# Honda S2000 Conversion Thread



## powerhouse (Apr 1, 2011)

Alright, I figured its time I create a thread on here. 

I've been wanting to create an electric car for quite some time, and about a month ago I took delivery of a 2003 Honda S2000, which will be the donor for my conversion. 
This car was chosen due to my fathers criteria, being that the car had to be manufactured after 2000, it had to have air bags, and it had to be cheap. 
I chose the car since it was one of the lighter cars I could get, that looked decent 

GAME PLAN! My goals for the conversion, include getting a 0-60 mph times of 3-4 seconds, a range of 80-90 miles of everyday driving (50% highway, 50% city), top speed of ~ 90 mph, and the total cost of the conversion should stay below $40,000. 

COMPONENTS!?
Currently, my list of components is very similar to crodriver's previous set ups. 
-Zilla 2k 
-Warp 11HV, preferably from Jim Husted (if he starts answering emails...)
-16 Ah Headway batteries; I contacted the company, and they offered me each cell for $19. I will most likely get anywhere from 550-720 cells, depending on my final configuration. Will most likely need at least 28Kwh of energy. 

I plan on setting the car up in direct drive  since it makes more sense in my head; less weight, less things to break. Plus, a couple of people have suggested it to me.

I hope to get this car done in about 6 months time, which seems possible. The entire project will commence once I receive my motor, at which point I will begin disassembling the car. 

Time for some pictures!!! Notice how big, and spacious the engine compartment is, you can see the ground from the top of the engine bay. 

Edit:
*Major decisions regarding the components chosen and the path I had anticipated taking have significantly changed since this thread first spawned. That said, I am choosing not to edit this first post since it exemplifies the maturation of the project, and is a part of its history.

Timeline:
4/XX/11: Idea conceived 
6/9/11: S2000 delivered
10/1/11: Tear down begins
10/10/11: Zilla 2k arrives
12/3/11: Motors picked up from Rebirth Auto
12/21/11: Engine & tranny removed from car
*​ 
-----------------------------------------------------------------------------------------------------------------------------------------------


----------



## albano (Jan 12, 2009)

Hello powerhouse, 

Nice looking Honda you got there! 

For the motor I would prefer Dennis Berube, as he build nice strong and reliable motor.


----------



## drgrieve (Apr 14, 2011)

This car is on my list as well. Looking forward in seeing how it goes.

I would do some serious research on direct drive. I don,t think you will be able to go 4 seconds and top speed of 90 miles without a transmission. The rpm range of the warp 11 hv is not that wide.

Have a look at jack rickards recent video on the warp motor.


----------



## rwaudio (May 22, 2008)

Nice car for a project, good choice in motor  ambitious goal for the 0-60 time, but if you can keep the weight reasonable it should be possible. Given the budget you might want to look at A123 20ah pouches and copy crodrivers final DC setup. It would bring the weight and size of the pack down a bit over headways. In testing I found that the A123's also stay cooler at the same C rates with less sag (I tested the 10ah headways though, not 16ah). Good luck with the project, I'll be watching.


----------



## powerhouse (Apr 1, 2011)

drgrieve said:


> This car is on my list as well. Looking forward in seeing how it goes.
> 
> I would do some serious research on direct drive. I don,t think you will be able to go 4 seconds and top speed of 90 miles without a transmission. The rpm range of the warp 11 hv is not that wide.
> 
> Have a look at jack rickards video on it.


I expect that the Warp will be able to handle it with the proper gearing. Heck, if I could go 70 mph (highway speed) I would be content with the system. It is possible, proven by Cro's set up, however execution would be tricky for sure!



rwaudio said:


> Nice car for a project, good choice in motor  ambitious goal for the 0-60 time, but if you can keep the weight reasonable it should be possible. Given the budget you might want to look at A123 20ah pouches and copy crodrivers final DC setup. It would bring the weight and size of the pack down a bit over headways. In testing I found that the A123's also stay cooler at the same C rates with less sag (I tested the 10ah headways though, not 16ah). Good luck with the project, I'll be watching.


I don't really want to go into the pouches; even with the higher power, the additional cost and work to put together the packs would be unbearable. Designing the boxes, bus bars, testing, etc. After the entire thing was done, and running, im almost positive that the pack alone would cost $45k+


----------



## rwaudio (May 22, 2008)

powerhouse said:


> I don't really want to go into the pouches; even with the higher power, the additional cost and work to put together the packs would be unbearable. Designing the boxes, bus bars, testing, etc. After the entire thing was done, and running, im almost positive that the pack alone would cost $45k+


I guess it all depends on what you can do yourself. I would suggest a quick PM to crodriver and see if he has some input based on his experience. I know headways are good, I've tested them and almost went with them for my build. Given the lower range requirements for my build A123 made much more sense based on weight/power/voltage sag. Even with headways you're going to have a little rocket.


----------



## Bowser330 (Jun 15, 2008)

rwaudio said:


> I guess it all depends on what you can do yourself. I would suggest a quick PM to crodriver and see if he has some input based on his experience. I know headways are good, I've tested them and almost went with them for my build. Given the lower range requirements for my build A123 made much more sense based on weight/power/voltage sag. Even with headways you're going to have a little rocket.


RwAudio: Have you updated your blog with that info? I didnt know you were switching to A123's!?

PowerHouse: Headway 16AH (15C burst) 19$, 500g, 3.2 nom (3.65V charged) each
94 in series = 300V Nom (340V @ 3.6V Charged)
5 in parallel = 80A & could burst to 1200A @ 15C
9K$ & 500lbs
24kwh would give you 100 mile range (100% Dod) @ 240wh/mile

I would go maximum voltage if I were you, more voltage allows for higher rpm and higher peak power and higher rpm, CroDriver was able to peg 270V (sagged) & 1400A @ 4500rpm, with his 33?V pack of Headways 8AH power cells...


