# Check this battery out and tell me what you think!



## Jokerzwild (Jun 11, 2009)

Voltage
6V
Length
10.20 in.
Width
7.09 in.
Height 
10.72 in.
Weight
66 lbs.
Reserve Capacity (min.)
490 min.
Amp-Hour
200 AH​​​ 








As I am a newb I am realy trying to move forward and not spend a huge amount on my 1st build. I do not mind spending $ on a good engine since I can pull it and stick it into my next car. 

So My question is this a good option and how manny would I need to go 100 miles with a 2000lb car on a warp11 engine?


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## JRP3 (Mar 7, 2008)

Jokerzwild said:


> So My question is this a good option and how manny would I need to go 100 miles with a 2000lb car on a warp11 engine?


You can't do that, not even close, sorry. To go 100 miles with those batteries your pack would weigh more than the car.


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## favguy (May 2, 2008)

Well, 
24 of those will get you a 144 volt string. This will make your 2000lb car weigh 3500lbs! At 200Ah this will get you about 60 miles with a very light foot, drive it like a normal gas car and you'll get about 45 miles. (I doubt that battery would last long though as it doesn't appear to be a true traction battery, Trojan or US Battery floodies are the cheapest option for you that will actually last a while if treated well, but I'm sure will be 50% or so more in cost)

You probably don't want a warp 11 either, lots more cash and overkill for the size of car you're looking at, a warp 9 or ADC 4001 would be a better match.

If you really need to go 100 miles per charge, you'll need to go with something like 180Ah/200Ah Lifepo4, these only weigh half as much as lead and will get you twice the range (ish). Around 2&1/2 times the cost of lead now with BMS, but might last 10 years (we are all hoping!!) 

somebody once said, with an EV you can choose any 2 _*only! *_of the following: *RANGE, SPEED, LOW COST*. Unfortunately it is very true.

Happy EV'ing 

Paul


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## Jokerzwild (Jun 11, 2009)

How manny lipepo4 bats do you think i need?


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## EVComponents (Apr 20, 2009)

Jokerzwild said:


> How manny lipepo4 bats do you think i need?


http://www.evcomponents.com/SearchResults.asp?Cat=28

Here is the lowest price anywhere on LiFePO4 batteries.

Contact us to get the specs on your order. We will try to help you get the components that meet your EV goals.

[email protected]


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## favguy (May 2, 2008)

Lifepo4 are 3.2v nominal, so if you were to go with a 144v system you'll be looking at 45. Lowest current cost is $1.10 per Ah, so if you went with 160Ah (the very minimum you'd need to achieve a 100 mile range) thats $1.10 x 160 x 45 = $7,920, then you need to choose a Battery Management System, these vary greatly in cost and features, if I were you I'd take Dave up on his offer of a chat 

Paul


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## Tesseract (Sep 27, 2008)

Jokerzwild said:


> 6V
> 66 lbs.
> 200 AH​​
> As I am a newb I am realy trying to move forward and not spend a huge amount on my 1st build. I do not mind spending $ on a good engine since I can pull it and stick it into my next car.
> ...


Without knowing drag coefficient, gear ratios, average speed/acceleration, etc., you can only get a very rough estimate that could be as much as 50% off.

But if you assume you will need an average of 400W-hr per mile then to go 100 miles per charge the pack will need to deliver 40kw-hr of usable energy. If you limit depth of discharge to 80% then the pack needs an actual capacity of 50kw-hr. These batteries are 6V/200Ah or 1.2kw-hr each so you will need 42 of them. 42 x 66 lbs each = 2772 lbs. Oops. The rest of your vehicle needs to weigh -772lbs to meet your weight target.

The short answer is, there is absolutely no way you can achieve a 100 mile range with lead-acid batteries. You can get this range with Lithium Iron Phosphate batteries, and at a best price of around $1.10/Ah you can expect to spend somewhere around $20,000 for the batteries.

Isn't this covered in the Wiki somewhere?


