# Electric Miata, my 2nd EV conversion



## kerrymann (Feb 17, 2011)

Picture of the "new" car:


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## kerrymann (Feb 17, 2011)

And a couple pics for inspiration:


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## kerrymann (Feb 17, 2011)

Today my clutch kit arrived, aluminum flywheel, etc. I went with a Stage 3 becasue the electric motor can put out more then twice the torque as the stock engine. 


​ 
This clutch and flywheel is the lightest I have ever held. The flywheel is only 8 lbs which is 33% less then the stock cast iron and I am going to lighten it up a bit more.  Weight here is particularly important because it is mass rotating at <8000rpm. I was suprised that in all my searchining for deals on kits adding the flywheel only cost $60 more. It would cost me haldf that to have the cast iron resurfaced.


​ 

I don't need the starter ring so I am taking it off to save the weight. 


​ 

Yes I am trying to make my flywheel cooler, but I am not making a pun. To help I threw it in the deep freeze. The aluminum shrinks much faster then the steel ring so this will give me a fighting chance of being able to get it off.

Now if only I knew where my motor adapter is going to come I would start ripping out the motor.... :-/


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## kerrymann (Feb 17, 2011)

After 30 mintues in the deep freeze and 3 minutes of hammering, the starter ring is off. The flywheel now only weighs 5.7lbs. 

​


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## kerrymann (Feb 17, 2011)

No progress on the car as I am still waiting for my motor adapter. It is supposed to be done this week and at which time I will start ripping things out. But I have started the first steps on my pack.

*Battery Testing *

Last night I received a batch of A123 cells and I am starting testing. For those that don't know these are very good batteries that can put out over 20C and have shown very good life cycle in the labs at more reasonable discharge rates. 

http://www.a123systems.com/products-cells-prismatic-pouch-cell.htm​ 

The problem is they don't sell to individuals, only OEMs. So the only way to buy them is on the gray market. There is a lot of speculation about how they get on the gray market; some are rejects that don't meet specs (usually slight low capacities) and many have had the tabs cut to make them difficult to use. The other theory is they are not selling as may as they planned so there South Korean factory is selling them out the back door without corporate knowing about it. Finally some are just outright fakes. But all of them have to be bought from China (since people will sell ANYTHING in china without fear of lawsuits). I bought 8 of them from my supplier to make sure they were good before going off and blowing $5k on the ~220 cells for a full pack. If these check out then I will use them to make up my 12V battery. 


​ 

I am pretty confident these are real A123s that came out the back door given the serial numbers were sharpied out and some of the other markings. 

*Romulus Anode?*


​ 

The first check with a DMM and not a good sign on three. The 3 cells with an extra sticker that says "Romulus Anode" have just over 2V.  I am doing a 2 cycle charge/discharge on one of the cells right now so we will see how it comes out when I get home from work tonight. 


​ 

FYI, Romulus doesn't refer to StarTrek rather it's Romulus, MI where A123 makes they anodes as opposed to the Chinese supplier they used before. I have been doing more research on the fabrication of these cells and it seems a bit odd. They are all labelled made in the USA but common knowledge holds that they are actually made in South Korea. I find it odd that A123 would fabricate components in the USA then ship to Korea for assembly and them ship them back to USA to assemble into packs. I would think they would manage their supply change better then that.


*Test Cell*


​ 

Here is my test station. A CellPro PowerLab 6 hooked to a PC. It's a bit ad-hoc right now as I can't find my other set of test leads and I have to do some more digging to figure out how to get the PL6 to go to 40amps instead of the 10amps I am limited to now. Even though I have selected a battery power source with 40amp max, the highest it will let me select is 10amps. Speaking of the power source it is a couple of left over 24V batteries from the leadwing project with a trickle charger. I am also using a book plus a battery to provide some compression on the sides of the cell during cycles. This evening I will make some improvements to the set-up.

​


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## steven4601 (Nov 11, 2010)

Building an EV is nice, building a 2nd EV is even nicer.

Where did you order the pouch cells? Did you consider already how to mount/package them?


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## kerrymann (Feb 17, 2011)

steven4601 said:


> Building an EV is nice, building a 2nd EV is even nicer.
> 
> Where did you order the pouch cells? Did you consider already how to mount/package them?


I have a couple of people I am looking at weighing cost and risk. 

My current plan is a stacked pack. Turns out very similar to A123's set-up but without laser welding. 

​
Originally I was planning on 3 packs with just 66 cells in series but a BMS makes that less then ideal so I think I will be doing 3 packs of 3P11S. I am still working on the electical connection but am leaning toward a simple clamp and spacer system.


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## kerrymann (Feb 17, 2011)

Well so far so good. The 2V Roumuls anode cell actually showed the highest capacity at just over 19ah which is much better then expected. Most people have been reporting capacities in the 17.5-18.5 range. 




I still need to check the remaining cells since I only have a sample set of 3 so far. Right now I have cell #4 doing infinite cycles and I will check tonight and see how it is doing. 

I still haven't spent anytime trying to get the software to go to 40 amps. Anyone have any suggestions? Doing it at 10 amps obviously takes 4 times as long.

One other thought I had is that there are several people on DIY forum that are testing these batteries from different vendors using the CellPro Powerlab6. If we all use the same test settings and post our data we can make a community pool of cell data that people can reference.


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## drgrieve (Apr 14, 2011)

kerrymann said:


> I still haven't spent anytime trying to get the software to go to 40 amps. Anyone have any suggestions? Doing it at 10 amps obviously takes 4 times as long.


Post this question in the battery sub-forum, there will be a few folks there that can answer this question.

They can also share their test settings.

Cheers.


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## kerrymann (Feb 17, 2011)

Since I am still waiting for my motor adapter I have been doing some work on the battery pack. I have tested the 8 cells I received and found the capacity ranged from 17.2ah to over 19.2ah.  Not very good for building a balanced pack. I contacted the seller but have yet to hear back. We'll see what happens but this is exactly why I ordered 8 first instead of jumping in to the full 220. There are other suppliers of these cells that I am looking into so I have certainly not given up on them. 

I did some prototyping of a pack by making up some end plates so I could band the pack and get good compression on the cells. Does anyone know how much pressure you need to need on the cells? 

My design uses a .120 aluminum sheet cut and bent to serve as endplates. To make fabrication easier I made a plywood template for the flat pattern of the plates. I should have used MDF but I happened to have a correct sized piece of ply laying around

​
I then used a .25" carbide router bit in a normal router and now I can make a blank in less then a minute.

​
I made one up using some scrap aluminium I had laying around and the first tab I bent promptly broke off. I guess it's T6.  So 30 seconds with the torch and I annealed it so I was able to bend it with hand tools. Not ideal but works for proving out the design.

Here is how the end plate looks on 7 of the cells I have.

​I am going to do a bit of tweaking of the design and see if I get get some 6061-T0 otherwise I'll just aneall the stuff I have and make a prototype 1p8s pack.


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## kerrymann (Feb 17, 2011)

*The conversion begins*

Well today the conversion started in earnest. I was waiting for my adapter and hub to come but I got the answer of "it'll be done next week" for the third time. I saw someone post that Electric Car Company could not get a delivery date right to save their lives and I am having to agree. :-(

Anyway I got tired of waiting and so I started tearing the car down. I wanted to have everything but the pack kitted before I started, but what the heck... I pulled the exhaust first along with the convertible top, emptied out the truck. 

​ 
This was 131lbs removed from the car! I then turned my attention to the front where I pulled the radiator, A/C PS, headers, etc. I was surprised how relatively easy everything came out. It's nice not having every nut and bolt rusted solid.  

​ 
​ 

So after 3 hours of work I now have the engine all disconnected and as soon as I locate a engine hoist I will pull the long block.


​ 
It helped having my 3 year old son "working" with me. 

​ 
Another 75lbs of parts plus a couple gallons of fluid means I have easily dropped 200lbs that is not going back into the car. 

​ 
​ 
One part I will be saving and reusing is the AC accumulator. It will make a good reservoir for the electric vacuum pump I am using for the brakes. It's a little small but it's light, has fittings and a mount already, and it was free.


​ 
Interesting thing I found was the AC compressor was MISSING. Something the previous owner blatantly lied about when he said the AC worked. :-/ There were quite a few things about this car that would have been a real pain had I not been converting it. You would think a Pre-Law grad would have had better ethics... never mind...

On the bright side a guy bought the stock catback for $50 (got to love CL) and I found a place that will buy the catalytic converter for $90 (scrap platinum).


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## kerrymann (Feb 17, 2011)

Well this morning my wife and son were out doing the weekly shopping so I decide to tackle the removal of the fuel tank since the fuel vapor and torch are not 3 year old friendly. 

The first step was draining the fuel tank and line from the lowest point I just bent down one of the lines from the engine bay and into a 5 gal can. 



​
I then pulled the fuel pump assembly out which gave me great access to the tank. I used a hand pump to siphon out the last bit of fuel from the tank. 


​

Then I filled the tank with soapy water. Make sure you leave the filler neck on so you can fill the entire tank. Luckily today was nice a windy so with the garage door open I had great ventilation.




​
The next step was removing the tank. It's held in with 4 bolts that are easily removed but the problem is to drop the tank you need to pull out the rear sub frame. So instead I decided to cut out the sheetmetal above using a oxyacetylene torch. I need the sheetmetal out anyway because I need the space for batteries. This is not for the faint of heart. I doused the area with water to minimize the chance of igniting the insulation but did have a few minor flare ups due to all the oil suck underneath. The pass rear diff seal was leaking and slinging oil everywhere. If you do this make sure you fill the fuel lines with water too. Again don't try this at home unless you know what you are doing.



​
I am draining the tank of water and will get around to start the fun part of yanking and cutting.



​But that will wait for another day.​


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## drgrieve (Apr 14, 2011)

One thing you can do to minimise the ah difference between cells is to match the paralleled cell to the ah average of your pack.

See this thread for more info: http://www.diyelectriccar.com/forums/showthread.php?t=67805


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## kerrymann (Feb 17, 2011)

drgrieve said:


> One thing you can do to minimise the ah difference between cells is to match the paralleled cell to the ah average of your pack.
> 
> See this thread for more info: http://www.diyelectriccar.com/forums/showthread.php?t=67805


Thanks, I have been reading up on Electric Porsche's build and kakheath's. That is definitely what I will do but the wider the ah range the more challenging the matching. The way my pack is designed now I will be doing 2 packs of 2p100s which may make it impossible with this large range of capacity. I have one outlier in the 8 so if I through out that one cell the std deviation becomes much more reasonable. I am talking with the seller now about what he will guarantee as I can't eat 12% in "bad" cells.


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## kerrymann (Feb 17, 2011)

BTW I did figure out why I couldn't get the 40amp charge discharge on my PL6. The FMA cable was pinned wrong the positive which was supposed to be on pin 9 was instead on pin 7. This is why I was getting a bad cell count warning. The tech support guy said they must have sent me a wrong cable (xh?) but a quick change and I can now overheat my "heavy duty" test leads at 40 amps.


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## kerrymann (Feb 17, 2011)

*Old engine out, just waiting for the new motor*

*Old engine out, just waiting for the new motor *

Well today I pulled engine because I finally got a buyer for the engine from my CL ad. He bought it for $650 and the best part was he brought a engine hoist to pull the motor. It went pretty easy once I got the starter pulled.


​ 
​ 
I would love to install the motor but I am STILL waiting for my adapter from Electric Car Company International. I was told it would be delivered in less then a week and a half of payment. It has now been about a month and a half!!!! I knew I should have just built my own. Buying one was supposed to be faster and easier.... yeah right. It is supposed to be delivered on Monday, we'll see....


​ 

Until the motor adapter and hum finally arrives I have to sit in as the powerplant. Unfortunately my power to weight ratio is much worse then the 9" motor.


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## njloof (Nov 21, 2011)

Looking good, man. I think you're gonna be solidly ahead of me, I'm pulling my engine next week.

Sorry to hear about your adapter plate woes, mine arrived very quickly from EV Source.