----------



## rwaudio (May 22, 2008)

Bowser330 said:


> RwAudio: Have you updated your blog with that info? I didnt know you were switching to A123's!?


I haven't updated it yet. It's a very recent decision. Powerhouse I'm sorry for the high-jack, I won't post anything else off topic in your thread.


----------



## steven4601 (Nov 11, 2010)

That is a pretty good car as an EV. Also your plans sounds like it will be a rocket.

Robin, that looks like some battery origami for the next few weeks  What config 100S2P ? How much did that set you back? $65,- the piece?


----------



## DavidDymaxion (Dec 1, 2008)

This sounds like a great build! It's good to see you have a decent budget.

The 16 Ahr Headway cell has 4 times the internal resistance of two 8 Ahr P cells in parallel. The 16 Ahr has 8 milliohms of internal resistance, the 8 Ahr P has 4 milliohms per cell, but 2 in parallel then has 2 milliohms. That means you'll get 4 times the Voltage sag with the 16 Ahr cells that you would with the same total Ahr of the 8 Ahr P cells. Four times the internal resistance also means only 1/4 the peak power than can be drawn. Since you are aiming for speed (a quest I applaud!) I think you should consider the 8 Ahr P cells, or with that budget maybe even A123 batteries (they have a new 20 Ahr cell that looks promising).

It's easy enough to calculate the sagged power that it is worth doing:

Power = 
number_cells_in_series
* ( 3.35V - current * internal_resistance / number_cells_in_parallel)
* current

Let's try it for the two types of Headway cells, and run at 2000 Amps. You'd need eight 16 Ahr cells in parallel for that, and sixteen 8 Ahr P cells in parallel for the same Ahr.

94 * (3.35V - 2000A * 8 mohm / 8) * 2000A = 254 kW
94 * (3.35V - 2000A * 4 mohm / 16) * 2000A = 534 kW

It's no contest, the 8 Ahr P cells win. The higher the current the more pronounced the difference will be.

On a different topic, Honda S2000s have a reputation for sudden oversteer -- so you'll want to keep that in mind with respect to putting weight in the trunk, and you might need to do some suspension tweaks to keep the handling safe.


Bowser330 said:


> RwAudio: Have you updated your blog with that info? I didnt know you were switching to A123's!?
> 
> PowerHouse: Headway 16AH (15C burst) 19$, 500g, 3.2 nom (3.65V charged) each
> 94 in series = 310V Nom (340V @ 3.6V Charged)
> ...


----------



## drgrieve (Apr 14, 2011)

> 94 * (3.35V - 2000A * 8 mohm / 8) * 2000A = 254 kW
> 94 * (3.35V - 2000A * 4 mohm / 16) * 2000A = 534 kW


I haven't seen this calculation before (the dividing by parallel part). Do you know of a video which shows this during battery testing? I find that easier to digest.

Interesting when you plug in 1000A

94 * (3.35V - 1000A * 8 mohm / 8) * 1000A = 221 kW
94 * (3.35V - 1000A * 4 mohm / 16) * 1000A = 291 kW

Doubling the amps for the 16ah only gains you ~15% more power ....

This gives me much food for thought.


----------



## DavidDymaxion (Dec 1, 2008)

I don't know of a video, but it is basic electronics. Resistive loads in parallel lead to less overall resistance. Because the resistances are presumably the same between the batteries, you can just divide the resistance of one battery by the number of batteries in parallel.

Testing batteries is not rocket science. Buy a Harbor Freight adjustable battery tester (about $50), buy a few 16 Ahr and 8 Ahr P Headway cells, and see for yourself how the power differs. I wear safety glasses, put in ear plugs, and throw a mat over the batteries when I test.


drgrieve said:


> I haven't seen this calculation before (the dividing by parallel part). Do you know of a video which shows this during battery testing? I find that easier to digest.
> 
> Interesting when you plug in 1000A
> 
> ...


----------



## rwaudio (May 22, 2008)

steven4601 said:


> That is a pretty good car as an EV. Also your plans sounds like it will be a rocket.
> 
> Robin, that looks like some battery origami for the next few weeks  What config 100S2P ? How much did that set you back? $65,- the piece?


Yes, lots of work with the batteries, and with my current schedule, more than a couple weeks. 96S2P as a minimum but ideally 96S3P... less than $65/pc

I will admit the headways were a lot easier to work with. It's too bad these A123's aren't more "available" it would probably spawn 5 companies to build DIY assembly systems for the cells so that just about anyone could use them...


----------



## powerhouse (Apr 1, 2011)

OK im back, ive been busy doing nothing

good news, ZILLA 2000 is on its way!

I am going to have Dennis Berube build my motor
A couple of things have been decided with his advice
The car will be running @ 350ish volts, as opposed to the 280ish I was planning before
Also, the car will contain 2 Traction packs, 1 consisting of 10 AH Headway cells, in parallel, enough to get 2000 Amps out of it. And another traction pack made up of GBS batteries, which are practically thunderskys, but better.. This pack is going to be in series, and will be a high voltage low current pack.


----------



## albano (Jan 12, 2009)

powerhouse said:


> OK im back, ive been busy doing nothing
> 
> good news, ZILLA 2000 is on its way!
> 
> I am going to have Dennis Berube build my motor


Good choice you got here,


----------



## Bowser330 (Jun 15, 2008)

powerhouse said:


> OK im back, ive been busy doing nothing
> 
> good news, ZILLA 2000 is on its way!
> 
> ...


^^^ This!
(1) Great Donor
(2) High Voltage Built Motor
(3) Interesting hybrid battery pack

So when the controller demands the amperage from the battery pack, the Headway's will provide the amps and the GBS's will not be damaged?


