I think you are correct. I need to get the voltage up high enough to prevent the pack voltage from dropping below 170 under full load sag. I just don't know where I'm going to fit 7 additional batteries and the pack weight is starting to climb. I need to look at how many of the 130 A Hr cells I could fit.


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## drgrieve (Apr 14, 2011)

> Assume both packs have a 3C discharge rating and can burst 5C for up to 10 seconds. That is, the voltage sag will be similar for either packs when normalized in terms of C rating.


Actually there is a difference in C rating between the 100ah and the 180ah cells. Or more accurately a difference in voltage sag under load.

I've being collecting peoples reports on voltage sag for their packs in finished EVs on dynos.

The 180ah sags from 3.3 to 2.7v under 5.5C load (1000 amps) and the 100ah cells sags to 2.7v under 800 amp load.

So 100*2.7*800 = 216 kW vs 56*2.7*1000 = 151 kW a big difference.

Regarding RPM range. If your consider warp9 max RPM to be at 170 volts, then with 180ah cells under load you are only seeing 150 volts - which will limit upper RPM band slightly. With the 100ah cell this is not a problem, you can trade battery volts for motor amps using Soliton and limit motor voltage to 170v even under max load.

However since Soliton 1 max motor amps is 1000, the maximum you will get is 170*1000 => 170 kW.

This works out to be 100*2.85*600 = 171 kW

So 170/150 = 13% more power and less stressed batteries due to less voltage sag @ 6C.


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## Joey (Oct 12, 2007)

drgrieve said:


> Actually there is a difference in C rating between the 100ah and the 180ah cells. Or more accurately a difference in voltage sag under load.
> 
> I've being collecting peoples reports on voltage sag for their packs in finished EVs on dynos.
> 
> ...


You and David have convinced me that I need to go with a higher voltage. I just can't shake the notion that 100 cells is a lot. The 130 ah cells are nearly as stiff as the 100 ah, and I would only need 76 cells.


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## drgrieve (Apr 14, 2011)

I don't have any reports on the 130ah cell, but I think due to motor amp limiting you will get 165 to 170kw motor input with these cells.

Or at least very close to the 100ah cells.

Perhaps the biggest issue is finding room for all the batteries and seeing what ah size fits best.


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## Joey (Oct 12, 2007)

I put together the following comparison where (using David's example for calculating voltage sag) I found the minimum number of cells to keep the pack voltage above 170 Volts while producing 1000 amps on the motor side of the controller.









The clear winner is the 100 ahr cells. It is $1400 cheaper and weighs 100 lbs less than the 56 cell, 180 ahr pack I was originally considering. The only drawback is 13 miles less range. I can live with that.

Now to see if they will fit.


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## maxvtol (Nov 11, 2009)

Not sure how efficiency plays into this but if you figure maybe 80% motor and controller efficiency, then 170v * 1000a /.8 = 212.5kw of power required on the battery side. Each battery 2.7v * 800a = 2.16kw, so 212.5kw/2.16kw per battery = 98.4 batteries. Come on, you can do it! you really don't need any passengers do ya?


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## Joey (Oct 12, 2007)

89 batteries will fit. I still have to find room for all the other components, but there is room up front, so it should work. 

35 cells up front where the gas tank lived. (Needs metal work to the raised tray for the 12 V battery.)
16 batteries on each side of the motor (32 total).
6 cells on each side of the motor bay (12 total)
10 cells along the back shelf

Goals of keeping the controller and motor visible, and keeping the cells upright are met.

Front/Back weight distribution shifts toward the front (was 38%/62%, now 40%/60%). So far the conversion is 250 lbs over stock. I haven't included cables and battery racks yet.

The reduced range 90 vs 75 miles is the only downside to going with the 100 ahr batteries vs. 180 ahr cells (size picture for size comparison). The shorter cells means the batteries in the gas tank hole will be subflush to the trunk floor, and will look stock with the upostry back in place.


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## Joey (Oct 12, 2007)

My adaptor plate arrived. I'm quite disappointed. Based on the information on the supplier web site, I thought I would be getting a taper lock hub. Instead I have a key way and set screw hub. I will need to speak to the supplier, and figure out my options. I really want a taper lock. (In case you don't want to go through the whole thread, I'm keeping the clutch.)


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## cruisin (Jun 3, 2009)

Joey said:


> My adaptor plate arrived. I'm quite disappointed. Based on the information on the supplier web site, I thought I would be getting a taper lock hub. Instead I have a key way and set screw hub. I will need to speak to the supplier, and figure out my options. I really want a taper lock. (In case you don't want to go through the whole thread, I'm keeping the clutch.)


Taper lock hub's have had a high failure rate and are no longer used by most proffessional suppliers. Why would you want one? You need to talk to people who have installed a lot of both for feedback, not one on the forum who made his own to save a $.


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## Joey (Oct 12, 2007)

cruisin said:


> Taper lock hub's have had a high failure rate and are no longer used by most proffessional suppliers. Why would you want one? You need to talk to people who have installed a lot of both for feedback, not one on the forum who made his own to save a $.


Cruisin, thanks for your feedback. I emailed the supplier to see why they apparently switched from a taper to set screw hub. I'll let you know how they respond. 

The installation instructions recommend heating the hub to 200 degrees F, to open the bore enough to install it on the motor shaft. An interference mount seams much better to me than a clearance hole that relies entirely on a set screw to hold everything together.

On a ganite block, I measured the thickness delta of the adaptor plate that connects the motor to the transmission. The mating surfaces are parallel to within 10 mdeg. The max height difference was 0.002 inches over a 10.5 inch span. The transmission bellhousing on the porsche is circular. It is interesting that the mating surface for the motor is painted. For better percision, I would think a bare surface would be preferred. But 10 mdeg is probably good enough.


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## cruisin (Jun 3, 2009)

Joey said:


> Cruisin, thanks for your feedback. I emailed the supplier to see why they apparently switched from a taper to set screw hub. I'll let you know how they respond.
> 
> The installation instructions recommend heating the hub to 200 degrees F, to open the bore enough to install it on the motor shaft. An interference mount seams much better to me than a clearance hole that relies entirely on a set screw to hold everything together.
> 
> On a ganite block, I measured the thickness delta of the adaptor plate that connects the motor to the transmission. The mating surfaces are parallel to within 10 mdeg. The max height difference was 0.002 inches over a 10.5 inch span. The transmission bellhousing on the porsche is circular. It is interesting that the mating surface for the motor is painted. For better percision, I would think a bare surface would be preferred. But 10 mdeg is probably good enough.


 
Your supplier is probably Canev who makes most of the adapters people use. I have sold many of their adapters and installed many on a car just like yours and most models that Porsche and VW makes. Your concerns are way out in left field as you appear to be re-engineering the whole hobby.


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## dladd (Jun 1, 2011)

fwiw, if I recall correctly I have seen Randy from CanEV say on the EVDL some time ago that the switch from taperlock to smooth bore and setscrew was mostly done because of increased user error upon installation of the taperlocks since they are harder to install correctly. It was not changed because the smooth bore/setscrew is better, just easier and less callbacks for them.


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## coulombKid (Jan 10, 2009)

dladd said:


> fwiw, if I recall correctly I have seen Randy from CanEV say on the EVDL some time ago that the switch from taperlock to smooth bore and setscrew was mostly done because of increased user error upon installation of the taperlocks since they are harder to install correctly. It was not changed because the smooth bore/setscrew is better, just easier and less callbacks for them.


 In a life time of industrial applications the taper lock has the edge IF installed correctly. A taper lock is, by design, self centering. Any key and set screw arrangement, that is a slip fit, will be off as soon as the set screw is tightened. The most common cause of failure for a taper lock is to use anti-seize on the mating surfaces. It just kills them. If you must use a lubricant a light oil should be used, even better yet WD-40 because it goes away over time.
I would totally believe the following two things about your supplier: 1) They never over packed proper instructions for installation of a taper lock. and 2) They've figured out how to make more money on the inferior (in my opinion) option they pawned off on you.


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## Joey (Oct 12, 2007)

coulombKid said:


> In a life time of industrial applications the taper lock has the edge IF installed correctly. A taper lock is, by design, self centering. Any key and set screw arrangement, that is a slip fit, will be off as soon as the set screw is tightened. The most common cause of failure for a taper lock is to use anti-seize on the mating surfaces. It just kills them. If you must use a lubricant a light oil should be used, even better yet WD-40 because it goes away over time.
> I would totally believe the following two things about your supplier: 1) They never over packed proper instructions for installation of a taper lock. and 2) They've figured out how to make more money on the inferior (in my opinion) option they pawned off on you.


I too have a preferrence for the taper lock. Installation with a dial indictor to check for runout shouldn't be too difficult. A slip fit keyway and set screw is unacceptable. In your opinion, how much of a compromise is there in a keyway with an interference fit?


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## Joey (Oct 12, 2007)

cruisin said:


> Your supplier is probably Canev who makes most of the adapters people use. I have sold many of their adapters and installed many on a car just like yours and most models that Porsche and VW makes. Your concerns are way out in left field as you appear to be re-engineering the whole hobby.


Thanks for your feedback on this style of hub. It is good to know that you have had success with them. 

I'm an engineer, and over engineering something is something I enjoy doing. I don't see a problem with asking how things work and why certian design choices are made. I'm not in a position to yet judge the quality of this adaptor, so I prefer not to mention the supplier until I can make an informed comment.


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## coulombKid (Jan 10, 2009)

Joey said:


> I too have a preferrence for the taper lock. Installation with a dial indictor to check for runout shouldn't be too difficult. A slip fit keyway and set screw is unacceptable. In your opinion, how much of a compromise is there in a keyway with an interference fit?


While I have all the heavy-duty pullers to remove a shrink fit hub with out damage it can present big problems for the non-journeymen. A lot of pullers out their just aren't up to the job. I hope the motor suppliers never go to stainless shafting in their motors because if they do galling and shaft destruction is assured when you have to pull a shrink fit hub. Getting it "right" on the first try for depth of hub install doesn't sound like the kind of dice roll I like. So much for that "magic number" you gave your adapter fabricator.


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## rs27carrera (Apr 13, 2012)

Nice project you have!! I am 911 man with too many old 911s, but I love them.

I am new to this forum too but few notes from mechanicla point of view:

1.) location of charging socket. I noted you plan to use old fuel filler place. That lid and locking system is not naturally the best one and you may get some trouble if frequently used. Also cable will by time make some scratches to paint in fender, so I would propose to install socket to front pumber, it is solid aluminum piece and it will be easy to access.

2.) You mentioned to have clutch, do electric motors have also longitual bearing as clutch will put pressure to that direction as well? If there is no such a bearing, it may damage main bearings over the time. Maybe this is well sorted out but you see I am new to this .

3.) Have you considered to make kind of box or bottom plate to rear part of the car? This would enable you to prevent dirt and water entering electric parts in rear?

I am following this thread with interest, as I do have also one spare 911 what is very suitable to EV conversion too.

Regards, Harri


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## Joey (Oct 12, 2007)

rs27carrera said:


> Nice project you have!! I am 911 man with too many old 911s, but I love them.
> 
> I am new to this forum too but few notes from mechanicla point of view:
> 
> ...


Hi Harri,
This is my first 911, but I'm a big fan of the car. The more I work on the car, the more impressed I become with the engineering that went into the car.

Thanks for your input on the car. I have noticed that the release on the fuel door might not be up to daily use. I had thought about mounting the power cord in a way to avoid contact with the fender. I will think about your idea.

The electric motor has thrust bearings designed to take the load of actuating the clutch release. It was designed for automotive an application.

Protecting the motor and batteries from dirt and road grime in the back of the car will be a priority. The battery racks will privide a mounting surface for some kind of pan or plastic spray shield.


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## Joey (Oct 12, 2007)

cruisin said:


> Taper lock hub's have had a high failure rate and are no longer used by most proffessional suppliers. Why would you want one?





cruisin said:


> I have sold many of their adapters and installed many on a car just like yours and most models that Porsche and VW makes. Your concerns are way out in left field as you appear to be re-engineering the whole hobby.


Cruisin, have you installed the set screw style hub with a pull type clutch release? The manufacture claims that because the hub seats against the motor shaft bearing, that the set screws are not load bearing, but this is not the case with a pull-release pressure plate. The setscrew would be the only thing clamping the hub in my application.

Also, the installation instructions say to heat the hub to 200 degrees for installation. I assume this is to minimize the play between the hub and shaft, that would act to loosen the set screws over time. My hub slides on easily at room temp.



dladd said:


> fwiw, if I recall correctly I have seen Randy from CanEV say on the EVDL some time ago that the switch from taperlock to smooth bore and setscrew was mostly done because of increased user error upon installation of the taperlocks since they are harder to install correctly. It was not changed because the smooth bore/setscrew is better, just easier and less callbacks for them.


The CanEV website is very clear that they switched to a set screw style hub, and it is because it is easier to install. The CanEV product has a good reputation. I bought my adaptor from another site, that subs the work out to CanEV. The other site has old documentation still up documenting the taperlock installation. I wanted a taper lock and thought that was what I was ordering.

The search is on for a taper lock supplier. CanEV doesn't seem to want to supply them anymore (but I should contact them directly, if the intermediate supplier won't respond). Electro-Auto has my year car listed on their website. I have a positive review from a local man thta converted a 944, but I know others have had trouble getting parts in a reasonable amount of time. Any suggestions?


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## DavidDymaxion (Dec 1, 2008)

I have an electric 911 http://ExplodingDinosaurs.com .

I have a triple clamping force pressure plate -- so far so good no problem with motor bearings.

That's a good point about a set screw getting pulled off (the 911 pulls to do the clutch). I have a taperlock, so far so good.

Steve Clunn http://www.grassrootsev.com has a neat video where he puts on a conventional pulley taperlock. He then spins it with the motor itself to machine it. This guarantees the taperlock is square to the axis of rotation (read no wobble or off center, so less vibration).

The Porsche has very little clearance for the flywheel and pressure plate. If I were to do it again I would consider using a small diameter racing clutch.


rs27carrera said:


> Nice project you have!! I am 911 man with too many old 911s, but I love them.
> 
> I am new to this forum too but few notes from mechanicla point of view:
> 
> ...


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## PThompson509 (Jul 9, 2009)

Joey said:


> ...
> The search is on for a taper lock supplier. CanEV doesn't seem to want to supply them anymore (but I should contact them directly, if the intermediate supplier won't respond). Electro-Auto has my year car listed on their website. I have a positive review from a local man thta converted a 944, but I know others have had trouble getting parts in a reasonable amount of time. Any suggestions?


<rant>DO NOT BUY FROM ELECTRO-AUTO. THEY WILL TAKE YOUR MONEY AND NOT SHIP YOU PARTS.</rant>

Too many people have been suckered by them - save your money and use one of the reputable vendors that advertise on this site. I'm sure that KTA would have one for you (not affiliated with KTA or EA - just very happy with KTA and still REALLY pissed off at EA).

Cheers, Peter


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## Joey (Oct 12, 2007)

PThompson509 said:


> <rant>DO NOT BUY FROM ELECTRO-AUTO. THEY WILL TAKE YOUR MONEY AND NOT SHIP YOU PARTS.</rant>
> 
> Too many people have been suckered by them - save your money and use one of the reputable vendors that advertise on this site. I'm sure that KTA would have one for you (not affiliated with KTA or EA - just very happy with KTA and still REALLY pissed off at EA).
> 
> Cheers, Peter


Looks like KTA is a retailer for CanEV. CanEV has a good reputation, but in my application (pull-style clutch release) I need a taper-lock. I'll send them an email and see if they offer other options.


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## PThompson509 (Jul 9, 2009)

Some other sources I've had good luck with:

www.evsource.com
www.evparts.com
www.evolveelectrics.com
www.kta-ev.com


Others I've heard good things about:
www.electriccarinternational.com
www.ev-propulsion.com
www.cloudelectric.com

Most of these sites have the taper-lock available.

Cheers, Peter


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## Joey (Oct 12, 2007)

Peter, Thanks for posting the list. I have been in communication with a supplier that seems willing to make the hub for me. I will post with details when I have more information to share.

I'm in the process now of conditioning my motor to seat the brushes with 12 volts. My target is to get about 40 hours of run time.

I measured the vibration of the motor under a number of conditions with an accelerometer and spectrum analyzer that is sensitive to about 2 nanometers, mounted radial outward on the drive end plate of the motor body.

The motor runs no load with 12 volts at 36.25 Hz (2175 rpm). The vibration peak was 47 mg's acceleration (9 um displacement).

I added the CanEV hub and saw rpm drop by 40, but the vibration actually improved to 7 um. Could the material for the keyway slot on the shaft cause the extra unbalance with no hub? I'll have to do the calculation later.

Then I added the flywheel and got another 40 rpm drop in motor speed and the vibration increased to 10 um. Overall I would say this is a good result. The hub and flywheel didn't add significantly to the vibration. 

I measured about 0.002" of runout on the flywheel perimeter, and 0.0025" of wobble on the flywheel face (measured at a 100 mm radius from the rotation axis). I can't visible see any wobble or run out with the motor spinning. The body of the motor has a slight feel of vibration, like a small transformer humm.

The CanEV hub seems to be a well made part. It would probably do really well in a push release clutch. I just can't trust set screws to hold in a pull clutch application.


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## Joey (Oct 12, 2007)

I'm 17 hours into seating the brushes on the Warp9. So far everything looks good. I measure greater than 10 MOhms from any terminal to the motor body, so brush dust accumulation is not a problem so far. Over a 1 hour run, the only place I can feel heat is on the commutator motor shaft, and it only gets warm to the touch.

I'm trying to determine how much water proofing I need to at the rear deck grill. I'm thinking of laying up a fiber glass tray to go between the deck and grill and using weather stipping to seal things up.


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## Joey (Oct 12, 2007)

I made a fiberglass tray to go between the deck lid opening and the grill. I made a molds of the deck opening and trays that fit into the grill openings. The voids were filled with foam. The tray is painted with marine grade polyurethane paint. It raises the grill a slight amount, but it is a small price to pay for keeping water off the motor, controller and batteries.








































I'll post more pictures once I'm done painting and the grill is installed.


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## Joey (Oct 12, 2007)

I have another update on my hub situation. In February I ordered what I thought was a taper lock hub, and received a set screw/ keyway hub instead. The manufacturer of the hub and adaptor plate is very clear on their web site about what they make and why. And it performs well for many people, I'm told. The problem is I purchased this part from a representative company that has out of date information on their site. I thought I had ordered a taper lock hub. I don't think the setscrew hub is appropriate with a pull release clutch.

A few weeks ago I contacted this company: http://www.electriccarinternational.com/Interconnecting-Hubs.php

Today the new hub arrived. It looks pretty good. I'll post numbers on runout when I put the clutch together. 



















I'm really excited to be getting on with connecting the motor and transmission after this little detour.


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## Joey (Oct 12, 2007)

I bolted up the hub and flywheel. I used a dial indictor to pull the hub and taper bush together and minimized the wobble on the face of the hub. I get about 0.001" (25 microns) of wobble, measured at the outer rim of the flywheel. The runout on the flywheel is about 0.002". 

Things aren't all good though. The runout on the hub is quite large (0.015" or 380 microns). You can see it when I spin the motor with 12 Volts - the flywheel is centered and true, and the hub has a visible wiggle. So I'm thinking of mounting the hub on a 1.125" shaft, truing up the face of the hub with the dial indicator, and taking enough material from the sides of the hub on a lathe to eliminate the runout.


