# Tennessee RX8 Conversion



## skooler (Mar 26, 2011)

kakheath said:


> Well I finally broke down and bought a car so I guess this project is finally starting. Just picked up a very nice RX8 with 110k miles for $5k. I think it was a great price since the motor seems fine. I figured that the motor was completely shot since they were asking $6k. They said that the cat was clogged and needed to be replaced. I told them that I was planning to remove the cat anyway so it really didn't matter. I'll check the compression before I pull the motor to be sure. If the seals aren't too far gone I might actually be able to sell it and recoup some of the purchase price. I heard skooler and Spyder.ev have been able to recover a fair amount by selling their removed ICE parts.
> 
> Planned conversion details. These are mostly in theory at this time as I haven't actually ordered anything yet. Mostly just gathering quotes etc. right now.
> 
> ...


Great start,

20KWH of Headways will get you moving fast with a Warp 9.

34KWH and 2 warp 9s will REALLY move, and give a good range (70-100 Miles)

by selling off the ICE parts I recouped over £800, with a faulty engine!

Good luck!

Cheers

Mike


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## kakheath (Jan 7, 2012)

I'm taking my inspiration from some of the drag car setups, but not sure how practical it will be to drive it on the street everyday. Does anyone have any real experience with 2 WarP 9's without the trans? 

I've heard that a single TransWarP motor can be a dog until about 50mph. Will I need to step up to a 2K Zilla to get this thing moving fast or will 1000A from the Soliton 1 satisfy my needs?


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## Bowser330 (Jun 15, 2008)

kakheath said:


> I'm taking my inspiration from some of the drag car setups, but not sure how practical it will be to drive it on the street everyday. Does anyone have any real experience with 2 WarP 9's without the trans?
> 
> I've heard that a single TransWarP motor can be a dog until about 50mph. Will I need to step up to a 2K Zilla to get this thing moving fast or will 1000A from the Soliton 1 satisfy my needs?


john wayland drives the white zombie with dual 9's with his Zilla Z2k and claims he gets 100 mile range, i think his pack is only ~24kwh, so 240wh/mile is damn good efficiency, but keep in mind his car weighs ~2200lbs...check his blog for more information...

With a transmission and a single warp9 the Soliton1 will be plenty for your first phase...1000A in a warp9 ~200ftlbs of torque the newer warp9s have improved voltage handling parts, i think the motor limit was stated before at 192V, I would advise to build the battery pack to a higher voltage so that with sag you would be around 150-192V this will maximize the performance of the warp9, your peak power would be over 4000rpm, which would make shifting the car feel more "normal".

The 2011 RX8 has 232hp @ 159ftlbs

When you go dual Warp9 you can program the Soliton1 for series parallel shifting...so you would power the motors in Series first, which means each gets 1000A and 1/2 voltage (if your pack is 300V nominal, then 150V each before sag) so that's 400ftlbs from 0rpm!

At a specific rpm you will figure out with testing you will program the series parallel shift, and then the motors will each get 500A and full motor voltage, 192V would be how you set it up, any more and you risk arcing and motor damage. With the higher pack voltage your sag would be minimal and the warp9s should be able to spin up the peak power to ~5000rpm...
Torque would be lower only 500A each so total 200ftlbs but that's still more than the 2011 RX8 torque and the power is close..~200hp


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## kakheath (Jan 7, 2012)

Thanks for the great feedback Bower330! I was hoping for more than a stock RX8. Now I'm even more convinced that I want the Zilla 2K instead of the Soliton 1. I like to Sol a lot, but I was really wanting even more torque off the line. How many amps can a WarP9 handle before it fails?


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## Bowser330 (Jun 15, 2008)

kakheath said:


> Thanks for the great feedback Bower330! I was hoping for more than a stock RX8. Now I'm even more convinced that I want the Zilla 2K instead of the Soliton 1. I like to Sol a lot, but I was really wanting even more torque off the line. How many amps can a WarP9 handle before it fails?


I think the highest that has been tested is 2000A from a Zilla 2K...

A Zilla2KHV ~6000$ so its double the cost of a Soliton1. However it does have the ability to series parallel shift so it can deliver 2000A to each motor from 0-rpm. That's 400ftlbs EACH, total 800ftlbs of starting torque, in order to not break all the other components within your drive line I suggest you retard the throttle sensitivity in the software to allow for a more natural take-off.