----------



## x88x (Aug 19, 2011)

powerhouse said:


> Also, the car will contain 2 Traction packs, 1 consisting of 10 AH Headway cells, in parallel, enough to get 2000 Amps out of it. And another traction pack made up of GBS batteries, which are practically thunderskys, but better.. This pack is going to be in series, and will be a high voltage low current pack.


Interesting hybrid pack choice. There may be a problem with that though. What it sounds like you're proposing in your description (please correct me if I'm wrong) is a low voltage pack of headways several wide, stuck in series with a high voltage pack of GBS. That won't achieve the results you're looking for. The headway pack would be boosting the voltage, yes, but the pack would not benefit from the additional current-draw ability of the headways. What _would_ achieve the intended results would be to turn that on its head. Have two packs the same voltage, one GBS, one headway. Wire these packs in parallel, and the headways should serve to boost the current draw capability of the pack. I have seen this done with success before using Turnigy Nano-tech LiPo packs in parallel with SLA. That required a bit of protection circuitry because the packs were different chemistries and thus slightly different voltages, but the end result worked quite well. Here's the guy that did it:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=26797

EDIT:
That being said, assuming you can pull ~1,000A out of the GBS (assuming 100Ah cells; btw, you might want to take a look at the CALB cells; at least on paper they look a little better), you would need a 7P pack of 10Ah headways pushing at 15C (1,050A) to make up the difference. That would be almost $12,000 for the headway booster pack (at CurrentEVTech's prices) for a 94S pack...that's almost what the GBS pack would cost. Personally, I would look at just building a wider GBS/whatever pack; say, a 200Ah. That would still be able to hit 2,000A (according to the specs), but would give you twice the range when you're _not_ pushing massive power draw. If you can fit it in the car, imo that would be a better choice.


----------



## x88x (Aug 19, 2011)

powerhouse said:


> BUT some news! I'm currently planning on purchasing about 20kwh worth of A123 Batteries, the same type CroDriver is using, except more consistent and reliable. .


Nice. From which vendor? What sort of price were they? They're really nice cells, I just tend to ignore them since there's no non-grey-market way to buy them and even grey-market sources tend to be at least twice the cost per Wh compared to, say, TS, CALB, or TS.


----------



## powerhouse (Apr 1, 2011)

Better news!


Battery order is going in this week!


Decided im going to go with 1018 8ah Headway cells, 112s/9p
Should have a peak power of 551kw, according to the formula supplied above. The batteries are rated at 25c continuous, so I figured that they should be able to handle 28c for 3 seconds! 


The completed pack should get me about 100 miles of range, assuming 250whm^-1 , and a pack energy of about 26kw's 


WOO!! Im excited!
Batteries should take 3 weeks to arrive after I order them. For those wondering, the unit price will be about $12.50, and the customs/shipping cost will come up to $700


The Zilla should get here in the next two weeks I hope, however it is the first Zilla 2k EHV coming from Manzanita Micro (BTW they have great service, very helpful!). 


I *need* to get this car done by Dec. 31st 2011, in order to get a tax credit on the conversion. 


therefore, the Motor order is also going in this week!


One question for everyone, what BMS should I use on this thing??? I really like Crodrivers, however I dont think he will disclose any info on it. A visual display would be really nice on the car. 

Thanks for the help everyone!!


----------



## Bowser330 (Jun 15, 2008)

Super excited to hear more about your build.

Has the S2000 been replaced by the Exige?


----------



## powerhouse (Apr 1, 2011)

Bowser330 said:


> Super excited to hear more about your build.
> 
> Has the S2000 been replaced by the Exige?


Unfortunately no.
The exige deal didn't work out, it was a salvage, and the owner lied saying it had no frame damage. It did though, so I backed out.
On another note, the exige has even less space for batteries, I dont think it would have worked out having 1000 headways in there.


----------



## Bowser330 (Jun 15, 2008)

powerhouse said:


> Unfortunately no.
> The exige deal didn't work out, it was a salvage, and the owner lied saying it had no frame damage. It did though, so I backed out.
> On another note, the exige has even less space for batteries, I dont think it would have worked out having 1000 headways in there.


1008 headways @ 300g each = 665lbs, not too shabby for 26kwh and 2000A capable!


----------



## x88x (Aug 19, 2011)

Congrats! 



powerhouse said:


> The batteries are rated at 25c continuous, so I figured that they should be able to handle 28c for 3 seconds!


You sure about that? According the the specs Headway list on their own store site, they're 15C continuous, 25C burst. Though, who knows how long that "continuous" or "burst" actually are... On their site, CurrentEVTech lists them as 5C continuous, 15C for 4 minutes, or 20C for 3 minutes.

Sorry, not meaning to rain on your parade, just don't want you to blow up $13,000 of batteries.  Speaking of which, that's a great price for them! Where'd you find that?

Another thing to keep in mind is that if you only take them to 80%DOD they should last for another 500 cycles. Just something to keep in mind once you're driving around on them; it'd be worth it, imo, to spend a little time planning your drive in exchange for increasing the life of your pack by 30% (though 1500 cycles still might last you the life of the vehicle...).


----------



## x88x (Aug 19, 2011)

Well, either they improved their chemistry or they have multiple translators. 

Anyways, I would recommend monitoring the cells heavily before pushing them to those levels. I look forward to seeing that S2000 _move!_


----------



## Tesseract (Sep 27, 2008)

powerhouse said:


> ...
> either way, if it doesnt work out, can always just add an extra battery to each series, which will make 2000amps at 25c, as opposed to the 28c for 9 in parallel!


Rebirth Auto just shipped a Jaguar XK8 conversion to a client in the Netherlands that used a 10p95s pack of Headway 8Ah "power" cells. Scanning through a logfile from one of the test drives shows the pack sitting at 311V when pulling 20A from it then dropping down to 266V when battery current increases to 900A, giving a total sag of 45V (for a total resistance in the battery circuit of 50 milliohms).