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## Jokerzwild (Jun 11, 2009)

I kind of figured that out, I dont think it is practicle to use anything but lifepo4's for any distance. Now I am thinking about building 2 cars


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## Nomad (May 8, 2009)

Jokerzwild said:


> I kind of figured that out, I dont think it is practicle to use anything but lifepo4's for any distance. Now I am thinking about building 2 cars


Ya thats why I scrapped my project and bought a rental house.
Now I'm just a lurker 

I'll be back, but I still haven't figured out if I want 144v or 320v


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## Technologic (Jul 20, 2008)

Tesseract said:


> The short answer is, there is absolutely no way you can achieve a 100 mile range with lead-acid batteries. You can get this range with Lithium Iron Phosphate batteries, and at a best price of around $1.10/Ah you can expect to spend somewhere around $20,000 for the batteries.
> 
> Isn't this covered in the Wiki somewhere?



Your math is just a taaaaad off there Tesser..
that's a 57 kilowatt hour battery pack... you think that is necessary in a normal car to get a mere 100 miles? Really?

That's a larger pack than the highly inefficient Tesla Roadster uses and it gets about 3 times that range out of it. (inefficient because it uses Li-ion's, has a 0.45 Cd, and weighs in at around 3000lbs)

Try again...

100 miles = what children? $7000! And that's IF you don't plan properly and just grab any ol' used car. With proper planning I'm sure you could reasonably get a $7000 pack 150-170 miles...


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## JRP3 (Mar 7, 2008)

Tesla Roadster does something like 133wh/mi in the EPA test cycle. It is not an inefficient vehicle at all if you don't drive it hard. For most real world conversions you better figure on about 250-300wh/mi from what I've seen, and be happy if you do better.


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## Technologic (Jul 20, 2008)

JRP3 said:


> Tesla Roadster does something like 133wh/mi in the EPA test cycle. It is not an inefficient vehicle at all if you don't drive it hard. For most real world conversions you better figure on about 250-300wh/mi from what I've seen, and be happy if you do better.


133wh/mi = 400 miles of range on the Tesla.... off a "$18,000" pack?

I assume driving it hard means not driving it fast though.... where the drag coefficient comes into play.

even with 250 wh/mi a $10k battery pack would do more than 100 miles. Though mitsubishi got like 180 wh/mi at highway speeds out of their new EV... Their pack gets about 100 miles at a cost of around $5000. Nothing special about it either, weighs 2000lbs+, Cd in the 0.3 range.


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## JRP3 (Mar 7, 2008)

Technologic said:


> 133wh/mi = 400 miles of range on the Tesla.... off a "$18,000" pack?


Remember you can't count every kwh in a pack, not if you want it to last long.



> even with 250 wh/mi a $10k battery pack would do more than 100 miles.


 Just barely unless you take it to extremes.


> Though mitsubishi got like 180 wh/mi at highway speeds out of their new EV... Their pack gets about 100 miles at a cost of around $5000. Nothing special about it either, weighs 2000lbs+, Cd in the 0.3 range.


Where'd you get those numbers, especially the wh/mi at highway speed and the cost of their pack?


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## Technologic (Jul 20, 2008)

JRP3 said:


> Remember you can't count every kwh in a pack, not if you want it to last long.
> 
> Just barely unless you take it too extremes.
> Where'd you get those numbers, especially the wh/mi at highway speed and the cost of their pack?


The pack is 16kwhr... and has a reported range of around 100 miles... 180 wh/mi was a bit of an overestimate actually.

http://techon.nikkeibp.co.jp/english/NEWS_EN/20080124/146156/

Pack cost is just the cost for a single pack from Thundersky etc... between $5000-6000... I'm sure volume discounts are way less, but it's best not to assume. It appears to use a straight low amperage/high voltage prismatic pack (probably making the controller they use obnoxiously cheap as well).


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## dimitri (May 16, 2008)

Technologic said:


> Try again...
> 
> 100 miles = what children? $7000! And that's IF you don't plan properly and just grab any ol' used car. With proper planning I'm sure you could reasonably get a $7000 pack 150-170 miles...


Ok, Daddy, please teach me a lesson (no spanking allowed )...

I grabbed any ol' used 2002 Mazda Protege5 ( 2700 Lb curb weight , not sure of Cd, but probably around 0.5 guesstimate )

I put $8000 ( in today's prices ) of LiFePo4 cells in it....

Assuming I don't plan properly, like using a wasteful auto tranny and wasteful belt driven AC and PS  , I should be getting 100 miles range, or so you claim...

So, please, oh smart and powerful Oz ( I mean Techno  ) , tell me what I did wrong since I am only getting 50-60 miles range?????