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## Joey (Oct 12, 2007)

Today was a good day. I solved some problems that have been causing long delays.

I chucked an aluminum rod in the lathe, and turned the shaft to 1.125" - the diametrer of the warp9 shaft. I mounted my hub on the shaft and squared up the end face of the hub using a dial indicator to carefully pull the hub and taper lock bush together. Then I removed enough material from the sides of the hub to true up the hub - there was 0.015" (0.38 mm) of runout.

I also had to do some machining on the adaptor plate. There wasn't enough clearance behind the flywheel, and the flywheel was rubbing. I had to remove 2 mm of thickness and countersink the mounting bolts deeper.

After mounting everything up as best as I could, with many cycles of assembly and disassembly, I finally got the wobble of the flywheel down to 0.003" (difference between max and min measured out on the outer rim of the flywheel) and the runout is 0.002". Spinning with 12 volts, the vibration is very minimal. I'm very happy.


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## DavidDymaxion (Dec 1, 2008)

That's great stuff, thanks for the pics, too.

If you can get the motor up onto your machine, you can square the hub with the electric motor spinning it (a Steve Clunn trick).


Joey said:


> Today was a good day. I solved some problems that have been causing long delays.
> 
> I chucked an aluminum rod in the lathe, and turned the shaft to 1.125" - the diametrer of the warp9 shaft. I mounted my hub on the shaft and squared up the end face of the hub using a dial indicator to carefully pull the hub and taper lock bush together. Then I removed enough material from the sides of the hub to true up the hub - there was 0.015" (0.38 mm) of runout.
> 
> ...


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## Joey (Oct 12, 2007)

And here is the transmission and motor joined together. 








And a video of the transmission spinning:




The rattle in the video is the throw out bearing. It doesn't seam bad and I'm not too worried. Anyone have an opinion?


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## TigerNut (Dec 18, 2009)

Joey said:


> And here is the transmission and motor joined together.
> View attachment 13192
> 
> 
> ...


Throwout bearings should be totally silent... unless it's made of unobtanium or hideously expensive, I'd replace it.


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## DavidDymaxion (Dec 1, 2008)

Here's a video of mine spinning (only the 1st 5 seconds or so has sound):

http://www.youtube.com/watch?v=EJmh1o7ievU

Yours seems noisier. It is full of oil? Mine has a spring that always puts a litlte preload on the clutch, plus some adjustment to take out slack -- is your release arm loose at all?



Joey said:


> And here is the transmission and motor joined together.
> View attachment 13192
> 
> 
> ...


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## Joey (Oct 12, 2007)

TigerNut said:


> Throwout bearings should be totally silent... unless it's made of unobtanium or hideously expensive, I'd replace it.


The bearing is brand new. I figured out what is likely causing the noise. I just checked my repair manual. There is a missing oring that is supposed to go between the throwout bearing and the bearing guide tube. I'll get the oring installed and I bet it takes care of the noise. Thanks for the feedback on silent operation.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> Here's a video of mine spinning (only the 1st 5 seconds or so has sound):
> 
> http://www.youtube.com/watch?v=EJmh1o7ievU
> 
> Yours seems noisier. It is full of oil? Mine has a spring that always puts a litlte preload on the clutch, plus some adjustment to take out slack -- is your release arm loose at all?


There is new fluid in the gear box. I haven't installed the clutch springs yet either. I'll install them and the missing guide tube o-ring before powering it up again.


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## Joey (Oct 12, 2007)

So the O-ring goes behind the guide tube, to seal transmission fluid from entering the bell housing. It does not center the bearing on the guide tube as I had thought. With a small amount of force on the throw out arm, the noise goes away completely. The noise was rattling of the bearing mount sliding around on the pressure plate springs. Is the throw out fork the only thing that centers the bearing? The bearing has some clamping force on the mount to the pressure plate, but it can move around a little. It isn't any different that the bearing that was removed. Seams that the guide tube is there only to protect the bearing from contacting the input shaft. Anyway I'm sure the noise will be gone once the helper spring and return spring are installed. We will see.


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## Joey (Oct 12, 2007)

My Soliton1 showed up today. A few years back when the Zilla was out of production, controller options were scarce. The whine of the curtis controller and the poor reliability of other options was a deal breaker for the whole project. Then evnetics started up and introduced their controller, and it is awesome. Can't wait to hook it up and see it spin the motor. What a great looking component.


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## Joey (Oct 12, 2007)

This update is a big one for me. I made my motor mounting bracket and got the motor and transmission mounted into the car. At the end of this post is a video of the wheels spinning under electric power for the first time ever.

Now the details. I'm reusing the stock cross bar to connect to the rear motor mounts. I needed a way to locate how the rear cross bar is positioned relative to the electric motor. Taking measurements on the gas motor proved to be difficult, so I made a jig that connected to the transmission mounting flange on the gas block, wraps around the engine, and bolts to the cross bar. The the jig could then be mounted to the transmission flange on the electric motor adaptor plate. The cross bar is now held in the correct position and I could connect it to the electric motor with some metal bits. 
































I made a disk out of 1/4 inch (6 mm) steel plate to bolt to the end of the motor with 4 bolts. I used 2 inch (50 mm) square tubing to span the gap to the cross bar. Some metal tabs were added to bolt the assembly to the cross bar. For now the parts are just tack welded, in case any adjustments are needed.




















After checking the alignment, I will remove the parts, weld them up fully, and have them painted. There is also one additional cross bar that will be added to the top of the mounting bracket. It will be welded to the 2 "L" tubes, and the top portion of the disk.

Here it is mounted in the car.














And here is the video of the wheels spinning under electric power:





 

The slight whine/squeak is from the throwout bearing. It goes completely quiet with the slightest amount of pressure on the throw out fork lever. I don't have the clutch cable reconnected yet.


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## Caps18 (Jun 8, 2008)

It is looking good. I hope to get to that stage in the next few months.


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## Joey (Oct 12, 2007)

Thanks Caps18. I'm following your progress on your thread.

I took the motor out to weld up the motor mount, and to do a little painting. The engine compartment was covered in adhesive.








I removed by as much material as I could by wire brush and sanding. Then I applied some touch up paint.














The bracket was welded, sanded, primed and painted.


























Then the motor was re-installed.














I hooked up the clutch cable and tested the shifting under 12 volt power. Everything worked well. I could get to all the gears. With the cable connected, the trowout bearing rattle was completely gone. I'm very excited to reach this point.


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## LawLie (Jul 11, 2012)

Hi,
Do you plan to re-use the fuel gauge as a battery gauge ?


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## onegreenev (May 18, 2012)

Joey,

You know you can imbed the youtube's in this forum. That way folks can stay on the forum and not be taken to youtube.


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## Joey (Oct 12, 2007)

onegreenev said:


> Joey,
> 
> You know you can imbed the youtube's in this forum. That way folks can stay on the forum and not be taken to youtube.


I do now. Thanks. I edited the old post.


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## Joey (Oct 12, 2007)

LawLie said:


> Hi,
> Do you plan to re-use the fuel gauge as a battery gauge ?


I plan to use the EV display. It can drive the old fuel gauge based on remaining battery charge. 
http://minibms.mybigcommerce.com/products/EV-Display.html

There is also a version that syncs to a mobile device and has a cool interface. I will look for a link and update my post.


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## ricklearned (Mar 3, 2012)

I bought the one that syncs to an Android. It is sold by evwerks. I have only used it while working on my car, and trying some dry runs with the wheels off the ground. I think it is going to be great.


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## Joey (Oct 12, 2007)

onegreenev said:


> Joey,
> 
> You know you can imbed the youtube's in this forum. That way folks can stay on the forum and not be taken to youtube.


I was having a very hard time embedding the youtube video. The trick for me was to click the "remove format" button, after pasting the youtube link into the embed wrap. Without removing the format, I was getting strange results, even though everything appearred to be correct in the edit window. Here is a picture that shows the external link, the embedding format, and the remove formatting button.


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## Joey (Oct 12, 2007)

ricklearned said:


> I bought the one that syncs to an Android. It is sold by evwerks. I have only used it while working on my car, and trying some dry runs with the wheels off the ground. I think it is going to be great.


I think this is the link. http://www.emotorwerks.com/emw3/product/ev-dashboard-by-emw-basic-edition/

They worked with Dimitri , who makes the miniBMS and EV Display, to add the blue tooth connectivity. The UI is slick.


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## dladd (Jun 1, 2011)

Joey said:


> I think this is the link. http://www.emotorwerks.com/emw3/product/ev-dashboard-by-emw-basic-edition/
> 
> They worked with Dimitri , who makes the miniBMS and EV Display, to add the blue tooth connectivity. The UI is slick.


i have that in my car, it is very cool! Eventually I also want to wire it up to the stock fuel gauge, but haven't yet (but in the meantime there is a little analog looking fuel gauge on the display). The phone (i have a DroidX) can still receive calls and emails and stuff at the same time, very integrated, and the UI is indeed very nice.


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## ricklearned (Mar 3, 2012)

dladd said:


> i have that in my car, it is very cool! Eventually I also want to wire it up to the stock fuel gauge, but haven't yet.......


I want to do that too! I also have an old Android phone that I want to mount on the dash so I can leave it in the car. In the meantime I have a few more things to do to get my VW road worthy.


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## onegreenev (May 18, 2012)

Joey said:


> I was having a very hard time embedding the youtube video. The trick for me was to click the "remove format" button, after pasting the youtube link into the embed wrap. Without removing the format, I was getting strange results, even though everything appearred to be correct in the edit window. Here is a picture that shows the external link, the embedding format, and the remove formatting button.


It is easier than that. Go to any youtube video. Here is a normal link you may find. 
h ttp://www.youtube.com/watchv=dXpZK5hOKJA&feature=channel&list=UL

What you want is to only select the part of the link that is between the = sign and & sign. The part in red is what you past in the youtube link when you post. 

The link should look like this. [ YOUTUBE]dXpZK5hOKJA[/YOUTUBE ] I disabled the link to show you what part goes in the link. 


So here is the same video in the post using only the selected text in red. All youtube videos will have a similar link. If there is no ampersand you use the part behind the = sign. 






Try it out.


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## Joey (Oct 12, 2007)

onegreenev said:


> It is easier than that. Go to any youtube video. Here is a normal link you may find.
> h ttp://www.youtube.com/watchv=dXpZK5hOKJA&feature=channel&list=UL
> 
> What you want is to only select the part of the link that is between the = sign and & sign. The part in red is what you past in the youtube link when you post.
> ...


When I copy and paste the section of the link you like you say, like this: [ YOUTUBE]dXpZK5hOKJA[/YOUTUBE ], I get this:





 
And if all I do is I highlight the text inside the youtube wrapper, and click the "remove text formatting" button, I get this:




 
So there must be some formatting that tags along when I paste in the embedded path. I don't know.


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## onegreenev (May 18, 2012)

Any of the parts of the code in RED that is given for any youtube video can be copied and pasted in the youtube code that comes up when you want to embed a in a post. Don't copy past my examples as they are disabled. Just copy paste the parts of the code you see in red. Don't copy paste the MY EXAMPLES. Go to any video and try it. Be sure you don't copy any other part of any spaces or anything like that. Sometimes it might bring a space and not show anything. Preview your post before submitting it to be sure it worked or works. 


This is the URL Header: 
h ttp://www.youtube.com/watch?v=dXpZK5hOKJA&feature=channel&list=UL

This is the share code: 
h ttp://youtu.be/dXpZK5hOKJA

This is the embed code:
< iframe width="420" height="315" src="http://www.youtube.com/embed/dXpZK5hOKJA" frameborder="0" allowfullscreen></iframe>


Buy the way. What operating system do you use?


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## onegreenev (May 18, 2012)

Trying again: Seems to work the same for Ubuntu with Firefox as it does with my Mac. Always preview. When pasting this one I missed the last little s in the copy pasted code and it did not work. Be sure there are no spaces or missing letters or numbers. Remember only the code between the = and &. Nothing else. 






I put in a space below in the youtube code to disable the code. The above video you see is from this code. No deformatting or any thing. 


[YOUTUBE ]U_JMjCAlMPs[/YOUTUBE]


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## jrod84 (Jan 20, 2011)

Joey, 

I just wanted to thank you for pictures of the motor and clutch coupling to the transmission. I believe its the pictures on your blog. Seeing those pictures, step by step, helped me to visual what is actually happening versus an animation.

I have my donor car, planned the budget down to specific parts and from where. The motor coupling was one of the last unknowns for me. Now, I have the confidence and understanding to tackle it when it comes in my conversion.

Thanks dude.


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## Joey (Oct 12, 2007)

jrod84 said:


> Joey,
> 
> I just wanted to thank you for pictures of the motor and clutch coupling to the transmission. I believe its the pictures on your blog. Seeing those pictures, step by step, helped me to visual what is actually happening versus an animation.
> 
> ...


Sure thing. I'm enjoying the documentation nearly as much as the build itself. Good luck with your project.


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## Joey (Oct 12, 2007)

It is time to order the batteries. The new gray CALB CA cells look very attractive. The price is a bit more (10%) over the blue SE cells, but the lifetime is supposed to be better and the current output (C rate) is about 50% greater. Before the gray cells became available, I was considering 100 cells at 100 Ah of the blue CALB SE cells, because the 100 Ah cells had a much better C rating than the 180 cells. The new CA gray cells appear to have similar discharge rates (10C for a burst), so my preference is to minimize the cell count, and go with 60 cells at 180 Ah capacity.

This will give me a 100 mile range (if I get 275 Wh/mile @ 80% dod, 34.5 kWh energy), with a 750 lbs pack. The challenge will be figuring out where to fit them all. The easiest solution would be to fit 36 cells in the front (where the gas tank used to live) and 24 cells in the back, 12 on each side of the motor. This would shift the weight distribution from 38/62 (front/back), to 44/56. This configuration has a net 330 lbs added to the front and 25 lbs added to the back. I'm afraid that this is too much change and would require re-tuning the suspension to restore ride height, and make the manually steering more stiff. Splitting the pack 30 cells in front and 30 in back gives a 42/58 distribution and 80 pounds less mass up front. Finding a place for the extra cells in back is tough because I want to keep the cells oriented vertically and maintain access to the cell terminals for taking voltage measurements.


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## Ziggythewiz (May 16, 2010)

Quotes i've gotten for CAs were the same as SEs. I suppose some vendors are afraid of getting stuck holding the blues, so they may be offering discounts.


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## drgrieve (Apr 14, 2011)

Agree that you should go for the grey cells.

In regard to which size just choose the type that fits best into the car.


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## northvan (Aug 2, 2012)

Hey Joey,

I am also going to be converting a 78-89 Porsche 911, and am currently in the donor-car hunt. I must confess I am in the early stages, probably where you were a year ago. As you can imagine, I have my eyes glued to your project blog

Regarding your dilemma about cell placement, I have also thought about that quite a bit and am looking into adding an after-market 930 style Turbo Tail, as I believe that it may allow you to go a few inches vertical a bit more for some of the lighter massed components, like the controller and electrics shelf.










Waterproofing would be an issue, though (I am in the pac northwest). It's only a seed in my brain at this point, as well, as I haven't gotten my hands on one yet to really see if the dimensions will work.

After hearing stories from ev-converters with battery-box stories such as "if only I had an extra 1/4 inch in there", I got the idea for this -- but I still want to keep the motor and pack as low as possible for keeping the C of G where it should be.

BTW: I really appreciate the attention to detail you have been providing on your blog. Keep up the great work!


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## Joey (Oct 12, 2007)

I received the parts for my controller water cooling loop. The pump is recommended in the Soliton1 owner’s manual of the controller – a Laing D5 hot water circulation pump. I did select the brass pump body instead of plastic. It is designed for solar hot water heating applications and runs on 12 VDC. The radiator is an aftermarket auxillary radiator with fan. The reservoir is an aluminum expansion tank. It holds 1.25 quarts (1.2 liters) of fluid. It will be located at the highest point in the cooling loop to purge air bubbles and for filling. The fill neck accepts standard radiator caps. I selected a cap rated for 7 psi. The plumbing is steel braid jacketed rubber hose with -6 AN type compression fittings. I will make a plenum for the radiator mount, and the heat will be routed out of the engine compartment to the right rear wheel well, through an opening that was left behind when I removed the stock oil tank.








And in other news, my batteries are supposed to arrive this evening. I ordered 60 CALB CA 180 (gray cells). Feels like Christmas.


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## Joey (Oct 12, 2007)

UPS showed up yesterday with their big truck to drop off my batteries. After awhile, the guy came out and said he didn't have the batteries on the truck, and someone would call me later. Turns out they put them on the wrong truck. Well it turned out OK. They found them and I got them today. 

They came well packaged. I have factory data on about 60% of the cells (shipped voltage and capacity). Looks like they shipped them at 3.3 V, and the capacity of the cells for which I have data is between 193 and 196 Ah. Now it is time to figure out where they will all live.


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## Caps18 (Jun 8, 2008)

That is a lot of batteries! You didn't really need a passenger seat did you?


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## Joey (Oct 12, 2007)

Caps18 said:


> That is a lot of batteries! You didn't really need a passenger seat did you?


 I was thinking the same thing when I was un-crating them. I think I have a plan that will not encroach on the passenger compartment, but there won't be much trunk space either.


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## Joey (Oct 12, 2007)

So what do you do when you get some batteries? Measure the voltage. This is the resting voltage, as they were shipped to me:













The average was 3.3002 V, standard deviation = 1.1 mV, and the difference between the max and min cell was 4.7 mV. I used a Fluke 287, that reads to 1/10 of a milivolt.

There was a data sheet that shipped with the cells. I could match serial numbers to about 75% of my cells. The test data stated that the capacity of the cells is between 195 and 197 Ah. Seems like a lot for a nominal 180 Ah cell. Too good to be true?


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## onegreenev (May 18, 2012)

No, not too good to be true. Most of the Chinese products actually give more than the stated capacity unlike the American versions which give less. Example of A123 which is touted as a 20ah pouch and routinely gives 18 to 19 AH. Ouch. You should have over 180 Ah in those cells. Be thankful that the Chinese do this. 

Pete 

Bottom balance those suckers then charge them up. I have a good machine to discharge my cells and can do so with the same algorithm as I use with charging. That way I can be sure all my cells are exactly at the same point at discharge. Takes some time but it works great. Only one cell at a time. With 60 cells I could do like 2 or 3 per day. I do work so that is about right. Less than a month and they would all be bottom balanced and it only needs to be done once. Perfect.


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## drgrieve (Apr 14, 2011)

Awesome looking pack this Porsche is going to fly!

The factory ah rating will be at a very low discharge rate, but yes in general the chinese lifepo4 cells will give 5 to 10% more than the nominal.

At 1 C discharge you'll find around 190 ah as an average to 2.7v static. Which is practically 100% DOD. I would guess that the factory measures ah between the very extreme points of SOC.

There is also a theory that the cells gain a few ah in capacity in the few first cycles as well to consider.

In regards to bottom balancing (which is the camp I'm in) you should be able to do it over a couple of long days. Bring the pack down to 3.0v under a load and then individually from there down to 2.700v static each.

Either way top or bottom there are loads of advice out there. Unfortunately some is a little off. A good way to work it out of yourself is too chart a discharge/charge curve of your lowest and highest ah cells.

Cheers!


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## rwaudio (May 22, 2008)

Joey said:


> So what do you do when you get some batteries? Measure the voltage. This is the resting voltage, as they were shipped to me:
> View attachment 14207
> View attachment 14208
> 
> ...