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## kerrymann (Feb 17, 2011)

njloof said:


> Looking good, man. I think you're gonna be solidly ahead of me, I'm pulling my engine next week.
> 
> Sorry to hear about your adapter plate woes, mine arrived very quickly from EV Source.


Thanks. I actually feel like things have been moving slowly because I have been working/traveling a lot recently. Hopefully I won't have to travel for work again until end of May and my adapter will be here tomorrow so I can start making more progess.


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## kerrymann (Feb 17, 2011)

*Armstrong power steering *



Tiny update today. I did a power steering delete tonight. For cars this light power steering is really not needed. It will take a little effort in parking lots but it's really not needed. This saves me the weight , energy and and it's really easy. I have done this before on a 1987 BMW 325 track car I had for the 24 hours of Lemons, but that is another story...

Anyway there are several ways to do this:

#1: - Install a non-powered rack. 
This gives it a factory manual ratio but you have to find a rack (which is not easy given the popularity of spec miata racing) and has a slower rate that helps in the parking lots but not so much on the twisties.

#2 - Depower the rack. 
This is keeping your original rack and modifying it to operate manually. And there are two ways to do this the hard way and a really easy way.

#2a - Sealectomy
Which is to pull the rack apart and remove the internal seals and reassemble it:

http://www.flyinmiata.com/tech/depower.php

While it is the *best* way, I think it is overkill.

#2b - Plug and loop (what I did)
Here you start by plugging the ports from the power steering lines. If you just did this the steering would be very stiff because you are having to pump the fluid back and forth. To solve this, you cut the lines small lines that go from the valve to the rack and the turn the steering lock to lock to blow out the extra fluid. This will not remove all of the fluid so it will still lubricate the rack and pinion gears. To keep dirt, water, condensation, bugs, etc from getting it you put two short pieces of hose between so when you steer you just move air from one side of the rack to the other.


​ I actually reused some of the fuel hose I removed with the fuel tank. I know people that have done this to their miata's and 7 years later they are still going strong. 

In the end it cost me $0 and took 15 minutes. 

Simplify and add lightness.


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## kerrymann (Feb 17, 2011)

*One step forward, one step back*

One step forward, one step back 

The long awaited adapter and hub arrived today and for the most part it seems good except for a couple of issues which I will go into more later. I started by nailing a couple pieces of wood to my workbench to cradle the motor. The last thing I wanted was a 180lb chunk of metal to roll of the workbench on to my toes!
​ 

*The adapter plate*

​ 
The adapter is made of 3 pieces of aluminum plate that apparently have been water-jet cut. They are attached to the motor with 4 bolts that were included along with 8 flat washers (presumably to keep the bolt from shanking out) and 4 split washers. I normally don’t see plate this thick water-jetted because of the kerf from the jet fanning out. It is okay as long as you account for it by giving plenty of clearance to adjacent parts. I am not crazy about it for the mounting bolts but this plate is so thick it shouldn’t be a factor. 

​ 
The first really issue is the hole in the plates for the hub is just barely oversized and the tolerance of the plate means it’s not quite centered on the shaft. Because there was so small of a gap designed between the hub and plate, this just bearly causes an interference. There is no play in the bolts mounting the plates to the hub so the hole in the plates must be opened up or the hub turned down (I think the best answer is both). 

This really could have been avoided by making center hole ID (Inside Diameter) much bigger. All of that aluminum inside the 4 motor mounting holes is not doing any good. It doesn’t carry any load and is just dead weight that should have been just put into the recycle bin for the machine shop to get a few bucks back.

​ 

One last note on those split washers. In this application they are useless because you have to use the flat washers underneath them. Split washers only *work* when they make contact between the base part and the fastener. I will be using Loctite to keep these in place.

*The hub*

​ 
The design of the hub is… interesting. It looks like part of a cast shaft coupling that screwed into the actual hub by 3 M10? socket head cap screws. These screws alone would not be sufficient to carry the repeated +200ft-lbs torque of the 9” motor but since the coupling appears to be wedged in (kind of like a taper lock) when you clamp it up it should be strong enough. The hub is also larger in OD (Outside Diameter) then it needs to be which like the ID of the adapter is un-necessary weight and leads to the interference above but also causes a interference with the flywheel. The flywheel has a recess that would normally go around the end of the crankshaft. The hub is considerably larger OD then the original crank so it does not fit inside.

I am going to email Electric Car Company and we’ll see what they say. I am sure they will fix the issues but it's a matter of how long it will take. I have a feeling I may be borrowing some lathe time soon to turn down the hub OD and opening up the plate IDs myself just to make it happen faster.

One other issue is I don’t have bolts for the flywheel. :-( This is 100% my fault because I should have resused the ones from the engine. But I left the old clutch and flywheel on for the guy who bought the engine as he was converting from auto to manual. Oops.


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## TigerNut (Dec 18, 2009)

Maybe you can use the other three holes in the adapter to install dowel pins? You'd want to be sure that those never crept out and gouged their way around the motor bearing... but it would more than double your torque capability.

Is there anything on the three waterjet-cut plates that registers them together, and centers the motor and transmission using the OEM dowel pins and the motor's bearing end register? If not, you can easily be far enough out of alignment between the motor shaft and the transmission shaft to cause long-term bearing life issues. The typical alignment error on an OEM engine to transmission bellhousing is under 0.005" (that's the maximum runout limit suggested by Lakewood) and probably more like 0.002".


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## kerrymann (Feb 17, 2011)

TigerNut said:


> Maybe you can use the other three holes in the adapter to install dowel pins? You'd want to be sure that those never crept out and gouged their way around the motor bearing... but it would more than double your torque capability.
> 
> Is there anything on the three waterjet-cut plates that registers them together, and centers the motor and transmission using the OEM dowel pins and the motor's bearing end register? If not, you can easily be far enough out of alignment between the motor shaft and the transmission shaft to cause long-term bearing life issues. The typical alignment error on an OEM engine to transmission bellhousing is under 0.005" (that's the maximum runout limit suggested by Lakewood) and probably more like 0.002".


The lack of registration is a concern of mine as well (among a few others). There is a reason the original engine had 2 large dowel pins that engauged the bellhousing, for alignment, just as you said. Then add the tolerance stack-up of 3 plates that are waterjet cut and it's no strech to think it could be out as much as .030". Measuring the misalignement of the hub to the input shaft isn't easy though...


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## TigerNut (Dec 18, 2009)

kerrymann said:


> The lack of registration is a concern of mine as well (among a few others). There is a reason the original engine had 2 large dowel pins that engauged the bellhousing, for alignment, just as you said. Then add the tolerance stack-up of 3 plates that are waterjet cut and it's no strech to think it could be out as much as .030". Measuring the misalignement of the hub to the input shaft isn't easy though...


Maybe try talking to Flyin' Miata and see if they have coordinates for the dowel pins and bellhousing bolt locations relative to the OEM crankshaft center. That would give you one side of the answer, anyway... then you'd have to determine how to register the motor drive end on the last plate, and key the three plates together.

http://www.flyinmiata.com


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## Tesseract (Sep 27, 2008)

kerrymann said:


> The lack of registration is a concern of mine as well (among a few others). There is a reason the original engine had 2 large dowel pins that engauged the bellhousing, for alignment, just as you said. Then add the tolerance stack-up of 3 plates that are waterjet cut and it's no strech to think it could be out as much as .030". Measuring the misalignement of the hub to the input shaft isn't easy though...


Did you consider (and reject on price) this Rebirth Auto adapter for the Mazda Miata?


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## kerrymann (Feb 17, 2011)

TigerNut said:


> Maybe try talking to Flyin' Miata and see if they have coordinates for the dowel pins and bellhousing bolt locations relative to the OEM crankshaft center. That would give you one side of the answer, anyway... then you'd have to determine how to register the motor drive end on the last plate, and key the three plates together.
> 
> http://www.flyinmiata.com


This morning I measured the mis-alignment between the center of the adapter and the motor shaft and it is 0.035" (.070" total runout). This doesn't even include the slop and mis-alignment between the bellhousing and the plate which is probably going to be another .005-.015. The only "fix" I see to these issues is to lathe the hub down so it fits the flywheel, and chuck the 3 plates into a mill to open up the ID and add registration pins. Based on the experience so far I don't dare to hope this will happen
quickly. I am at the point where I asked to have to return this,
get a refund, and buy from another supplier. We'll see what they say.



Tesseract said:


> Did you consider (and reject on price) this Rebirth Auto adapter for the Mazda Miata?


Yes... I did. Ironically that part was what I was originally planning for but I believe last summer when I spec'd it was about $900 shipped as opposed to $1300 shipped. I guess I had a hard time swallowing paying more for the adapter then I did for the motor...

In hindsight I am wondering if I should have skipped the cost of the clutch and adapter and just gotten a Transwarp 11 motor and gone direct drive for the same price. Of course direct drive has it's own considerations....

Kerry


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## kerrymann (Feb 17, 2011)

*Motor Dry Fit!*

*Motor Dry Fit! *



Well I am still in discussions with Electric Car Company about my adapter. I just heard from Steve at Rebirth that a adapter from them will be a 7-10 day lead time. Lesson learned...

So yesterday I pressure washed the 178,000 miles off grease of the car so when I work on it I don't look like a coal miner. 

​ 
And tonight I deiced to go ahead and dry fit the motor without the hub. I first needed to layout the motor cradle so I found a short section of heavy wall 1.25" pipe that had a nice tight fit over the input shaft. This allowed me to measure the height and see that the cradle fit really well if I welded it to the sub-frame.

​ 
The cradle is the same style I used on the leadwing. It's actually a mount for large high pressure cylinders (9" OD) in military ships. It even comes with a warranty plate circa 1988. Either way it is very stout, comes with all the hardware, and was $30 for two of them shipped! 

It will need some modification but for now I just tacked it into place to dry fit the motor.


​ 
I am glad that I went with the 9" motor as once I put on the adapter on the assembly weighed over 210lbs! This really wasn't bad to lift, carry and man-handle into place, but if I had a 11" (~350lbs) I would have definitely need a hoist.

​ 

Anyway the motor fits in really well. I am going to trim the cradle away some before I weld it all in as I think I can lower it about another 1" to give a little better CG. Seems excessive but this is the heaviest single item on the car.


​ 
You can also see the the great space in front of the motor for one of the pack modules (with the help of my assistant). I was originally planning on splitting the pack into 2 modules but it would be a little too long. So I am going to do 3 instead to fit between the the frame rails.


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## kerrymann (Feb 17, 2011)

*Controller fitting*

​ 
I also test fit the controller. That Soliton1 is such a great piece of eye candy that I couldn't tuck it off into a corner. So just like on the leadwing I am going to put it front and center. I am considering 2 options: This first is mounting it parallel to the motor. Looks nice and would be fairly easy to mount. 



And a 4 year old in thedriver's seat making motor noises makes it even better 

I might even put it in a bit of an angle just to show it off more and get a little more clearance in the front for the pack. 

​ 
The other option is to put in perpendicular. I am planning on putting in a strut tower brace so it would be REALLY easy to mount the controller and it hides the wiring by pointing toward the firewall. But it doesn't look right.... I'll do some more head scratching but I am leaning towards putting it in long way. I think if I did it sideways it would be a detail that would bug me.

​ 
Of course every knows that blowing bubbles on your controller is good luck for an EV....

​ 
If only the adapter was correct I would be really close to hooking up a few SLAs and driving arounf the driveway....​


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## kerrymann (Feb 17, 2011)

*Getting the charge on the charge card*

*Getting the charge on the charge card *



A bit of an update on the project. I haven't done much on the actual build due to the adapter woes but I have spent a fair bit of money.

I ordered and received my batteries! 250 A123 cells with full tabs. I really wonder when the delivery driver looked at the shipment he had thoughts of being used as a drug mule. 