Remember though that the Zilla 2K 2000A is not the continuous rating, like it is for the Soliton1, I believe the continuous rating is/was 600A. I am not sure with liquid cooling how long the controller can deliver 2000A...

An interesting middle ground controller is the Netgain controls industrial controller. I am not sure of the specifics, but I know its got a similar voltage rating as the soliton1 and the zillaHV but it has a peak of 1400A, it is priced at 4000$ http://www.ngcontrols.com/wd2.php
It has a 550A continuous rating, but has a peak of 1400A. I am not sure if series/parallel shifting is an option, but if it is, then 1400A ~280ftlbs each motor, total 560ftlbs in series mode...


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## kakheath (Jan 7, 2012)

OK let's say I had a Zilla Z2K and 600 Headways 15Ah arranged in 50s12p for pack voltage of 170V. Assuming 10C would put out 1800A. What would be the resulting series/parallel output in ftlbs? Would the combined output be at 400ftlbs in both series and parallel?


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## Bowser330 (Jun 15, 2008)

kakheath said:


> OK let's say I had a Zilla Z2K and 600 Headways 15Ah arranged in 50s12p for pack voltage of 170V. Assuming 10C would put out 1800A. What would be the resulting series/parallel output in ftlbs? Would the combined output be at 400ftlbs in both series and parallel?


so i guess we are still presuming you will have two warp 9s.

so, if 500A ~100fltbs in a Warp9

then 1800A = 360ftlbs

so in Series mode, each motor is getting 1800A and 85V (you wont have much rpm with 85V) so total 720ftlbs but again at a very low rpm only...due to 85V

when you shift into parallel mode then each motor will get 900A & 170V which is around 180ftlbs x2 = 360fltbs and probably up to 4000rpm (when you consider the cells will sag below 170V)

If you are choosing to do dual motors it makes sense to support the motors with a higher voltage pack, Racers max out the battery voltage capacity of the controller for a reason....

3.2 cell is commonly charged to 3.5V, so the Zilla has a limit of 400V peak, so 400V/3.5 =114 cells * 3.2 = 365V, 114 cells in series is what I would shoot for.


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## kakheath (Jan 7, 2012)

Are you saying that motor torque is independent of voltage? So voltage is only driving the speed of the motor?

So if I run with only 1 motor (with trans) and a Zilla Z2K and the pack (40152-15Ah Headways) is arranged 50s12p for 170V and 1800A (10C) then the single motor would put out 360 ftlbs off the line and then have 170V to run up to highway speeds.

When I add the 2nd motor (losing the trans), I could run in series and get 720ftlbs off the line, but with a very small voltage 85V. Then shift to parallel to have 170V to both motors, but the torque would then drop back down to 360ftlbs at higher speeds.

So the only benefit of the second motor is really for the off-the-line torque. Is this correct? Is there any correlation of motor rpm to voltage to get an idea when the series-to-parallel shift point would be?

I know I'm not accounting for voltage sag in my calculations, but is there a better battery configuration to maximize the 0-60mph times.


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## Bowser330 (Jun 15, 2008)

kakheath said:


> Are you saying that motor torque is independent of voltage? So voltage is only driving the speed of the motor?
> 
> So if I run with only 1 motor (with trans) and a Zilla Z2K and the pack (40152-15Ah Headways) is arranged 50s12p for 170V and 1800A (10C) then the single motor would put out 360 ftlbs off the line and then have 170V to run up to highway speeds.
> 
> ...


motor torque is relative to amperage, motor rpm is relative to voltage....

If you have 1800A into a motor at only 85V it may only have 1800A up to 1000rpm, that's considering it sagging a bit to 50-60V. Remember battery voltage can sag ~20% when large amperage is drawn from them, anything ~1000A+ would be a large amount.

But remember 1800A even if you have 170V will only last until ~2000rpm


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## kakheath (Jan 7, 2012)

So let's say I want to be able to go 0-60mph in <4.0s, but then ease off and then drive a good 70 miles more to work and back. What battery setup would you recommend? With a constraint of $30k total for everything including battery pack, controller, 2 motors, and accessories to make it all work. 

This is really my goal. I just thought that I could derive the configuration from other people's experience, but since I'm relatively new to this field I still need some help from the Pros.


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## drgrieve (Apr 14, 2011)

Very interesting questions. This sort of set up would be similar to the set ups used by drag guys a few years back. Perhaps you could look from advice from them?