Keep in mind that 900A from an 80Ah pack is only ~11C... sag at 25C will be closer to 100V.

Assembling a ~1000 cell Headway pack is a formidable task. Here's the one that is going into the Porsche 911 that Rebirth Auto is converting right now:


----------



## Bowser330 (Jun 15, 2008)

Tesseract said:


> Rebirth Auto just shipped a Jaguar XK8 conversion to a client in the Netherlands that used a 10p95s pack of Headway 8Ah "power" cells. Scanning through a logfile from one of the test drives shows the pack sitting at 311V when pulling 20A from it then dropping down to 266V when battery current increases to 900A, giving a total sag of 45V (for a total resistance in the battery circuit of 50 milliohms).
> 
> Keep in mind that 900A from an 80Ah pack is only ~11C... sag at 25C will be closer to 100V.
> 
> Assembling a ~1000 cell Headway pack is a formidable task. Here's the one that is going into the Porsche 911 that Rebirth Auto is converting right now:


That's really interesting data......I believe CroDriver's Headway pack saw a similar amount of sag, its just with such a high starting voltage, it still allows for a lot of power output out of this Jesus motor.


----------



## lonestarrpm (Aug 18, 2011)

Bowser330 said:


> That's really interesting data......I believe CroDriver's Headway pack saw a similar amount of sag, its just with such a high starting voltage, it still allows for a lot of power output out of this Jesus motor.


100V sag at 1000A -- isn't that 10kW of heat to dissipate?

That sounds like a problem in of itself.

With most things they get more resistive with age and heat -- 
is this true with these batteries as well?

mike


----------



## Tesseract (Sep 27, 2008)

lonestarrpm said:


> 100V sag at 1000A -- isn't that 10kW of heat to dissipate?


It's actually 100kW, but 100V of sag would occur at 25C, or 2000A from a 80Ah pack, and that would be 200kW of loss. Note that the maximum power from a battery pack (or any other source, really) occurs when the load resistance and internal resistance are the same (ie - the pack voltage has sagged to 1/2 its nominal value) but that means that an equal amount of power is dissipated inside the pack as in the load (motor).

And it is, indeed, a problem. This is more or less what limits the maximum C rate from a cell (more specifically, the amount of heat produced from the internal resistance vs. the surface area to dissipate it).

I don't have enough data on these cells to say for sure whether their internal resistance increases with age; it definitely increases with abuse (over charging or discharging).


----------



## lonestarrpm (Aug 18, 2011)

Tesseract said:


> It's actually 100kW, but 100V of sag would occur at 25C, or 2000A from a 80Ah pack, and that would be 200kW of loss. Note that the maximum power from a battery pack (or any other source, really) occurs when the load resistance and internal resistance are the same (ie - the pack voltage has sagged to 1/2 its nominal value) but that means that an equal amount of power is dissipated inside the pack as in the load (motor).
> 
> And it is, indeed, a problem. This is more or less what limits the maximum C rate from a cell (more specifically, the amount of heat produced from the internal resistance vs. the surface area to dissipate it).
> 
> I don't have enough data on these cells to say for sure whether their internal resistance increases with age; it definitely increases with abuse (over charging or discharging).


Yeah I can't do simple math 

But my point is that's a lot of heat to dissipate in the batteries.

Mike


----------



## DavidDymaxion (Dec 1, 2008)

I did a quick back-of-the-envelope... 2200 Amps (200 Amps, or 25C per cell). If you assume the batteries are all water, and run at 25C until 8 Ahr is gone... I get a temperature rise of about 48C. If your batteries are cool to start with they might survive that...


lonestarrpm said:


> ... my point is that's a lot of heat to dissipate in the batteries. ...


Love that Porsche pic -- are there more pics of the batteries in front or back?


----------



## Tesseract (Sep 27, 2008)

powerhouse said:


> Hmm... I don't understand how the 10ah battery pack with more internal resistance has the same voltage sag, thus power, as the 8ah battery pack ?


I wouldn't place too much faith into calculations of what the sag *should* be based on these Chinese cell manufacturer's datasheets. To paraphrase Mark Twain, there are lies, damn lies and battery datasheets.

From the PM you sent to me, you wish to construct an 8p112s pack (note the order of p and s - that helps to clarify that you are first paralleling the cells then putting them in series) and the claimed internal resistance - Ri or R[int] - is 6 milliohms per cell.

The Ri in milliohms of a group of 8 cells in parallel would be: 

1/((1/6mΩ)*8) = 0.75mΩ

And 112 of those in series would be 112 * 0.75mΩ = 84mΩ

To calculate the voltage drop due to Ri you simply multiply the battery current and the total resistance of the pack while to calculate power *lost* to Ri you multiply by current again:

1000A * 84mΩ = 84V; 1000A * 84V = 84kW
2000A * 84mΩ = 168V; 2000A * 168V = 336kW

The maximum power occurs when the load impedance (or resistance) matches the source impedance (or Ri here) because at that point half of the voltage is lost to Ri and half to the load. In other words, when voltage sag from Ri is half the nominal pack voltage (assume 3.2V per LFP cell, so 358.4V total) then trying to draw more current results in less actual power being delivered. In this case we want to find the amount of current that results the pack dropping to half of 358.4V, or 179.2V:

179.2V / 84mΩ = 2133.3A
179.2V * 2133.3A = 382.3kW

If you need more convincing this is true, the voltage drop and total power at 3000A and 4000A:

3000A * 84mΩ = 252V; (358.4V - 252V) * 3000A = 319.2kW (63.1kW less)
4000A * 84mΩ = 336V; (358.4V - 336V) * 4000A = 89.6kW (292.7kW less)

But all of this is the *theoretical* performance of your battery pack. You won't actually know what the voltage sag of your pack is until you have built it and measured the actual difference in voltage at two non-zero currents (as I did previously in this thread).