​ 
The bad news is my PL6 died but the good news is the warranty replacement is supposed to arrive Monday. Once it arrives I will start taking data and post the results here:

http://www.diyelectriccar.com/forums/showthread.php/standardized-pl6-testing-a123-cells-and-71283.html


I got my cable and crimper and connectors so I can start making up my cables. I was able to find a good US made bench top manual crimper, new for a decent price. Luckily for me the seller didn't do a good job of describing it on ebay and it took 30 minutes of websurfing to find out exactly what it was. http://www.uzengprod.com/ I wanted a crimper that, when used with the right terminals, would be UL listed and would have at least 3 crimp points. I did some searching and found most lug install specs require a minimum of 3 crimp points (NASA says 4 but this isn't a spacecraft  so that eliminated all of the cheap crimpers except the the Chinese green lee hydraulic knock offs. I will gladly spend a few extra buck for an American made product.

​ 
The connectors are new Molex lugs and the cable is very good 2/0 bright orange cable (safety requirement for first responders) that I ordered from Trystar. I like to buy in bulk and so I have enough to do 4 or 5 cars. I am thinking about offering to make cables for whom ever doesn't want to go out and buy a good crimper and do it themselves. When I did the Leadwing I used a battery cable company but they were pricey for cables over a few feet.


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## kerrymann (Feb 17, 2011)

*Not-so Adapting Adapter*

*Not-so Adapting Adapter *



I emailed Electric Car Company and told them I was returning it for a full refund and asked for a return shipping label. A few days later I received a return shipping label but no other communication from them. I mailed it out and hope to get my refund soon. BTW that adapter weighed in at 28lbs!

So I went ahead and ordered the performance adapter from rebirth auto since they said 7-10 day turn around.

http://rebirthauto.com/mazdamiatamotoradapter.aspx

​


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## EV-propulsion.com (Jun 1, 2009)

*Re: Not-so Adapting Adapter*

We use those adapters in our miata conversions, it is a work of art, you are really going to like it. The full floating coupler eliminates all kinds of issues. 
Mike
www.EV-propulsion.com


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## kerrymann (Feb 17, 2011)

*Re: Not-so Adapting Adapter*



EV-propulsion.com said:


> We use those adapters in our miata conversions, it is a work of art, you are really going to like it. The full floating coupler eliminates all kinds of issues.
> Mike
> www.EV-propulsion.com


Yeah, I have no doubt I will be happy with it. Everything I have seen says they are a good group of guys and have many happy customers. Sometimes you get what you pay for (at this price I certainly hope so. .


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## kerrymann (Feb 17, 2011)

*Wait! Weight?!?*

*Wait! Weight?!? *



Well with the car down to a roller I decided to see what the weight was. Lesson learned from prototyping aircraft is to follow-up and check the weight periodically to avoid the surprise of having a 200lb useful load.  The weight always creeps up and you have to deal with it, this car was no exception.  

Unfortunately I never did get it to the gravel yard to weigh it before hand but the published curb weight is 2400lbs. Now that 2400lbs doesn't include any options and my donor was fully loaded with PS, AC, AM/FM/CD, leather seats with built in speakers, etc. I have been weighing all of my parts as they come off the car with a bathroom scale. I have been doing it in boxes so that the accuracy errors don't add up (errors are rarely linear). I did not weigh the engine I removed but research says it should be about 300lbs wet. I also did not weight fluids but everything else was accounted for:

3/15:
Exhaust: 36.2lbs
Spare Tire: 22lbs
Top and Frame: 34.6lbs
Top parts, rear compartment panels, rear carpet: 38.2lbs 
131.2lbs removed

3/17
Radiator 17.6lb
Airfilter and Misc: 12.2lbs
Header and downpipe: 18.0lbs
PS + hoses, AC (partial), misc 24.6lbs
72.4lbs removed

Engine: 300lbs (est)
Fuel tank and hoses: 27lbs

*630.6lbs removed (ERROR should be 530.6)*
2400lbs - 5*3*0.6lbs = 1*8*69.4lbs

Now how to weigh my roller? Well I could spend $1700 for a nice set of race scales that I would but under all 4 wheels but I don't have that money to blow so I went for a cheap solution. I bought 2 scales with a 440lb weight limit for $25 each (you can find them on sale for $17 sometimes). 

http://www.amazon.com/gp/product/B00472I1V2/ref=oh_o01_s00_i00_details

Now based on a few tests I would say the scales are accurate to ±5lbs but that is good enough for my for the car weight. So to avoid exceeding the max weight I put a 2x6 across the 2 scales and recorded both weights. I jacked up each corner and got 4 weights, one at a time.

​ 
FL: 248.6+220.0=468.6lbs
FR: 264.2+220.0=484.2lbs
RL: 293.6+212.8=506.4lbs
RR: 286.7+222.0=508.7lbs

That puts the roller weight at: 1925.9lbs  I am 75lbs over my estimate of where I should be today

Now adding up the weights of my other parts the weight will be ~2800lbs at in street form. Well above my final target of 2204lb (1 metric ton) but I do have some more weight reduction (heater, air conditioning, stereo, lighter seats, windows.....). That 1ton goal is for a very stripped down version but all this doesn't fully add up since I know of people with ICE powered NA miatas at 1800lbs. Part of the weight increase is I have upped my pack size. 
BTW I apologize for using the antiquated units, my old scale was in lbs but from now on I will be recording in the proper units, SI.

Hopefully next week I will have my PL6 battery tester back and a motor adapter so I can make some real progress.


----------



## rwaudio (May 22, 2008)

*Re: Wait! Weight?!?*



kerrymann said:


> *Wait! Weight?!? *
> 
> 
> 
> ...


I was contemplating doing the same thing to weigh my 944 but didn't have anything suitable at the time to level the opposite side of the car. I'm not sure how you did yours but if the other 3 tires are flat on the floor your results will be a bit "heavy". For it to work properly you should have 3 spacer blocks the same height as your scales + 2x6 so that the suspension is always at the same height on all 4 corners. Then you just trade a spacer block with the scale set-up to measure each corner.


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## kerrymann (Feb 17, 2011)

*Re: Wait! Weight?!?*



rwaudio said:


> I was contemplating doing the same thing to weigh my 944 but didn't have anything suitable at the time to level the opposite side of the car. I'm not sure how you did yours but if the other 3 tires are flat on the floor your results will be a bit "heavy". For it to work properly you should have 3 spacer blocks the same height as your scales + 2x6 so that the suspension is always at the same height on all 4 corners. Then you just trade a spacer block with the scale set-up to measure each corner.


I had throught about that but assumed the difference was small enough it would be in the noise: cosine of the angle, blah, blah, blah... But reading your reply one of my favorite phrases popped into my head : "One test is worth a thousand expert opinions." I'll try it with blocks here in a bit and let you know.


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## kerrymann (Feb 17, 2011)

Well, I was wrong. Unless you consider 12% to be "in the noise"

FL: 80.2+76.6=156.8kg
FR: 103.4+85.4=188.8kg
RL: 97.7+80.7=178.4kg
RR: 74.4+109.7=184.1kg

*Total=708.1kg=1561lbs!* 

That is a 200 pound difference and means I am *25lbs under* where my calcs say I should be. This is only ~10% lower then my first measurement but it makes a big difference. I did do a few measurements and found it was repeatable within a couple kgs. The real answer will be when I weigh it finished but it's good to know I am on the right track (pun intended).

Thanks!


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## somanywelps (Jan 25, 2012)

yay. 

Looking good


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## rwaudio (May 22, 2008)

kerrymann said:


> Well, I was wrong. Unless you consider 12% to be "in the noise"
> 
> FL: 80.2+76.6=156.8kg
> FR: 103.4+85.4=188.8kg
> ...


Nice 

200lbs is significant

Edit... your new difference is 364lbs, is there a typo somewhere?


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## kerrymann (Feb 17, 2011)

rwaudio said:


> Nice
> 
> 200lbs is significant
> 
> Edit... your new difference is 364lbs, is there a typo somewhere?


Entirely possible, the disadvantages of multitasking is not checking your work.  That and while rum does speed up disassembly it can hamper the quality of calculations. . Now that the family is asleep, the weight reduction continues, and I should have a better weight in the morning.

Edit :. You are right. I am actually 200 lbs under my *estimate* which makes me skeptical (good news always makes me skeptical). The cheapo measurement system needs more research.


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## kerrymann (Feb 17, 2011)

For those removing the dash in a Miata to strip those pesky (heavy) ECS systems, here is a great write up on pulling the dash:

http://www.miata.net/garage/DashRmv_89_93.pdf


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## Ziggythewiz (May 16, 2010)

kerrymann said:


> skeptical (good news always makes me skeptical). The cheapo measurement system needs more research.


Have you checked to see if there are any DOT weigh stations near you? I've heard of many people using these, don't have any within my range though.


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## kerrymann (Feb 17, 2011)

Ziggythewiz said:


> Have you checked to see if there are any DOT weigh stations near you? I've heard of many people using these, don't have any within my range though.


None nearby. There is a gravel yard semi closes that I was intending on using before I tore out the ICE but now don't I want to spend the time towing it down. Instead I am going to weigh our prius. We are driving down to Colorado Springs to see the in-laws and there is a weigh station on the way. Once I get that weight I have have a well known value that I can use to try to work out the kinks in the cheapo scales.


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## kerrymann (Feb 17, 2011)

Check your work

As I stated back in the first post I was planning the car in two phases:

"Stage 1: Get it Running
A pretty straight froward EV conversion using the motor and controller I tested on the Leadwing. I will get it running and registered keeping the rest of the car pretty stock. Many other people have done miata conversions with adapters and mounts being available off the shelf. The big question for me (as is most converters) is the battery pack. Right now I am leaning toward some gray market A123 cells. Specifically the AMP20M1HD-A. I am talking with one guy and going to order a few for testing.

Stage 2: Get Crazy
The second stage will be stripping the car down to a fair weather only superlight speedster. No top, maybe even no windshield depending on how crazy I get. I will be replacing the front bumper with some custom fiberglass to get rid of the engine cooling scoop but I am toying around with a fiberglass front clip to save more weight. I will fab a real roll hoop/cage for protection. Without the constraints for a top I can make a cage that will provide real head protection. I used to run SCCA time trials"

For my miata there are actually 2 starting and finished weights I am concerned with. 

1: Street form: conversion of the ICE to EV but all other things pretty much left alone. Starting weight 2400lbs
2: Superlite form: stripped down to a fair weather only car. Starting weight: ~1825lbs with ICE. See http://www.lightweightmiata.com/beast/

In my excel that I was using to track weights I was getting the values for these two stages confused. This is due largely to the delays surrounding the adapter I have started into stage 2 stuff to keep the ball rolling and I will end up with a stage 1.5. Also looking at my original calcs i carried the 1 one too many times so I had weighed 530lbs of stuff I took off, not 630 (I went back and corrected my post). I dove into the weights more and here is where I should have been yesterday:

Mazda 
lb kg Miata 
Stock Miata 1082.7
Exhaust 36.2 16.5 1066.3
Spare Tire 22 10.0 1056.3
Top and Frame 34.6 15.7 1040.5
Top parts, rear compartment panels, rear carpet 38.2 17.4 1023.2
Radiator 17.6 8.0 1015.2
Airfilter and Misc 12.2 5.5 1009.6
Header and downpipe 18 8.2 1001.5
PS + hoses, AC (partial) 24.6 11.2 990.3
Engine 300 136.4 853.9
Fuel tank and hoses 27 12.3 841.6
10 gallons of gas 60 27.3 814.4
5 quarts of oil 8.8 4.0 810.4
1 gallon of coolant 7 3.2 *807.2kg*


The final error I found was one of the last cells I mis-typed my conversion from kg to lbs as 2.6:1 instead of 2.2. That puts me at an estimated 2273lbs or 1033kg EV curb weight. Right where I planned to be.

So I have gotten my weight estimates straightened up but I still have some work on the cheapo weigh station. The two weights I got yesterday were: 1925lbs and 1561lbs with reality lying somewhere in between. Like I was saying, we are driving down to Colorado Springs to see the in-laws and there is a weigh station on the way that we will weigh our Prius. . Once I get that weight I have have a well known value that I can use to try to work out the kinks in the cheapo scales. 