The one thing to consider is the capacity would be measured by CALB at the "recommended/ideal" discharge rate which is usually 0.3C, but the good news is even at higher (real for a normal EV's) discharge rates you will have over 180Ah, but likely not 195-197.


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## northvan (Aug 2, 2012)

Wow, thatsa lotta batteries! I will be watching closely on how you make battery boxes for those greystacks, and if you will indeed have to resort to re-purposing the back seat. Looks like you do have a well thought out plan, though.

BTW: Check this out, just posted today...

1986 911 Porsche Targa EV
http://www.ebay.ca/itm/Porsche-911-Electric-EV-/150915276330?pt=US_Cars_Trucks&hash=item2323405e2a

It has a Soliton, but 16 Pb-acids though. It will still be interesting to see what this goes for, if it does sell -- not that I will be even thinking of selling once I get mine done...


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## TEV (Nov 25, 2011)

Joey said:


> I was thinking the same thing when I was un-crating them. I think I have a plan that will not encroach on the passenger compartment, but there won't be much trunk space either.


This is why I wanted a truck bed 

Good job. Bigger it's always better  .


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## Joey (Oct 12, 2007)

I'm working on the battery racks now. I'll post when I make some real progress.



northvan said:


> Wow, thatsa lotta batteries! I will be watching closely on how you make battery boxes for those greystacks, and if you will indeed have to resort to re-purposing the back seat. Looks like you do have a well thought out plan, though.
> 
> BTW: Check this out, just posted today...
> 
> ...


I never would have thought of mounting the Soliton upside down on the firewall.


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## Joey (Oct 12, 2007)

The balancing process is underway. I'm going the top balance route. I know there are pros and cons for each, but it comes down to this: I will be charging the pack near the top more than I will be discharging the pack to the bottom. I will also be using a BMS, but I prefer to use it as a backup monitoring system. THe charger should be set with a conservative termination voltage, and the driver should mind the amp hour meter. The BMS would only intervene in extrordinary cases.

I'm using a programmable voltmeter to monitor the charge process. It will open a relay to interupt the charge at 3.42 volts, and resume charging at 3.4 volts. The goal is to get a resting cell voltage of 3.4 volts. All of the cells are wired in parallel with 12 AWG wire. I was getting quite a voltage drop across the 60 cell string, so mid pack, I added several runs back to the power supply. The supply is giving 16 amps, so this is going to take a while - 15-20 days maybe.


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## Ziggythewiz (May 16, 2010)

Nice setup! I noticed you have several branches on the + line, but just the one string on the -. Any reason?

What size cells are those? Do you have access to any other charger? 2 weeks is along time.

When I balanced mine (I made busbars) I realized it was a ton of work for something used for just a couple days, and thought it would be great if others could use it too. Mine was not flexible at all though and would be a little difficult to send anywhere. Yours appears very flexible and would adapt to nearly anything with ease, so you might consider selling it when you're done to recoup some of the cost (effort) while saving someone else lots of work. Or if you're a in a local EV group it'd be an awesome tool to loan out!


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## Joey (Oct 12, 2007)

Ziggythewiz said:


> Nice setup! I noticed you have several branches on the + line, but just the one string on the -. Any reason?
> 
> What size cells are those? Do you have access to any other charger? 2 weeks is along time.
> 
> When I balanced mine (I made busbars) I realized it was a ton of work for something used for just a couple days, and thought it would be great if others could use it too. Mine was not flexible at all though and would be a little difficult to send anywhere. Yours appears very flexible and would adapt to nearly anything with ease, so you might consider selling it when you're done to recoup some of the cost (effort) while saving someone else lots of work. Or if you're a in a local EV group it'd be an awesome tool to loan out!


I corrected the diagram to show the extra runs on the negative terminals. If you look on my charging plots, the lower voltage traces are earlier in the charge. Originally I had a single lead papir to the power supply, and the cells closer to the charger where getting more voltage than the cells at the end of the line. The blue voltage trace is a "u" shape. Then I added 2 more mid pack runs back the the power supply (red, "W" trace). Eventually, I added three more run pairs to make it a total of seven runs (every 10 cells). 

This is the only power supply charger I have right now. It would be a lot quicker to bulk charge the cells in series with a high voltage charger (pack voltage is 192 volts, 60 cells) just short of full, and to use this setup to finish and balance. The cells will be sitting in the garage for a while anyway while I'm making battery boxesl, so no problem with a few weeks of charging.

I did see your bus bars and it was pretty cool. It is amazing how a few tenths of ohms add up in series when you start to push amps through them.


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## Ziggythewiz (May 16, 2010)

Sounds good. I thought I was going to build a box w/some insulation but on closer measuring found the lithium fit exactly in the frames from the floodies, so I just stuck em in and keep telling myself I'll make a box for em.


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## PThompson509 (Jul 9, 2009)

Ziggythewiz said:


> Sounds good. I thought I was going to build a box w/some insulation but on closer measuring found the lithium fit exactly in the frames from the floodies, so I just stuck em in and keep telling myself I'll make a box for em.


Hah, that sounds familiar! The kit I bought for my 914 was designed for floodies, but didn't have enough voltage. So I used the racks and fit in lithiums. I do have boxes, but they aren't insulated - probably don't need to in San Diego.


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## Joey (Oct 12, 2007)

I made some progress on the battery boxes this weekend. It is going to be a tight squeeze to get everything to fit. Standard angle iron frames, sheet metal skins. There are quite a few curves of the frame I will have to negotiate to get the box frames squared up. 













My grandfather gave me the framing square for Christmas when I was five. He is following my blog.














The motor is wrapped in plastic to keep frabrication debris out.


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## northvan (Aug 2, 2012)

Good to see the progress, Joey -- lookin' good! I'm sure this is a rewarding part of the process for you.

I note that you originally had planned for 16 batteries on each side of the motor:










Is that because originally you had figured on using 100AH batts, or is the space fighting you a bit more as you had originally thought (as you note a bit on your blog)? I know you are planning on 26 less batteries now, so I assume it is from going from 100AH to 180AH.

Also, I know one of the *big *advantages of going with angle and tube iron over aluminum must be that it is much easier to weld, especially by us weekend mechanic-mortals. I believe steel is around 3x heavier by volume than aluminum is, but I'm wondering how that factors in to the overall weight gain of the car. I'm also sure that steel is going to help out in holding up those 150+ pounds of batteries on each side of your motor, let alone the ones that will be sitting above the motor and in the frunk.

BTW: I really appreciate the fact you've been closely detailing the weight of the car, front/back balancing, ICE components removed, and EV components added. Very useful info!

Keep up the great work!


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## Joey (Oct 12, 2007)

northvan said:


> Good to see the progress, Joey -- lookin' good! I'm sure this is a rewarding part of the process for you.
> 
> I note that you originally had planned for 16 batteries on each side of the motor:
> 
> ...


There are a few factors here. The old CALB SE (blue) cells had better C discharge rating at 100 aH than at 180 aH. So I was planning on 80 or so of the 100 aH cells. The new CA cells have similar discharge rating on the 100 vs. the 180 aH size. I picked 192 volts, 180 aH cells because at 1000 amp disharge (5.5 C) the voltage sag would be somewhere near 170 volts - the max I'm willing to let the motor see for a burst. In general you get less line loss at higher voltage, lower current, but the reduced cell count seemed very appealing to me because the lower cell count means less electrical connections to go bad. I think 52 cells will fit very nicely. 24 cells in back and 28 in front. It will be a 3D puzzle to fit the last 8 cells.

You are correct, iron is easier for me to work with. The weight won't be too bad if I fight my urge to overbuild the boxes.


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## northvan (Aug 2, 2012)

Joey said:


> I think 52 cells will fit very nicely. 24 cells in back and 28 in front. It will be a 3D puzzle to fit the last 8 cells.


Cool, thanks for sharing. Does this mean that the CALB 180AHs are too high to go at the back, above the motor against the firewall (like your original drawing), perhaps then leaving no room for the Soliton1?

When you were mentioning in a previous post about how you were going to balance the weight distribution, I guess in the best scenario your 3D puzzle has the extra 100+ lbs of the 8 remaining cells going somewhere behind the driver (not sacrificing your son's reserved spot in the rear jump-seat, or course!), so the firewall may be the ticket. But... an obvious one, otherwise I'm sure you would have mentioned it.


Good luck with your cell-Tetris. Looking forward to seeing how you make out!


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## Joey (Oct 12, 2007)

northvan said:


> Cool, thanks for sharing. Does this mean that the CALB 180AHs are too high to go at the back, above the motor against the firewall (like your original drawing), perhaps then leaving no room for the Soliton1?
> 
> When you were mentioning in a previous post about how you were going to balance the weight distribution, I guess in the best scenario your 3D puzzle has the extra 100+ lbs of the 8 remaining cells going somewhere behind the driver (not sacrificing your son's reserved spot in the rear jump-seat, or course!), so the firewall may be the ticket. But... an obvious one, otherwise I'm sure you would have mentioned it.
> 
> ...


The problem I have with a single row of cells snugged up against the firewall is that with the taller 180 aH cells, there is no clearance on the top (only 1 to 1.5") to connect up the cells. The box would have to be populated outside of the car and hoisted into place -doable but not fun. The Soliton would have room, but would have to be tilted at 45 degrees to fit. 

So this is what I'm thinking for the last 8 cells - a battery box of 4x2 cells, where the rear cells are first placed in front, connected, and then slid back into the box. Then the front 4 cells could be installed and connected. The upper box has to slide to the right a few inches to make room for the hinges of the rear deck lid.

The black item on the right is the radiator for the Soliton1 cooling loop. I know it is bigger than it needs to be. Placement is not final by any means. I like it near the right hand side because there is an opening in the engine compartment from where the oil tank filler neck used to live, that would make for a cool way to exhaust heat from the engine bay. I'm also toying with the idea of mounting it in the rear wheel well, but that may not be a good idea.


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## Joey (Oct 12, 2007)

After 15 days on the charger, my multimeter finally measured 3.4 v on the high cell and the charger was disconnected. I have the 60 cells in parallel, with a 16 amp supply. 

I'm measuring 40 mV difference over all of the cells, so with the charger disconnected the cell voltages will converge. When My high cell drops to 3.385 V, the charger turns back on. The process will repeat until the cells stay above 3.385 volts without the charger on.

The cool thing is over the last day I have seen the voltage rise in my high cell accelerate - the knee in the voltage curve that lets you know you are near full charge. 

The manufacturer recommends charging at 3.6 V constant voltage, and terminating the charge when current drops to 9 amp (0.5 C for 180 aH cells). Because I'm wired in parallel, my 16 amp charge is close to 260 mA per cell. Bringing the cells up to 3.6 at this current would over charge them. The goal is a resting voltage of 3.4 volts, for all of the cells.


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## Joey (Oct 12, 2007)

I worked on the first battery box this weekend. Things are tacked together and I'm working on the fit in the engine bay. I have a 1/2" clearance between the box frame and the transmission adaptor plate. Once I figure out one more m ounting point, and ensure there are no interefence issues, I'll weld and paint the box.


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## northvan (Aug 2, 2012)

Joey said:


> The black item on the right is the radiator for the Soliton1 cooling loop. I know it is bigger than it needs to be. Placement is not final by any means. I like it near the right hand side because there is an opening in the engine compartment from where the oil tank filler neck used to live, that would make for a cool way to exhaust heat from the engine bay. I'm also toying with the idea of mounting it in the rear wheel well, but that may not be a good idea.


I like your proposed solution here, with a few small suggestions: 

<armchair>

I would consider swapping positions of your radiator and stack of 8 cells. Moving the 100 pounds to the right (passenger) side will perhaps help offset the driver's weight to better balance the vehicle from side-to-side when your are the sole occupant. 

Also, regarding your suggestion about placing the radiator in the wheel well, that does sounds like a good solution, keeping the radiator outside of the car, as well as in an airflow path. I am wondering about whether the front wheel well is a better location, though? The oil cool is (was) in the front wheel well -- standard starting with the SC -- and there must have been a reason why they ran the longer oil lines up there as opposed to using the closer rear wheel wells, although I can only guess at a few reasons why that may be.

</armchair>

I tired to reasearch why that is, and came across this discussion on Pelican Parts:

http://forums.pelicanparts.com/911-...-forum/487865-rear-wheel-well-oil-cooler.html

..also...

http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_ENGoil_pg7.htm

If you do place your controller-cooler rad in one of the wheel wells, would you then split your top 8 cell group into 4 cells left and 4 cells right?


Interesting puzzle, though. I am very interested in your final solutions!


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## northvan (Aug 2, 2012)

Joey said:


> I worked on the first battery box this weekend. Things are tacked together and I'm working on the fit in the engine bay. I have a 1/2" clearance between the box frame and the transmission adaptor plate. Once I figure out one more m ounting point, and ensure there are no interefence issues, I'll weld and paint the box.


Nice to see the progress on these boxes! The first one you have there looks good and solid, and I like how you are mounting them, nice and secure.

Q: How do you feel about the 1/2" of clearance? Is it "just enough", or do you think the motor torque may cause the transmission/motor mounts to flex enough to cause the adaptor plate to rub against your batt box? My guess is that with 1/2" left + 1/2" right, that 1" of room is probably adequate, but interested in your thoughts there.

I also looked at the photos on your blog (thanks for posting that detail), and looks like you _just_ have enough room there vertically as well, with a little bit of clearance below the rear engine mount corner "shelf". Glad to see that is working out for you, too!


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## Joey (Oct 12, 2007)

I am a little concerned about the clearance between the adaptor plate and the corner of the battery box. If I could push the box toward the rear of the car, there would be no issues, but the rear cross bar of the motor mount is in the way. DavidDymaxion has a 911 and solved this issue by mounting the crossbar on the top of the motor mounts. This weekend I will see if there is anything I can do to make more room.

Another concern is the vertical clearance under the rear motor mount brackets. I have an inch and half. If I lower the battery box, I risk making the boxes ready visible under the rear valance and dragging the box backing out of the driveway.

The radiator was on the left because there is already an opening in the sheet metal from where the oil tank was removed, and I could duct heat from the radiator through it. The after market radiators in your link is a good idea. I already removed the oil lines and puchased a different radiator, though.

There is an option to keep the 8 batteries centered, in a single row across the firewall (in line with the row of 4 that are toward the front of the car), but I would have to build the rack so that it tipped to the rear of the car to make electrical connections, and then bolt it up into place.


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## Joey (Oct 12, 2007)

More progress on the battery boxes. I gained 1/4 inch (6 mm) of additional clearance by smashing down a "c" channel of thin sheet metal along the lower edge of the car frame. This groove held a rubber strip to seal the engine compartment against the old gas engine. The rack rests against this crushed metal, into and under the frame rail.







The box does stick out the bottom of the car. Most angles, it is not visible, but if you are low enough, or far enough away, it will be visible under the rubber bumper. Painting the rack black should help it blend in.








Two corners of the box are bolted at the top of a vertical length of angle iron. A clearance issue forces me to support the third corner with an offset length of flat bar. The fourth corner is close to a tie down plate on the frame of the car. 




















The box just needs some sheetmetal side panels. The box will be lined with 3 mm thick rubber excersize mat (TPE).


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## northvan (Aug 2, 2012)

Joey said:


> More progress on the battery boxes. I gained 1/4 inch (6 mm) of additional clearance by smashing down a "c" channel of thin sheet metal along the lower edge of the car frame. This groove held a rubber strip to seal the engine compartment against the old gas engine. The rack rests against this crushed metal, into and under the frame rail.


Great idea! So, are you happier now with 1 1/2" total (3/4" per side) clearance? I don't have any idea how much a good torquey start off the line will laterally move the tranny, but am guessing the extra 1/2" you found may be just the ticket.



Joey said:


> The box does stick out the bottom of the car. Most angles, it is not visible, but if you are low enough, or far enough away, it will be visible under the rubber bumper. Painting the rack black should help it blend in.


I agree that it is hardly noticeable. Instead of black paint (more arm-chairing, sorry...) you could also try attaching a black rubber strip for a more finished look, something like this (Home Depot, Rubber Replacement for Garage Door Bottom, $9.97) :







 



Joey said:


> The box just needs some sheetmetal side panels. The box will be lined with 3 mm thick rubber excersize mat (TPE).


That will be great to see that when you are done. Q: Is the mat for heat insulation, or just battery protection?

I have been thinking a lot about how these cells behave in cold weather, and while Vancouver (BC, not WA) is a little bit North of Portland, we do have similar mild winters. But... the temps to get down below freezing occasionally during a cold snap. I, like you, have an insulated garage for charging -- but the car will be parked in a cold underground spot all day (when driving to work). I am debating adding a heater on the bottom of each batt-box. Hmmmm...

Keep it up, I am enjoying your updates!


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## Joey (Oct 12, 2007)

northvan said:


> Great idea! So, are you happier now with 1 1/2" total (3/4" per side) clearance? I don't have any idea how much a good torquey start off the line will laterally move the tranny, but am guessing the extra 1/2" you found may be just the ticket.
> 
> 
> 
> ...


Thanks for the feedback. If the motor does rub against the boxes, my solution will be to use stiffer racing/autocross motor mounts. Hopefully 3/4 of an inch is enough. I like your idea for trimming the bottom of the boxes. It could match the bumper well and look less out of place. 

The 3 mm foam rubber is recommended in the calb manual to reduce vibration. I would consider kapton heaters if you need to heat the battery. You can connect two of the 120 V heaters in series to heat with 240 V. http://www.omega.com/pptst/KHR_KHLV_KH.html The write up I got from evtv with my cells says to charge above 32 degrees F and discharge above 0 degree F.


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## northvan (Aug 2, 2012)

Joey said:


> If the motor does rub against the boxes, my solution will be to use stiffer racing/autocross motor mounts. Hopefully 3/4 of an inch is enough.


That's a great idea -- I didn't know about that option. I hope it doesn't come to that, but good to know there's a "plan B".



Joey said:


> I would consider kapton heaters if you need to heat the battery. You can connect two of the 120 V heaters in series to heat with 240 V. http://www.omega.com/pptst/KHR_KHLV_KH.html The write up I got from evtv with my cells says to charge above 32 degrees F and discharge above 0 degree F.


Thanks for the link, that's exactly the type of heater I had in mind. However, sounds like I may not need them according to the EVTV cell guide that came with your CALBs; I knew about the >32F for charging, but didn't know about the >0F for discharging. I doubt I'll have a problem up here, as the coldest it gets here during the winter is about 10F (-12C), and that's just during a cold snap. I may not want to take an electrically heated thin foldable-roofed car out in that weather anyway (yes, looking for a Targa roller as well). Also, Vancouver is the only Canadian city with an average winter temperature *above *32F (0C).

Thanks again for the tips, and for blazing that 80's 911 EV-ifying trail...


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## Duncan (Dec 8, 2008)

Joey said:


> Thanks for the feedback. If the motor does rub against the boxes, my solution will be to use stiffer racing/autocross motor mounts. Hopefully 3/4 of an inch is enough. .


With an electric motor stiffer mounts will be fine, - automotive engine mounts are soft so they don't transmit the IC engine - bangs - to the chassis especially at low revs

Electric motors do away with the problem


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## Joey (Oct 12, 2007)

I'm sure there are cheaper options, but I really like dealing with this company. There are stock, solid, and semi-solid mounts available. I'm thinking semi-solid, if needed:
http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_ENGmis_pg3.htm

northvan, thanks for the compliment, but I can't take credit for being the first. Check these guys out:
http://www.explodingdinosaurs.com/9electric/2009saltflats/index.html

http://evtv.projectooc.com/car_profile.php?id=68


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## Joey (Oct 12, 2007)

I finished the first battery box today. 3 more to go.