To put my money where my mouth is, I will send you $100 if you tell me how to get 100 miles range without adding more batteries and without spending over $1000 more or doing major body work on the car... 


Botom line, Techno, with all due respect, all the info you post is purely theoretical. I know you are busy with moving to Hong Kong and becoming a high price lawyer and all that, but please, make a real EV that actually drives, see how much range you get, then share results, i.e. put YOUR money where YOUR mouth is.... because its just getting old to read same theoretical comments over and over again....


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## Technologic (Jul 20, 2008)

dimitri said:


> So, please, oh smart and powerful Oz ( I mean Techno  ) , tell me what I did wrong since I am only getting 50-60 miles range?????
> 
> To put my money where my mouth is, I will send you $100 if you tell me how to get 100 miles range without adding more batteries and without spending over $1000 more or doing major body work on the car...


No Regen? horrible Cd? mostly highway speeds? consistent high amperage discharge? Not using much more efficient heating/cooling systems off electricity?

I dunno there's lots of reasons... of course the major body work would probably double-triple your range off that pack...
By suggesting "any ol' used car" I was thinking of basically every sedan made since 1994... with a roughly 0.29-0.35 Cd. A 0.5 is equitable to a Hummer2... so you might need to retry the choice of car body 

If you are actually using a 23kwhr pack (which is "today's price" of $8000)... I don't really get how you could possibly only get 50-60 miles... that means you are getting well over 350 wh/mi off LiFePO... you accomplished a feat in inefficiency not even Detroit has been able to match  
I can have a look over your page if this is the case and see if anything jumps out at me... how much does your car weigh after finished 4000+ lbs?

23kwhr should easily take any standard car well over 100 miles... in fact I can't think of any cars, no matter how inefficient, that don't get at least 250wh/mi off of their packs (like the Tesla Roadster with a Cd of 0.43 and curb weight over 3000 lbs IIRC)



> Botom line, Techno, with all due respect, all the info you post is purely theoretical. I know you are busy with moving to Hong Kong and becoming a high price lawyer and all that, but please, make a real EV that actually drives, see how much range you get, then share results, i.e. put YOUR money where YOUR mouth is.... because its just getting old to read same theoretical comments over and over again....


I will be, but I won't be back in the US until July... which is the proposed start date... However suggesting a $20,000 battery was necessary is by all stretches of the imagination simply incorrect. 

Unless you're building a 300hp tow truck EV... 100 miles of range can be done for a LOT cheaper in any circumstances.

I have been quite busy since Mid-may, but I have been accumulating data when I have time to make sure my build goes as smoothly as can be hoped. Professional connections always come first and 2L resumes in September.


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## JRP3 (Mar 7, 2008)

I found .32 cd for 2002 Mazda Protege, not bad at all.


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## dimitri (May 16, 2008)

> By suggesting "any ol' used car" I was thinking of basically every sedan made since 1994... with a roughly 0.29-0.35 Cd. A 0.5 is equitable to a Hummer2... so you might need to retry the choice of car body


I am not good at estimating Cd, but since my car falls into "every sedan made since 1994" category, then my Cd is 0.29-0.35 based on your own data. I will have to take your word for it until I find actual Cd data for my car. Anyone has a link to database of Cd's for modern cars?



> No Regen? mostly highway speeds? consistent high amperage discharge? Not using much more efficient heating/cooling systems off electricity?


Yes, these are all drawbacks of typical DC conversion, trying to stay in reasonable budget, but according to your statement this still falls into "100miles without proper planning" category...



> If you are actually using a 23kwhr pack (which is "today's price" of $8000)... I don't really get how you could possibly only get 50-60 miles... that means you are getting well over 350 wh/mi off LiFePO... you accomplished a feat in inefficiency not even Detroit has been able to match
> I can have a look over your page if this is the case and see if anything jumps out at me... how much does your car weigh after finished 4000+ lbs?


Its a 20kwhr pack since I bought 160AH before 180AH SkyEnergy were available. And assuming 80% DoD, I have 16kwhr to spare, so I will need an average 160Wh/mile to get your promised 100 mile range.

Now tell me, how can I get average of 160Wh/mile on "any ol' sedan" , "without proper planning" ?

I admit, you don't need $20,000 pack for 100 miles, but $7000 is far from real..... perhaps the truth is somewhere in between, say $12,000 pack of 60 180AH cells giving us 27kwhr usable for more realistic 270Wh/mile 100 mile range? Then I would agree with you....