I haven't seen much discussion in the open on details you are looking after. The only dual motor set up with a public price is the Kostov dual 9". They are actually priced very reasonable at less than the price of two single motors. Not sure what peak amps they can take. Perhaps 750 each.

Anyway I think a better approach (as it's easier) would be to use a single HV 11 inch motor. Pick between Kostov 11" 250v or the Warp 11 HV 288v. Both can be custom tuned to get 300V (no idea who actually does that for you.)

Jack Richard put just over 1300 amps into his Warp 11 HV but with voltage sag he peaked out close to 170V. He needed a better pack. Still he was under 6 seconds.

What is a better pack? Cells with high power density - your choice would be headways or grey market A123s. Headways have been done before many times, but the A123 route is still frontier knowledge, but depending on your skills (or budget to get some else to assemble them) there is no better LifeP04 cell available to DIYers currently for power.

A 25 kwH pack of A123s would give you over 300 kw of power available for short bursts.

Perhaps still use the Zilla 2000 or one of the HV WarpDrive from Netgain. I would go for the Soliton 1 as 1000 amps @ 280V (after sag) would meet you goals of 4 seconds or at least very close to it if you gear the car correctly.

A pack 4p96s of A123 would fit the Warp 11 HV and Soliton 1 very well.

Then look into a racing clutch / transmission / brakes if needed for the power generated. These are just as expensive as the electric drive train.


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## kakheath (Jan 7, 2012)

Thanks for the recommendations drgrieve. Assuming your talking about the 20Ah pouch A123 cells, it would be great to only have about 400 cells. The weight savings would be nice too . What cycle life have you seen on these? I saw a couple listed on alibaba at 500 cycles. I was hoping for more like 2000 cycles.

As far as the WarP11HV, I would love to have this motor, but I heard from skooler that it might be too large for the space (that it interferes with the electric power steering module on the RX8). Plus, the stock trans on the RX8 is pretty wimpy compared to this power. I think Spyder.ev is going to try an 11" motor in his RX8, but I thought I would wait until he got it in place to be certain .


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## drgrieve (Apr 14, 2011)

Yes the 20ah cell. I believe the cycle life is the same or better then the average LifeP04 cell 2000+ cycles @ 80% DOD with the proviso that other folks have tested capacity and power of these cheaply available cells but not cycle life.

If you are pushed for room the Kostov 11" 250v is 1 inch smaller in both diameter and length. It also weights 40 pounds less and is cheaper.


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## kakheath (Jan 7, 2012)

I did more research on the A123 batteries. These things are amazing. Why isn't everyone using them? I got a very reasonable quote directly from China. The price is comparable to the Headways. This seem like a no brainer for pack choice.

I always thought most people favor the Netgains. What's the reliability and power of the Kostovs? I hadn't looked into them much, because I had assumed the Netgains were better. I like the information you've given me so far. I'll start looking into the Kostov motors. Thanks for the advice. With every exchange with you my project is getting more and more affordable. Thanks a lot drgrieve !


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## skooler (Mar 26, 2011)

kakheath said:


> As far as the WarP11HV, I would love to have this motor, but I heard from skooler that it might be too large for the space (that it interferes with the electric power steering module on the RX8). .


Hi kakheath,

Its tight but might just be do-able with an 11".

My nine inch is about 18" long and the back of the motor will rest on the bracket for the power steering with the gearbox in roughly the original position.

I have increased the angle of mine in order to avoid interference. (The gearbox points upwards about 15 degrees more than standard).

I will post pictures and measure up once I finish welding up my mounts tomorrow.

You could always lose the gearbox and go direct drive?

Cheers,

Mike


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## kakheath (Jan 7, 2012)

Thanks for the info skooler. Can you check to see what the largest diameter motor will fit in place of the trans. Here's a summary I found on motor diameters (ref. rebirthauto.com Kostov motor data):

Motor------Diameter
Kostov9-----8.66"
WarP9------9.25"
Kostov10---10.43"
Kostov11---10.43"
WarP11-----11.45"

I'm wanting to know my possibilities for dual motors. I just assumed that dual WarP 9s would fit, but let's say I wanted to go with dual K10s or K11s. I'll probably need some room for forced cooling and of course the electrical connections to the motors.

I still would like to do this in phases. Phase 1 gets me going on 1 motor and Phase 2 adds the second motor with rear diff and axles upgrades.

BTW, why doesn't my pic show up in my postings? Is this a newby thing or have I not selected the correct profile option?