This afternoon I will also total up my additional weight reduction from last night and see how that has helped.


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## kerrymann (Feb 17, 2011)

According to the weigh station our prius (sans people) was 3200lbs ±20lbs. Using the cheapo scales was challenging because this was right at the limit so I needed to make sure the scales in the front shared the load equally which required numerous attmepts. 

The final answer was 1402.5kg=3092lbs difference of 98lbs ±20lbs from the certified scales.

This means on average each corner is off about 24lbs, so each scale is off 12lbs

I did do some more repeatablity tests and found a maximum variance of 11.1kg=24.5lbs at one corner! I dug deeper into the scales and got a maximum variance of 8lbs with me just getting on and off over a long time period. I noticed the scales do not leave enough time for the load to settle before displaying the final reading which I think is the main cause.

In the end the scales are pretty bad. I selected these because I had good luck with the previous model, which they don't make anymore and figured the new ones would work as good, or better. Amazon is getting a return: 8lb variance is unacceptable for even a bathroom scale.

I could try with new scales but it's has already been more trouble then it's worth.

On the bright side I removed another 16.7kg by yanking out the heat, AC, engine noise insulation, stereo, etc. Also the seats weighed in at just shy of 19kg each! The seats I am going to use are 5kg. This means 44.7kgs are coming off the car but not going back on.


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## Mark C (Jun 25, 2010)

I know you considered DOT weigh stations, but have you considered your local garbage dump. I've weighed my cars there for free before, they just let me drive on and weigh them. I usually pull only the front tires on, get a weight, move it onto the scale with all four, get a weight and then drive the fronts off the scales and get a final weight. 

Of course, you have to do this when there isn't anyone waiting to drop their garbage off. On a similar vein, do you have a scrap metal yard nearby? They might be willing to do this too, as long as there isn't a line waiting at the scales.


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## kerrymann (Feb 17, 2011)

*More batteries and some progress on the car *



Well I just got back in town and realized I am way past due for a blog update. I was out this past week for a seminar on energy storage at Ohio State University for work that was presented by EWI. While I wasn't working on the car during the week (my excuse for lack of progress), I got to hear a lot about lithium based batteries and electric vehicles (among many other things). Ohio State/EWI has a very impressive program with some interesting results on battery life testing/modeling, methods for building packs, as well as talking to the staff about thir ECOcar and the very impressive buckeye bullet (current EV land speed record holder), and finally a presentation from Ford on there take on the EV market.


​
Before I left I did make some progress on the car but most of it was centered on cell testing. I have actually put together a testing procedure/lessons learned that I hope to release this weekend. But as of this post I have just over 200 cells tested. I think I should be done testing early next week!

I did complete the mounting for the Soliton1, the vacuum pump for the brakes, and the throttle is just about done.

The mount for the controller was made from some scrap steel using a torch and a hammer.


http://1.bp.blogspot.com/-XSkrKjd0h...6pfgul1BxFE/s1600/6935486612_7792b55cb7_m.jpg

​


I think in a previous life I was a blacksmith. 


​
For the throttle I ordered the evnetics one which was backordered and just came in. Like the controller it is a really nice piece of CNC work. The TPS is a automotive one and the even included a weatherpack connector with a pigtail ready to wire. Now that evnetics is making the throttles I wonder if their next controller can/will have a built in the throttle? This would reduce a lot of the faults/noise that people get when wiring it up themselves and are not careful enough. Anyway for my installation, I enlarged the outer hole just a little bit and cut two notches so I could slip the stock Mazda cable in. Anyone familiar with bikes will recognize this method for connecting brake cables.

​


I am going to mount it to my strut brace/controller mount. Why have one part only do 2 things when it can do 3? 


​

I have been also been spending time reviewing wiring diagrams. My plan right now is to utilize the stock wiring from the motor to pull of the few pins I need for the EV components. I found the wiring diagram online which made this pretty easy. 

www.madracki.com/*miata*/*wiring*.html

When testing I did notice that I am getting 2-3VDC with the key off. This probably explains why the previous owner kept having the battery die on him. I also found it interesting that the back of the cluster wa labeled at the connectors which made wiring easier.

​
The adapter was a little delayed from Rebirth because they couldn't get the dowel pins from Mazda in time. So they jut made some for me. Unfortunately it arrived while I was in Ohio so It has been sitting in the box waiting for me to return. When I got home I unboxed it and what a nice piece of engineering and CNC manufacturing. It's almost a shame it's going to be hardly seen. 

​
I did run into one problem when I tried to bolt on the flywheel. The hub is course threaded and the miata crankbolts are fine thread. I am not sure if there was supposed to a set of hardware included as I didn't get bolts for the motor interface either (I did get the key and the other parts that I ordered) Or was the hub supposed to be tapped for fine thread. I emailed Steve at rebirth and i'll see what he says but I will be making a trip to ACE to see what hardware I can find there.


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## kerrymann (Feb 17, 2011)

Mark C said:


> I know you considered DOT weigh stations, but have you considered your local garbage dump. I've weighed my cars there for free before, they just let me drive on and weigh them. I usually pull only the front tires on, get a weight, move it onto the scale with all four, get a weight and then drive the fronts off the scales and get a final weight.
> 
> Of course, you have to do this when there isn't anyone waiting to drop their garbage off. On a similar vein, do you have a scrap metal yard nearby? They might be willing to do this too, as long as there isn't a line waiting at the scales.


I have the gravel yard nearby that I can take it to that should work fine. I was just hoping I could have a cheap simple system that I could use while I am building the car to keep an eye on weight.


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## Tesseract (Sep 27, 2008)

kerrymann said:


> ...Now that evnetics is making the throttles I wonder if their next controller can/will have a built in the throttle? This would reduce a lot of the faults/noise that people get when wiring it up themselves and are not careful enough. ....


Huh? What are you wondering and what faults/noise are you talking about?


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## kerrymann (Feb 17, 2011)

Tesseract said:


> Huh? What are you wondering and what faults/noise are you talking about?


Sorry I wasn't very clear. When I was installing the throttle, I kept wanting to mount in on the controller itself. The half DEVELOPED thought was if the throttle was integrated to the contoller itself then it wouldn't need to be mounted/wired/or calibrated by the user (an a TPS housing you wouldn't need to build). Same ideas as the contactors. You knew the users would need a contactor and precharge circuit and just intergrated it in. This was one of the features that drew me to the Soliton over others. Of course this only works if the user doesn't need/want to user another throttle... 

As for the faults, I just saw a couple posts with users having faulty wiring that caused uninteded motor failures. This was at no fault of the controllers. Intergrated would be less noisey but I that isn't even an issue for these pots anyway (hall effect maybe a different mater).

Like I said, a half baked thought,


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## Tesseract (Sep 27, 2008)

kerrymann said:


> Sorry I wasn't very clear. When I was installing the throttle, I kept wanting to mount in on the controller itself. The half baked thought was if the throttle was integrated to the contoller itself then it wouldn't need to be mounted/wired/or calibrated by the user (an a TPS housing you wouldn't need to build).


Oh... that's a... very unique idea, let's call it...  

Obviously that would be exceptionally limiting as far as where to mount the controller, and it wouldn't alleviate the need to calibrate the throttle since not every accelerator pedal can "throw" the distance needed to move the TPS over its full range. 



kerrymann said:


> Same ideas as the contactors. You knew the users would need a contactor and precharge circuit and just intergrated it in.


I didn't do that because I wanted to make the user's life easier; I did it to make *my* life easier! Integrating the contactors and precharge was the only way I could ensure it was done properly and safely (have you noticed how many people use a *single* contactor - and I ain't talking a Bubba, either - for their Z1K and even Z2K installations?!?). At the very least I'd be put in the uncomfortable situation of having to tell those customers who connected their battery pack backwards or "forgot" to install the precharge resistor that their mishaps aren't covered under the warranty (NB - connecting a high enough voltage battery pack backwards to all controllers but the Shiva can still fatally damage the precharge circuit).




kerrymann said:


> As for the faults, I just saw a couple posts with users having faulty wiring that caused uninteded motor failures. This was at no fault of the controllers. Intergrated would be less noisey but I that isn't even an issue for these pots anyway (hall effect maybe a different mater)....


The two incidents I am aware of were not caused by noise at all. One person hit the "reset to factory defaults" button which clears the throttle calibration data (among other things) - we have since changed the code so that hitting the factory defaults button also disables the controller. The second person did not fully plug in the cable to the throttle assembly and apparently the ground wire wasn't making contact. He got out of his car - with the controller still in running mode - and fiddled around with the throttle until the connector reseated and the controller obliging unblocked the throttle, as it saw "zero" as required on startup for just a moment. There's nothing we can do about that one.

Getting noise out of the throttle signal is one of the most critical requirements for a motor controller and as far as I know we have never - not even during the prototyping period - had an issue with it.


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## kerrymann (Feb 17, 2011)

Tesseract said:


> Oh... that's a... very unique idea, let's call it...  .


I didn't say it was a good one. 



Tesseract said:


> The two incidents I am aware of were not caused by noise at all. One person hit the "reset to factory defaults" button which clears the throttle calibration data (among other things) - we have since changed the code so that hitting the factory defaults button also disables the controller. The second person did not fully plug in the cable to the throttle assembly and apparently the ground wire wasn't making contact. He got out of his car - with the controller still in running mode - and fiddled around with the throttle until the connector reseated and the controller obliging unblocked the throttle, as it saw "zero" as required on startup for just a moment. There's nothing we can do about that one.
> 
> Getting noise out of the throttle signal is one of the most critical requirements for a motor controller and as far as I know we have never - not even during the prototyping period - had an issue with it.


Yep, those were the couple of cases. Like I said it was faulty user wiring, not noise, and no fault of the controller.

Back on the build: ACE was no luck for the flywheel bolts but at least I got the socket head cap screws I need to mount the adapter. Next stop is Lowes. If no luck there then I have some bolts left over from an old ICE rebuild that I could cut down.....


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## kerrymann (Feb 17, 2011)

*Motor is in!*

*Motor is in! *




Well after a hour or two of driving around I was finally able to find the bolts I needed at Lowes. M12 1.75 x 25mm Class 8.8s...


I torqued them to 75ftlbs in criss-cross pattern. To hold the motor while I did I stuck a screw drive between the cooling fins and the fan (very carefully). I originally was trying to hold the other shaft end but it wasn't working for me. Probably not the best way but I was not sure how others do it and no harm was done.
​​

Then a clutch install was pretty straight forward. Without a pilot bearing in this adapter you can't use the alignment tool so I did my best to get the clutch centered.
​​

Then it was time to put the motor into the car. The goofy grin come from holding a 200lb motor while someone says smile to take a picture. BTW I recommend most people use a hoist, or at least steel toe'd boots. 
​​

The motor went in easily. I just dropped it into the cradle and slid it home. It fit in nice but it took some wiggling to get both dowel pins lined up.​
​

A couple things I noticed when I wen to bolt everything up. The first was the adapter is tapped so the bolts have to install from the rear, just like the ICE. I was originally designing around the plate adapter so I was planning on having the bolts install from the front with a nut on the back. With the tapped holes this isn't a option.


This lead to the second issue was I was having problems tightening all of the bolts. I would start them by hand (you do NOT want to cross thread the aluminum adapter) and pretty easily tightening the bolt but then it would start feeling like it was binding. At first I thought I didn't have the adapter quite lined up so I spent an hour fiddling with the adapter then it dawned on me that the problem was the holes are blind tapped and I was bottoming out the bolts. I was checking that I wasn't running out of grip but hadn't thought about the OAL. Not sure why I am bottoming these out (which are the stock bolts) but it's back to the hardware store tomorrow. So far installing the motor I have spent more time tracking down bolts then actual turning a wrench.  But hey it's in... (mostly)
​​​﻿​


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## marc02228 (Jan 15, 2011)

What Motor has been in the car? 1.6 or 1.8l? It's interesting because of the weight calculations. 
Just ordered a kostov 11 alpha for my miata conversion. Didn't buy a donor, yet. I'm not sure whether to take a 1.6 or a 1.8l.