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## JRP3 (Mar 7, 2008)

We can also look at daniel's Porsche with a 28.8kwh pack getting only 80 miles of range. I think there are some inefficiencies going on there, but he's a way's off from 100 miles, and that's with 28.8kwh to play with.


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## Technologic (Jul 20, 2008)

dimitri said:


> Its a 20kwhr pack since I bought 160AH before 180AH SkyEnergy were available. And assuming 80% DoD, I have 16kwhr to spare, so I will need an average 160Wh/mile to get your promised 100 mile range.


That's a $7000 pack, on the nose  80% DoD is rather high? any reason? Most lifepo's (even prismatics) can do 90%+ safely... including SkyEnery/TS... if you're using headways you can do 95%



> Now tell me, how can I get average of 160Wh/mile on "any ol' sedan" , "without proper planning" ?


Well firstly I'd suggest dropping the expensive/large DC motor, tranny and doing two sepex motors to each of the rear tires... that'd be a rather large start




> I admit, you don't need $20,000 pack for 100 miles, but $7000 is far from real..... perhaps the truth is somewhere in between, say $12,000 pack of 60 180AH cells giving us 27kwhr usable for more realistic 270Wh/mile 100 mile range? Then I would agree with you....


20kwhr is far from real? A LOT of production cars are doing that off 4000+lbs... I don't think I'm being terribly unrealistic.

Using LiFePO without regen still strikes me as odd, especially with a such a large pack. Sure there aren't many options, but generally something can be done for a moderate price.
I really should finish my AC controller design  painful options for most cars I guess.

Spending $12,000 on a pack that a $7000 battery clearly can do (ie. just look at production cars with nothing more than AC motors) seems like a huge waste of money


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## Technologic (Jul 20, 2008)

JRP3 said:


> We can also look at daniel's Porsche with a 28.8kwh pack getting only 80 miles of range. I think there are some inefficiencies going on there, but he's a way's off from 100 miles, and that's with 28.8kwh to play with.



We're still about 2.5 times lower than the $20,000 price tag originally suggested


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## JRP3 (Mar 7, 2008)

dimitri said:


> Anyone has a link to database of Cd's for modern cars?


Wikipedia has a chart for many vehicles but I found yours just by googling "2002 mazda protege coefficient of drag"


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## JRP3 (Mar 7, 2008)

Technologic said:


> We're still about 2.5 times lower than the $20,000 price tag originally suggested


I agree the original statement was high, just as yours was low  I'll say that you are probably less wrong


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## dimitri (May 16, 2008)

> 80% DoD is rather high? any reason? Most lifepo's (even prismatics) can do 90%+ safely... including SkyEnery/TS... if you're using headways you can do 95%


Not for long.... TS claims 2000 cycles at 80% DoD and 3000 at 70% DoD. I want my battery to last around 10 years, so I am not going over %80 DoD....

BTW, my car is at 3000Lb after conversion...

I admit that my 55-60 miles range is what I call "comfortable", means I don't hypermill, floor it sometimes just for fun , not feeling range anxiety, drive with windows rolled down, or occasionally use AC on a real hot day , etc.

I could probably squeeze 65-70 miles if I watch my ammeter like a hawk, close all windows, turn off AC and sweat like a pig  while driving at 45mph, but what's the fun in that???


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## Technologic (Jul 20, 2008)

dimitri said:


> I admit that my 55-60 miles range is what I call "comfortable", means I don't hypermill, floor it sometimes just for fun , not feeling range anxiety, drive with windows rolled down, or occasionally use AC on a real hot day , etc.
> 
> I could probably squeeze 65-70 miles if I watch my ammeter like a hawk, close all windows, turn off AC and sweat like a pig  while driving at 45mph, but what's the fun in that???


I swear my biggest contribution to this forum would be to finish that damn AC controller (especially if it winds up working decently in sensorless mode without significant reprogramming).

I just need some time ugh! I'm usually too exhausted on my weekends right now


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## dimitri (May 16, 2008)

technologic said:


> i swear my biggest contribution to this forum would be to finish that damn ac controller (especially if it winds up working decently in sensorless mode without significant reprogramming).
> 
> I just need some time ugh! I'm usually too exhausted on my weekends right now


 
amen to that !!!!