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## drgrieve (Apr 14, 2011)

A123 doesn't sell direct to public. These cheap cells have only recently become available (again). The main issue is how to build a pack out of them. 
JR of EVTV is currently doing a few episodes on trying to discover a method. There is also on endless sphere a few threads on building packs with tabs for ebikes. Usually spot welding. 
Also on there is forum member by the name of cellman who builds completed packs with BMS built in.

On this forum Netgain motor are more popular, in Europe I think the Kostov is more popular. Either motor is fine. The heavier the motor the more amps it can take is a general rule of thumb. Josser uses a K11 HV in his Mazda - I think he runs it fairly hard.

One thing to consider in choosing the controller for track is the continuous amp rating. You don't want the controller derating itself halfway through a lap.


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## kakheath (Jan 7, 2012)

Well, I placed the order for 500 A123 20Ah pouch cells. They are coming by UPS in 36 boxes weighing about 20lbs each. They cost $18.2 each, but with the air freight, customs and using Paypal. I ended up paying around $23 each. That's so far been the biggest investment to date. That's more than twice the cost of the fully functioning car.

I have a design that I like for the pack. I think I'm gonna copy something like this guy: http://vimeo.com/35673354

Except that I want to use two rods through each tab. This way I can have more clamping force and ensure that the blocks are not twisted during assembly. I also thought of weaving a couple layers of extra thick aluminum foil between each battery to wick off heat. Any thoughts on this design?

The next question really is what is the best configuration for phase 1. If I only have one warp 9, should I still build my battery pack with 110s. I'm thinking of reducing it for the 1 warp setup and then later reconfiguring it for max voltage once I'm ready for phase 2 with a second motor etc. So what do you guys think about pack setup phase 1?

Phase 1
1 warp 9 with Z2K-EHV
3 modules of 70s2p in series for 224V nominal assuming 0.7V sag, this would leave 175V for the motor. 

I would then choose whether I wanted to use all 3 modules in parallel or just 1 module. Each would theoretically give me 25 miles each. Of course I would not be able to pull the full Z2K amp draw with only 1 module, but I probably could get very close with 2 module meaning 70s4p. Am I way off on this design idea or do you guys think it will work?


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## drgrieve (Apr 14, 2011)

Wow! This build is going to be very exciting to follow.

I'd recommend making a separate thread in the battery section for your battery pack build. You should get more responses that way. rwaudio on this forum is also building a pack I'd recommend talking to him for suggestions. He is using the block approach. You might also cross post on endless sphere, the ev bike guys quite often use tab cells.

I don't of anyone who actually has a pack of these cells in a running car and has documented the build in detail. There is a honda insight guy you can search for and there is nabilahmad on youtube building packs.

JR of EVTV used very thin anodised aluminium to separate each 2 cells, so that 1 side of each cell had contact. This was bent at the end so it made a end plate with them all together.

Assuming the ZEHV works like the Soliton (Extra voltage over max motor voltage is turned into amps) I would at first build the packs in final parallel configuration and when you complete the pack, add more in serial. This would be easiest down the track but may limit you in top speed during phase 1 due to lack of voltage.

I wouldn't wire two assembled packs in parallel you would need to strip down the packs and rewire the cells in parallel for phase 2 if you went high voltage now.

A couple of other points. Check out how much continuous amps you need and see how you can cool the Zilla to achieve that and check out rwaudio's thread on cell matching.


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## drgrieve (Apr 14, 2011)

I just realised how many cells you order. 500 A123 20 ah cells is more than enough to power 2 warp 9's. 32 kWh at 15C @ 15% sag is 410 kW motor input! Not sure of the best config for that. I would ask George at Netgain motors for advice on how much voltage and amps you can run with a good margin of error to try and work the best configuration with the Zilla. I don;t see how to get more than 350 kW with the warp 9's.

32 kWh should also be good for 100 - 140 miles range depending on speed travelled.


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## vidmaster89 (Feb 27, 2011)

Where did you order these cells from? Victpower? Looking to buy the same cells from china with paypal for my own project merc., right now searching for a reliable vendor (of black market cells, seems crazy, yeah ) for my order.


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## kakheath (Jan 7, 2012)

I bought my A123 cells from:

xin wang Shenzhen Victpower Technology Co., Ltd. [email protected] W:http://www.victpower.cn

I just got the tracking numbers for DHL today. I'm very excited about the deal.  I wish they used sea freight. It would have taken a lot longer, but saved a lot of cash. 