----------



## Bowser330 (Jun 15, 2008)

Tesseract said:


> From the PM you sent to me, you wish to construct an 8p112s pack (note the order of p and s - that helps to clarify that you are first paralleling the cells then putting them in series) and the claimed internal resistance - Ri or R[int] - is 6 milliohms per cell.


Can you help me with the formulas if instead of having the pack setup in 112 clusters of 8 cells each it was setup with 8 clusters of 112 cells each (112s8p)? I am assuming since you specified that previous arrangement that there is an impact to the IR of the pack as a whole.


----------



## dladd (Jun 1, 2011)

powerhouse said:


> I don't think theres any difference between the 112s/8p or 8p/112s
> theyre both the same, however you're supposed to put parallel first.


physically, there is a difference, right? 112s8p means you have eight strings of 112 cells in parallel. 8p112s means you have 112 sets of battery packs consisting of 8 parallel cells, which are then put in series. Do those two configurations behave the same?


----------



## Bowser330 (Jun 15, 2008)

112s8p = 112 Series 8 Parallel

Cells in Parallel add Amperage
Cells in Series add Voltage

so no matter is you write 112s8p or 8p112s they mean the same thing, right?

112p8s is what makes things crazy, as you already described.

I was just wondering if you had to make battery modules because you couldn't fit one huge brick of cells...which would be better?

Eight modules in series, each 44.8V & 64A (14s8p) 8*14 = 112s

or

Eight modules in parallel, each 358V & 8A (112s1p) 8*1 = 8p

Any difference?


----------



## x88x (Aug 19, 2011)

Bowser330 said:


> so no matter is you write 112s8p or 8p112s they mean the same thing, right?


The difference is in how you physically build the pack. 112s8p would be 8 strings of 112, paralleled at the ends. 8p112s would be a single string of 112 blocks of 8 paralleled cells. Building them the latter manner is supposed to be better for the batteries.


----------



## powerhouse (Apr 1, 2011)

Back again!

Well this build is going slower than I had hoped :/
My father insists that we order one component at a time, since he isn't in any rush, but I was really hoping to finish the vehicle by the end of the year. Oh well, better safe than sorry.

Approximately 4 weeks ago I ordered the motors from Rebirth Auto, hoping they would arrive within the week, however they still haven't arrived which is upsetting but understandable. I ordered a transwarp 9 and a warp 9, which I intend on coupling together. I don't fully know how I am going to couple them together, but I hope for it to be rather straight forward. 

Once the motors come in, I will post pictures of them for you guys to see. I also plan on picking up some small little tid bits while I am down in Tampa picking up the motors. Wire, connectors, contactors...

Once the motors arrive, I plan on ordering a 3 or 2 speed gear vendors transmission to finish off the drive train. I know that Ron (Team haiyan) and John Metric (DC plasma) are using the gear vendors, so I know I am purchasing a tranny that has some proof in the pudding. 








The transmission!!

Since my last update, I have disassembled the car to the bare engine and transmission. I Have yet been able to remove the drive shaft, which is the only thing stopping me from extracting the drive train. Its STUCK on there, since the dumb honda engineers decided to use 6mm, galvanized steel hex nuts to hold the driveshaft in place. So of course they stripped out, and now have to be cut off. 

















These pictures were taken a while ago, since then many more components have been removed 








My Zilla 2k EHV also arrived too! The first thing I noticed was how heavy it was. It came nicely wrapped in a cardboard cocoon, ensuring it would get to me safely. Manzanita Micro made the process very quick and easy, something I applaud them for. 








The hair ball has so many inputs, so many possibilities 

Hopefully, next weekend I will be down in Tampa picking up my motors and a bunch of other components. Once I get the motors installed in the car, the batteries will be ordered, something I cant wait for.


----------



## dtbaker (Jan 5, 2008)

good lord... warp9+transwarp w/ zilla 2k!
you're gonna be breaking things. 

have you looked at a drag racing tranny like Lenco?
http://www.lencoracing.com


----------



## powerhouse (Apr 1, 2011)

*SHAZAM! They have arrived*


----------



## powerhouse (Apr 1, 2011)

Mocked up

The motors fit in the AMG!!!



















Kinda cramped


----------



## thinmint (Dec 6, 2011)

Cant wait to see this thing get going!!


----------



## Bowser330 (Jun 15, 2008)

awesome powerhouse! I cant wait to see this S2K on video!


----------



## Yabert (Feb 7, 2010)

Hey! If you don't have yet purchase your cells, watch link bellow.

From the spec sheet, those 38120 HP will offer you 25% more power at motor shaft compare to 38120 P cells. Lower impedance = Less power lost in heat in the cells and more availiable power at motor terminals!

2000A / 8 = 250A per cell
250A x 0.003 ohm = 0.75 - 3.2v = 2.45v x 104 cells = 255v x 2000A = 510 Kw..... motors will don't probably take it, but less voltage sag is always a good thing!


----------



## powerhouse (Apr 1, 2011)

Well I finally got the motor (including tranny) completely out.

Took a while since I wasn't really working very often on it, maybe once a weekend.
I was rather complacent once the engines were removed, it was something I needed to get out of the way, but haven't bothered. I'll let the pictures do the talking.










Finally got the wheels off thanks to my new impact










The transmission had to be removed from beneath the car










Lifting...










Out!










Glory shot
​In other news, I managed to pick up a sponsorship from Headway Batteries for their new high power cells.
The discharge curve for these cells is even better than their predecessor, not to mention they are now a fire red.
I expect some really nice discharge from these cells. Hopefully they last a couple of cell cycles too. Only time will tell.










Discharge curve for the new cells​
Since I have picked up the motors, I have been designing a 3d model to aid in constructing a common plate for them. Its interesting learning a new program, but it gets tiring having to learn multiple programs just to meet a single goal.