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## JRP3 (Mar 7, 2008)

Technologic said:


> Well firstly I'd suggest dropping the expensive/large DC motor, tranny and doing two sepex motors to each of the rear tires... that'd be a rather large start


Let's see, no gearing so high amperage draw for much of the time, bad idea, efficiency losses of 2 instead of one motor, bad idea, finding a higher voltage sepex controller, impossible?




> Using LiFePO without regen still strikes me as odd, especially with a such a large pack. Sure there aren't many options, but generally something can be done for a moderate price.


Unless you do a lot of stop and go and/or a lot of hills regen isn't worth the extra expense it usually entails.


> I really should finish my AC controller design


Yes you should, we need powerful, inexpensive, universal AC controllers.


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## Tesseract (Sep 27, 2008)

Oh - what a surprise... Technologic disagrees with me. Again... 

I maintain that 400W-hr/mile is a FAR more realistic energy consumption rate than 200W-hr/mi, both because I am basing it on real world performance data collected from my controller and because the OP has been talking about fitting his conversion with Siamese Warp 11's and wanting blazing fast 0-60 times in other threads.

Clearly, he's not interested in hypermiling his way down to a sub-200W-hr/mi consumption rate.

Therefore, I stand by my _educated guess_ that the OP - who will likely end up with a car weighing north of 3500lbs; who wants good performance and good range - will need approximately 50kW-hr of battery pack and at the going rate of $1.10/Ah (~$0.35/W-hr) that works out to $17,500. Add in BMS and charger and $20,000 doesn't seem like such a stretch.

I am puzzled why you chose to ignore the very first line of my reply which was, "*Without knowing drag coefficient, gear ratios, average speed/acceleration, etc., you can only get a very rough estimate that could be as much as 50% off.*"

Maybe he only needs 300W-hr-mi; that's still a ~38kW-hr battery pack ($13k + BMS/Charger) or maybe he will become a hypermiler and only need 200W-hr/mi as you claim - that's still $9k + bms/charger.

But you go right on thinking he can get the performance he wants with a mere $7k of battery pack...


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## Nomad (May 8, 2009)

Most HyperM will get you about 30% and I base my claim off of my personal experience so I guess thats not a great way to do it but meh, other people report between 25-40%. I got 59 from 44 with the prius before I modded it to hell. Civic 42 from 32, Olds Achiva 30 from 23.

Taking Regen into account you have to HyperM or you won't see it. I regen in the prius about 1wK in a 30 min trip going 15-20miles. I still don't know how this would apply to Ev's tho. 

Can someone can tell me how far a 26kW pack (80 [email protected] @80% DOD for ~2000 cycles) On a 2000-2500lbs car with a cD of .30 would take under HyperM driving (City 45-50mph) ? And how you reached that answer.

Futher I drive about 20,000 miles a year and as such spend about $1000 @ 60MPG @ 3$ a gallon in fuel. If LiFePo4 @ 2000 cycles is only getting a 80 mile range then it cost more to be electric and as such doesn't seem worth it at first, however, at 5$ per gallon a 8 year pack would have to cost 14k to compare and Since it's only 5400-8800 60ah vs 100ah and the price will do down for battery packs instead of up like fuel.


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## rillip3 (Jun 19, 2009)

Nomad said:


> Futher I drive about 20,000 miles a year and as such spend about $1000 @ 60MPG @ 3$ a gallon in fuel. If LiFePo4 @ 2000 cycles is only getting a 80 mile range then it cost more to be electric and as such doesn't seem worth it at first, however, at 5$ per gallon a 8 year pack would have to cost 14k to compare and Since it's only 5400-8800 60ah vs 100ah and the price will do down for battery packs instead of up like fuel.


Well, sort of. 20,000 mi / 80 mi/cycle = 250 cycles. So you would get around 8 years of service, meaning a pack more than $8000 would be more expesive than 60 MPG @ $3 /gal.

But that only works if you're actually driving the full 80 miles each cycle. If you're driving 60 miles, you reduce your cycles by 25%. This means 200 cycles a year, equalling 10 years of service, making the batteries $2k (-charging), more economical over the long run. Taking into account charging, 10 Amps x 120v = 1200W = 1.2kW. If it takes you 6 hours to charge (given that it's only 80% discharged), you get 7.2kWh per charge. At $.08/kWh (price here for electricity) you get $.56 per cycle, or $112 per year. Over ten years, 1120, making the batteries 2000 -1120 = $880 cheaper. 