I want to stay as close as possible to the original curb weight due to the registration.

How many A123 Cells will you use in the car? You ordered 250, right?


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## kerrymann (Feb 17, 2011)

marc02228 said:


> What Motor has been in the car? 1.6 or 1.8l? It's interesting because of the weight calculations.
> Just ordered a kostov 11 alpha for my miata conversion. Didn't buy a donor, yet. I'm not sure whether to take a 1.6 or a 1.8l.
> 
> I want to stay as close as possible to the original curb weight due to the registration.
> ...


The car had a 1.8 but it really doesn't matter because it comes out anyway. Everything else is the same. 1994 and after weighs an extra 100-200lbs because Mazda added extra safety gear (door bars, lateral bar) and I think PS became standard. 

Currently I am using 216 but may use more.


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## njloof (Nov 21, 2011)

You may have an easier time selling your 1.8 than I'm having selling my 1.6.


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## kerrymann (Feb 17, 2011)

njloof said:


> You may have an easier time selling your 1.8 than I'm having selling my 1.6.


That is a very good point. I got $650 for mine and sold it pretty easily.


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## TigerNut (Dec 18, 2009)

*Re: Motor is in!*



kerrymann said:


> *Motor is in! *
> 
> 
> 
> ...


In terms of tensile strength, the metric 8.8 standard is slightly better than SAE grade 5, but well below grade 8. This chart gives typical torque limits for the various fasteners for 8.8, 10.9 and 12.9 metric bolts.

http://www.cncexpo.com/MetricBoltTorque.aspx

Typically, the quality of load-bearing fasteners for cars are way better than hardware store grade, and for critical items like flywheels, internal engine/transmission/rear axle fasteners, and suspension components, it is a good idea to use the OEM fasteners.
Even though you're not going to be operating with the same vibration levels that an ICE might impose on the flywheel, the operating speeds are going to be the same, and the force imposed by the clutch is the same...


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## kerrymann (Feb 17, 2011)

*Re: Motor is in!*



TigerNut said:


> In terms of tensile strength, the metric 8.8 standard is slightly better than SAE grade 5, but well below grade 8. This chart gives typical torque limits for the various fasteners for 8.8, 10.9 and 12.9 metric bolts.
> 
> http://www.cncexpo.com/MetricBoltTorque.aspx
> 
> ...


100% agree. I would have really loved to use the stock bolts. It would have saved me a bunch of time and headache and I would have had the motor in Friday night. In fact I have a set of new ARP bolts that I bought for this weeks ago. The problem is the adapter hub has course threads, instead of the fine thread you would find tapped in a miata crank. I haven't heard back from Steve yet (probably still catching up on messages from the weekend) so I can't say why this is. 

The best I could find was a set of 10.9 flange bolts but the thicker head interfered with the clutch. I would not have done the 8.8s if I was still running a ICE and doing launches by reving the motor and dumping the clutch. But I feel it would be okay for now. If you assume 300 ftlbs of torque from the motor then it comes out to 600lbs per bolt in single shear which is a very healthy margin over the 7200lbf (32000N) allowable. Dynamic effects are of course a much bigger issue but I am not going to be really pushing the car for a a few months and I can swap out then with the *right* hardware.


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## TigerNut (Dec 18, 2009)

I forgot to mention: When I was doing regular engine in/out stuff on Toyotas, I made a flywheel stop that used one of the bellhousing bolts, and engaged the ring gear teeth, so that I could torque the flywheel bolts without loading any other part of the assembly. Since you don't have a ring gear, you can't do that, but you could make a restraint out of a piece of 1 x 1/8" steel strap that had a hole sized to fit a pressure plate dowel pin, and then a larger hole on the other end so you can attach it to the bellhousing adapter. The length of the strap would need to be such that the strap ends up more or less tangential to the radius of where the dowel pin is...


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## kerrymann (Feb 17, 2011)

*Controller Mounted*

*Controller Mounted *



Well progress has been slow but steady and I am way past due for an update. I have gone back and forth on the mounting of the motor. I ran into several issues with my original plan for mounting the controller. The original plan was the front of the controller would be supported by the strut tower brace. Well I decided to flip the controller around so the motor terminals faced forward because I wanted to have the wiring connections on the passenger side. I am using the stock wiring harness and the wires I needed to power the Soliton1, connect the tach output, etc were right there. This made the clearance between the traction terminals and the hood too close for comfort and so I had to move the "strut brace" down which made it rather pointless for stiffening the tops of the strut towers. 

The other challenge was the fact that the adapter had blind holes for all the bellhousing bolts. I was going to use the bolts sticking out the front of the original adapter to mount a L bracket for the back of the controller. I do really like the rebirth adapter but there are some parts of the plate style adapters I like better. If I were going to do it again I think I might try the Jimerico adpater for $500 less.

http://www.jimerico.net/index.php?main_page=product_info&cPath=69&products_id=24 

I bought my Soliton1 from them (Jim Husted + Eric Pedersen) and had no problems. Again the Rebirth adapter is great but I had been planning around a plate style adapter so life got a little more complicated. I did hear back from Steve and he said their drawing called out the right thread pitch on the hub but the machinist made a mistake. He offered to send it back and they would fix it but I already have it in the car with the bolts I had found.

Anyway I then went through a couple design gyrations and finally decided to make a L-bracket that was mounted to the back of the bellhousing. 

​
I then made a bracket that supported the front of the controller from the front of the 9" motor and mounted the throttle to the front controller bracket. 

​
I later cut down the throttle lever to go from 7%-73% travel on the pot.

As you can see I also made up the cables to go from the controller to the motor using the nice 2/0 cable and some molex lugs.

 

I then spent some time reviewing the Miata wiring manual and pull the leads I needed from from the wiring harness. I also started trimming down all the unnecessary pigtails and cleaned up the engine bay. When I cut the bundles I was careful to tap of each individual wire so I wouldn't cause any shorts. I also installed my $27 strut tower brace that was nickle plated aluminum which happened to match the Soliton1. 


​
I turned all of the settings on the controller way down to get ready for the first test. For instance I set a max motor voltage of 12V just in case something went wrong I knew I couldn't overspeed the motor.


----------



## kerrymann (Feb 17, 2011)

TigerNut said:


> I forgot to mention: When I was doing regular engine in/out stuff on Toyotas, I made a flywheel stop that used one of the bellhousing bolts, and engaged the ring gear teeth, so that I could torque the flywheel bolts without loading any other part of the assembly. Since you don't have a ring gear, you can't do that, but you could make a restraint out of a piece of 1 x 1/8" steel strap that had a hole sized to fit a pressure plate dowel pin, and then a larger hole on the other end so you can attach it to the bellhousing adapter. The length of the strap would need to be such that the strap ends up more or less tangential to the radius of where the dowel pin is...


Yep. That is the right way to do it.  I would just use a flat blade scewdriver between the dowel pin and the ring gear but lacking a ring gear....


----------



## kerrymann (Feb 17, 2011)

*It is ALIVE! *



Well after triple checking everything I decided it was time to make the wheels spin. The controller was all wired up but I still have to put my A123 pack together. Luckily I happened to have a few old 24V SLA batteries literally lying around. So I threw a battery in the the passenger seat and hooked up my jumper cables and slowly drove it out the garage! 



​
One battery was enough to make it move but not much more then that. So I grabbed a few more batteries out of the backyard and whipped up a quick 96VDC pack.

 


​I drove the car up and down the drive and slowly upped the limits for the motor voltage (120V) and current until I was spinning the rear wheels on the gravel. Finally the fun ended when I got on the go pedal and the car lurched to a stop with a faint wiff of acrid spoke!!!! My first concern was that I done something to the Soliton1 but I should have known better. A quick check showed one of the batteries had shorted internally, the second battery my Soliton1 has sent to it's grave. Not too surprising considering they are 6 year old mistreated lead acid batteries. I simply moved the jumper cables over and drove the car into the garage under 72VDC.


​


----------



## njloof (Nov 21, 2011)

Nice! Very exciting. How were the brakes without hydraulic pressure?


----------



## kerrymann (Feb 17, 2011)

njloof said:


> Nice! Very exciting. How were the brakes without hydraulic pressure?


I assume you mean without the vacuum assist? The pedal was very hard. It worked for driving 10mph up and down the driveway. If you are thinking of going non-assisted I can tell you that would not be safe for the road (unless you change the master cylinder for a non-boosted model). 

I have the vacuum pump wired up I just need to get some barb fitting to hook up the lines from the pump to the booster.


----------



## kerrymann (Feb 17, 2011)

*Odds and ends*

*Odds and ends *



After posting about actually driving the car I realised that I missed a few things and wanted to get it caught up. This first is a minor change to depowering the rack. When went looking for ARP flywheel bolts I found http://www.miataroadster.com/ had the best price. I ordered them but of course I didn't end up using them because of the thread issue on the adapter. On the plus side when I ordered from Bill he was interested in my project read the blog and sent me a free set of rack depower plugs!

​
They are just block off plugs, but the custom aluminum plugs sure look nicer then my hack.

​
I am looking at a roll bar and noticed that Bill carries the Boss Frog MAXX double hoop roll bar:


http://www.miataroadster.com/boss_frog/boss_frog_roll_bars_doublehoop_retro_style_with_individual_hoops_behind_seats/bfmdsrx/i-411853.aspx 


I was originally planning on building my own but these are bolt in bars that are FIA and SCCA legal. All the other double hoop bars are not FIA or SCCA rated and mostly for looks but I want something that looks good and works to protect me (crazy thought). The price is reasonable but I am still going back and forth on building my own.

​

I mounted my vacuum pump right below the brake master cylinder. I am going to forgo a reservoir for now and to a few tests to see if I think it is okay.



​
I also wanted to say that these Dewalt pilot point drill bits rock! I usually try to go "Made in the USA" for everything but German made cutting tools are pretty much impossible to beat.


​On that note, I thought it would be interesting to point out that 100% of all the components, parts, fasteners, etc that I have bought for this conversion were made in the USA. EVERYTHING. A great point to bring up when people doubt green tech's benefit the american economy.
​​​


----------



## kerrymann (Feb 17, 2011)

*While I was away UPS left some presents*

*While I was away UPS left some presents *



While I was away working in Spain for 2 weeks the UPS driver left a few boxes on my doorstep. So after unpacking the bags it was time to unpack the new toys:

The first is the EMW EV Android Dashboard. 

http://www.emotorwerks.com/emw3/product/ev-dashboard-by-emw-basic-edition/ 

​
It measures the current flowing from the pack to the controller in order to estimate the state of charge (SOC) of the battery cells. Unlike other batter chemistries you cannot estimate SOC from the voltage. Lithium has a very flat voltage curve from 10-90%. Great for performance but it's hard to know how many electrons you still have in the tank. This uses a hall effect sensor to measure the current flow. It is designed to work with a android device so I was able to get a good deal on a new Toshiba 10.1 thrive tablet. It has bluetooth to communicate with the current sensor and a GPS chip for navigation and a nice bright scree. It's not the best tablet in general because it's a little bulky and not the most robust case. But none of that matters for me as I am mounting it in the center dash.


​One other cool feature is that there is an output on the Bluetooth unit so it will drive the stock fuel gauge too. 
I need to play with it more but it doesn't seem to work in landscape mode. Hopefully this is something that I haven't figured out yet or will get added soon. The other thing is that I wish the gauges were more adjustable as far as ranges and it would be really nice to add the option for warning lights (for high batt temp, SOC < 10% etc). It seems like this would be easy to add but I have only used a android device for 15 minutes....