​Im sure I will have some more news in the days to come, stay tuned!


----------



## Bowser330 (Jun 15, 2008)

Great progress and congrats on the sponsorship.

Many of us are eager to hear more about the new 8AH Headway power cells....

Are you planning on utilizing the electrical and mechanical methods of shifting together?

Example:
Series
Parallel 
Mechanical upshift
Series
Parallel


----------



## Joey (Oct 12, 2007)

Your car is going to be great. The S2000 was one of my final three choices for my project. I subscribed to your blog and hope to see more good stuff.


----------



## powerhouse (Apr 1, 2011)

Hey guys!
First off, I really want to thank everyone for the encouraging words and compliments. I love questions, and it helps push me forward. 



Bowser330 said:


> Great progress and congrats on the sponsorship.
> 
> Many of us are eager to hear more about the new 8AH Headway power cells....
> 
> ...


After reading this update, you will see that I am no longer using a tranny (for now, atleast), but otherwise, I will most likely wire the motors in permanent series. 


Since the last update, I have completed a couple of small things.
After discovering the immense amount of space the soft top occupies, I went directly to removing it.

Originally, I had anticipated purchasing a hard top for the car, but after driving it while it had a gas engine in it, with the top down, I found my decision to use a hardtop or soft top fluctuating.
Replacing the soft top is expensive, but a hardtop is even more expensive.

After removing the soft top (which is extremely heavy), and finding an immense space available for batteries, I made a final choice to purchase a hardtop.

Since an OEM hardtop would have a cost rivaling that of the entire car, I will most likely go with a cheaper, more aerodynamic approach. A knock-off Spoon 2 piece hard top from VIS will most likely be the winner in this hardtop showdown. Not only will it make the car appear more stealthy (  ), but it will also increase aerodynamics, while still allowing for the space previously occupied by the soft top to be used for battery placement.










VIS Spoon Replica Top









What I hope the car will look like with the top installed​After much deliberation, and studying, I have decided to shy away from using an under/overdrive. Cost, extra work, and extra complications involved while using a transmission have been the primary deciders for me.

Instead, I will use a direct drive approach, coupling the motors directly to the rear differential. With this decision, it will be necessary for the weak stock s2000 differential to be replaced with a 8.8" Ford pumpkin.
A day or two after posting on craigslist proved successful, and I picked up a 8.8" with 3.73 gears for $75 from a man half an hour away from my home. Work has already begun on adapting the large chunk to fit into the s2000.










The 8.8 with cover removed









Some calculations showing RPM vs. MPH​
A major effort to design a suitable motor mounting plate has been made over the last two weeks. I have done an innumerable amount of research on the topic, until I stumbled upon the John Wayland's dual 8" warfield design from late 2000.

John employed a simple U-channel design, constructed out of a single piece of aluminum to hold his motors in place. 

I seized the opportunity, and designed a common plate for my dual 9" motors, taking ideas from John, and introducing some of my own. 

While I have not completed the final rough draft, I have already a metal worker assisting me, and should have the basic U channel out of the shop by next Wednesday. 










John's common plate









Another view










Another view, without motors










My first draft of a common plate
​I also purchased a single Kilovac Bubba contactor, its a lot bigger than it looks!








​

More updates soon!


----------



## powerhouse (Apr 1, 2011)

Alright lets bump this thread back up!
This is going to be more of a teaser update, as the tasks I have been working on are only half completed.

The main job I have been working on lately has been the motor mounting. 
I am by no means a fabricator, but I did my best.

A test fit with the motors in the U channel









Then later in the week I welded and triangularly bostered the motor mount arms 









As you can see, there is an aluminum plate inside the channel. I have four of these, and two of them are going to be welded to the U channel, while the other two will bolt on. 

I will have the motor mount completed by next weekend.

I have also begun dismantling the backside of the car.

I first removed the rear subframe, then moved onto disconnecting the axles, and finally removing the rear differential.










With the rear sub frame out, I can now easily access the gas tank to take it out










That big black thing is the gas tank

I received a 8.8 diff cover a week or so ago that makes it much easier to adapt it to the s2000 rear subframe. 
Hopefully I will have it mounted in the next two weeks.










My father has agreed to order the batteries the moment I have the motors mounted inside the engine bay. 
This prompted me to begin searching for a BMS and begin designing a pack / looking for a place to put the batteries.

Fortunately, after removing the soft top, a large compartment is suddenly accessible.
Its about 42" by 18" by 15".
With this in mind I began designing a battery pack to fit the extra space. 

Heres the newly acquired space








Oddly it looks much smaller than it actually is.. Oh well

After hours of fiddling around with CAD, I finished designing a pack. Now that I know how to use the program, I am almost sure that I could make another pack in 20 minutes or less.

Here she is









And I know that in order for the pack to work, I have to connect the series rows, however I can't figure out how to add a buss bar... I will most likely end up printing it out, and drawing it on with a pencil.

I hope you enjoy seeing the car progress as much as I do!
Until next time!


----------



## Duncan (Dec 8, 2008)

Hi Powerhouse

Looks like a great project,
One niggle - are you going to make the hardtop removable?

If you intend running with it all/most of the time you should have started with a fixed head car 
There are hundreds of hardtops for every soft top out there it seems such a waste to turn a rag top into a boring old saloon

If you intend running it as an open car and fitting the hardtop occasionally then I withdraw my niggle!


----------



## powerhouse (Apr 1, 2011)

Duncan said:


> Hi Powerhouse
> 
> Looks like a great project,
> One niggle - are you going to make the hardtop removable?
> ...