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## powerhouse (Apr 1, 2011)

Woah!!!

Awesome work Joey! Last time I checked the thread you were mounting the motor, a lot has gotten done since then.

paint all that steel before it gets all rusty and gross!


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## northvan (Aug 2, 2012)

Joey said:


> northvan, thanks for the compliment, but I can't take credit for being the first. Check these guys out:
> http://www.explodingdinosaurs.com/9electric/2009saltflats/index.html
> 
> http://evtv.projectooc.com/car_profile.php?id=68


Hey Joey, thanks for the links, and I am already familiary with those and have also found a few others; eg: HPEVs photo-blog on AC-izing their SC 911:

http://hpevs.com/porsche-photo-gallery1.htm

Having seen all the other doing similar projects, I still have to give you *mega-props* because up until your blog and DIYEC posts, the steps and challenges in converting an 80's 911 just wasn't out there. Your attention to detail is unmatched, and very appreciated!


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## Joey (Oct 12, 2007)

I figured out how I'm going to layout the front battery box. 28 cells will fit. I wanted to minimize the number of jumper cables I would have to make, because my cells came with braided cell jumpers. I managed to limit the total to two short cable connections. The area in the front near the bumper appears to have more room, but there are raised features that would lift the cells too high and make contact with the hood (bonnet?). The area on the right is where the stock battery lived. I won't need anything quite so large, but this are is raised a couple inches and has the same issue with the clearing the hood. If I was feeling ambitious I could grind out the battery platform and fit about 6 more cells, but I'm worried about adding too much weight up from, and this space aleady has all of the wiring for the 12 volt system conviently located. So the aux battery will go there, and I will see if I can fit anything else there.

I made a plywood template, and I will clamp up the rack parts to the template before welding.


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## Ziggythewiz (May 16, 2010)

That's a pretty innovative battery layout. I like how it ends at the beginning. 

Do your braided straps fit both side-side and end-end?


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## Joey (Oct 12, 2007)

Thanks. It took a few tries to get an acceptable configuration.

On the cells, the side-to-side distance between terminals is just a few milimeters different than the end-to-end length. The braided jumpers are slotted a bit to handle both positions. You can also form a slight upward bow into the braid to take up a few mm of slack.


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## PThompson509 (Jul 9, 2009)

I have those braided connectors, and they are great. However, here's a few tips for you: 
1) Make sure you have the proper length bolts for those connectors (including washer and BMS).
2) Make sure that the bolt will actually fit through the connector - some of the connectors holes aren't quite big enough.
3) give the connector a good sanding prior to putting on top of the battery.

Only #1 is absolutely essential - I lost a battery due to a short bolt causing the connector to bounce on the battery.

Cheers!


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## Joey (Oct 12, 2007)

After the base frame was completed, I made tabs that fit the gas tank mounting locations and tack welded them to the battery rack. Then I made the upper frame of the battery rack. The right front corner of the frame bolts into place and is designed to clamp the batteries securely in place. There will be a sheet metal base to support the cells, and open sides, as the cells in the trunk are fully protected from road splash. The top will be covered with an acrylic sheet to protect against voltage hazard, but still keep the cells visible - especially important if the car is ever displayed.


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## northvan (Aug 2, 2012)

Joey said:


> After the base frame was completed, I made tabs that fit the gas tank mounting locations and tack welded them to the battery rack. Then I made the upper frame of the battery rack.


Great work! I you sure you weren't a fabricator in another life?


I see you are using some interesting magnets to hold the pieces together before you tack them in. Where'd you get those toys? Handy-dandy.

Also, you sure have some nice clean angle and straight cuts there. Are you using one of those dry-cut saws? It doesn't look like you are using an abrasive chop saw by the look of it. Care to share the secret?

I am really enjoying the progress you are making, and it looks like soon you'll be back to wiring up the motor, controller, etc. 

Keep up the great work!


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## TEV (Nov 25, 2011)

northvan said:


> Great work! I you sure you weren't a fabricator in another life?
> 
> 
> I see you are using some interesting magnets to hold the pieces together before you tack them in. Where'd you get those toys? Handy-dandy.


Welding magnets at Harbor Freight :


http://www.harborfreight.com/4-3-4-quarter-inch-multipurpose-magnet-holder-1938.html


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## gary k (Aug 19, 2008)

Wish I got in on this earlier, just found it. Probably too late to provide any help but I did a couple 911's at www.zwheelz.com. They were lead acid but some stuff may still help. Email me at [email protected] if you have any questions. Good work and good luck!


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## Joey (Oct 12, 2007)

northvan said:


> Great work! I you sure you weren't a fabricator in another life?
> 
> 
> I see you are using some interesting magnets to hold the pieces together before you tack them in. Where'd you get those toys? Handy-dandy.
> ...


The magnets and the chop saw (12 inch abrasive wheel) came from harbor freight. I didn't think I would use the saw as much as I am, and would probably be better off to have gotten one with a better fence. I do wish I had a set of stronger magnets. I use clamps, speed square, and patience setting everything up before setting the first tack weld. The only trick is to spend time setting up the fence to get the correct angle and letting the saw do the work of cutting. If you push down too hard the blade will walk on you. It is easier to clean the raw metal before cutting it up. And you don't see the pile of material cut to almost the correct dimension.

I was out of the country for a while and should have some more progress to report soon. Thanks for your encouragement.


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## Joey (Oct 12, 2007)

gary k said:


> Wish I got in on this earlier, just found it. Probably too late to provide any help but I did a couple 911's at www.zwheelz.com. They were lead acid but some stuff may still help. Email me at [email protected] if you have any questions. Good work and good luck!


Gary, you have made some beautiful projects. I think you are right that the cleaner it looks = more time spent in layout. And you learn better arrangements the second time around. I'm worried that my engine bay will be a bit cramped because of my cell count. I have 8 cells out of 60 that don't yet have an obvious place to live.


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## Ziggythewiz (May 16, 2010)

Joey said:


> And you don't see the pile of material cut to almost the correct dimension.


Haha...if I could sell those...

For your homeless cells is there room for another layer of them somewhere?


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## Joey (Oct 12, 2007)

Ziggythewiz said:


> For your homeless cells is there room for another layer of them somewhere?


Yes, I will likely stack them in a second layer over the rear pack. It will make checking cell voltage more complicated, but the extra voltage and pack capacity will be worthwhile.


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## northvan (Aug 2, 2012)

Joey said:


> The magnets and the chop saw (12 inch abrasive wheel) came from harbor freight. I didn't think I would use the saw as much as I am, and would probably be better off to have gotten one with a better fence.


Thanks to you (and TEV) for the finger point to Harbor Freight. If anyone knows of stronger magnets, let me know -- thanks! In the meantime, I think I will order Milwaukee's dry-cut saw. The reviews are pretty good, and a bit more pricier than an abrasive saw, but cleaner cuts and a lot less flying sparks! The fence looks pretty decent, too.

Going to look at an Arena Red '82 Targa with a factory RS whale tail this weekend. Not everyone likes the look of a tail on a 911, but I am definitely one of 'em!

Look forward to more pics/posts of your recent activities. Keep it up!


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## Joey (Oct 12, 2007)

northvan said:


> Thanks to you (and TEV) for the finger point to Harbor Freight. If anyone knows of stronger magnets, let me know -- thanks! In the meantime, I think I will order Milwaukee's dry-cut saw. The reviews are pretty good, and a bit more pricier than an abrasive saw, but cleaner cuts and a lot less flying sparks! The fence looks pretty decent, too.
> 
> Going to look at an Arena Red '82 Targa with a factory RS whale tail this weekend. Not everyone likes the look of a tail on a 911, but I am definitely one of 'em!
> 
> Look forward to more pics/posts of your recent activities. Keep it up!


Nice looking saw. You get what you pay for most of the time. It will be quieter and throw less dust and spark than my abrasive chop saw. You won't regret it.

Once you get your donor you must document the build here or on a blog site. Good luck and hopefully the car is priced right and in good shape. Red was on my short list of colors (red, black, blue, bronze). The whale tail is bold and stock it looks good. I do like the duck bill too, but the clean look really gets me. I'm really glad I got a car with almost no issues. It will set you back in time, money, and risk if you get the wrong donor.


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## northvan (Aug 2, 2012)

Joey said:


> Nice looking saw. You get what you pay for most of the time. It will be quieter and throw less dust and spark than my abrasive chop saw. You won't regret it.


Thanks for pushing me in the right direction -- I ended up picking up the saw. Amazon delivered it the next day. I don't mind spending a few extra bucks on tools that help make my life easier when it comes to cutting the 1,042 pieces (error pile included) of angle iron that I will no doubt be diving into, judging from your detailed pics. 



Joey said:


> Once you get your donor you must document the build here or on a blog site. Good luck and hopefully the car is priced right and in good shape. Red was on my short list of colors (red, black, blue, bronze).


Alas, the guy who had the Arena Red '82 turned out to be a bit flakey, and there was a lot of daylight between what was advertised and what I saw in person. I am now looking at a black '88, with stock RS tail, but it is definitely on the high end, but could be offset if I can get a decent buck for the old ICE 3.2 Litre.

Did you have any luck selling your ICE components, and may I ask what kind of dollar you got for certain components? That may help me in my purchase, as the market for 1980's 911s in Vancouver is lacking, and nice clean potential rollers are well into the $20Ks and $30Ks here.




Joey said:


> The whale tail is bold and stock it looks good. I do like the duck bill too, but the clean look really gets me. I'm really glad I got a car with almost no issues. It will set you back in time, money, and risk if you get the wrong donor.


Great advice, thanks. I also don't want an after-market tail, as I have rarely seen those done well, and I also do like the duck bill spoiler, but I think that was available pre-SC, but could be wrong. Not that adding 700+ lbs of LiFePO4 cells is period correct either, mind you!

And I hear you on getting the right roller in the first place. If I just wanted to get a fixer-upper, I'd already have one by now as there's a lot of "junk" out there -- but I want to focus mybuild on the electric conversion aspect, and not worry about rebuilding, repainting, re-upholstering, etc. 

Looking forward to more reports on how your's is doing, as I always appreciate the great detail you provide. Thanks again.


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## Joey (Oct 12, 2007)

northvan said:


> Did you have any luck selling your ICE components, and may I ask what kind of dollar you got for certain components? That may help me in my purchase, as the market for 1980's 911s in Vancouver is lacking, and nice clean potential rollers are well into the $20Ks and $30Ks here.


I haven't listed my components yet. I wanted to get the electrical sorted before I start selling stuff. The brake lights and reverse switch will have to be re-wired because these signals were routed through the engine wire harness.


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## Joey (Oct 12, 2007)

Three battery boxes are completed –the two pictured here and the rack in the front. I have 8 cells left and they will be the most challenging to fit.


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## Joey (Oct 12, 2007)

And now it is time to make a decision. I cut a plywood template fitted above the motor and 2 of the battery boxes to help layout my components (the plywood will not be permanent). I need to fit 8 cells, the controller, fuses, contactor, and my water cooling system in the back. I think I've narrowed it down to two choices: controller horizontal, with 8 cells lined up in a single row near the back, or controller vertical with a 2x4 box of cells off to one side. It looks like the only place my radiator will fit is in the cavity of the rear bumper. I'm thinking horizontal looks better, but vertical leaves more room for other components. Any and all feedback or input is welcome.

Horizontal:








Vertical:


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## Ziggythewiz (May 16, 2010)

Horizontal looks cooler and will be easier to reach the terminals.


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## corbin (Apr 6, 2010)

Joey said:


> Three battery boxes are completed –the two pictured here and the rack in the front. I have 8 cells left and they will be the most challenging to fit.
> 
> View attachment 15682
> View attachment 15683
> View attachment 15684


Looks awesome! How are you planning on strapping the cells down, so they don’t pop up in the event of a roll over?

corbin


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## northvan (Aug 2, 2012)

That's a clever idea, using the plywood like that. Sure makes trial layout easy.

Perhaps a third (and better?) option is to go with the vertical, except split the pack 4 + 4, left and right, to either side of the controller at the back. This would also provide for better lateral balance for those tight and fast corners that 911s are known for, which is also why the horizontal layout also works as well. It could also provide room for other components.


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## Ziggythewiz (May 16, 2010)

northvan said:


> That's a clever idea, using the plywood like that. Sure makes trial layout easy.


That's what I did when I needed to redesign and drill my aluminum electronics mounting plate. The plywood was so quick and easy it's still there a year or two later


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## dladd (Jun 1, 2011)

Ziggythewiz said:


> Horizontal looks cooler and will be easier to reach the terminals.


I agree. But I know that on my build, fitting everything in trumps aesthetics so if you need the space, you need the space!


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## Joey (Oct 12, 2007)

corbin said:


> Looks awesome! How are you planning on strapping the cells down, so they don’t pop up in the event of a roll over?
> 
> corbin


So the reason you don't see primer on these boxes yet is because I'm still working out where I'm going to weld hold down points for covers. I also want to protect against electrical shock hazard when showing off the car (or roll over). It would also be nice if I could get service access to most areas of the car without removing all the components. Too many competing objectives! 

I'm going to line the boxes with 3 mm thick closed cell foam rubber to get the cells packed tightly in the boxes. Then I'm thinking of covering the tops of the boxes with something like 1/4" (6 mm) thick polycarbonate (insulating, transparent, and impact resistant). I will need to make sure that there are no big spans of polycarbonate without some metal frame crossing over to strengthen the cover. 

A major concern I have is poor scratch resistance of polycarbonate. Still figuring it out.


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## Joey (Oct 12, 2007)

northvan said:


> That's a clever idea, using the plywood like that. Sure makes trial layout easy.
> 
> Perhaps a third (and better?) option is to go with the vertical, except split the pack 4 + 4, left and right, to either side of the controller at the back. This would also provide for better lateral balance for those tight and fast corners that 911s are known for, which is also why the horizontal layout also works as well. It could also provide room for other components.


Yeah I got the plywood idea from this forum, but it was so long ago I don't remember where.

I've resisted the idea of splitting the last 8 cells and upping the number of boxes I have to make, but I will consider it: Better weight distribution (but we are only talking about 100 lbs), better clearance for the motor terminals, and there is still room for components.


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## Ziggythewiz (May 16, 2010)

I wouldn't split a pack for weight distribution unless you also need a crash dummy in the passenger seat when not otherwise occupied. Just push the cells to one side and put the DC-DC or charger thing on the other.


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## Joey (Oct 12, 2007)

In the end I chose this configuration,









because I needed space for the throttle linkage (just visible between the controller and cells), fuses, contactors. I did like the horizontal controller position, but I just couldn't get it to work. I didn't want to split the last battery box (8 cells) but I compromised by sliding them over to the passenger side.

I got started on making the last battery box. I'm not planning on lining the frame with sheet metal.


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## Joey (Oct 12, 2007)

The R&D manager of my group at work asked me to present my electric car project next month to the group (30-40 EEs, MEs and systems engineers). I'm pretty excited. I need to figure out how to make it somewhat relavent to the organization, so I'm thinking of covering the tradeoffs made in design (AC vs DC, range vs. power), modeling (simple excel models can be powerful development tools) , and reliability.


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## Ziggythewiz (May 16, 2010)

Sounds cool. I'm presenting for a Green Team event next month but the presentation I developed was designed for hackers so I'm sure I need to trim a lot of the real DIY details.


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## Joey (Oct 12, 2007)

I got the last rack cranked out. I still need to make a cross bar for the front to clamp the cells in the rack.


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## Mark C (Jun 25, 2010)

I know you must be getting excited at being close to the finish line on this build. It sure looks like it's going to be one sweet ride!


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## Joey (Oct 12, 2007)

Mark C said:


> I know you must be getting excited at being close to the finish line on this build. It sure looks like it's going to be one sweet ride!


Thanks. I am getting excited. It feels like I'm getting close to giving it a first drive, but there is a long way to go to get it done (if they ever are done).

To test drive it: Mount the controller, throttle/pot, wire up the batteries, charger, fuses and contactor, and 12 V system.

To finish: painting, battery covers, BMS, instramentation, heater, water cooling on the controller, air cooling on the motor.

But, completing the battery boxes feels like a big deal.


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## Joey (Oct 12, 2007)

I mounted the controller. The mounts are still only tack welded. I also need to grind away some of the mounting tab to make sure the rubber mounts don't contact any sharp edges. The wood mock up really helped to get the correct layout and geometery of the mount, because dang, that controller is heavy.


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## Joey (Oct 12, 2007)

I have 3 runs of 3/4" conduit - two on one side for battery cable, and one on the driver's side for signal and low power.

I used the heater ducts on each side of the car because they are well protected and no longer used now that the car is electric. There were sharp edges in the duct, so I wanted conduit. I couldn't get two runs in a single duct. So I ran another conduit in the channel tucked into the passenger side rocker panel that was used for the oil cooler that ran to the front wheel well. I had to punch a hole in the wheel well to mount a liquid tight fitting to get the cable into the front trunk.


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## Ziggythewiz (May 16, 2010)

Joey said:


> I have 3 runs of 3/4" conduit - two on one side for battery cable, and one on the driver's side for signal and low power.
> 
> I couldn't get two runs in a single duct.


So you can't fit 2 3/4 conduits through the heater channel..I wonder what the largest conduit is that would fit, and what size/quantity of cabling would fit through it.


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## Joey (Oct 12, 2007)

Ziggythewiz said:


> So you can't fit 2 3/4 conduits through the heater channel..I wonder what the largest conduit is that would fit, and what size/quantity of cabling would fit through it.


I might be able to get a 1" conduit to go, but my wire diamter is 0.62", so it wouldn't buy me much. The problem is a sharp 90 degree bend near the rear exit that really constricts the available space, and another softer bend at the front for the door. It seemed to work best feeding the front and pulling at the back. I could push past the front bend, and by the time you get to the back sharp corner, you can reach in with channel locks and wrestle the conduit out.


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## northvan (Aug 2, 2012)

Joey said:


> I have 3 runs of 3/4" conduit - two on one side for battery cable, and one on the driver's side for signal and low power.


More great work on the project -- you've been busy!

That's a great idea using a knockout punch to get through the wheel well -- thanks for the tip. I'm sure it is pretty tight quarters in there, and trying to use a power drill would be problematic.

Question on the conduit: Did you run a nylon string through it first, or now that you have the conduit in place you find you can easily chase your conductors (or fish-tape) through? Looks like you have a few tight bends there, so I'm not sure.

BTW: I'm still trying to chase down that illusive roller! Frustrating, but that's what I get for narrowing my 911 model year from '87 to '89. I test-drove a nice '88 Targa in Guards Red a few weekends ago, but it wasn't clean enough for my liking: faded paint, leaky Targa seals, and the seats and interior needed repair. Plus a high sticker because of a recent $10K+ top-end rebuild, which is kind of moot considering the whole EV conversion thing(!). I guess I am also still holding out for the black '88 I found out about a few months back that is still waiting to be de-winterized so I can drive over (2.5 hours away) and take a look at it. There's a sweet Arctic Silver '88 Targa on eBay with low miles, but a) it's eBay, and b) it's down in Houston, TX and I'm up in Vancouver, BC. I don't have a clue how easy/difficult it is to ship across the border, but assume it is far from hassle-free.

In the meantime, all I can do is take notes and admire the progress you are making. Keep it up!


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## Joey (Oct 12, 2007)

Hi Northvan,
The conduit fishing was something I had been dreading. It wasn't fun, but not as bad as I imagined. 