If you do find a source that ships by sea, I have a number for a good customs broker that only charges about $125 per transaction.http://www.rogers-brown.com/

They quoted me about $175 freight from the port of Charleston to East TN. This was for 420 Headways though. So the freight for 500 A123s would be a bit more. My guess is that shipping by sea would have saved about $1000. It's worth it if you can find a source willing to do this and can wait that long. Another problem with sea freight is that Paypal protection only lasts 45 days. So sea freight might eat most of this time up.


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## Bowser330 (Jun 15, 2008)

drgrieve said:


> Wow! This build is going to be very exciting to follow.
> 
> I wouldn't wire two assembled packs in parallel you would need to strip down the packs and rewire the cells in parallel for phase 2 if you went high voltage now....


I agree, very exciting.

Can you elaborate more on why you don't recommend building the pack with full voltage and then add more parallel strings to add range and peak power potential? It seems to be an easier way to build up a pack...

Example: 500, 20AH cells 3.2V each.

100s = 320V and 2p = 40AH (7C on those cells only dips to 2.85V)
so...285V * 280A = ~80kw 

Then for phase2 add the remaining 300cells in parallel with the phase1 pack.

100s = 320V and 2p + 3p = 5p = 100AH (7C = 2.85V)
285V * 700A = ~200kw @ 7C

20C =~ 2.3V after sag, so 230V * 2000A = 460kw potential battery burst power


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## dladd (Jun 1, 2011)

great build, awesome battery pack! Looking forward to following your progress on assembling the packs.


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## Yabert (Feb 7, 2010)

kakheath said:


> Well, I placed the order for 500 A123 20Ah pouch cells.


It will be really interesting to see the quality of those cells.
1.2$ / Ah including shipping is awesome for those powerful cells.

About battery pack, I think you should build final pack (high voltage) and simply limit the maximum motor voltage if you decide to go with a single Warp 9 on phase 1.


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## Bowser330 (Jun 15, 2008)

Yabert said:


> It will be really interesting to see the quality of those cells.
> 1.2$ / Ah including shipping is awesome for those powerful cells.
> 
> About battery pack, I think you should build final pack (high voltage) and simply limit the maximum motor voltage if you decide to go with a single Warp 9 on phase 1.


+1, I agree. That way even if there is voltage sag at the cell/battery level you may not experience it as much at the motor.

Within the controller parameters you can set a maximum motor voltage. The controller has a maximum battery voltage parameter where it will shut down and not work if the voltage is higher than that parameter. example: The soliton1 will not function if the battery voltage is over 340V. (that means you need to keep in mind the fully charged voltage of your cells, nominal is 3.2V but you will set your charger to 3.5V)


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## kakheath (Jan 7, 2012)

I've got Batteries!!!!!


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## Yabert (Feb 7, 2010)

Made in USA...

Please share test result with us.


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## kakheath (Jan 7, 2012)

I've opened every box and checked the as-received voltage on every cell. All cells were very consistent at 3.27-3.28V. There was one cell missing out of the total 500 ordered. All cells were individually wrapped in bubble wrap. About 5 or 6 were deformed from the use of 3 different types of trays. This doesn't appear to be a big deal as they easily straighten out with a little pressure on a flat surface. The rest of them look absolutely brand new with perfect tabs and everything .

I'm using a Powerlab 6 and have tested the first cell last night. I'm very new to this, so I'm not sure if I have all the settings correct. I'm using a small power supply and the system seems limited to 10A charge and discharge. This made it take about 2hrs each way. This is not practical for all my cells, so I have to find another way . 

The resulting discharge capacity of this first cell going from full charge to 3.65V down to 2.5V appears to be 18,233mAh. I think this seems consistent with JR from EVTV and what rwaudio has been seeing .

I need some help with a practical way forward. What if I used the PL6 just to top them all up to 3.65V. Then just measured the capacities of a sampling of the cells, say about every tenth one or 50 total. This information would be more for confidence in the cells than for matching purposes. If I then just randomly assembled them into groups of 5 in parallel, would this work out ?


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## drgrieve (Apr 14, 2011)

Congrats on getting the batteries, that was quick.

In regards to matching - if doing every cell proves to be too arduous then I would sample 30 to 50 cells randomly to find your average and variance. If the variance is not large or is acceptable then assemble randomly but check the capacity of each assembled module. If it's capacity is close to the average then your good to go. Otherwise put back in pile.