If you have to use the entire range every day, it definitely will not be a cost savings over 60 MPG @ $3/gal. What are you driving now that's giving 60 MPG btw? That's some hella-milage.


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## Nomad (May 8, 2009)

rillip3 said:


> Well, sort of. 20,000 mi / 80 mi/cycle = 250 cycles. So you would get around 8 years of service, meaning a pack more than $8000 would be more expesive than 60 MPG @ $3 /gal.
> 
> But that only works if you're actually driving the full 80 miles each cycle. If you're driving 60 miles, you reduce your cycles by 25%. This means 200 cycles a year, equalling 10 years of service, making the batteries $2k (-charging), more economical over the long run. Taking into account charging, 10 Amps x 120v = 1200W = 1.2kW. If it takes you 6 hours to charge (given that it's only 80% discharged), you get 7.2kWh per charge. At $.08/kWh (price here for electricity) you get $.56 per cycle, or $112 per year. Over ten years, 1120, making the batteries 2000 -1120 = $880 cheaper.
> 
> If you have to use the entire range every day, it definitely will not be a cost savings over 60 MPG @ $3/gal. What are you driving now that's giving 60 MPG btw? That's some hella-milage.


Yes, but then it's 12k a year./60mpg*3$ = 600$ in gas or 6k over 10 years Making Gas 2k cheaper than a 8k pack. Or 200$ a year cheaper.

And Ya w00t w00t to the prius.


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## Tesseract (Sep 27, 2008)

We are drifting rather far afield from the original post, but since "Elvis has left the building" it probably doesn't matter...

Nomad - at the risk of pointing out the bleedingly obvious, not all conversions make economic sense. 

That said, try to keep the following factoids in mind:

* the energy content of gasoline is ~33kw-hr/gal.
* the energy consumption rates for most EVs is 300-400W-hr/mi

Roughly speaking, then, the equivalent mileage of most EVs will be somewhere around 100 mpg.

Now, whether that improvement in "mileage" offsets the cost of conversion depends greatly on whether the donor vehicle got 20mpg (most cars) or 60mpg (very, very few) in the first place. Converting a Prius or Jetta TDI probably doesn't make a lot of sense until fuel averages $4/gal over the expected life of the battery pack. Converting an SUV or truck, though, practically can't miss unless gas drops below a buck...

Now I'm no commodities trader, but I'd sooner bet on seeing an average price of $4/gal. than $1/gal.


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## Nomad (May 8, 2009)

Tesseract said:


> Nomad - at the risk of pointing out the bleedingly obvious, not all conversions make economic sense.
> 
> That said, try to keep the following factoids in mind:
> * the energy content of gasoline is ~33kw-hr/gal.
> ...


I would love to see a EV Hummer and the price tag on that. Or any Full size truck for that matter.

You know that. I know that. But others don't and I was just pointing out for everyone else who doesn't. 
There are some people who don't undersand that the cost of an EV isn't balanced very well right now.

Assume the same details @ your 25mpg Car (Closer to Avg than 20)
Your looking at a 33wK*1.2 for DoD 40wK pack to reach the same power as a gallon of Gas.

So for a 40wK pack you can get 60 miles(Since EV's are 3 time more Eff). Using the same example of charging everyday. @ 60miles a day or 12,000 a year.

1440 a year in Fuel cost.
49 LiFePo4 @ 260 AH ~ 40kW pak @ 14,000
100 LiFePo4 @ 125 AH ~ 40kW pack @ 13,500

~ 10 years @ $3/g=14400 gas or 13,500 electric Which is what I would call a wash.

A lot of people don't see that currently at best case your going to be spending just as much on fuel as you are on batteries. And that is what I was trying to point out. If you want to do it for Mother Earth, thats effin Awesome; however, I would wager only a few of the EVers did it for the Earth and most do it for their pocket books. I would also wager that people think they are saving big bucks by making an ev and the Lead Acid are the ones who are really getting shafted by having to replace batteries once a year (To keep up with the 12k a year math)

Now is that going to stop me from building one because it's hella cool? F no. But to not point it out would just be wrong IMHO. 

If as gas reaches 5$ a gallon or 6$ money would still be better invested in a rental property netting 300 a month, but thats another story.