I pushed the fishtape from the front, tied on a string at the back, and pulled the string through to the front. Then at the back, I tied my string to the fishtape, and used the string to pull the fishtape from the back to the front. Then the conduit was duct taped to the fishtape at the front and pulled through. The whole reason for all of that is I could not feed fishtape or conduit from the back. Something would obstruct progress 2/3 of the way there. I also think that the conduit lubricant is a good thing. I haven't fished any of the wire inside the conduit yet, but with lube and fishtape it should be easy. The length is about 9 feet per run.

For the conduit penetration in the wheel well - you still have to open up a small hole with a drill to get the punch started, and the drill angle is about 30 degrees from being square. I started wth a center punch and a small bit and worked up in size. The hole was chewed up pretty good, but the punch left behind a perfect opening. Then, getting the nut onto the fitting is difficult. You have to reach your hand from the trunk into the wheel well cavity (between the wheel well and trunk is a cavivity with a three inch opening on the trunck side. You can see where the conduit is exiting in one of my earlier pictures), and if the nut drops I don't think you will get it back, and with my luck it would rattle and haunt me for the rest of the car's life. So I put a long coat hanger wire through the 90 degree conduit fitting, sticking out on both sides and well into the trunck space, and slid the nut over the wire. The wire would keep the nut from getting lost if I dropped it trying to get it threaded on the fitting.

Keep looking for your car. It will be great to see how your project progresses.


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## powerhouse (Apr 1, 2011)

Great job Joey!

Make sure you paint that steel so it doesnt rust!


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## powerhouse (Apr 1, 2011)

Also, when you run the wire through your conduit, put a bunch of talcum powder through the conduit first. This will help you slip the wire through! Otherwise it may get difficult with all the twists and turns.


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## Joey (Oct 12, 2007)

powerhouse said:


> Great job Joey!
> 
> Make sure you paint that steel so it doesnt rust!
> 
> Also, when you run the wire through your conduit, put a bunch of talcum powder through the conduit first. This will help you slip the wire through! Otherwise it may get difficult with all the twists and turns.


I am worried that it will rust, but so far so good. I want to weld everything first (I still need mounts for the polycarb lids), and then days of sanding, primer and 3 coats will go on.

I was planning on using wire lube. It is very slippery and evaporates after a while. It worked well to get the conduit through the ducts. The talcum poweder would probably work well too.


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## dladd (Jun 1, 2011)

Joey said:


> I am worried that it will rust, but so far so good. I want to weld everything first (I still need mounts for the polycarb lids), and then days of sanding, primer and 3 coats will go on.


I installed my motor mount and battery hold downs over a year ago and 10k miles ago, and haven't gotten around to painting them yet. They look fine, just a little surface rust for character.


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## northvan (Aug 2, 2012)

Joey said:


> For the conduit penetration in the wheel well - you still have to open up a small hole with a drill to get the punch started, and the drill angle is about 30 degrees from being square. I started wth a center punch and a small bit and worked up in size.


Good to know, and good idea on using the punch. I have a Milwaukee M12 drill to help out in these types of situations -- a great little compact torquer that I find I am grabbing more often than its big brother lately. I'm sure I will be getting a lot of use out of it on this project.



Joey said:


> ...if the nut drops I don't think you will get it back, and with my luck it would rattle and haunt me for the rest of the car's life. So I put a long coat hanger wire through the 90 degree conduit fitting, sticking out on both sides and well into the trunck space, and slid the nut over the wire. The wire would keep the nut from getting lost if I dropped it trying to get it threaded on the fitting.


And yet another great tip. I am also the type that would end up pulling off a quarter panel to get to stop a road rattle...


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## Joey (Oct 12, 2007)

I've been working on the 12 volt system. I traced out how to tap into the following signals for the controller: 12 volts switched by the ignition switch, brakes, reverse, and the tachometer. 








I connected power and the throttle pot to the controller and fired up the 12 volt system for the first time since the project was started 15 months ago. The controller came on when I switched the key to the run position and I was able to connect to the programming page through the ethernet port and a web browser. Programming the controller is very straight forward. The wiring is a mess, but I have split loom tubing to organize and protect the wires.








I also measured the current draw of each of the major components of the car at 13.5 volts: headlights (14 A high 10.7 A low), brake lights (3.9 A), power windows (6.8), turn signals (3.9), ventilation fan (8.5 high, 5 med, 2.8 low), off (27 mA), run (1.7 not sure what is drawing this current), Soliton1 in standby (0.5).

My battery fuses and auxilary relay arrived. I made a temperary plywood board to figure out the best arrangement for the components. The wood will be replaced with aluminum once I figure out how to fit everything. I still need to add bus bars and fuses for connecitng the heater, charger, and DC-DC to the pack, and 12 volt relays for the controller cooling loop.


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## Joey (Oct 12, 2007)

The tachometer is complete, installed and and tested. To make the parts, I decided to get a quick change tool post for my lathe. I wanted a better way to set the tool Z position than using shims. The real benefit was a more solid tool mount, and better quality on the finish of the turned parts. I ordered a PNP inductive proximity sensor, so I needed a pull down resistor on the tach signal. The pulldown provides a path to ground, to keep the tach signal from floating and possibly causing erroneous data, when the sensor switch is open. I have 1 mm clearance between the bolt head and the sensor. I also printed up some promo cards. I'm hoping to get a lot of interest whan I drive thing thing around town.


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## Joey (Oct 12, 2007)

The throttle position sensor, A.K.A the pot, is now installed. The throttle linkage is routed through a bellcrank on the transmission, so I decided to mount my throttle position sensor to the transmission adaptor plate to avoid throttle surging due to torque induced twisting of the transmission during acceleration. The adaptor plate has a cutout feature at the bolt mount that I used to key the throttle bracket.


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## powerhouse (Apr 1, 2011)

Do you mind me asking where you got that fitting for the end of the throttle cable? What is it called?


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## Joey (Oct 12, 2007)

powerhouse said:


> Do you mind me asking where you got that fitting for the end of the throttle cable? What is it called?


It is a ball joint rod end or ball joint linkage. I got it at Mcmaster Carr: http://www.mcmaster.com/#end-links/=mj7hwb

My linkage is threaded rod, but they also make them to crimp or compress on a stranded cable or wire rope.

The ball and socket come as one unit, already mated. Some disconnect for service (like the original shown seperate in the picture).


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## 1-ev.com (Nov 4, 2010)

Nice work !!!

Have you been on Pelican Parts forums? Lot of Porsche repair info there 

http://forums.pelicanparts.com/

-Y.


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## Joey (Oct 12, 2007)

1-ev.com said:


> Nice work !!!
> 
> Have you been on Pelican Parts forums? Lot of Porsche repair info there
> 
> ...


I do like Pelican Parts. I got most of my Porsche parts from them. They are not the cheapest (fair prices), but they have a lot of stocked parts and good technical information like you said.

I also have a build thread there:
http://forums.pelicanparts.com/pors...315-1983-911sc-conversion-electric-drive.html


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## Joey (Oct 12, 2007)

It's alive. I took the first electric drive today. Went a couple of miles around in my neighborhood. Pictures and video to follow soon (out of town family guests and some family events are vying for my time). Since my dad was in town and he helped the last two days getting me on the road, I gave him the first ride.

I have the motor voltage limited to 120 V and the motor current at 500 amps. Seems a little sluggish with these settings. Hoping it wakes up a bit as I ramp the controller settings. First issue to figure out - the front drivers side is too low. I need to crawl under and see whats happening. Might be a good excuse to get coil overs, but first I'll try to figure out what's happening.


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## northvan (Aug 2, 2012)

Joey said:


> It's alive. I took the first electric drive today.


Congrats!! How's that EV Grin?!

Your timing is pretty bizarre, almost like an EV 911 torch passing. I _just_ bought a 1989 Silver 911 Carrera Coupe earlier today. I literally swept out the garage yesterday, and parked it in there a few hours ago. I'm in 7th heaven, and I am sure you you can no doubt relate! Pics, blogs, etc. coming soon...

Have fun burning those Amp-Hours, and am looking forward to your pictures.


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## Joey (Oct 12, 2007)

northvan said:


> Congrats!! How's that EV Grin?!
> 
> Your timing is pretty bizarre, almost like an EV 911 torch passing. I _just_ bought a 1989 Silver 911 Carrera Coupe earlier today. I literally swept out the garage yesterday, and parked it in there a few hours ago. I'm in 7th heaven, and I am sure you you can no doubt relate! Pics, blogs, etc. coming soon...
> 
> Have fun burning those Amp-Hours, and am looking forward to your pictures.


Great news, northvan. Sounds like an awesome ride. Definately post links to your blog and photos. I will follow your progress.

Man, I'm loving the ride. It's only going to get better as I finish up all the loose ends and work out the bugs.


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## Joey (Oct 12, 2007)

Here is the video of the first ev test drive.


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## 1-ev.com (Nov 4, 2010)

Congrats!!! 

You have mentioned that Dr Side is low, You might have to corner balance and Align car with you inside.

Also, I see that you have 56 of CALB-180 and range around 80 miles, that coul be improved with "Ecopia" tires. I have 50 Calb-100, (all fit in the back) and my car makes 65 miles and if I roll to the traffic light, that makes 70 miles on charge. 

Also, there is 12KW charger out there, that what I plan to do next ...

http://www.emotorwerks.com/products...bled-and-tested-emw-smartcharge-12000-charger

http://www.diyelectriccar.com/forums/showthread.php?t=59210&highlight=12kw+charger

Contact me through my website or PM here if you have any Qs 

CheeRS,

-Y.


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## Joey (Oct 12, 2007)

1-ev.com said:


> Congrats!!!
> 
> You have mentioned that Dr Side is low, You might have to corner balance and Align car with you inside.


Yeah, when the driver is 5 to 10% of the total vehicle weight it makes sense to balance with the driver inside. As it is now, with no driver, the left front is lower by an inch. My backup plan is to install stiffer torsion bars, if I run out of adjustment range setting the preload on the existing bars.



1-ev.com said:


> Also, I see that you have 56 of CALB-180 and range around 80 miles, that coul be improved with "Ecopia" tires. I have 50 Calb-100, (all fit in the back) and my car makes 65 miles and if I roll to the traffic light, that makes 70 miles on charge.


I was planning 56 cells, but ended up with 60. My range estimates were done with an estimated 300 wh/mile. It will take some time to collect good range data as right now I'm having too much trouble keeping my right foot high enough above the accelerator pedal. I seem to be losing a lot a lot of amps just after the stop signs. But it sure is fun. And I still have the motor amps limited at 500 and motor voltage at 120 until I get a few more miles on the brushes. I did run the motor for 25 hours with a 12 volt battery until the old starter battery couldn't hold a charge.



1-ev.com said:


> Also, there is 12KW charger out there, that what I plan to do next ...
> 
> http://www.emotorwerks.com/products...bled-and-tested-emw-smartcharge-12000-charger
> 
> ...


I'll check it out.


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## rwaudio (May 22, 2008)

Joey said:


> Yeah, when the driver is 5 to 10% of the total vehicle weight it makes sense to balance with the driver inside. As it is now, with no driver, the left front is lower by an inch. My backup plan is to install stiffer torsion bars, if I run out of adjustment range setting the preload on the existing bars.
> 
> 
> I was planning 56 cells, but ended up with 60. My range estimates were done with an estimated 300 wh/mile. It will take some time to collect good range data as right now I'm having too much trouble keeping my right foot high enough above the accelerator pedal. I seem to be losing a lot a lot of amps just after the stop signs. But it sure is fun. And I still have the motor amps limited at 500 and motor voltage at 120 until I get a few more miles on the brushes. I did run the motor for 25 hours with a 12 volt battery until the old starter battery couldn't hold a charge.
> ...


You're gonna love 1000 motor amps!! The difference is very significant, as well as higher motor volts. My 11HV was transformed going from a 150v battery to 300v.

But now I'm in a similar suspension modification stage. I added 300lbs to the rear and removed 100lbs on the front vs stock. Time to learn more about torsion bars.


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## 1-ev.com (Nov 4, 2010)

there are plenty info about coil-overs and TB on Pelican, search for "coilovers" :
http://forums.pelicanparts.com/pors...le-wanted/658403-coilover-springs-160-lb.html

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/601507-2-25-coilover-spring.html

http://forums.pelicanparts.com/pors...1575-what-size-torsion-bars-best-hot-rod.html

OR such as my thread, where my car weights are + Rebel Racing and Elephant Racing pics:
http://forums.pelicanparts.com/porsche-911-technical-forum/635148-rear-coilovers-68-swb.html

my 2c -Y.


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## northvan (Aug 2, 2012)

1-ev.com said:


> You have mentioned that Dr Side is low, You might have to corner balance and Align car with you inside.


That's funny, as that is only the second time I have heard the term "corner balanced", and all within the last 3 days. When the seller was going over the '89 I just bought, he mentioned that the car had been "corner balanced", and I had no clue what he was talking about!


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## 1-ev.com (Nov 4, 2010)

Corner balance is Very important for race cars...


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## Joey (Oct 12, 2007)

1-ev.com said:


> there are plenty info about coil-overs and TB on Pelican, search for "coilovers" :
> http://forums.pelicanparts.com/pors...le-wanted/658403-coilover-springs-160-lb.html
> 
> http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/601507-2-25-coilover-spring.html
> ...


Thanks for the links. They helped a bunch. I've decided to upgrade the tension bars, and it basically comes down to price. The coilovers give you adjustability to dial in to the track at $1500, and it just didn't fit in with my indended purpose (i.e. my wife says I'm nearing the end of the budget for this project).

This is a good reference for calculating torsion spring rates on the 911 suspension: http://tech.rennlist.com/911/pdf/torsionbars.PDF

My stock torsion bars are 19 mm diameter in front and 24 mm in back. This is about 110 lb/in in front and 120 lb/in in back. Based on my before and after ride height measurements and the mass of the car, I estimate that I would need to use 20 mm/ 25 mm bars to get back to a stock ride height. In the front I'm 1.125 inches lower than stock with an extra 250 lbs from 28 batteries in the front, and a little more than 0.5 inches down in the back. 

A lot of people like to stiffen the suspension for better handling, and 21/28 or 22/30 are common setups depending on how much rattling you can tolerate. With my extra mass I would need to go about 1 mm bigger diameter than these common setups.

I think I will order a 22/29 mm setup. This is 60% more stiff in front and 100% more stiff in back. The explaination I found online (so it has to be true, right), is that the stiffer spring rate in back takes out some of the understeer that was induced with the relatively soft rear rates. The tail heavy weight distribution tends to oversteer, and the factory put soft rates in the rear to try and enhance street driving.

I'm not a suspension guy, so do your own research. I feel good in my calculations because they are so close to what is considered a good setup.


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## Joey (Oct 12, 2007)

Now that the car is consuming power, I need to complete the charging system. For the first couple charges I've been lugging the charger over to the car, and it will be nice to simply plug in. So I did what a lot of people have done. I mounted the charge plug in the filler tube for the old gas tank. The door opening is smaller than the base area where I want to install the plug, so I came up with a 3 piece aluminum base plate - basically a disk the size I want, cut down the middle so I could get it into the cavity, and a backing plate to hold the to pieces together. Then I mounted a twist lock plug (NEMA L6-30P) and ran my AC cord in conduit to the back of the car.


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## 1-ev.com (Nov 4, 2010)

you can buy j1772 connector from those guys: http://modularevpower.com/


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## corbin (Apr 6, 2010)

Joey said:


> Now that the car is consuming power, I need to complete the charging system. For the first couple charges I've been lugging the charger over to the car, and it will be nice to simply plug in. So I did what a lot of people have done. I mounted the charge plug in the filler tube for the old gas tank. The door opening is smaller than the base area where I want to install the plug, so I came up with a 3 piece aluminum base plate - basically a disk the size I want, cut down the middle so I could get it into the cavity, and a backing plate to hold the to pieces together. Then I mounted a twist lock plug (NEMA L6-30P) and ran my AC cord in conduit to the back of the car.
> 
> View attachment 16402
> View attachment 16403



what charger do you have? if it is drawing 30amps, be careful; the LS30 will not be adequate. Also, it becomes loose over time, and will eventually start to have higher resistance, and might melt. It happened to me: http://www.corbinstreehouse.com/blog/2012/04/plug-bug-burnt-plugs/

Use a J1772 inlet plug instead...you’ll be much happier! Sources of them:

http://code.google.com/p/open-evse/wiki/J1772CableSources


—corbin


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## northvan (Aug 2, 2012)

Joey said:


> I mounted the charge plug in the filler tube for the old gas tank. The door opening is smaller than the base area where I want to install the plug, so I came up with a 3 piece aluminum base plate - basically a disk the size I want, cut down the middle so I could get it into the cavity, and a backing plate to hold the to pieces together.


Nice work! And clever, I have to remember that tip. I was thinking about the fit just yesterday as I was pacing around the car (for the 118th time) with all the doors, hoods, hatches, etc. open.



Joey said:


> Then I mounted a twist lock plug (NEMA L6-30P) and ran my AC cord in conduit to the back of the car.


I see 1-ev has already suggested this, but I am planning to go with David Kerzel's J1772 and NEMA 5-15 setup here. I was also planning on fitting his nice billet aluminum J1772 inlet where the filler tube was, and then put the NEMA 5-15 in the "frunk", as I would probably only occasionally use it when opportunity charging. I am also going to attempt to build my own EVSE using his board here. Cheaper than buying a GE Wattstation!


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## Joey (Oct 12, 2007)

corbin said:


> what charger do you have? if it is drawing 30amps, be careful; the LS30 will not be adequate. Also, it becomes loose over time, and will eventually start to have higher resistance, and might melt. It happened to me: http://www.corbinstreehouse.com/blog/2012/04/plug-bug-burnt-plugs/
> 
> Use a J1772 inlet plug instead...you’ll be much happier! Sources of them:
> 
> ...


I'm using an Elcon 1500. It only draws 7 amps. I don't plan on using public charging stations (except maybe to get a free parking spot downtown). The problem with loosening connections is a concern, and while I hate the idea of dropping a few hundred on a connector, I guess it it is better than burning down my project. Thanks for the feedback everyone.


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## rwaudio (May 22, 2008)

Joey said:


> I'm using an Elcon 1500. It only draws 7 amps. I don't plan on using public charging stations (except maybe to get a free parking spot downtown). The problem with loosening connections is a concern, and while I hate the idea of dropping a few hundred on a connector, I guess it it is better than burning down my project. Thanks for the feedback everyone.


I'm using the L6-20, and have my doubts about its reliability as well. When I have the option I plug into the car first, then plug the cord into the wall.

I already have the aluminium J1772 socket for the car (not installed yet), I was planning to keep the L6-20 for plugging in at home or on the road, but I might try and get a cheap factory 115v J1772 plug from a leaf/volt etc for that purpose.

Did you make any decisions on suspension? I've been going through the same stuff for my 944 and just bought new torsion bars to give a bit more spring rate to the rear.


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## Joey (Oct 12, 2007)

1-EV sent me links to a Pelican Parts forum where common racing and autocross setups were discussed. I chose a street-able setup and calculated that I needed 1 mm larger diameter for my extra mass. I have 22 mm front bars and 29 mm rear bars on order. I'll post an update when I get them installed.


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## Joey (Oct 12, 2007)

Does anyone know anything about the vendor TucsonEV? They offer what appears to be a chennic J1772 receptacle ($90) and a plug ($155). Both are rated for 70 amps, if you use the proper gauge wire. http://www.tucsonev.com/


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## Hollie Maea (Dec 9, 2009)

Nice meeting you, Joey! Great build...looking forward to seeing it at EV celebration day.