Not doubt out of 100 or so assembled modules there would be a few that will be outliers and will reduce your pack capacity if not checked.

One benefit you'll miss is removing x smallest capacity cells from your pack to be used as 12v supply. Not sure if you are intending to use all 500 cells in this car?


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## kakheath (Jan 7, 2012)

drgrieve said:


> Congrats on getting the batteries, that was quick.
> 
> In regards to matching - if doing every cell proves to be too arduous then I would sample 30 to 50 cells randomly to find your average and variance. If the variance is not large or is acceptable then assemble randomly but check the capacity of each assembled module. If it's capacity is close to the average then your good to go. Otherwise put back in pile.
> 
> ...


I'm planning to use 92s5p which leaves 40 for a 12V supply plus some extras. This voltage is meant to align with a Z2K-HV. Since 90% of them are exactly the same voltage right now, couldn't I assemble them as-is without top or bottom balancing?


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## drgrieve (Apr 14, 2011)

Yes and no. The only true way to balance them is to have each set of cells the exact same ah. The number of builds that can do that is very few. So

1. Middle balance (as you are now). Issue when get to top (will over charge small cells at top). Issue when get to bottom (will reverse and kill small cells at bottom)
2. Top balance. Fine when charging but will kill cells at bottom.
3. Bottom balance. Fine if run pack down to 0 but will over charge the small cells if charge to 100% full.

My take => Bottom balance as the most evil is cell reversal at bottom, and by under charging your pack slightly top issue is avoided and make for a longer lasting pack anyway.


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## dougingraham (Jul 26, 2011)

kakheath said:


> I'm planning to use 92s5p which leaves 40 for a 12V supply plus some extras. This voltage is meant to align with a Z2K-HV. Since 90% of them are exactly the same voltage right now, couldn't I assemble them as-is without top or bottom balancing?


Probably not. They will be within a few percent of balanced but that is not close enough. Resting voltage is a relative state of charge only. Temperature makes a difference too as does actual capacity. You could get away with it only if you never over discharge and never try to fill up the pack.

I did an initial discharge test on a few of my cells and found that they all were charged to between 54 and 55 AH. The amount contained did not correlate with the initial voltage. It also didn't correlate with capacity of the cell. If I had placed these cells in series the imbalance between the highest and lowest cell would have been less than an AH at the bottom but a little over 2AH at the top (100AH cells)


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## kakheath (Jan 7, 2012)

Time for an update. 

257/500 cells tested and counting. I probably have enough data to start my cell sudoku of matching them into equal capacity sets of 5 (around 90Ah total). Despite some upcoming travel, I hope to be getting very close to finishing the cell testing around Easter. As rwaudio advised, I'll probably do some testing of the assembled 4s5p modules before installing them in the car. Final pack will be 23 of these modules for a total configuration of 92s5p 20Ah A123 pouch cells.

I pulled the engine this past weekend. It took me 5 hours. I found a very helpful series of postings from an RX8 forum. I don't see how it could be done in the 3 hours mentioned in the write-up, but I don't think 5 hours was too bad for a 1st timer. http://www.rx8club.com/showthread.php?t=178937

There's a surprising amount of space in front of the electric power steering rack once you remove the radiator and fans. I've decided to mount the remainder of the batteries in this location.

I removed the exhaust system and cut a hole in the trunk for the prep work to install the trunk battery box.

Thanks for viewing,
Kevin


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## kakheath (Jan 7, 2012)

I'm heading down to TN this weekend to hopefully make some more progress on the car. My plans are to build prototype battery boxes in the trunk and front of the car. I fear that I may need a third box due to clearance issues, but hopefully this will be confirmed over the weekend.

I've finished the battery testing. I'll post the detail later, but the short version is:
3.65V to 2.5V at 38A testing using a PL6
440 batteries tested (virgin cells - as received)
Min 15959, Max 19037
After culling out about 15 of the lowest cells, the average was 17951mAh per cell. This is just 1 cycle. 

I've disassembled the three power supply packs (20 cells each) and have found that they are significantly higher capacity than the rest of the virgin cells. So, I have to balance those 60 cells among themselves only. Their average is more like 19000mAh since they had been cycled a 100+ times during all the individual cell testing.