The second item was my BMS system:


I went with Lithiumate Lite, EV Li-Ion Battery Management System (BMS).


http://elithion.com/lithiumate_lite_overview.php 
​​



It monitors each cell group (in my case 3 cells in parallel) and make sure that the cell doesn't get over charged or over discharged. I went back and forth on needing a BMS and I think bottom balancing a pack that has had the capacity matched would be fine. But this is my first time with lithium and wanted the "insurance" of the BMS. I knew I at least wanted monitoring of all of my gray market A123 cells and going to a full blown management system wasn't anymore expensive with the Lithiumate Lite. Also on the bright side, not only are they made in the US, they are made here in Colorado!


To be honest having the EMW dash and the Lithiumate is redundant but I wanted to try out both and see how they compared.​


----------



## njloof (Nov 21, 2011)

What lead length on the BMS modules did you choose to fit the batteries? I figured you could get those modules to
fit even though they only "officially" support A123s with the lithiumate pro.


----------



## kerrymann (Feb 17, 2011)

njloof said:


> What lead length on the BMS modules did you choose to fit the batteries? I figured you could get those modules to
> fit even though they only "officially" support A123s with the lithiumate pro.


I went with "Prismatic, M8 bolt, 106 mm max spacing" but the "Prismatic, M6 bolt, 64 mm max spacing" would have worked too.


----------



## kerrymann (Feb 17, 2011)

*Pack assembly*

*Pack assembly *




Right now I am grouping the cells together. I was able to balance the capacities within ±0.15ah which is probably withing the uncertainty of my testing. 

​

The most time consuming thing is peeling off all the stickers and getting all the pressure sensitive adhesive off. PSA is not known for it's high conductivity.  So I get to sit in front of the TV with rag and some rubbing alcohol.

For making my connections I was able to modify a 3 hole punch with a simple MDF block to make all the holes in the tabs. 

​
Works well but I might put a better spring in the punches because they often get stuck and I have to wiggle the cell to get it back out.

​


----------



## Ziggythewiz (May 16, 2010)

*Re: Pack assembly*



kerrymann said:


> The most time consuming thing is peeling off all the stickers and getting all the pressure sensitive adhesive off. PSA is not known for it's high conductivity.  So I get to sit in front of the TV with rag and some rubbing alcohol.


 
If you've never used a heat gun on a sticker you'd be surprised.


----------



## kerrymann (Feb 17, 2011)

*Re: Pack assembly*



Ziggythewiz said:


> If you've never used a heat gun on a sticker you'd be surprised.


I have I just don't think it would be a good idea using it on a cell. The sticker comes off well enough and the alcohol only takes 15-30 seconds but when you have almost 300 cells it takes a while.


----------



## marc02228 (Jan 15, 2011)

How did you hold the Transmission in position after removing the engine?


----------



## kerrymann (Feb 17, 2011)

marc02228 said:


> How did you hold the Transmission in position after removing the engine?


The miata has a small cross member that the tranny can rest on and the back of the transmission is actually connected to the rear diff with a truss. It's cool becasue you can actually pull off the miata's unibody and still have a rolling chassis:


----------



## marc02228 (Jan 15, 2011)

kerrymann said:


> The miata has a small cross member that the tranny can rest on and the back of the transmission is actually connected to the rear diff with a truss. It's cool becasue you can actually pull off the miata's unibody and still have a rolling chassis:


Was the transmission fixed to the cross member?

I removed my engine a couple days ago. 
After I removed it, the end of the transmission was connected to the rear diff by the truss but the front of the transmission hang on the clutch slave cylinder. 

I screwed off the clutch slave cylinder, put two of the bolts (motor to transmission bolt) back in and put the transmission on a piece of wood...


----------



## kerrymann (Feb 17, 2011)

marc02228 said:


> Was the transmission fixed to the cross member?
> 
> I removed my engine a couple days ago.
> After I removed it, the end of the transmission was connected to the rear diff by the truss but the front of the transmission hang on the clutch slave cylinder.
> ...


It's not actually connected to the transmission but when you unbolt the engine it will drop 30mm or so and just rest onto of the brace. You can see it in this picture just behind the bell housing (ignore the green arrow):


----------



## rochesterricer (Jan 5, 2011)

kerrymann said:


> The miata has a small cross member that the tranny can rest on and the back of the transmission is actually connected to the rear diff with a truss. It's cool becasue you can actually pull off the miata's unibody and still have a rolling chassis:
> 
> [IMGhttp://flyinmiata.com/projects/installation_photos/IMG_6843.jpg[/IMG]


Thats interesting, I didn't know that. I wonder, was that done to improve chassis rigidity?


----------



## marc02228 (Jan 15, 2011)

kerrymann said:


> It's not actually connected to the transmission but when you unbolt the engine it will drop 30mm or so and just rest onto of the brace. You can see it in this picture just behind the bell housing (ignore the green arrow):


I am not sure if I do have this cross member and I'm not at the car this week, to check. Maybe It's something that only the cars have, which were built after 1994.


----------



## kerrymann (Feb 17, 2011)

marc02228 said:


> I am not sure if I do have this cross member and I'm not at the car this week, to check. Maybe It's something that only the cars have, which were built after 1994.


I am 99% sure all Miatas have this brace. It could be a European difference but I doubt it. My guess is it was removed and some point for doing the clutch or rear main and the mechanic neglected to re-install it. You do want it. The Miata is a very good handling car but the chassis isn't the stiffest and you certainly don't want it less stiff then stock.


----------



## kerrymann (Feb 17, 2011)

*Cell Socks*

*Cell Socks *



Short update: The battery assembly is moving forward slowly with a few set-backs. The main setback was I changed my mind on the tab connections. I assembled part of a back with rivets which worked pretty well but reconsidered as I wanted to be able to replace cells relatively easily. I have tested all of them but these gray market cells... 

One other thing while assembling I brushed a tab with a rivet and got a bit of an arc. No damage done but with 250 of these cells the chances are I would do it again. To prevent that I made up some covers (which my wife called cell socks). It's just some fairly dense packing foam that I cut a slit in so it would slid over a cell tab.



​
Meanwhile it's back to peeling stickers and assembling packs. Though I did recently discover EVTV so I have been watching it on YouTube and it has been *interesting* watching the shows. The show is kind of like "the Thirsty Traveler" stays home and tinkers in his garage. It's entertaining and makes this more tedious work go by faster.


----------



## marc02228 (Jan 15, 2011)

kerrymann said:


>


Does this thing have a name?
I just had a look under my car and it is missing.


----------



## kerrymann (Feb 17, 2011)

marc02228 said:


> Does this thing have a name?
> I just had a look under my car and it is missing.


The holes for it are still there right? I believe it is just called: "brace, front subframe; Simple cross bar. Ties end of front subframe together"

http://www.flyinmiata.com/salvage/chassis.php

It's only $10 for a used one here in the US but I can't imagine it would be much more expensive in DE.


----------



## kerrymann (Feb 17, 2011)

*Now I have power! *



Well I finally got a few hours to assemble my 250 A123 cells into modules. Once I got the system down it went pretty quickly. I have the cells assembled into 4 modules. 3 identical ones made of 3p18s that will go behind the seats where the gas tank used to go. The other cells get mounted in a single module of 3p29s that goes up front where the radiator used to be. I went back and forth on how I was assembling the modules but the final design just uses bolts nuts and washers do make it very DIY friendly. If people are interested I can post specific details on the tab connections. 





​

Once I had all the tab connections I needed a way to mount them. I made up some quick end plates with some L brackets so I can connect cables to clamp them together.


​



For cables I actually had a bunch of left over flight control cables. I simply cut them down and spliced them together. I originally going to use some eye bolts but happened to have these cables. 


​

I also cut up some .008 aluminum into 8" squares to act as cooling fins. I slid them in between every other cell. 


​ This greatly increases the heat transfer from the cells. Individually the cells will be just fine but when you stack them together you decrease the cooling surface area by several orders of magnitude. To solve this aluminum uses the large surface area from the sides and conducts the heat away to the fins. The fins stick out 1" from either end of the cell for convection to wick the heat away. Keeping the cells cool is critical to maintain cell life. This is a fair weather car so I won't be driving it in the cold but this also could be used for heating if you needed.





This pack still needs some adjustment but I wanted to get it made before I left town for a few weeks.​


----------



## marc02228 (Jan 15, 2011)

Maybe you could place a spring between the nut and the L bracket. That's the way I am planning to assemble my pack.

Great idea with the cooling. But maybe the cells could get damaged when they are rubbing to the aluminum while driving? If I remember right the cells have a thin isolated coat around them.

Did you mount your motor directly to the frame of the car? 
Someone, who was looking at my miata told me, to use the original dumper to mount the electric motor due to vibrations from the gearbox, wheels, etc. But I am not sure, what's the best way to do it.


----------



## kerrymann (Feb 17, 2011)

marc02228 said:


> Maybe you could place a spring between the nut and the L bracket. That's the way I am planning to assemble my pack.
> 
> Great idea with the cooling. But maybe the cells could get damaged when they are rubbing to the aluminum while driving? If I remember right the cells have a thin isolated coat around them.
> 
> ...


I thought about a spring but decided it's really not needed. The cables were proof tested to 1100lbf so I don't have to worry about the 2-300lbf tension I am putting on them. Even if your cables were to stretch just re-torquing them once should be fine. If you are really worried about it I would actually recommend a couple Belleville washers.

The cooling fins aren't my idea, just a copy of what A123 does for their modules. The cells are restrained completely by the tension on the cables. You want to make sure that the cells do not move at all so they don't rub against the fins or whatever kind of battery box you are putting it in, not to mention the cell tabs flexing. I recommend 9g forward, 6g down and 4.5g sidewards for sizing.

I mounted my motor directly to the subframe.


----------



## kerrymann (Feb 17, 2011)

*DIY A123 modules ready to go*

*DIY A123 modules ready to go *



Now that I am back stateside I took the afternoon to build the final version of my modules.

​
I made up some quick templates to crank out new cooling fins that look a lot more professional then Rev 0. 



​

...I also made up new end plates and end bars...

​
...and replaced the end cables with .25" all thread...

So in short I remade everything but the cells from before.  The result is a module design that I am finally happy with and can easily made with pretty basic hand tools cheap and quickly. I'd say once the cells were ready (tested, destickered and 2 hole punched) I took me about 4-8 hours to assemble 250 cells into modules. 

I dry fit the modules in the back of the Miata so I can start on the mounting brackets.



​
3 modules get installed here where the fuel tank used to be and a 4th one get's installed up front where the radiator used to hang.

Next up is the mounting brackets for the modules and installing the BMS. Assuming I don't have to suddenly leave the continent for work again those items shouldn't take too long.


----------



## kerrymann (Feb 17, 2011)

*Charge! *



Since I have battery packs now I need a way to charge them. So I got the charger mounted tonight:
http://www.blogger.com/goog_1430434918

http://www.blogger.com/goog_1430434918
I chose this location because I wanted the weight up front to help with weight distribution. It is also next to the battery terminals at the charger making the cable run short. I also wanted to place it on the passenger side to offset some of my weight as I will be driving it to work sans passenger most of the times.
http://www.blogger.com/goog_1430434915

http://www.blogger.com/goog_1430434915
I went with the Manzanita Micro PFC20. I could have gone with the cheaper Chinese made Elcon but I wanted a made in the USA quality unit and the capability of adjusting the current draw on the fly. We have seen great improvements in controllers (i.e. Evnetics) but this charger really seems right out of the 90's. For my relatively small pack 20amp max is plenty though if I got that PFC60 I could recharge from my morning commute in less then 30 minutes.  I have something special in mind for the charge port but more on that later....


----------



## kerrymann (Feb 17, 2011)

*BMS install *



I got all the BMS mid boards installed today. The Lithiumate Lite is about as simple a system to install as possible (short of not having a BMS . 

Some of the things I like about it so far is the board to board connection is realatively easy and the diagnostic light on the PCB that blinks 6 times to let you know you installed it correctly and that it is working. The boards are pretty small and fit well with 3 cells in parallel. Part of the way through I realized if I installed half of the boards upside down this gave you a bit of extra clearance.