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## Joey (Oct 12, 2007)

I went to the local electric car association meeting and met a few really nice people. The EV celebration day is coming up next month and it looks like I'll be able to have my car on display for the event.

I spent the day properly mounting the 12 volt battery and DC to DC. Loose with foam wedges was not an attractive look. Hooking up vacuum assist on the brakes is the goal for tomorrow.


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## corbin (Apr 6, 2010)

Joey said:


> I'm using an Elcon 1500. It only draws 7 amps. I don't plan on using public charging stations (except maybe to get a free parking spot downtown). The problem with loosening connections is a concern, and while I hate the idea of dropping a few hundred on a connector, I guess it it is better than burning down my project. Thanks for the feedback everyone.


You’ll probably be fine with the L6-30 in that case. 7 amps won’t hurt it.

I have used the adapter from Tucscon EV — worked great! I since switched over to my own J1772 control.

-corbin


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## Joey (Oct 12, 2007)

We'll see if charging at home is sufficient or if I will need to get a more powerful charger to top off away from home.

I hooked up my vacuum pump for the brake booster. I was pleased that there are no leaks in the system. My resevior is is 2.5 liters, or enough for 2-3 brake cycles. I did need to convert from 12 mm vacuum hose to 3/8" with a 1/2 inch to 3/8 inch reducing barbed hose coupler.


























I also secured my 12 volt battery and DC-DC with something a little better than foam wedges.


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## Joey (Oct 12, 2007)

The black project box in my previous post is the fuse, inductor, and diode filter circuit for the input of the DC-DC convertor. Here is the circuit I used:


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## Joey (Oct 12, 2007)

The stock torsion bars in the front suspension are 19 mm in diameter. A commonly recommended setup for autocross and street use is a 21 mm torsion bar. I did some calculations, to take into account the extra mass of my batteries, and determined that the 22 mm bars would be good in my car.
Installation wasn’t too bad. It took me about four hours, following the procedure on the Pelican Parts website: http://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/64-Torsion_Bars/64-Torsion_Bars.htm


The ride height was restored to factory specification. I took the car out for a test drive, and I must say the difference is astounding. The biggest issue was tire rub, and the new springs completely solved that problem. But surprisingly, the steering was much lighter, and more like I remember from when the car was still gasoline powered. I think the alignment and steering geometry must have been compromised with the lower position (-1.125 inches). Further, I can feel that the back end of the car moves around more than the front. There is a rolling feel or slow bounce that is distinctly occurring in the back of the car, coming out of turns or cresting rolling hills. I can’t wait to see how the car handles when I get the new rear springs installed.


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## 914Mike (May 12, 2013)

Slow bounce _should_ be taken care of by stiffening, but don't forget the shock absorbers. I'm running the adjustable Koni's on my 914, and they added that last little bit of control that was lacking with the stockish ones that were in there, even after changing out the springs. Stiffer bushings might be the next step after that, but I have not felt the need to go "full race" yet, I kind of like being able to survive road bumps...


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## northvan (Aug 2, 2012)

Joey said:


> The black project box in my previous post is the fuse, inductor, and diode filter circuit for the input of the DC-DC convertor. Here is the circuit I used:


Hey Joey, lookin' good! Coming up on that last mile...

I take it that the filter box you created below, is to house the inductor and diode (and fuse?) for this circuit, from what it looks like?










3 Q's:

- What part numbers and/or where did you pick up those components?

- Are you using a Chennic 400W 192V DC-DC converter?

- Is that a heat sink on the other side of the box? If so, is that for the diode? Picks up a bit of heat, does it?

Thanks, great work, and keep up the great posts!


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## Joey (Oct 12, 2007)

914Mike said:


> Slow bounce _should_ be taken care of by stiffening, but don't forget the shock absorbers. I'm running the adjustable Koni's on my 914, and they added that last little bit of control that was lacking with the stockish ones that were in there, even after changing out the springs. Stiffer bushings might be the next step after that, but I have not felt the need to go "full race" yet, I kind of like being able to survive road bumps...


Yeah, I'm hoping the springs do the trick. Thanks for the tip on the shocks. I've also been told that a stiffer roll/sway bar is a common upgrade. This isn't a race car build, so I hope I don't have to go there. The handling was fine before the conversion, so I think the springs will fix it. I'm going from 24 mm to 29 mm rear torsion bars.


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## Duncan (Dec 8, 2008)

Hi Guys
When you guys are changing torsion bars you are aware that the stiffness goes up with the fourth power of the bar diameter?
From 19mm to 22mm is an increase of nearly 80%
From 24mm to 29mm is more than doubling the spring rate

To retain the handling characteristics of the Porsche you should be increasing the spring rate the same amount as you are increasing the corner weights

So unless you have a tonne of lead on board....


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## Joey (Oct 12, 2007)

northvan said:


> Hey Joey, lookin' good! Coming up on that last mile...
> 
> I take it that the filter box you created below, is to house the inductor and diode (and fuse?) for this circuit, from what it looks like?
> 
> ...


The project box and heat sink were purchased at a local electronics surplus shop. It houses the filter circuit and fuse for the DC-DC input. The diode is mounted on the heat sink, and yes the heat sink is total overkill, but it was only $1, surplus. The diode will dissipate 0.83 V * 3 A = 2.5 watts, max. The diode drops 0.83 volts in forward bias, and the DC-DC only draws 3 amps on the input.

I ordered the ACME DC-DC from Evolve Electric. It is rated 600 watts, has an adjustable output voltage, and wide input voltage range. When I opened up the enclosure (to check that my mounting screws were not too long, of course) I noticed the silkscreen on the boards have “Meanwell” markings. The only issues with this unit so far: open enclosure vents so the mounting location must be dry and protected from any moisture, and once the battery reaches full charge, a relay inside the unit will cycle the output on and off every 3 seconds. I'm actually trying to figure out if anyone has any ideas for adding a bit of hysteresis, because I really don't need to float charge my 12 volt battery with 50 mV precision, and while there is very little switching current, I don’t like the idea of cycling he relay so frequently.

I purchased the parts at digikey.com and here is the Digikey PN and price list:

M8377-ND CHOKE RF HI CURR 100UH $7.17
497-6089-5-ND DIODE ULT FAST 400V ISOTOP 1 $27.93


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## Joey (Oct 12, 2007)

Duncan said:


> Hi Guys
> When you guys are changing torsion bars you are aware that the stiffness goes up with the fourth power of the bar diameter?
> From 19mm to 22mm is an increase of nearly 80%
> From 24mm to 29mm is more than doubling the spring rate
> ...


I would need to only go up in diameter by about 1 mm in front and back to get my ride height back to stock (with the same spring preload). The stock spring rates are only a little above 100 lbs/inch.

However, as long as I'm in there making changes, there is an opportunity to tinker. And I just can't resist.

There is a lot of discussion on the Pelican Parts and the Rennlist websites discussing common setups for 911 autocross and street usage. A 21/28 mm combo is a commonly recommended setup (some go even bigger). So I decided to use 22/29 because of my extra mass. This is not outside the envolope of common practice.

This is a much stiffer setup than stock. And as you pointed out, the percentage increase is not uniform front to rear. It seems that Porsche used softer springs in the rear to try to tame the tailheavy tendancy to oversteer. The increase in stiffness in the back is a move toward a more neutral balance. This article sums it up very well:
http://tech.rennlist.com/911/pdf/torsionbars.PDF


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## 914Mike (May 12, 2013)

Neutral balance can be a blast to drive, that's for sure! Until you lose the tail and do a 360. Rule one is, if you go into a corner too hot, don't try to slow down...

One thing I noticed that's a little on the un-safe side is the front battery pack has both ends of the string next to each other. That's considered bad form. Drop something metal in that spot and the full voltage of that portion of your pack will weld those two terminals together until the mid pack fuse blows. (You do have a fuse in there, right?)

It would be safer to have another jumper or two somewhere to get the most positive and most negative terminals of that block of cells further apart.


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## Duncan (Dec 8, 2008)

Just a thought about spring rates
You guys are in the USA?
Do Porsche have USA spec cars with softer spring?
The only Porsches I have been in (in the UK) had quite sporty suspension
would not have wanted to stiffen them up much

_if you go into a corner too hot, don't try to slow down..._

That was the rule for a fast mini as well - don't even think about lifting off


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## Joey (Oct 12, 2007)

Duncan said:


> Just a thought about spring rates
> You guys are in the USA?
> Do Porsche have USA spec cars with softer spring?
> The only Porsches I have been in (in the UK) had quite sporty suspension
> ...


You may be on to something. The US ride height was higher to comply with bumper height regulations. I'm not sure if the spring rates were different. I know most American targeted rides are soft and squishy. The most agressive suspension I've ridden in was on a friend's BMW M3 that was set up quite agressively for track. If you ran over a cigarette butt, you felt it. It was too much for me on the street. The ride on the 911 is not harsh at all with the stiffer springs, even by my wife's standards. I'm really happy with the improved handling, it is quite a big improvement. I'm going to try and get the rear springs in this weekend.


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## 914Mike (May 12, 2013)

*Re: Terminal Voltages*

Here is what the CALB Manual says on page 7 #8:

"Within large amount of cells layout circumstance, the condition of terminal voltage between battery modules which exceed safety voltage connection method shall be avoided, in case of electric shock during construction and overhauling."

Translated, that means keeping the voltage between adjacent terminals to a minimum. Fusing the block of cells somewhere near the middle of the string is also recommended. so that a short will pop that fuse and not meltdown however many batteries are shorted. 

I always try to have one cable leaving the block from one side and the other from the opposite side.

Like this, only three jumpers, one of which is a fuse:


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## Joey (Oct 12, 2007)

*Re: Terminal Voltages*



914Mike said:


> Here is what the CALB Manual says on page 7 #8:
> 
> "Within large amount of cells layout circumstance, the condition of terminal voltage between battery modules which exceed safety voltage connection method shall be avoided, in case of electric shock during construction and overhauling."
> 
> ...


Hi 914Mike. Thanks for your feedback. I probably could have optimized the cell layout a little better. I do have 2 fuses in the string, and one of them is very near center of the pack. They are the big, expensive 400 amp slow blow fuses.

Couple issues:
It would be difficult to mount a fuse above the cells. I would need some structure to mount the fuse base.

The jumpers that cross the cells at odd angles would make BMS installation more difficult.

I'm not so worried about issues during installation and maintanence. I use insulated tools, and work carefully. Sections of cells are built up into relatively low voltage blocks, and only at the end is the full pack voltage connected.

There is enough space between cell terminals, that a cable terminal cannot short out by twisting, given the failure mode of a loose cell connection bolt.

The most likely failure mode I have to worry about is a crow bar situation across unfused cells (a short across fused cells would be no picnic either). That is why I'm planning to add lexan covers, soon.


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## 914Mike (May 12, 2013)

*Re: HV Fuses*

I started out thinking the fuse should be feeding the contactor, just as you have it drawn, but decided that it belonged in the center of the block. I had to run it out from my rack, mounted next to it. The one bent jumper there in the corner would be a good spot if there is room...


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## Joey (Oct 12, 2007)

*Re: HV Fuses*

Rear torsion bars are in. Car test driven. Driver very happy, but tired. I've been working late into the night the last couple weeks, trying to get the car ready for EV celebration day in Portland on July 13. I still need to get the ride height adjusted. I'm within 0.75 inches. The front is as easy as turning an ajustment bolt . The back is a set of bolts for a small adjustment, but it looks like I need to move the radius arm 1 tooth on the torsion bar spline (remove tire, remove radius arm, test, repeat until it is correct). Oh well. It will be worth it in the end. 

The torsion bar has a clever feature. One end has 44 splines (8.2 degrees per tooth) and the other has 40 splines (9 degrees per tooth). What this means is, you can get 0.8 degree adjustment by moving the bar 1 tooth in one direction on the inner bar, and the radius arm one tooth in the other direction on the outer bar (9-8.2 = 0.8).


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## Joey (Oct 12, 2007)

914Mike said:


> Slow bounce _should_ be taken care of by stiffening, but don't forget the shock absorbers. I'm running the adjustable Koni's on my 914, and they added that last little bit of control that was lacking with the stockish ones that were in there, even after changing out the springs. Stiffer bushings might be the next step after that, but I have not felt the need to go "full race" yet, I kind of like being able to survive road bumps...


The rear springs did the trick. Ride height adjusted tonight. I am very happy. Here are a few pictures.



























This is not a bolt for when you drill the hole slightly off center: 







The offset collar adjusts wheel alignment as the bolt is twisted. Because I don't know how to align the car without an alignment rack (or with a rack for that matter), I marked the previous bolt alignment with a paint pen (gold arrow) so that I could get the alignment back after installing the new torsion rods.


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## tylerwatts (Feb 9, 2012)

Nice Joey, now how about a pic of your beast poised to shred rubber?!


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## Duncan (Dec 8, 2008)

_Because I don't know how to align the car without an alignment rack

_You can do a decent job with some pieces of wood string and a tape measure
Being paranoid and having seen some professional systems that were badly setup I would always do a manual check

Its easy -
Clamp a couple of straight bits of wood to your wheels doesn't need to be a strong clamp some elastic trhough the wheels is good
Rest them on something so they are about the middle of the wheels in height - 
Then measure the wood to see how parallel they are

The reason you want to use lengths of wood is to move the measurement area in front of or behind the car so you can get a straight run with the tape

Another really easy check once you have driven for a few miles
Rub your hand across your tires in and out perpendicular to the direction of motion
The* in* should feel the same as the *out*
It is amazingly sensitive - you are detecting the tire tread blocks wearing incorrectly
If the tracking is out the individual clocks will wear at an angle and you will feel it like moving your thumb along a hacksaw blade


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## Joey (Oct 12, 2007)

tylerwatts said:


> Nice Joey, now how about a pic of your beast poised to shred rubber?!


How is this?


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## Joey (Oct 12, 2007)

Duncan said:


> _Because I don't know how to align the car without an alignment rack_
> 
> You can do a decent job with some pieces of wood string and a tape measure
> Being paranoid and having seen some professional systems that were badly setup I would always do a manual check
> ...


Thanks. That makes sense. It would be easy enough to use the wood to check toe. 

It might have to be a modified piece of wood to check camber, because:

Vertically it will be more diffficult to clear the wheel arches
The the tire protrudes more than the rim and because the tire is fatter at the contact patch, I can't just reference the tire.
I'll try the touch method too. Right now everything is uniformly smooth.


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## northvan (Aug 2, 2012)

Joey said:


> How is this?


A sweet looking gilded ride, made even sweeter by the EV-metamorphisis.

And here's what it will look like in silver...









Thanks for posting all of the detail on how to adjust the ride height, and for all of the research you've done on sizing the torsion bars, and how they get installed. As someone who hasn't really gotten their hands dirty since monkey-wrenching my cars about 25-30 years ago, your postings are solid gold. As I am at the start of the journey that you are basically finishing, it does look make the task ahead a lot less daunting. Thanks again!


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## tylerwatts (Feb 9, 2012)

Joey that's a handsome car! Always loved that era Porsche. Congrats sir! How's the car performing?


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## Duncan (Dec 8, 2008)

_It might have to be a modified piece of wood to check camber,_

You need a "Special tool" 

The only thing that is difficult to check is Castor (AKA King Pin Inclination) and that is very insensitive

It takes a lot of change of castor to make an appreciable difference


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## northvan (Aug 2, 2012)

Joey said:


> I hooked up my vacuum pump for the brake booster. I was pleased that there are no leaks in the system. My resevior is is 2.5 liters, or enough for 2-3 brake cycles. I did need to convert from 12 mm vacuum hose to 3/8" with a 1/2 inch to 3/8 inch reducing barbed hose coupler.


I ended up buying the VBS-VPDP-EV-12 system plus their reservoir tank from Evolve Electrics. It just arrived today, and it looks like it will do the trick. And thanks to your pictures/diagrams, I know pretty much how to plug 'er in. I'll let you know how noisy/quiet it is once I get it installed. So... let you know in about a year or so...

BTW: If any Canadians are reading this, Evolve is a great place to buy components like this, but you do need to phone them as they don't handle Canadian sales and shipping online. They shipped quickly, and the price was right. I only got dinged $10 brokerage fee from FedEx, and there was only GST (no duty). They even threw in a free copy of "Charged" magazine (nice touch).


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## Joey (Oct 12, 2007)

tylerwatts said:


> Joey that's a handsome car! Always loved that era Porsche. Congrats sir! How's the car performing?


The car is performing really well. I'm still trying to take it easy on the brushes. I've got 400 electric miles logged. The controller max current is now up to 700 amps. I'm increasing the performance settings slowly. 

I've been starting in 2nd gear, and while the torque off the line doesn't spin the tires at these settings and with 9 inches of rubber on the rear wheels, the cars in the rear view get small pretty quickly. It does jump pretty good in first, but I'm up to 5000 rpm so quickly, there is almost no point. So while the torque is a little on the low side off the line, anywhere from 10 to 70 mph, the full torque kicks in instantly, and the acceleration is more than I could have hoped for. As RWAudio said, "If you like 500 amps, you're going to love 1000 amps." I'm shifting into 3rd just above 4000 RPM at 45 MPH. I like to keep it cruising above 3000 RPM.

The 915 is not known as the smoothest shifting gear box (I'm jealous of NorthVan's G50). I have to pause just a bit to allow the synchros to do their thing on shifts. Not a big deal, just something you learn to do to keep the transmission happy.

I found that off the line I hit 700 amps, with the motor voltage around 114 V. I expect the voltage to go up as I move the controller limit up to 1000 amps. But I'm not sure if I will ever see conditions where the 170 V and 1000 A limits are observed simulataneously. The practical implication is I may have oversized my battery pack, and the extra mass is a major negative. The 192 volt pack was intended to sag to 170 volts under a 1000 amp load. On the plus side, I am stressing the pack less with lower pack current, and the extra range is nice.


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## pinetree (Jun 10, 2010)

Porsche's lightest production model was the 914-- about 2000 lb; way better than the 944; the 911/912 lies in between. No wonder a good number have been converted. But no rear jump seats. Can be had really cheap compared to 911, and low weight makes battery cost much lower than in a 944. There's a 914EV-conversion yahoo-group, too; give them a look.


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## DavidDymaxion (Dec 1, 2008)

Did you test the car without vacuum assist? Just curious how badly needed vacuum would be.



Joey said:


> We'll see if charging at home is sufficient or if I will need to get a more powerful charger to top off away from home.
> 
> I hooked up my vacuum pump for the brake booster. I was pleased that there are no leaks in the system. My resevior is is 2.5 liters, or enough for 2-3 brake cycles. I did need to convert from 12 mm vacuum hose to 3/8" with a 1/2 inch to 3/8 inch reducing barbed hose coupler.
> View attachment 16419
> ...


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## DavidDymaxion (Dec 1, 2008)

The 911 motor is around 200 lbs heavier than the 914 motor, plus you get remove more oil system stuff. That makes the 911 glider about 10% heavier than a 914, so that's not too bad a compromise. Both cars are pretty good about going fast on low horsepower.


pinetree said:


> Porsche's lightest production model was the 914-- about 2000 lb; way better than the 944; the 911/912 lies in between. No wonder a good number have been converted. But no rear jump seats. Can be had really cheap compared to 911, and low weight makes battery cost much lower than in a 944. There's a 914EV-conversion yahoo-group, too; give them a look.