Other updates are that I've purchased a Soliton 1 as my controller. Big thanks to Sebastien and his crew at Evnetics for the nice tour of his production and test facility. I'll soon post some pics of where I hope to install it in the car. I've chosen a very prominent spot for it where the ICE airbox used to be. It will be the most visible item since the rest of the equipment will hopefully be tucked neatly into enclosed boxes.

I've also ordered my charger. I'm going with the PFC5000. I think this is the best compromise between charge rate and cost with the option of both 110 and 220 inputs. I thought I would mount this in the trunk up-side-down hanging from the rear window shelf.


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## powerhouse (Apr 1, 2011)

kakheath said:


> I've disassembled the three power supply packs (20 cells each) and have found that they are significantly higher capacity than the rest of the virgin cells. So, I have to balance those 60 cells among themselves only. Their average is more like 19000mAh since they had been cycled a 100+ times during all the individual cell testing.


Hmm thats odd, the capacity went up as cycles were put on them.
Maybe the cells need to be worked in? Interesting find though


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## dougingraham (Jul 26, 2011)

powerhouse said:


> Hmm thats odd, the capacity went up as cycles were put on them.
> Maybe the cells need to be worked in? Interesting find though


The typical behavior of LiFePo4 cells is that the capacity increases slightly for about the first 30 cycles.


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## kakheath (Jan 7, 2012)

OK Long time no update. Sorry about that. I've been very busy lately on the car and have a lot of progress to report. I guess the first step was the trans adapter and hub. I got this from Electric Car Company and it was full of issues. It took what seemed like forever and when the hub arrived it did not work properly. The trans adapter was well done though and they even let me request some additional mounting tabs for my motor mounts.

It looks like the machine shop thought the motor shaft was 1 inch longer than it was. In the pics below you can see that it fully engages the flywheel on the back side, but sticks out an inch past the flywheel. There's an internal snap ring that I suppose was to limit the hub from going too far towards the motor, but since it's an inch longer the hub bottoms out before the snap ring touches. The flywheel, however, can be pushed more towards the motor when the clutch is pressed. If this were to happen it would press against the motor bearing and damage it.

The next issue was that it did not fit snug on the adapter it kind of wabbled. They have milled out the inside of the flywheel and left a small taper which caused the flywheel to not set properly onto the hub.

For others doing the same conversion, I would recommend the unit from CANEV. It seemed to work well for Spyder.ev.


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## kakheath (Jan 7, 2012)

To keep from having futher delays, I decided to correct what I could in order to make the hub work. I ended up cutting an inch off the hub and truing up the end with the lathe. This was the end with the internal snap ring. I turned it around and place this fresh cut side towards the motor using the snap ring as the backstop for the fylwheel to press against when the clutch is depressed. To keep the flywheel from moving towards the trans, I drilled and tapped two bolts to keep the flywheel tight against the snap ring. The only tricky part what that I had to respect the 1.5 inch spacing between the trans mounting surface on the adapter plate and the clutch surface. With all this done, I was finally able to get going again.


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## kakheath (Jan 7, 2012)

Now for some real progress. Here are some pics of the motor mating to the trans for the first time.


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## kakheath (Jan 7, 2012)

Here are the beginnings of the motor mounts. This is from 1/4 inch plate. I mounted these to the stock motor mounts. I want to take advantage of the factory rubber motor mounts to minimize any vibrations.


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## kakheath (Jan 7, 2012)

I wanted to maximize the available space under the trunk so I relocated the torsion bar mounts closer to the rear cross member (3/4"). Also, I cut out part of the body mounts and boxed them back for integrity. This allowed me to have more room for the box. 

I made a frame out of 1/8" aluminum angle. I turned the top out so that it could rest on the top surface of the trunk floor.


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## kakheath (Jan 7, 2012)

The trunk box with walls and a floor all from aluminum. I'm very lucky my father is a good welder.


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## kakheath (Jan 7, 2012)

Here's the trunk box in the car. The last pic shows the Lowe's floor mat made from recycled rubber. This is to help cushion the ride for the precious cargo.


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## kakheath (Jan 7, 2012)

They always say that things get easier the more you do it. We decided to make the lower front battery box out of aluminum sheet metal without the frame. This was much faster. Here's the initial version tacked. In these pix the box is being held in place with bungee cords. Also, you see the beginnings of some steel brackets welded to the frame rails. These are made from 1/4" steel flat bar. We're still debating on the best mount method.