​
Notice I said upside down NOT BACKWARDS! This brings me to one of the things I don't like on the system. If you install a cell backwards (i.e. wrong polarity) it is dead. Even for a millisecond. Elithion is very clear about this in their literature but it just seems like a diode to protect the boards would have been a easy fix. So with that in mind, I made sure I had a little installation procedure and followed it. Elithion manual seems very good along with some videos (with no audio for some reason) but for my application I set the pack on it's side and did half where the PCB would hang down to gravity. I was anal and checked every connection with the DMM first then verfied the LED blinked before tightening the nuts down. 

​
I did one full side then flipped the module and did the mid boards in the other direction.


​Cut then stripped all of the wires to the right length. 

​
I then made the connections, again one side at a time. 

​
This just helped to get in a pattern and ensure no mistakes.


​
Just to reiterate what I said about the BMS earlier. If I had cells that I was 100% confident in then I would not have bothered. But being this is an experimental pack design I am far from it (not even close to 3 sigma . So I decided I needed to montior each cell. I looked into Battery Monitoring Systems and wasn't impressed. I found the Elithion system gave this functionality along with a management system for a very reasonable price and had a lot more features. I must say for someone that is skeptical of BMS I am preety impressed with the system so far. But I am not done yet either... 

I am also looking if I can use the lithiumlite system just for monitoring and keep my pack bottom balanced.

BTW, Before I purchased I also found all the fabrication was done here in Colorado (Broomfield, CO). I am a big fan of buying locally so this was icing on the cake for what I already thought was the best system and best value.


I also bought a set of KYB struts with springs for only $150. I will hold off installing them till later:

​


----------



## marc02228 (Jan 15, 2011)

*Re: Controller Mounted*



kerrymann said:


> *
> 
> I bought my Soliton1 from them (Jim Husted + Eric Pedersen) and had no problems. Again the Rebirth adapter is great but I had been planning around a plate style adapter so life got a little more complicated. I did hear back from Steve and he said their drawing called out the right thread pitch on the hub but the machinist made a mistake. He offered to send it back and they would fix it but I already have it in the car with the bolts I had found.
> *


*

Yesterday I got the adapter, too. Nothing changed. Still blind holes and no fine threaded hub.
Even the dowel pins are missing^^

I ordered M12x20 grade 10.9 for the hub. I think 25mm length would be to long for me.

Are the 2-4 small ones and the motor connecting screws 3/8? 
What thread are the other screws?

Hard to find imperal screws here, in Germeny*


----------



## kerrymann (Feb 17, 2011)

*Re: Controller Mounted*



marc02228 said:


> Yesterday I got the adapter, too. Nothing changed. Still blind holes and no fine threaded hub.
> Even the dowel pins are missing^^
> 
> I ordered M12x20 grade 10.9 for the hub. I think 25mm length would be to long for me.
> ...


I think normally people reuse the pins from the motor. I had forgotten to remove mine before I sold it so I asked Steve for the dowel pins. They were back ordered from Mazda so they made me up a set. In fact I am not sure they ever charged me for them. The blind holes are the way the adapter was supposed to be. Nothing wrong with it, but for me it caused issues as I originally designed my controller mount around thru holes in the other adapter. 

I am surprised about the threads. Maybe it shipped before I found the issue?

The 4 bolts to the motor are 3/8". Not sure what you mean about the smaller ones. I'll be working in Spain in a month and I think my connection goes through Frankfurt. I drop off some of those ye olde train bolts.


----------



## marc02228 (Jan 15, 2011)

*Re: Controller Mounted*



kerrymann said:


> I think normally people reuse the pins from the motor. I had forgotten to remove mine before I sold it so I asked Steve for the dowel pins. They were back ordered from Mazda so they made me up a set. In fact I am not sure they ever charged me for them. The blind holes are the way the adapter was supposed to be. Nothing wrong with it, but for me it caused issues as I originally designed my controller mount around thru holes in the other adapter.
> 
> I am surprised about the threads. Maybe it shipped before I found the issue?
> 
> The 4 bolts to the motor are 3/8". Not sure what you mean about the smaller ones. I'll be working in Spain in a month and I think my connection goes through Frankfurt. I drop off some of those ye olde train bolts.


I don't know, I ordered the adapter at the end of June. 
Ok, it's annoying, but not that bad. I just thought they would have changed the thread in the meantime.

There are the bolts for the hub: M12 x 20
the bolts for the motor: 3/8" x ? (I don't have my measurements here, right now)
then there are two kind of threads for the connection from the adapter plate to the gearbox.
3-4 smaller threaded holes and the other are larger threaded. What kind of threads are these?

What do you mean with your last sentence? I don't understand that one


----------



## rwaudio (May 22, 2008)

nice work on the A123's how close are you to driving it?
I agree with the BMS on these cells, I've already caught a bad group (likely made bad by a single cell) and have another suspect. These were all from cell groups that I did my testing on and were abused a little bit. The "virgin" cells that were simply tested for capacity and assembled into packs are working perfectly so far.

A few unscientific tests show voltage sag at 990A battery current at 2.97v per 3P group. 

Are you worried about moisture entering the charger up front like that?
My 944 is currently a bit rear heavy and I'm likely going to move the dc/dc converter, charger, 12v battery up in front of the motor as low as I can build a tray.
I'm not sure how much water protection is required.

Are you going to liquid cool your Soliton? I'm using air cooling right now but I've already run into the de-rating on some short hi-way runs. It's typically between 35C and 45C but it doesn't take much to push it past 65C for short periods.


----------



## kerrymann (Feb 17, 2011)

*Quick update: The car runs.*



Sorry for the long time between post but between work and summer time in Colorado I haven't had much free time to update my build log. The short story is the car is running now but still tying up loose ends. Battery packs are all built and installed, 2/0 cables along with big manual disconnect, DC/DC converter is in and the vacuum for the brakes. 

​ 

​ 

Really all that is left is some small wiring tasks. I haven't done any real road testing yet as I am finishing the BMS install and more importantly I need to wire a 30amp 220V plug in my garage so I can actually charge up my cells.

​ 


​ 

I was hoping to have the car finished up this week as I am off to work on the other side of the globe for a few weeks. So I will probably get the car done in October just in time for the weather to get cold.


----------



## kerrymann (Feb 17, 2011)

rwaudio said:


> nice work on the A123's how close are you to driving it?
> I agree with the BMS on these cells, I've already caught a bad group (likely made bad by a single cell) and have another suspect. These were all from cell groups that I did my testing on and were abused a little bit. The "virgin" cells that were simply tested for capacity and assembled into packs are working perfectly so far.
> 
> A few unscientific tests show voltage sag at 990A battery current at 2.97v per 3P group.
> ...


Nice! That is not much sag for almost 20C! I haven't done any power tested until the BMS is finished. I will post the results when I do but I will only be pulling 600 battery amps. I think I have another bad cell (I have had 1 so far) too that I will have to pull and replace. It was easier then I expected and I am sure glad I changed the tab connections to bolts with lock nuts rather then my original rivet prototypes.

I will liquid cool for sure when I go to the second stage of the project this winter and closing up the bottom of the engine compartment to keep splash and spray out of the charger just to be safe.


----------



## kerrymann (Feb 17, 2011)

*Re: Controller Mounted*



marc02228 said:


> What do you mean with your last sentence? I don't understand that one


I was joking that I am going to be working in your part of the world and could bring you some bolts.


----------



## kerrymann (Feb 17, 2011)

Well today we got the Miata titled as a EV and plated! The first stage of this project was to to convert the car to a street legal EV and that is now complete. As with all projects like this there are little things that will be done (like the brake lights stopped working randomly) but getting it titled and registered is a big step.


​ 

​ 

Look ma, no exhaust!​ 

For people registering a EV conversion is Colorado it is actually very easy, depending on who you ask.  Do not take it to a emission center. They will tell you that you need to get a bunch of extra paperwork and inspections as if it were a kit car. Don't go down this road (pun intended). Instead call your local motor vehicle registration. All you really need is a VIN inspection which is easy and cheap ($8). 



​ 

We talked to the nice people (no sarcasm intended) at the Douglas County MVR and they told us that Douglas county even does onsite inspections! We called the number they gave us and sure enough an hour later a officer showed up and did the VIN inspection in my garage! For the conversion all the officer does is puts on the form that it is a title correction. He does the VIN check like normal but he just puts a E in for fuel type. Take that down the MVR and you get your plates a EV title will be mailed to you.


What's next? Well I am trying to decide on if I will do stage 2 and go dual motor with direct drive. I have a Brand new Transwarp9 on the bench ready to go but I don't know that I have the battery pack to make it worth while. My options would be but more A123 cells to pump the voltage from 184VDC to 307VDC or redo the whole pack in some CALB CA70's. Neither of which are particularly appealing. In the mean time I will be upgrading the suspension, adding a roll bar doing some body work this winter too.





I set a goal for myself to do one conversion a year. I think my conversion for 2012 will be a plug in hybrid. 
I have a 2005 GMC Canyon Crew Cab 4x4 with the 4 cylinder with the a 5 speed manual transmission which I am going to be adding a 108V LiFePO4 pack a Curtis 550amp controller and a AC24LS motor.

Merry Christmas!


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## rwaudio (May 22, 2008)

Great work! Have you been able to drive it much? 

I'm in the process of doing CALB 60's and they are so much easier to work with. They sag quite a bit more than A123's though. A single A123 has about the same sag under a 38-40A load as a single CALB 60, but I guess that makes sense as they have similar IR. After connection resistance is factored in, I would guess 3P A123's are about 1/2 - 2/3 the IR of a CALB 60, even less if you can alternate cell tabs in series connections.

If you do swap A123's with CALB's the 60's are a good fit and would likely make efficient use of your existing battery boxes. The 70's and all other CALB's below the 180's are shorter as well as wider/thicker than the 60's.

In the attached pictures it's a 2S4P group of A123's and a hand full of CALB 60's. As you can see a cell in each orientation is basically the same width as the A123 group. 

Merry Christmas!


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## marc02228 (Jan 15, 2011)

How is your clutch doing?
I ordered the same clutch as you, because I wanted the light flywheel and the clutch was just 50 USD or so extra.

I think I already killed the clutch. Didn't drove much with it. Maybe 40 miles.


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## dtbaker (Jan 5, 2008)

I have a '94 as well.... Warp9, Zilla, 156v nominal CALB 130ah.

I'm finding that the torque is so good I'm using pretty much just 3rd and 5th gear.... torque drops off above 4000rpm (80-90mph in 5th), so much so I'm thinking about trying to find a bigger gear for the diff. to get little more top end, and maybe use 2nd gear from stops. 

I can't tell if my clutch is still ok, it makes an 'interesting' slipping noise on take off, but tach doesn't slip up, so it may just be an audible, or the diff, or something else. Tires tend to break loose if I start too hard, even in 3rd.

...like your wheels by the way. what are they and where did you get them? I have stock wheels, which are ok, but I'm not crazy about them. Also have seat covers that are splitting that I'm not sure what to do with. Recover, cover, or replace seats completely with slicker lighter racing seats.


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## kerrymann (Feb 17, 2011)

marc02228 said:


> How is your clutch doing?
> I ordered the same clutch as you, because I wanted the light flywheel and the clutch was just 50 USD or so extra.
> 
> I think I already killed the clutch. Didn't drove much with it. Maybe 40 miles.


No problems yet but I have been breaking it in gently with 500 amps max. 

Is it just slipping from a stop? I don't know how you could kill it in 40 miles. Have you been using the clutch much? I only use it on fast shifts though I find myself trying to use it from a stop because that is what I have to do for the past decade and a half.

Have you checked to make sure the clutch is disengaging all the way? Did you clean it well when you installed it?


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## kerrymann (Feb 17, 2011)

dtbaker said:


> I have a '94 as well.... Warp9, Zilla, 156v nominal CALB 130ah.
> 
> I'm finding that the torque is so good I'm using pretty much just 3rd and 5th gear.... torque drops off above 4000rpm (80-90mph in 5th), so much so I'm thinking about trying to find a bigger gear for the diff. to get little more top end, and maybe use 2nd gear from stops.
> 
> I can't tell if my clutch is still ok, it makes an 'interesting' slipping noise on take off, but tach doesn't slip up, so it may just be an audible, or the diff, or something else. Tires tend to break loose if I start too hard, even in 3rd.