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## Joey (Oct 12, 2007)

DavidDymaxion said:


> Did you test the car without vacuum assist? Just curious how badly needed vacuum would be.


I did drive a few weeks with no assist. I loved the feel and feedback of manual brakes and manual steering, but above 40 MPH it did not feel safe.
It just would take too much foot pressure to stop quickly in an emergency at speed.


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## DavidDymaxion (Dec 1, 2008)

Good to know. My old electric 911 seems fine without vacuum assist, but I have only driven it on the street at town speeds and not the highway. I might try grabbier racing pads, also.


Joey said:


> I did drive a few weeks with no assist. I loved the feel and feedback of manual brakes and manual steering, but above 40 MPH it did not feel safe.
> It just would take too much foot pressure to stop quickly in an emergency at speed.


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## northvan (Aug 2, 2012)

Joey said:


> I did drive a few weeks with no assist. I loved the feel and feedback of manual brakes and manual steering, but above 40 MPH it did not feel safe.
> It just would take too much foot pressure to stop quickly in an emergency at speed.


That's pretty interesting. I wonder if, because I am going to be going with an AC solution, if the regen combined with a brake transducer will somewhat negate the need for an electric vaccum assist pump -- he wondered out loud. I know that someone local who converted a Boxter has a switch to disable his vacuum assist, which he only turns on for the wife. 

Back in the '80s, I had a short-box Chevy pickup with manual brakes and steering, and it sure gave me a good full body workout, especially coming to a quick stop, and in tight parking spaces. Driving the 911, at least the manual steering part, is a piece o' cake compared to the ol' truck.


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## PThompson509 (Jul 9, 2009)

When I had regen working with my 914, the brakes were *almost* as good as the ones in my wife's 911. Quite impressive! I still can't beat her 0-100mph yet.


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## Joey (Oct 12, 2007)

I mounted the charger into the car. I also added a cooling fan to blow across the heatsink. The fins were getting hot to the touch. This is the circuit I use to turn the fan on and off when the charger is plugged in. The Elcon can only output 50 mA, so I made the relay driver. The normally closed contacts of the relay could be used to interlock the main contactor, preventing the controller from turning on if the AC cord is plugged in. Others have pointed out that the interlock would not provide protection if there was an AC outage, and a contact switch on the plug might be a better option.


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## Hollie Maea (Dec 9, 2009)

Looking good! Will we get to see this thing tomorrow evening, or do we have to wait until Saturday?


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## 914Mike (May 12, 2013)

Joey said:


> Others have pointed out that the interlock would not provide protection if there was an AC outage, and a contact switch on the plug might be a better option.


 I used an alarm window/door switch. It's just a reed relay in a plastic housing with some screw terminals molded in, along with some mounting holes. NO or NC until they are close to a magnet. The matching magnet usually comes with. 

I put it on my charge door so that the magnet only gets close enough to flip the relay if it's latched. Took a little fiddling to find the right distance, at first it was too close and it would switch if the door just looked closed but was not latched.

None of this will protect against a brake "failure" either, which is why I prefer a non twist-lock plug that will simply pull out instead of ripping the plug out if the car happens to roll down the driveway. One guy on the EVDL described his system which uses the same sort of plug/sockets designed to power Ambulances. They can drive away without disconnecting the power, even under full AC load and not get even a spark...


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## Joey (Oct 12, 2007)

Hollie Maea said:


> Looking good! Will we get to see this thing tomorrow evening, or do we have to wait until Saturday?


Thanks. I plan on bringing it tomorrow to the OEVA meeting in Portland.



914Mike said:


> I used an alarm window/door switch. It's just a reed relay in a plastic housing with some screw terminals molded in, along with some mounting holes. NO or NC until they are close to a magnet. The matching magnet usually comes with.
> 
> I put it on my charge door so that the magnet only gets close enough to flip the relay if it's latched. Took a little fiddling to find the right distance, at first it was too close and it would switch if the door just looked closed but was not latched.
> 
> None of this will protect against a brake "failure" either, which is why I prefer a non twist-lock plug that will simply pull out instead of ripping the plug out if the car happens to roll down the driveway. One guy on the EVDL described his system which uses the same sort of plug/sockets designed to power Ambulances. They can drive away without disconnecting the power, even under full AC load and not get even a spark...


Good info there. Luckily my parking spot is level and the roll away issue is not a problem. You have to pick the level of safety interlock you are comfortable using.


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## 914Mike (May 12, 2013)

Yes, that's one reason to not put a J1772 socket in, it latches and could cause damage because of that.

Something to be said in favor of the OEM approach that won't let you move the "gear selector" out of the park position with the charge cord plugged in.

Have yet to see a solution like that for a manual trans car though.


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## njloof (Nov 21, 2011)

914Mike said:


> Yes, that's one reason to not put a J1772 socket in, it latches and could cause damage because of that.
> 
> Something to be said in favor of the OEM approach that won't let you move the "gear selector" out of the park position with the charge cord plugged in.
> 
> Have yet to see a solution like that for a manual trans car though.


I'm pulling the proximity signal forward to connect to the controller's drive disable. But yeah, there's nothing to stop me from putting it in neutral and rolling away with the plug in.


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## Ziggythewiz (May 16, 2010)

914Mike said:


> Something to be said in favor of the OEM approach that won't let you move the "gear selector" out of the park position with the charge cord plugged in.
> 
> Have yet to see a solution like that for a manual trans car though.


Not hard to put a lockout on the plug. You could shift all you want but no juice would flow while the plug is connected.


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## northvan (Aug 2, 2012)

Joey said:


> I mounted the charger into the car. I also added a cooling fan to blow across the heatsink. The fins were getting hot to the touch.


Hey, lookin' good, Joey! I like the blue LED PC fans, and was also thinking of adding those strings of blue LEDs around the edges of the battery boxes, tied to the deck-lid courtesy light.

So far, I am leaning towards the Elcon 4000, 168V (I have 48 cells), so no doubt it will be getting hot, too -- and your idea to mount a fan (or two) is a great idea.



Joey said:


> This is the circuit I use to turn the fan on and off when the charger is plugged in. The Elcon can only output 50 mA, so I made the relay driver.


I assume this may also work for the 4000W version, so another great circuit to "borrow".


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## Joey (Oct 12, 2007)

I may have found the cure for lead foot syndrome. Maybe only a partial treatment. It is too much fun playing the game where you make the cars in the rear view mirror very small. I installed a voltmeter in the car. 

I have been running without instrumentation (bad idea). Popping the hood every time to check pack voltage and keeping my trips short is a real drag. I have a BMS sitting in a box in the garage, that I plan on installing once I remove all of the components and paint all of my fabricated metal parts. I honestly did not think I would have been operating the car this long in such an unfinished state, but the weather is really nice, the car is really fun to drive, I've scheduled the car to to appear in a few electric car shows, and I'm sort of dreading all the sanding and paint prep that is in my near furure. 

Back to the voltmeter. When you see the voltage sag in real time, and the pack voltage never fully recovers back to the starting value as the amps get sucked out of the pack, your right foot doesn't sit quite as low in Z as it does without instrumentation. Ignorance was bliss (unless you blow up a few cells, then ignorance is expensive).

Here is a log graph of a five mile trip I make regularly from work to home. I was consuming 350 Wh/mile in my lead foot era (consistently getting 345 to 355 Wh/mile), and now I'm getting a voltmeter aided 280 Wh/mile consumption. If I can resist the urge to have any fun, then the car can make 123 miles in a charge, or 100 miles at an 80% dod. But you know, after driving the car for a few weeks, I think I'd rather trade some range for fun almost any day.


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## Joey (Oct 12, 2007)

There have been lots of requests for another video. 

A few notes on improvements from the last video: There is less controller noise with the Soliton 1 in quiet mode. There is less road noise when you aren't dragging bits of the car on the road (heater flap mechanical pull cables). 

The kids in the back seat don't have an EV grin. I don't know what's up with them, I'm quite pleased with the car.


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## MN Driver (Sep 29, 2009)

Cool video, nice to see a good scenic electric drive.
The first 50 seconds definitely weren't quiet mode. 

Great job with your conversion.


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## Joey (Oct 12, 2007)

MN Driver said:


> Cool video, nice to see a good scenic electric drive.
> The first 50 seconds definitely weren't quiet mode.
> 
> Great job with your conversion.


Thanks. The car is a lot of fun.

Yesterday I logged 1,000 EV miles. So I bumped the controller from 700 amps to 1000. The difference is significant and amazing. At 700 amps, the motor voltage was around 114, for about 80 kW peak or a little more than 100 horsepower. Stock the car had 170 HP. But with the wide and flat torque curve, the car seemed to be on par with the stock acceleration.

At 890 amps, the motor voltage is 135 volts for 120 kW or 160 HP. I was in traffic and didn't capture a log file with 1000 amps, yet. The car is leaping off the line. I'm very pleased. The 0 to 60 MPH time is in the ball park of 7 or 8 seconds. Stock was supposedly 7 seconds. The first 40 mph is much faster than 40 to 60 mph. I have no concept what the White Zombie's 0-60 in 1.8 seconds must feel like. My car is by no means a race car, but for a road going sports car with a 100 mile range**, the performance has exceeded all of my expectations for the project.

**I don't know if I could ever achieve a 100 mile run. I just can't keep my foot high enough on the pedal for a full 100 miles. Over a five mile run I averaged 280 Wh/mile. My 34.5 kWh pack should have a range at 80% d.o.d. of 98 miles. The pack sized to get long range is heavy (750 lbs) and not optimal for fast acceleration, but that was a design choice.


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## Joey (Oct 12, 2007)

I'm back from a family vacation, so it is time to get back to working on the electric car. I can’t say enough good things about Rothsport Racing, an automotive shop in Tualatin, Oregon specializing in Porsche. I took the car in to get an alignment after switching to stiffer torsion bars. The shop was great. There were six car up on lifts, a machine shop, and several 911s, some set up for full racing. I was a little apprehensive bringing an electric Porsche to a Porsche racing shop, because I wasn’t sure how the car would be received. Jeff Gamroth, the proprietor, introduced himself, and after a quick show and tell, we took the car for a quick spin down the street. He liked the torque, but said the lack of engine noise was strange. We then pulled the car around into the shop bay, and five mechanics immediately flocked to the car. The silent entrance certainly got everyone’s attention. “Was that you guys? We heard a strange sound going down the street.” Everyone seemed OK with the electric modifications, or at least kept their horror in check. There were lots of questions about the batteries, range, safety advice to avoid electrocution while working on the car, and for the first time someone noticed my tachometer sensor mounted on the electric motor tail shaft. One of the guys joked, “At least you didn’t bolt on an LS2,” a jab at the practice of installing a Chevy Corvette V8 motor in a 911. 

The alignment did wonders for the handling of the car. The steering is lighter and more precise. As a bonus, they also put the car on a scale. My conversion tips the scale at 3158 pounds (1432 kg), and is 408 pounds (185 kg) over stock. The front is heavier by 231 lbs and the back 177 lbs, shifting the front/back weight distribution from 38/62 to 40/60. The corner balance is within 40 lbs.


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## Joey (Oct 12, 2007)

I forgot to mention the best part. The shop owner accepted a trade of my ice parts (gas tank, oil tank, oil cooling loop) as payment for the work. Awesome.


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## rwaudio (May 22, 2008)

That's a good response, I've been contemplating taking my 944 to the local Porsche speed shop, or just a good alignment shop. I'd like to get my new torsion bars installed at the same time, I just can't do it in a single garage.

Have you worked up to full current yet? I bet the car is a lot of fun!


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## Joey (Oct 12, 2007)

rwaudio said:


> That's a good response, I've been contemplating taking my 944 to the local Porsche speed shop, or just a good alignment shop. I'd like to get my new torsion bars installed at the same time, I just can't do it in a single garage.
> 
> Have you worked up to full current yet? I bet the car is a lot of fun!


The shop owner became a lot more enthusiastic after I let him drive the car down the street. The Porsche shop would be better in my opinion because they are probably more familiar with the car, and can make recommendations on improvements. For me they recommended tie rod ends from the turbo version, anti-sway (or anti-roll) bar in the front from an '86 carrera, and the Europe specified C4 HID headlights to replace the "junk" sealed beams they put into US cars.

Yes, I'm up to full current, and the difference from 700 to 1000 amps was incredible. I timed a 6 second 0-60 MPH time. That's all the faster I'm planning to push it. I'm very happy with the car. The goal, with all of the batteries I stuffed in, was to match stock performance, and get a respectable range. For more speed, I think I would need to upgrade my 915 transmission to a 930 (from the turbo) and shed some battery weight, and add a second motor, but that is not the plan.


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## northvan (Aug 2, 2012)

Joey said:


> I was a little apprehensive bringing an electric Porsche to a Porsche racing shop, because I wasn’t sure how the car would be received. ... Everyone seemed OK with the electric modifications, or at least kept their horror in check.


You've nailed my fear down right there. Almost every "car" guy I've talked to so far is completely horrified at what I'm doing. I did get a lot of good advice from a local Porsche service shop on how to pick a good used '80s 911, but I never did let on (yet) on why I was buying it. I think, though, that you had the perfect approach: First, do an excellent job in your conversion and remain as "faithful" to the original HP/torque/handling of the original car, and then and only then show it off to the die-hards. I believe that will be my approach, too.




Joey said:


> The alignment did wonders for the handling of the car. The steering is lighter and more precise. As a bonus, they also put the car on a scale. My conversion tips the scale at 3158 pounds (1432 kg), and is 408 pounds (185 kg) over stock. The front is heavier by 231 lbs and the back 177 lbs, shifting the front/back weight distribution from 38/62 to 40/60.


That is really good data to know! I belive my '89 weighs 2756 lbs, although I would love to get it weighed. By your math, you were pretty much that weight at stock (3158-408=2750), so I'm surprised at that, because I thought the wieght went up a bit with the 3.2L plus the G50 transmission. If that's right, and I will be running 12 Calb CA180FI cells less than you, then I should be adding 408lbs -12 x 12.4lbs = 260lbs over stock. Mind you, there's other differences in tehre like I'll be running two controllers, and a but heavier motor and charger -- so we'll call it 300lbs over stock. Not a bad guestimate.

I'm still trying to figure out where I can get weighed before the conversoin, because it would be nice to also know how much over stock I end up when done. 




Joey said:


> The corner balance is within 40 lbs.


Dumb question -- what does that mean? Does that mean the side-to-side balance (so left side is +/- 40 lbs with right side, for both the front and back of the car?), as opposed to front/back weight distribution? Also, is that assuming just the driver is in the car?


Anyway, great update -- and glad it is pretty close to near stock handling and performance now. You must be pretty damned happy!


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## TEV (Nov 25, 2011)

northvan said:


> I'm still trying to figure out where I can get weighed before the conversoin, because it would be nice to also know how much over stock I end up when done.


In US any place selling landscaping supplies will have a scale ,you will be able to get the total, front and rear weight only, but should be good enough.
PS they don't even charged me . I have to go again to get an after conversion weight.


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## rwaudio (May 22, 2008)

northvan said:


> I'm still trying to figure out where I can get weighed before the conversoin, because it would be nice to also know how much over stock I end up when done.


I'm not sure about BC, but here in AB there are quite a few scales just on the outskirts of many cities for big trucks to self weight before they hit a mandatory scale or whatever. This one happens to be 10 mins away so I go weigh it after major changes. Easy to do front/total/rear. (This is total weight in kg for those wondering).


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## northvan (Aug 2, 2012)

rwaudio said:


> I'm not sure about BC, but here in AB there are quite a few scales just on the outskirts of many cities for big trucks to self weight before they hit a mandatory scale or whatever. This one happens to be 10 mins away so I go weigh it after major changes. Easy to do front/total/rear. (This is total weight in kg for those wondering).


Hey rwaudio, thanks for the tip. Unfortunately, I researched this awhile ago, and the trucks here have these transponders where they get weighed:

http://www.th.gov.bc.ca/weigh2GoBC/index.html

There are also some inspection stations that have scales, but they apparently aren't unattended, and quite a drive from where I live.

I think I may look at two suggestions: landscape materials places, and also garbage transfer stations -- although both of those I am hesitant at driving my 911 to!


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## Joey (Oct 12, 2007)

northvan said:


> I belive my '89 weighs 2756 lbs, although I would love to get it weighed. By your math, you were pretty much that weight at stock (3158-408=2750), so I'm surprised at that, because I thought the wieght went up a bit with the 3.2L plus the G50 transmission. If that's right, and I will be running 12 Calb CA180FI cells less than you, then I should be adding 408lbs -12 x 12.4lbs = 260lbs over stock. Mind you, there's other differences in tehre like I'll be running two controllers, and a but heavier motor and charger -- so we'll call it 300lbs over stock. Not a bad guestimate.
> 
> Dumb question -- what does that mean? Does that mean the side-to-side balance (so left side is +/- 40 lbs with right side, for both the front and back of the car?), as opposed to front/back weight distribution? Also, is that assuming just the driver is in the car?
> 
> ...


I am extremely happy. Most over the remaining work on the project will have very little performance impact - cosmetics, cleaning up my wiring, paint, and installing the BMS.

Here is a description of corner balancing: http://www.dietersmotorsports.com/tech/2001/cornerbalance.htm

You want the left and right loads on the tires to be matched, and be at the correct ride height. If one of the springs is adjusted wrong and the wheel extends too far, that corner of the car, and the wheel on the diagonal opposite side will carry more weight than the other two wheels. 

The shop put a scale under each wheel, and the difference between the sum of diagonal wheels was about 42 lbs. It is also common to use a ballast in the drivers seat during the measurement and setup, to account for the weight of the driver.


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## Joey (Oct 12, 2007)

I believe the targa is heavier than the coupe. I didn't measure my before weight, it is from the owners manual. That may explain why our cars have similar totals, despite your heavier motor and transmission.


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## palmer_md (Jul 22, 2011)

northvan said:


> Almost every "car" guy I've talked to so far is completely horrified at what I'm doing.


When I converted my Porsche in '96 I thought the Porsche guys would just be horrified, but after I completed it and took it to a Porsche event, there was nothing but complements. I had a crowd before I got parked. As I drove in, I was directed as to where to park, and as I idled around the parking lot headed to my designated area several attendees noted the lack of air cooled engine noise, and came over to have a look. It was fun. I'm sure you will have the same experience when you show off your completed car. It seems car guys are very much into anything done to the car, especially if you are doing something to keep it on the road. I'm sure if I had a numbers matching concours car and ripped it apart there might be a different reaction. But taking a car that was probably headed to the crusher in a few years and putting it back on the road in electric form made everyone smile. Heck, my car is approaching half its life as electric. 22years ICE and 17 years electric.


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## Joey (Oct 12, 2007)

palmer_md said:


> When I converted my Porsche in '96 I thought the Porsche guys would just be horrified, but after I completed it and took it to a Porsche event, there was nothing but complements. I had a crowd before I got parked. As I drove in, I was directed as to where to park, and as I idled around the parking lot headed to my designated area several attendees noted the lack of air cooled engine noise, and came over to have a look. It was fun. I'm sure you will have the same experience when you show off your completed car. It seems car guys are very much into anything done to the car, especially if you are doing something to keep it on the road. I'm sure if I had a numbers matching concours car and ripped it apart there might be a different reaction. But taking a car that was probably headed to the crusher in a few years and putting it back on the road in electric form made everyone smile. Heck, my car is approaching half its life as electric. 22years ICE and 17 years electric.