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## kakheath (Jan 7, 2012)

After driving Sebastien's amazing 911 with dual warp 9s, I decided to go with the Soliton controller. Here's a pic of it with some other parts. You see two Bubba contactors, a DC to DC converter, an inertia safety switch, 3 fuses for the battery packs and a couple of pancake fans I plan to use to cool the batteries. 

I'm splitting the battery pack into 3 locations, so I'm using 3 fuses mounted to the most positive posts of each box. The bubbas will be mounted on the most positive and most negative ends of the pack.

I plan to make a small 12V battery out of 8 left over A123s.

Other important components include an Orion BMS, Elcon PFC5000 charger, EV source's quiet vacuum pump kit, the Blowme9 kit from EVTV for cooling the motor using a converted Garrett Turbocharger. See pic below taken from Jack's website.


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## kakheath (Jan 7, 2012)

Almost every metal piece started out as cardboard. This mock up of the box above the motor is a composite of aluminum sheet metal and cardboard. I wanted to make progress over the weekend before I could get a sheet of diamond plate. You can see part of my single A123 mock-up for checking size etc inside the box. 








Since this box will get most of the attention, I wanted it to look a little nice than the rest. I really wanted to use the factory motor cover and had several ideas on how to do this, but in the end, it just was too tall.















As a compromise, I integrated the strut tower brace inside the battery box. The lid will close over top of it when complete.















I'm glad I finally stumbled onto the way to insert pics inside the verbiage by just going to the attachment icon again and selecting the pic you want to insert.


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## skooler (Mar 26, 2011)

Just sent you a PM (R.E. power steering)

I have an idea about getting it to you on the cheap!


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## kakheath (Jan 7, 2012)

skooler said:


> Just sent you a PM (R.E. power steering)
> 
> I have an idea about getting it to you on the cheap!


PM sent back to you. Thanks.


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## ScottyDont (Sep 29, 2013)

Hey Kakheath, any updates on your conversion? What method did you end up using to connect the pouch cells together?


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## kakheath (Jan 7, 2012)

Actually, a lot has happened since the last update here. I finished the car and took it to EVCCON 2012 and took home 3 trophies from the event. This was September 2012. I received a trophy for 2nd place at the car show, 3rd place in drag racing & 3rd place in the slalom course.

The current specs for the car are:

Warp 9, Soliton 1, 480 A123 gray cells 96s5p in 3 battery boxes, Orion bms, bluetooth adapter using Nexus 7 tablet to show all battery pack information, Elcon PFC5k, J1772 mounted in the gas fill port. I'm using the stock 6 speed transmission. 

Update as of 5 months ago, I wasn't happy with the way I had connected my batteries. The car performed well at EVCCON, but after about 6 months, I would have issues where the connections between the batteries would fail under max amps. The failure would be temporary thanks to the Soliton. Once I reset the Soliton, it would start working again. Ultimately, I had to repace all the aluminum bus bars with copper and the connections were also improved by fastening each group individually to the copper pieces. This has significantly reduced the voltage sag. When I was drag racing at EVCCON 2012, I saw extreme total voltage sag from ~330V down to ~170V (~50%). Now with the copper and much better connections, my sag is only about 10%.

Here's a pic of the transition from aluminum to copper:


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## dougingraham (Jul 26, 2011)

kakheath said:


> Ultimately, I had to repace all the aluminum bus bars with copper and the connections were also improved by fastening each group individually to the copper pieces. This has significantly reduced the voltage sag. When I was drag racing at EVCCON 2012, I saw extreme total voltage sag from ~330V down to ~170V (~50%). Now with the copper and much better connections, my sag is only about 10%.:


I missed you at EVCCON 2013. I was cuirous about your improvements over the year. For those who didn't see this car it is a spectactular conversion and deserved the awards it received. Jack talked about being embarrassed about showing off his cars, I felt the same way about my Rx7 after seeing this Rx8.

I was hoping to see you and was going to ask about this very topic as yours was the most ambitious DIY use of the A123 cells I had seen. Did you use any kind of anti oxidation grease on the original battery build? It sounds like it took a while but you probably ended up with an oxidation layer. Have you taken any measures to prevent the same thing from happening with the copper/battery terminal connections?


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## tylerwatts (Feb 9, 2012)

Kakheath would you be able to share some more photos of your lovely car please, details of how you put it together and what performance it has please. I've always been keen on the newer rx8 but was surprised to see the smaller warp9 motor in your vehicle. How does it perform please? 
Thanks


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