The hardtop will in fact be removable, as it will only weigh about 45 Lbs. 
A car with a stock hard top would have been heavier, and wouldn't have satisfying looks. 
A hardtop is also much more practical for me, as five out of seven days of the week I will be driving to and from school, an activity in which a soft top isnt very practical.
In a nutshell, I will intend on running it with the hardtop installed 75% of the time, but on the weekends I may take the top off and go for a cruise.


----------



## Duncan (Dec 8, 2008)

_but on the weekends I may take the top off and go for a cruise.

_Excellent 

My car is the opposite - no top at all - not even a windshield 
When I am driving to work in the rain I will envy you


----------



## Yabert (Feb 7, 2010)

powerhouse said:


> And I know that in order for the pack to work, I have to connect the series rows, however I can't figure out how to add a buss bar...


Take a look at my battery pack assembly.
The current flow is represented by the green line (154v 80Ah). 
http://www.diyelectriccar.com/forums/showthread.php/smart-fortwo-ev-high-power-version-51472p8.html

I strongly suggest to you to include (or think about) bms connection methode in your cad before start to build your pack. Also, think about how you will support each cell.
Cell thermial isn't strong enough to support cell by herself.


----------



## kakheath (Jan 7, 2012)

Sounds like a great project. I can't wait to see how it performs. I've been looking at a similar setup for my RX8. I may end up with the same drive train, but with A123 batteries. I'm still in the planning stages. I love seeing your progress. Good luck with the rest of the conversion.


----------



## powerhouse (Apr 1, 2011)

Thanks for the response Yabert!
I added some double bus bars today to the battery pack. I also got the final measurements for the compartments in the car, and I have decided I will make 2 packs. 

One pack will be located directly behind the drivers seats, where the convertible top was at once. The second pack will reside where the spare tire was previously.

One pack will be a 9p/36s, the other will be a 9p/72s pack. The larger pack (9p72s) will be the one behind the seats obviously. 

I know the weight distribution may be poor, but I want to see how it turns out. If necessary, I can move some batteries to the front. I dont think it will be too bad since the larger of the two battery packs will be almost in the center of the car, the smaller will be in back, and the two motors and controller and what not will be in front. 

I still have to find a way make them into a pack. I really like crodrivers idea of using some high density poly ethylene, which would run me about $200 to build the packs using 3/8" material.


----------



## drgrieve (Apr 14, 2011)

A couple of questions about headway pack building.

1. How much volume do you save by stacking the cells on a angle (like yabert) as opposed to straight up and down?
2. Do you need bus bars in the middle or can the cells just top and tail together?
3. Does each cell need to be supported twice or can be be just support once?. I see yabert justs supports once at one end of each cell.
4 And a question for Yabert. Why does it seems some of the cells in the picture are missing their support at the end of the pack (the ones near the middle)


----------



## powerhouse (Apr 1, 2011)

drgrieve said:


> A couple of questions about headway pack building.
> 
> 1. How much volume do you save by stacking the cells on a angle (like yabert) as opposed to straight up and down?
> 2. Do you need bus bars in the middle or can the cells just top and tail together?
> ...


1. Excellent question. I dont know exactly, but I would think about 1/3 savings.
I want to keep my cells separated so that they can cool effectively, since this will also be a track car.

2. The bus rails in the middle(s) help divide the power between the cells, and also provides a fail safe in case of a dead cell. If the middle bus bars werent installed, and a single cell failed, that entire series row of cells would no longer function. With the bus bars installed, there are 8 other cells which can transfer the power, if only one dies.

3. I am going to support each of my cells with a support, since my stack is much higher and heavier than yabert's.

In other news, im still building mock up packs. 
This one is using some 3/8" HDPE plates, with each cell separated .2"
There are support bars (threaded rods) that dictate the distance between the support plates.


----------



## Yabert (Feb 7, 2010)

drgrieve said:


> 3. Does each cell need to be supported twice or can be be just support once?. I see yabert justs supports once at one end of each cell.


Yes, it's related to availiable space and dificulty of build. No perfect, but I expect than the friction create by the torque between bus bar and cell terminal is enough to support the unsupported end.




> 4 And a question for Yabert. Why does it seems some of the cells in the picture are missing their support at the end of the pack (the ones near the middle


Don't ask...
I simply miss quantity during order!


----------



## MalcolmB (Jun 10, 2008)

drgrieve said:


> 1. How much volume do you save by stacking the cells on a angle (like yabert) as opposed to straight up and down?


You reduce the stacked height by around 13% (1 - [root 3]/2). But then you waste some space at either side unless you build a neat angled box like Yabert did.
(Assuming you maintain the same spacing between cells)


----------



## powerhouse (Apr 1, 2011)

*GOOD NEWS EVERYONE.*


----------



## Bowser330 (Jun 15, 2008)

powerhouse said:


> *GOOD NEWS EVERYONE.*
> ​


awesome, motors installed!

can you pm me what the price is for the 31820P-H cells?


----------



## powerhouse (Apr 1, 2011)

I PM'd you bowser

I have A LOT to share, but I am too lazy ( and loaded with homework ) to type it tonight. Hopefully I can find some time tomorrow, and I will post a huge update!


----------



## FireCrow (Nov 11, 2011)

can't wait for that big update!!! I hope there will be lots of pictures included, that conversion is getting really exciting!!!


----------



## powerhouse (Apr 1, 2011)

Long time no update.

Truth be told, lots of informative and pertinent information regarding the build has been gathered,but I have been much too lazy to type it all up. So I will now dump it onto the internet!

I am still rather upset at the slow pace at which this conversion is taking place. While I work on the designing the car for countless hours each week, I can't help but feel like I am moving in place. I assume most builds feel similar, but darn. Oh well, with the motors nearly mounted and the battery packs finalized, the so called 'light at the end of the tunnel' can now be seen with a telescope. 

Anyway, here we go.....