That's a cool story. And congratulations on having your car on the road for so long. So far, I've had 4 people go out of their way to express their displeasure at what I've done, out of hundreds of people. The overwhelming response is positive. I bet you would get more negative reaction describing your plans compared to showing off a completed, clean installation. Especially if performance has been increased.


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## palmer_md (Jul 22, 2011)

Joey said:


> So far, I've had 4 people go out of their way to express their displeasure at what I've done, out of hundreds of people. The overwhelming response is positive.


I bet the 4 who complained are not really car guys. Bet they did not own a Porsche let alone belong to a Porsche car club or any car club for that matter. People who complain about electric cars tend to not be car people in my experience. Seems they dislike any change. I don't bother to respond to these folks. There are plenty of others who are inquisitive and want to know all about it.


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## Hollie Maea (Dec 9, 2009)

Spotted in the wild:


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## Joey (Oct 12, 2007)

That's me, on my way to work. Thanks for posting the picture. Looks like it might have been taken today, because it looks like just ahead of me is my buddy's IS350, but it is hard to tell in the image.


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## Hollie Maea (Dec 9, 2009)

Yep, that was this morning. Your buddy's car is pretty peppy too...you guys were both jumping off the line pretty good. My crummy Accord didn't stand a chance


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## Joey (Oct 12, 2007)

I registered the car as electric with the DMV. The process was simple. Based on some of the horror stories, I was expecting an ordeal. It was just a change on the DMV computer in fuel type from gas to electric. No inspection or extra fees - just a warning not to get pulled over by the police with a gas engine in there.

I'm also experiencing my first issue with the car. The voltage on the battery pack is sagging more than normal under load. I'm running 60 CALB CA 180 cells. It started when the weather turned cold. In warm weather, the pack voltage would sag 23 volts (195 V -> 172) with a 670 amp draw on the battery. The motor was seeing 152 volts at 750 amps. Yesterday, under similar load conditions, the pack voltage was sagging to about 155 volts. I need to collect a log file from the Soliton1 controller to get more stats. I'm going to try and track down this issue, and here is my list in order of likelihood. I'd appreciate any and all input.

1) Normal performance for the batteries in cold weather. The average temp here was 75 deg F (24 C) and is now around 40 deg F (4 C), with colder dips in the unheated garage at night. Warm weather = 12% sag under 3.7 C discharge. Cold weather = 21% sag.

2) Some resistance in a connection somewhere in the battery string. 50 mOhms at 1000 amps would develop a 50 volt drop.

3) Bad cell. Doesn't seem to be the case. Checking cell voltages directly after a drive, everything is within a millivolt or two. My BMS isn't installed yet, so I don't know much about what's going on at the cell level under load. One cell could be taking the pack voltage down under load. I might be able to check this my monitoring the voltage of half the pack at a time, to see if one side of the pack is dropping more than the other under acceleration.

4) Problem with the motor. The commutator looks clean. Under "normal" driving conditions, you would never suspect an issue. Power delivery is very smooth. Low speed performance is normal. No indication that there is an issue with the motor.

5) Other drive train issues - not likely at all. The car coasts down normally, in gear. No strange noises.

Let me know what you think.


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## corbin (Apr 6, 2010)

Hey Joey,
My cells sag in a similar way when it is cold out. I live in Santa Cruz CA. It is normally around 50-60F, but it was in the 30’s for a while here, and the cells would sag really badly. I have 48 thunder sky cells (200ah), and I probably pull lower amps, like 300-400 typically at most. My BMS gets set off under load when it is cold out, and the SOC is less than 70%..just due to sagging. I have one “bad” cell that sags to about 2.3v; the others sag to about 2.5-2.7v (just guesses from looking at my gauges). When I charge during the cold, the cells have higher resistance, and sit at a higher voltage longer when charging.

So, I think it is “normal”. You will just use more amp-hours for a given distance due to the cold causing more resistance. (I think…). I’m not sure if this is “good” for the cells; i’m sure they would last longer if heated to a nice 60F before charging and discharging…but it probably isn’t worth the effort to add in a heating system if you live in a generally warm climate.

corbin


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## 1-ev.com (Nov 4, 2010)

Hey guys, I saw that Jack from evtv.me was using heated battery floor on his Escalade and run coolant with heater element... this on some of his videos.

Also, question: what state are you in? Do you know anyone in FL to receive title with EV on it? txs. -Y.

PS: i think this is in - Dec 16 2011 video here http://evtv.me/vidarch.html


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## Joey (Oct 12, 2007)

The battery pack perked up again once the cold weather moved east. 

I have the car on jack stands and I'm in the process of finally painting the battery racks. There's a bit of surface rust on the bare metal, but it cleans up easily enough.

The front rack is done, and the vacuum pump and reservoir tank are securely mounted (foam wedges weren't the long term look I was after). I added 3 mm thick closed cell foam to line the rack. I also added 6 mounts for an acrylic cover, the prevent a shocking experience for visitors at events where the car will be on display.











































I'm working on mounting a water cooling loop for the controller and forced air for the motor. The amount of dirt and road debris all over my rear cells has me investigating belly pan options.


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## Joey (Oct 12, 2007)

It also seems that my motor shipped with the H49 red top brushes. I've got a lot of carbon dust and a slight bit of wear on the commutator. The outer set of 4 brushes are about 3 mm shorter than the inner set of 4. I've got a new respect for those that can take a decent picture of the commutator area. I've got a set of H60 brushes on order. The H60 are supposed to be better suited for street usage. I've logged about 25 hours of run in at 12 volts to seat the brushes and 3500 miles of driving.








You can see (if you squint) that the upper (outer) brush sits about 3 mm lower than the lower (inner) brush, which is just about flush with the holder.








The wear is just a slight amount - much less that 0.25 mm (0.010 "), made to look worse by the difference in coloration.


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## Yabert (Feb 7, 2010)

Hi Joey
I've the same experiment as yours with the sag under cold weather and with the H49 vs H60 brushes.
Good work on your car.


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## Joey (Oct 12, 2007)

Yabert said:


> Hi Joey
> I've the same experiment as yours with the sag under cold weather and with the H49 vs H60 brushes.
> Good work on your car.


Yabert, I've been reading up on your thread. I need to thank you for posting pictures of your brushes. It was how I figured out I had the H49 brushes.


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## northvan (Aug 2, 2012)

Hey Joey,

Glad to see you back in the garage working on that sweet looking rid of yours! The weather in Vancouver is a little behind that of Portland's, so soon I have to get back to my 911, too. I can't wait to rip out that ICE and start working on the clutch/flywheel/adapter/etc. -- probably the same path thru the build that you took.



Joey said:


> I have the car on jack stands and I'm in the process of finally painting the battery racks. There's a bit of surface rust on the bare metal, but it cleans up easily enough.


Wow. The good news is that it looks like you are definitely getting a lot of use out of the car. I can see where this is a good time to start painting and covering up batteries.

BTW: A tip I got off of American Restoration, is to use cider vinegar to remove rust. Works great, although I use it to soak parts in. Not sure if you can work it in with a sponge, as those racks are pretty big for soaking I also used their tip to remove rust from chrome using good ol' aluminum foil and water -- works great.



Joey said:


> The front rack is done, and the vacuum pump and reservoir tank are securely mounted (foam wedges weren't the long term look I was after). I added 3 mm thick closed cell foam to line the rack. I also added 6 mounts for an acrylic cover, the prevent a shocking experience for visitors at events where the car will be on display.


Can't wait to see how you pull off the acrylic covers. Last I heard, you were going to try a heat rig to give 'em nice bends.




Joey said:


> I'm working on mounting a water cooling loop for the controller and forced air for the motor. The amount of dirt and road debris all over my rear cells has me investigating belly pan options.


I hear you there -- a belly pan would keep everything a lot cleaner, but for me who lives on the "wet coast", I am kind of concerned with rain getting up in everything as well.

Keep up the great work!


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## Joey (Oct 12, 2007)

I've been working on getting the cooling components into the car: a blower for the motor, and a water loop for the soliton. I made a rack to fit in the cavity of the rear bumper.















There are a lot of curves on a car, and this is the best I could manage to get everything to fit in the limited space I have left.






















There is a gap where the tailpipe once lived. I'm going to try a foam and fiberglass composite plug to fill the void.


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## Old.DSMer (May 18, 2012)

Joey said:


> I've been working on getting the cooling components into the car: a blower for the motor, and...


Impressive use of available space, Joey! I like the blower and air filter combo. What is it and where did you get it? I need to do forced cooling also, since I removed my fan due to space constraints.


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## Joey (Oct 12, 2007)

Old.DSMer said:


> Impressive use of available space, Joey! I like the blower and air filter combo. What is it and where did you get it? I need to do forced cooling also, since I removed my fan due to space constraints.


I got the blower kit from EVWest. http://www.evwest.com/catalog/product_info.php?cPath=30&products_id=231 It's not the cheapest.

It is also quite loud at full voltage. It sounds only a little better than a vacuum cleaner. I'm working on an arduino project that reads the motor thermistor and throttles the fan speed based on temperature feedback.

jackbauer posted this youtube video review:


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## Old.DSMer (May 18, 2012)

Joey said:


> I got the blower kit from EVWest. http://www.evwest.com/catalog/product_info.php?cPath=30&products_id=231 It's not the cheapest...


Thanks Joey, I'll have to check out that review when I have time. That fan is definitely pricey, but 800 CFM is nothing to scoff at. Especially in that compact package!


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## Joey (Oct 12, 2007)

I pulled the motor so that I can paint my battery racks and replace my brushes. Turns out the old brushes were pretty well spent - after 3500 miles. I would say the H49 brushes are definitely not suited for street use. I hope the H60 hold up better. 







The outer set of 4 brushes had significantly more wear than the inner set. The length of a new brush is 1.5 inches (from the top to the short side of the radius). The outer brushes were 0.85 inches and the inner set was 1.1 inches.

The other issue is I found washers on two of the brushes between the copper bar and the pigtail terminal of the brush. I took the washers out, because hardware does not belong in the electrical path.

*Edit: In the picture above, from left to right - new H60 brush, used H49 outer brush, used H49 inner brush. Looks like the easiest way to tell the H49 from an H60 is the terminal on the pigtail. H49 use spades, and H60 is a through hole.


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## sholland (Jan 16, 2012)

Beautiful work on your car!!

I had a great time reading almost the entire thread this weekend... I have just started a build that is using very similar equipment to yours, though with 67 160Ah cells and driving the front wheels. I have the exact same goals as you do too, so it was reassuring to see your final results almost exactly mirror what I could predict with any of the various simulations out there.

Here's my blog if you want to see my progress.
http://1996-civic-ev.blogspot.com

Thanks for sharing all of your build progress, and I hope to see more updates!!


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## Joey (Oct 12, 2007)

I painted my rear racks and got them into the car. The rust came off with sanding and wire brushing.















I installed some plastic edge trim on the raw metal edge of the box, to keep the nylon strapping from chaffing.














On the upper rack, I used draw latches to hold the cells securely.














I should have painted these boxes a long time ago.


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## Joey (Oct 12, 2007)

Here are a bunch of pictures of the BMS install and the start of my belly pan. I'm using 1/8" (3 mm) thick ABS sheet.





















Thanks to gdirwin for making me aware of wago 222 connectors in this post. They are awesome, and do a much better job of securely connecting wires.




















Make a template with cardboard. Cut the plastic with a jig saw set to slow. I still need to enclose the bottom of the engine compartment and the back of the rear wheel wells.









Blue sea makes nice terminal covers that works for post lugs. I ordered 4 red and 4 black for the motor and controller connections.

Blue Sea PN# 4012 - red, 2 - 2/0 wire
4013 - black, 2 - 2/0 wire
4014 - red, 3/0 - 4/0 wire
4015 - black, 3/0 - 4/0 wire


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## sholland (Jan 16, 2012)

Just curious... When you got the car registered did they have any requirements for the batteries to be boxed or covered? Maybe just any that are in the interior?


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## Joey (Oct 12, 2007)

There were no requirements as far as I know. There was no inspection. The change from gasoline to electric power was self declaring. When I asked about an inspection they simple said, "Don't get pulled over and have a gas engine in there."

It is a good idea to restrain your cells, and to provide some protection for curious fingers.


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## Joey (Oct 12, 2007)

Using a DC speed controller and Arduino, I built a PID controller for my motor blower. I also drive the old oil level gauge with the motor temperature.

























































Looks like the blower ends up being fully on or off, but with a PID controller, it does so very gracefully. I suspect that setting the temperature setpoint at 120 degrees F is a factor. The motor is certainly rated higher, but from the graphs, I see the temperture rise a few degrees at the end when the blower turns off. This tells me that the thermistor in the motor is not directly at the hottest part of the motor.


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## Joey (Oct 12, 2007)

I'm not so pleased with the performance of the blower. The air flow is too low, and the motor temperature climbs to around 210 deg F (100 deg C) at the motor thermistor at speeds above 45 mph sustained for 15-20 minutes. Based on the time lag between pushing current through the motor and seeing temperature rise, I'm guessing there is significant thermal mass between the thermistor and the heating source (brushes), so the commutator region is likely seeing higher temperatures.

I will collect a temperature graph of these conditions, and then go back to the stock cooling configuration (remove the blower band and reinstall the screen band around the motor). I never had the thermistor hooked up before, but the temperature seemed cooler to the touch before I added the blower.

Then I can decide if I need to look for a better blower. I'm considering a jabsco that is rated for 150 cfm (34739-0010 , 6.5 amps). There is a bigger unit rated for 250 cfm, but I don't think I can fit it in the car (35440-0000, 12 amps). The blower I have claims 800 cfm, but based on the 4 amp draw, and being an inline duct fan, there is no way I'm getting that kind of flow through my 2 inch duct with 18 inches of run and two 90 degree turns. I doubt the 800 cfm claim, even with no static pressure. And did I mention the blower sounds just like a shop vac - not a cool sound.


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## sholland (Jan 16, 2012)

After looking at all the specs, I settled on the Jabsco 35770-0092. It's a bit more expensive, buts it's rated for continuous use, so it should be more durable. I've turned it on and it's actually very quiet, so I may just leave it on all the time.

Here it is mounted. I haven't actually driven the car yet, as I have another month or so of work, so I can't share actual performance data... As you mentioned it is quite large...


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## Joey (Oct 12, 2007)

Thanks sholland for the picture and the info on noise. I wish there was a continuous duty 3 inch unit. That 4 inch unit should keep your motor cool. Time to crawl under the car and see if there is anyway I can make it fit.


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## Joey (Oct 12, 2007)

I removed the blower from the car. I was tired of the high motor temperature and the shop vac sound broadcasted from my otherwise quiet electric car. I took some temperature plots with and without the external blower. The temperature is measured using the thermistor that is built into the WarP motor.








The red trace was made with the blower cooling band installed, but the external blower was turned off. Obviously, this greatly reduces the ability of the internal fan to pull air into the motor. I ended this test early because the temperature rise showed no signs of slowing.

The green trace shows the motor temperature with the external blower turned on. The blower really doesn't do much until the temperature is greater than 175 degrees F.

The internal fan measurement was made with the original commutator screen installed and the external blower hardware removed. 

Conclusions: The internal fan did about as well as the external blower. The blower is underpowered. It is drawing about 4.5 amps at 12 volts. The 105 c.f.m jabsco draws about the same. The 150 cfm jabsco draws 6.5 amps, and the big 250 cfm unit draws 12 amps.

Noise is a big drawback for air cooling. My inline duct blower sounds like a shop vac. The main advantage of the external blower is the ability to cool the motor while the motor is not spinning.

A blower needs to move a lot of air, and ideally do so without a lot of noise.


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## corbin (Apr 6, 2010)

Awesome info. Thanks for sharing!

It makes me wonder if i should use the blower on my VW bug. I have it turned on via a temperature snap switch (very low-tech). It is glued onto the motor housing, so I'm sure there is a huge delay before it actually comes on.

corbin


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## DavidDymaxion (Dec 1, 2008)

Thank you for the data.

A local EVer just pointed the squirrel cage fan at his brushes, but did not use the band. He said it worked well and he quit overheating on hills.

Something I'm doing on my 911 is trying to mimic the ICE's air flow. Luckily my motor sits in a channel made by the sides of the battery boxes. With just a little coroplast work I can have air pull in from the top, go through the motor, and get pushed out the bottom, just like the ICE did. If I need to augment the air flow I can put some fans in the engine lid air opening. This has the benefit of also cooling my controller.



Joey said:


> I removed the blower from the car. I was tired of the high motor temperature and the shop vac sound broadcasted from my otherwise quiet electric car. I took some temperature plots with and without the external blower. The temperature is measured using the thermistor that is built into the WarP motor.
> View attachment 27249
> 
> 
> ...


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## dladd (Jun 1, 2011)

good data. And worrisome! I've been running my motor with the coverband but no blower for a while. I don't have the thermal switch wired up at all so I have no idea how hot it gets. I just assumed it was fine since I don't pump much power through it.

Think I'll just dump the cover and go naked. It never rains out here anyway.


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## Joey (Oct 12, 2007)

It's been a while since my last post. I've 8500 electric miles on the car, and no issues to report.

I've been taking the car to monthly electric vehicle association meetings, and various events to promote EVs. Almost all of the response is overwhelmingly positive. A few people are pretty upset with what I've done to a semi-classic car. They take it personally that I've messed with the "heart of the machine." 

A Porsche enthusiast online magazine, dedicated to first generation water cooled model of the Porsche line, captures this reaction in a recent article (with some interesting phrases):
http://flussigmagazine.com/2/post/2015/04/electric-porsches.html
They include links to my car and a few others that participate in this forum: RWAudio and the ReBirth 911.


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## RIPPERTON (Jan 26, 2010)

Joey said:


> It's been a while since my last post. I've 8500 electric miles on the car, and no issues to report.
> 
> I've been taking the car to monthly electric vehicle association meetings, and various events to promote EVs. Almost all of the response is overwhelmingly positive. A few people are pretty upset with what I've done to a semi-classic car. They take it personally that I've messed with the "heart of the machine."
> A Porsche enthusiast online magazine, dedicated to first generation water cooled model of the Porsche line, captures this reaction in a recent article (with some interesting phrases):
> ...


Sounds like a German website. Flussig means liquid.
The guy bagging your car admits to having a low IQ then demands everybody listens to his wise admonitions which are actually random gibberish from a clearly strained and undeveloped social conscience.
I only dream of doing as many miles in an EV as you have Joey, well done


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## RIPPERTON (Jan 26, 2010)

Try experimenting with this EDF for a blower.
Don't know if it will be quiet enough but these things sure blow a tornado.
Ive booted one of these things up trying to hold it with my hand and it nearly took off. lots of thrust and works on 12v.

http://www.ebay.com.au/itm/351128604714?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com.au/itm/371112218778?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT


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## Joey (Oct 12, 2007)

RIPPERTON said:


> Sounds like a German website. Flussig means liquid.
> The guy bagging your car admits to having a low IQ then demands everybody listens to his wise admonitions which are actually random gibberish from a clearly strained and undeveloped social conscience.
> I only dream of doing as many miles in an EV as you have Joey, well done


I think the site is USA, but the name is German-inspired for the first generation liquid cooled Porsches they follow.

For many people the roar of the ICE is a BIG deal. I've heard it over and over. I also like the roar of the mechanical symphony.

The article wasn't all that negative. It reflects some of the lack of information out there about electrics. But he does credit our videos for advancing his opinion and opening his mind to the performance that is possible: "clearly, I've some catching up to do." Not a bad response from a publisher of a Porsche enthusiast magazine.


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