What ratio do you have in the rear? The stock 3.41? What clutch are you running?



dtbaker said:


> ...like your wheels by the way. what are they and where did you get them? I have stock wheels, which are ok, but I'm not crazy about them. Also have seat covers that are splitting that I'm not sure what to do with. Recover, cover, or replace seats completely with slicker lighter racing seats.


Thanks, discount tires had a great deal on them through their ebay store back in the fall. They were about 60 bucks each delivered after mail in rebate and they nice and light too. They usually run the deal every 6 months so keep you eyes open for their $100MIR for buying 4.


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## kerrymann (Feb 17, 2011)

rwaudio said:


> Great work! Have you been able to drive it much?
> 
> I'm in the process of doing CALB 60's and they are so much easier to work with. They sag quite a bit more than A123's though. A single A123 has about the same sag under a 38-40A load as a single CALB 60, but I guess that makes sense as they have similar IR. After connection resistance is factored in, I would guess 3P A123's are about 1/2 - 2/3 the IR of a CALB 60, even less if you can alternate cell tabs in series connections.
> 
> ...


Not much, I have been working through little issues on the car and with no top it's not exactly a Colorado winter car. I am debating the CALBs so that is good to know. I have gone through all my spare A123 cells and while I don't seem to have any new cell issues I am really marginal on the range to work (35 miles @ 75mph). I don't want to buy more A123s so I am on the fence about switching to CALB and shelving the A123s for another project (or selling them). But for now I am just going to keep driving it here and there and get it to the track in the spring.


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## kerrymann (Feb 17, 2011)

*Spring cleanup*

*Spring cleanup *




This weekend between me, my son and a buddy I was able to wrap up some more big items to get the car track ready:

​
I found the original RR strut was blown after sitting all winter so decided it was time for those used KYBs I bought in the fall but then I found one had a dented tube, after I installed it L. So I ordered a new one and put it in

​


The KYBs seem pretty good. I am still sitting higher in the rear then I would like. I will eventually redo it all with a set of FM V-Maxx Classic coil overs http://www.flyinmiata.com/index.php?stocknumber=13-16210%20%201990-97%20NB) because I can really dial in the ride height. I plan to move the charger to the rear and some more batteries in back too which will help but for now it’s fine.

​
​
​

I also replaced the pads with some hawks and flushed the brakes with ATE SuperBlue. Now the brakes are really nice.

​
​
​I also finished securing the battery packs and putting covers on the terminals
.
Since this weekend the snow was gone and the weather was perfect I got the car out and started doing some real pulls, getting some data, and slowly upping the current and voltage. I live out in the sticks so it’s pretty easy to find a straight stretch of road with no traffic that I can do 0-60 times. So far the controller has been set to at 500 amps and 120V but after a hour or two of driving and reviewing the data logs I went up to 150V and 800amps on the motor. Now the cars is fun!  The best part was strapping the car seat in and taking my 5 year old son for a spin. 

​


​ I am holding off going to the full 1000a and 160V to keep the pack limited to 12C. At 12C and only 30% SOC the back sags about 15% which is on par with a CA series CALB. I still have one of the modules out of the car with the bad cells. Once/if I put them back in then I’ll try going to 1000a. 
I got my boss frog double hoop Maxx roll bar and they take their packing and shipping seriously.

​
​
​I like the look of the double hoop but I HAD to have something that was a real piece of safety equipment, otherwise there was no point. This car is going on the track and boss frog is the only one that is SCCA and FIA. http://www.bossfrog.biz/Miata_Rollbars.html​
​

​The installation was pretty straight forward and only took about 4 hours.​
​


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## ehansen007 (Mar 27, 2013)

This is a great thread. Keep up the great work.


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## jeff mccabe (Feb 23, 2010)

*Re: Spring cleanup*

Great conversion.
Hey do what I did to get my Porsche lower. Just cut a half coil out at a time till it is where you want it.

Jeff


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## kerrymann (Feb 17, 2011)

*First race *

*Getting there is half the fun*​ 
On Wednesday I found out that PPSCC was having an autocross on Saturday so I decided why not and started making plans. I was originally going to buy a car dolly to tow the Miata but after calling all the ads on CL only one wasn't already sold. On Friday after work I checked it out and found out there was a good reason that dolly hadn't sold, it was scary. So I had to figure out another plan. I checked recargo and there was a Level 2 at a Walgreens a couple miles away from the event. With a Level 2 it would only take me an hour to top of my pack but it was easier to leave it overnight. We called the store and they said it would be no problem leaving it to charge overnight. The week before I had just happened to order the parts for a J1772 charge port so at 7pm I wired it up and drove it down. ​ 

Apparently things were going to smoothly because just a few miles down the road a deer jumped into the road in front of me. Luckily I was only driving about 35mph and just pushed the deer forward a foot and it ran off. Because the speed was low the damage was light limited and after a quick check I continued driving to the charge station. However when I went to charge I found that the charger wasn't working with my port.​ 


​


I later figured out that it wasn't liking my non-isolated PFC-20 and tripping the GFCI. There was no 110V plug on the charger but down the road were some more chargers and went to try them. Keeping in the theme for the night they were wired up but not activated yet. Luckily my wonderful wife spotted a 110V outlet on a nearby light pole 30' away from those level 2s was. Great! ​ 



​ 
But I had left my 110 plug on my workbench a 30 minute drive back! D'oh! At this point common sense would have been to give up and call it a night but a quick run into Walgreen's along with a few minutes turned a power-strip, wire nuts, and some electric tape into a ad-hoc charge chord and left the car to charge overnight and we finally got to bed shortly after midnight.​ 

*Track time!*
The next morning was time for some racing! The car passed through tech and got a lot of questions from fellow racers. ​ 



​ 
There were a lot of nice fast cars out there Focus ST, FR-S, 370z, '13 Boss 302, several Miatas ranging from stock to turbos and race prepped full caged, and in general a lot of cool mustangs since PPSCC did the event in conjunction with the local mustang club. ​ 


​


Everyone was really nice but unfortunately my co-driver wasn’t allowed.​​ 

​
​ 
The autocross was a fun set-up with a nice high speed chicane and made a U-turn with a broken sweeping 270 that was a lot of fun to steer through with the right foot.  Unfortunately my mount for my camera wasn’t stiff enough to handle the g forces so no in car video but I am going to have a GoPro silver for next weekend’s race at PPIR.​ 



​ 
I have to say that my favorite part of driving the car is the throttle control. If I came in too hot to a corner I could *save* it by hitting the gas and bringing the rear of the car around. The Soliton1 and the 9” motor just delivered exactly the torque I wanted, whenever I asked for it. I am actually toying with the idea that my next project will be an electric drift car.​​ 

​
​ 
I have to say that I am not a great driver. I haven’t raced in 6 years and I was a slow driver way back then. Each lap I remembered how to drive and dropped almost a second each time around. I felt the car could have gone a lot faster but turns out the car was doing very well.​​ 

​
​ 

I am running the Soliton1 aircooled and it worked wonderfully. Starting in second gear the initial launch is a little off compared to what is best described as the feeling of thrust once it’s rolling. Looking at the logger I am being limited by the slew rate at launch for the second quarter of a second. I tired bumping it to 3000 but I need to do some more tweaking (mostly of the driver) and testing to get a good launch. I do want to get some more weight on the rear wheels. I am going to move the charger to the back and try to get my 4th module back together and installed.​
​ 

​
​ 
I was busy driving and working corners but my wife said when they posted the times everyone on the side lines were saying "I can't believe how fast that electric Miata is, it beat most of the cars out here." which made my day even better. Looking at the results out of the 44 racers 4 of them solidly beat my best time including an awesome sounding red mustang, a race rX7, a black mustang, and new 370z getting times of 42.5-44.5. I was within a few tenths of another 5 racers as it ended up that a bunch of us managed times right around 45.5. An overall 9th out of 44 was far better then I was thinking I was going to manage. Even more surprising was beating a new Boss 302, Focus ST and FR-S, which are some sweet cars. And that was with me behind the wheel and 70% power. For the next event I am going to bump the power from 800 to 1000 amps and move the voltage up to 155V to give me more pull off the line and a tiny bit better top end.​ 

Working corners my favorite two cars to watch were a really cool tuned up orange focus hatch and that fast red mustang with the white stripes. Both sounded awesome. I need to put some open headers on my 9” motor.J Needless to say I was really happy with the car's performance and really appreciative to PPSCC for putting on the event and everyone who showed up. ​


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## Mark C (Jun 25, 2010)

Congratulations on the event performance and THANKS for carrying the EV banner so very well! 

I had a 90 Miata several years ago and took an autocross class with the local car club in Huntsville, AL. My first pass was awful, I didn't hit a single cone, but I spun the car half way around five (5) times on that lap. Second lap I tried going a slight bit slower and as much smoother as I could. I gained several seconds. So much fun.......


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## rochesterricer (Jan 5, 2011)

Good stuff. What tires are you running? I imagine not having the stock drivetrain puts you into a class where you are racing against cars that are allowed to run DOT race tires like Hoosiers.


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## Joey (Oct 12, 2007)

First of all, nice write up on the autocross event. Sounds like you had a blast.

Secondly, I'm curious if you have any comments about your BMS, now that your car is up and running. Were you able to configure it to do monitoring?



kerrymann said:


> *BMS install *
> 
> Just to reiterate what I said about the BMS earlier. If I had cells that I was 100% confident in then I would not have bothered. But being this is an experimental pack design I am far from it (not even close to 3 sigma . So I decided I needed to montior each cell. I looked into Battery Monitoring Systems and wasn't impressed. I found the Elithion system gave this functionality along with a management system for a very reasonable price and had a lot more features. I must say for someone that is skeptical of BMS I am preety impressed with the system so far. But I am not done yet either...
> 
> I am also looking if I can use the lithiumlite system just for monitoring and keep my pack bottom balanced.


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## kerrymann (Feb 17, 2011)

jeff mccabe said:


> Great conversion.
> Hey do what I did to get my Porsche lower. Just cut a half coil out at a time till it is where you want it.
> 
> Jeff


Yeah but I can't cut it back on.  I hope to add more cells in back and the charger too to get more weight on the rear tires. I want to upgrade to something I can tune more but I have no complaints with my $230 suspension set-up and will run it all summer the way it is.



Mark C said:


> Congratulations on the event performance and THANKS for carrying the EV banner so very well!
> 
> I had a 90 Miata several years ago and took an autocross class with the local car club in Huntsville, AL. My first pass was awful, I didn't hit a single cone, but I spun the car half way around five (5) times on that lap. Second lap I tried going a slight bit slower and as much smoother as I could. I gained several seconds. So much fun.......


I am right there with you. Before this my only autocross was a 1996 Chevy caprice with a LT1. One lap I ended up doing a 360 but didn't hit any cones, they still DNF'd me though. 



rochesterricer said:


> Good stuff. What tires are you running? I imagine not having the stock drivetrain puts you into a class where you are racing against cars that are allowed to run DOT race tires like Hoosiers.


I ran a experimental class last time and going to run EM this Sunday (assuming my wife doesn't go into labor between now and then). I am running yoko S-drives that I got from discount for $60 a each. Great high performance street tire. I could run a lot stickier and get better times but these are fine for now. 



Joey said:


> Secondly, I'm curious if you have any comments about your BMS, now that your car is up and running. Were you able to configure it to do monitoring?


Yes I just configure my balancing voltage higher then my charge voltage. I don't charge my cells as high as most as I have my PFC20 set to a cut-off at ~3.55V The BMS still monitors the cell voltages and if they go over 3.65V (IIRC) it will cut the relays to the charger. I like the amount of control the Lithiumate gives me and except for a couple bad cell boards have been very happy with it.


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## Aboveliquidice (Feb 12, 2012)

Just an awesome thread... Thanks for sharing


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