Morale of the story? 
For those people who think building an EV will save money think again.
Until Bats come down in price to say .65/Ah (about half what they are now)
or
Gas goes up to 6$ a gallon

Don't rush out to build an EV thinking it's going to save you money.
Do it because it's cool, or you want to give the finger to greedy oil companies.


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## JRP3 (Mar 7, 2008)

Your numbers are off a bit. You say 60 miles out of a 33kwh pack but that's 550 wh/mi, which is terrible. If you pick the right donor vehicle and pay attention to aero and weight, and keep speeds down, you can hit 300 wh/mi or better. It depends a lot on the application, if you need highway miles your wh/mi will be a lot higher than around town or moderate speed back road driving.


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## Nomad (May 8, 2009)

JRP3 said:


> Your numbers are off a bit. You say 60 miles out of a 33kwh pack but that's 550 wh/mi, which is terrible. If you pick the right donor vehicle and pay attention to aero and weight, and keep speeds down, you can hit 300 wh/mi or better. It depends a lot on the application, if you need highway miles your wh/mi will be a lot higher than around town or moderate speed back road driving.


Does wkh=wk? Meaning does wkh=Volts*AH*#Bats?

If it does, don't forget 80% dod.. so only 26400 can be used or 440 wh/ml

A car that gets 25mpg is pretty bad too. If a gallon of gas is 33wkh and EV's are 3times better then 33wkh/25=1320 wh/mi /3 for EV eff. = 440 wh/ml

Math is right, but the 300% more Eff. might be off.


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## Tesseract (Sep 27, 2008)

Nomad - roughly speaking, you are about as pessimistic as Technologic is optimistic, but you aren't totally off the mark.



Nomad said:


> Assume ... 33wK*1.2 for DoD 40wK pack to reach the same power as a gallon of Gas.


No quibble with that.



Nomad said:


> So for a 40wK pack you can get 60 miles(Since EV's are 3 time more Eff).


This is too pessimistic. 300W to 400W-hr/mi is a reasonable consumption rate for mixed driving, from actual data downloaded from my controller, not a nebulous assumption or rule of thumb. Assume the middle of that range, or 350W-hr/mi, and you get a range of around 90 miles for 32kw-hr of usable pack capacity. 50% higher than your estimate.




Nomad said:


> 49 LiFePo4 @ 260 AH ~ 40kW pak @ 14,000
> 100 LiFePo4 @ 125 AH ~ 40kW pack @ 13,500
> 
> ~ 10 years @ $3/g=14400 gas or 13,500 electric Which is what I would call a wash.


Cost of the batteries looks good, now divide by the cycle life of 2000 to get a cost per cycle of $2 in amortized pack cost. Add the cost of electricity for each cycle (currently $0.10/kw-hr in Tampa, FL) which will be around $3.50, depending on charging efficiency (LFP is very efficient; Pb is not), and you get a per-charge cycle cost of $5.50

So, total cost is $5.50 to go 90 miles. Not bad, if you ask me. That's the equivalent of 45mpg at the current local pump price of $2.65/gal.

So, like I said, it doesn't make any sense to convert a TDI (~45mpg) or a hypermiling Prius (60mpg?), but for the average 20-25mpg vehicle? Sure, seems economically justifiable to me even after factoring in all of the other ancillary costs.

Oh yeah - it is kW, not wK


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## Nomad (May 8, 2009)

Tesseract said:


> Nomad - roughly speaking, you are about as pessimistic as Technologic is optimistic, but you aren't totally off the mark.


Ya.. I've been told that, but it's how I cheat the system. I'm never let down and always plesently surprised 

Ok, I think I see where the problem is.. it's with the Eff. Rating. Some ICE's are higher and some are lower so it's just not a good way to handle it. But it is cheap fast and easy. Maybe just bumb it up a little? Give ICE's a 27% and Elect 94%? That would give a 350% boost.

40kWh(Pak)/33kWh(Gas)*3.5*25~85 Miles?


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## Jokerzwild (Jun 11, 2009)

A couple more items: (yes I am allowed to comment since I started this post)

Don’t forget the costs: (Every time just using standard costs.)
Oil Changes $30
Standard Maintenance: $150
That hot chick down the street knowing that you care about the environment: Priceless!


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## Nomad (May 8, 2009)

Jokerzwild said:


> A couple more items: (yes I am allowed to comment since I started this post)
> 
> Don’t forget the costs: (Every time just using standard costs.)
> Oil Changes $30
> ...


HAHA... ok I yield.. I forgot about maintence cost.. I don't know how the hell that slipped my mind.. 

There is alot of good info on this thread tho.

I just don't see the point in lead...
How much are you looking to spend in batteries?


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## Jokerzwild (Jun 11, 2009)

I have just sold my 914 and picking up a banged up VW beetle next Tuesday. For my 1st build I decsided to go this route do to the EZ nature of the beetle. 

The motor and controller still up in the air:

Batteries I am going to try and keep the cost down and hit up old Marine yards in LB and try to buy there used batteries. This is why i probably will go DC and looking to spike the voltage at 240V. Some DC motors are good for short runs of 300V.

I am not looking for any distance anymore, just enough to get to the track. 15 miles away. 

I am still going to try to hit that 3.0 0-60 speed though.

Oh and of course a fiberglass and composit kit for the car.


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## Jokerzwild (Jun 11, 2009)

Lead, I will tell you my point.
I feal Lifepo4 and other batteries are on the same curve that computers where 5 years ago. I feal it will only get cheaper and better at a drastic rate. Because of this I do not want to spend a lot as of now for Lifepo4's.


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## Nomad (May 8, 2009)

Jokerzwild said:


> Lead, I will tell you my point.
> I feal Lifepo4 and other batteries are on the same curve that computers where 5 years ago. I feal it will only get cheaper and better at a drastic rate. Because of this I do not want to spend a lot as of now for Lifepo4's.


I hear ya. I wasn't aware you were looking for a dragster.


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## JRP3 (Mar 7, 2008)

Jokerzwild said:


> Batteries I am going to try and keep the cost down and hit up old Marine yards in LB and try to buy there used batteries. This is why i probably will go DC and looking to spike the voltage at 240V. Some DC motors are good for short runs of 300V.
> I am still going to try to hit that 3.0 0-60 speed though.


So you want to use 20 used marine batteries, weighing probably between 60-70lbs each, so lets say 65 average, 1300lbs of old batteries alone, and think you'll get a 3 second 0-60?


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## dimitri (May 16, 2008)

JRP3 said:


> So you want to use 20 used marine batteries, weighing probably between 60-70lbs each, so lets say 65 average, 1300lbs of old batteries alone, and think you'll get a 3 second 0-60?


Only if batteries stay on a pallet and connect to the car with a quarter mile extension cord


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## Nomad (May 8, 2009)

dimitri said:


> Only if batteries stay on a pallet and connect to the car with a quarter mile extension cord


Is that legal?


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## Jokerzwild (Jun 11, 2009)

No 10 24V marine batts.


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## JRP3 (Mar 7, 2008)

Jokerzwild said:


> No 10 24V marine batts.


Might be hard to find, and if they have any kind of ah capacity they won't be light either.


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## Nomad (May 8, 2009)

240 volt system? 

Lithium-$8250 @ 525lbs
Lead - $5600 @ 2640lbs

Based on 200ah for lead and 100ah for lithium.


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## Jokerzwild (Jun 11, 2009)

Just a newb question:
Can you mix battery types and AH?


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## rillip3 (Jun 19, 2009)

Jokerzwild said:


> Just a newb question:
> Can you mix battery types and AH?


Yes and no. Yes you can. No you shouldn't. You'll tend to dangerously overcharge some of the batteries or severely undercharge and overextend others. Either way, you drastically cut the life of the battery. In theorey, if you were using individual chargers, you could do this, but even then, while running your batteries would discharge quite unevenly, leading to unanticipated and unnecessary voltage drop, leading to poorer performance.

In short, it's just not a good idea. But if you were stuck in the middle of the desert, with an assortment of random batteries, yes you could make it work. Until it blew up, anyway.


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## favguy (May 2, 2008)

Nomad, I laughed out load at the thought of a 240volt 200Ah Pb pack  Can you imagine the acceleration, or lack of it!!! If you could even find a vehicle capable of carrying it all


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## JRP3 (Mar 7, 2008)

Closest I've seen, and still only half the voltage
http://www.evalbum.com/037


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## Jokerzwild (Jun 11, 2009)

Im not going to use lead acid at 240v 200ah, that would only be Lifepo #'s. Even then I would go around 240V 120ah. If I use Lead Acid it will be because I just want to run to the track and back so 240V 50ah.


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