Motors:

A serious milestone was passed when I was finally able to order a coupler for the two warp motors. I called probably 300 different businesses, trying to find a reliable and trust worthy solution to coupling the litte red monsters. The solution to all the chaos finally came when I gave up on locating an appropriately rated coupler, and purchased a $20 generic set screw coupling. 

It basically is a steel oxide coupler with a 2 1/4" outer diameter, and a 1 1/8" inner diameter, with a keyway. Not much to it, but it is only rated to 2500 RPM and 100 Ft Lbs of torque. My car will be hitting a 5500 Rpm redline, and have a max potential torque of 1500 Ft Lbs of torque. Quite a disparity between the two specifications, however I am hoping for the best. In the worst case scenario, the coupler explodes while on the freeway, sending shrapnel everywhere and destroying anything in its path. But what are the chances of that *knock on wood*??

With the coupler out of the way, I had a U channel made out of a 1/8" piece of aluminum. I then had two 1/4" arms welded to this channel, which would be situated in the original motor mount locations. The large U channel came out surprisingly cheap, ringing in at $60. Seeing how cheap a large piece of custom bended metal was, I returned back to the shop to have the 2 aluminum arms welded onto the channel. I was then hit hard with a $350 bill. I have no idea how two small arms took $350 of welding, regardless I was kinda upset and purchased a new tig machine.










I went ahead and spent a little extra to purchase a better 'starter' model. 
With the new machine, I carried on finishing up the motor mounting. Unfortunately, I soon discovered that having a nice welder doesn't ensure good welds.

My first project was to weld up some steel brackets to hold my differential in place. I used stick welding to do this, and was surprised by how straight forward and forgiving of a process it was. Needless to say, I welded up the two brackets, and had the differential mounted back into the car in a day or two. (more on this soon)

All my good luck was forsaken later that week when I began aluminum welding. I practiced on some scrap aluminum with relatively good results, however when the time came to weld two of the motor end place onto the U channel, my welding suffered severely. I could not get the base metal to melt, the filler rod would always bead up, I would constantly spoil my tungsten. It was simply a bad start. 

I never really got any better at it, and as a result the welds look horrible. But I suppose it works.
I feel as though my failure was due to the large shape of the U channel, which acted as a giant heatsink wicking away all the heat I was producing. 

Regardless, I was able to horribly weld the front most motor holding place, and I simply tack welded the back plate, so now I can drop it off at a welding shop and have them actually do it professionally. Two more plates will be bolted to the U channel, but will be removable to allow for the movement of the warp motors. 



















With the motor positions finalized, I will be able to put the motors in the car and get an accurate measurement for a driveshaft length. 
I hope to have the driveshaft ordered by tomorrow, since my custom driveshafts are ready to ship! (more about this soon also).

More update tomorrow on batteries & Differential


----------



## Tesseract (Sep 27, 2008)

powerhouse said:


> ...
> A serious milestone was passed when I was finally able to order a coupler for the two warp motors. I called probably 300 different businesses, trying to find a reliable and trust worthy solution to coupling the litte red monsters. The solution to all the chaos finally came when I gave up on locating an appropriately rated coupler, and purchased a $20 generic set screw coupling.
> 
> It basically is a steel oxide coupler with a 2 1/4" outer diameter, and a 1 1/8" inner diameter, with a keyway. Not much to it, but *it is only rated to 2500 RPM and 100 Ft Lbs of torque. My car will be hitting a 5500 Rpm redline, and have a max potential torque of 1500 Ft Lbs of torque.* Quite a disparity between the two specifications, however I am hoping for the best. In the worst case scenario, the coupler explodes while on the freeway, sending shrapnel everywhere and destroying anything in its path. But what are the chances of that *knock on wood*??..


April 1st is next weekend, not this weekend...

"What Could Possibly Go Wrong???"


----------



## MalcolmB (Jun 10, 2008)

Hi powerhouse,

I admire your ambition and have-a-go attitude, but honestly think you need to get some advice from a local engineer or fabricator who understands the amount of torque these motors produce.

I like using aluminium myself, but that 3 mm aluminium sheet is just not up to the job, the torque from your motors will twist and tear that channel like wet pasta the first time you apply power to them, even if your welding is perfect.

The channel should be intended solely to hold the motors in line, while the weight and torque should be carried directly from the motor end plates through heavy plate or square sections to the vehicle structure. If you use plate to transmit the torque, I'd suggest something like 5mm steel or 10mm aluminium, with plenty of stiffening.

I used 3mm aluminium channel for my 15 hp motorbike motor, and considered that just adequate. You're right about it soaking up heat. You need to preheat the larger component first with a propane torch or the like to get decent results. It's also worth remembering that whenever you weld an aluminium alloy it will reduce the strength in the weld zone to that of raw aluminium.


----------



## powerhouse (Apr 1, 2011)

MalcolmB said:


> Hi powerhouse,
> 
> I admire your ambition and have-a-go attitude, but honestly think you need to get some advice from a local engineer or fabricator who understands the amount of torque these motors produce.
> 
> ...


I completely agree with you on the strength of the aluminum. While is is somewhat rigid, I do feel as though it isn't strong enough. The main reason I chose 1/8" aluminum was because that is the thickest metal local shops can bend around here. So I basically said hell, why not, and figured I would try it out. 

I think I am going to try to finish up the car with the current motor mount, and see how it goes. If any noticeable vibration arises in the car, I will have to tear down the drivetrain and inspect. 

While I wasn't hoping for the motor mount plate to be super weak, I did want it to have some flexibility and some weakness. The flexibility will help since the car will be moving, and everything will be shifting. In addition to that, having the motor mount as the weakest component of the drivetrain means that if something stalls, or I hit something, the $350 motor mount will be the first piece to break, rather than my $4000 motors. 

While at the EV expo, I noted how the Miramar's pearl was set up. All they had were 2 pieces of steel angle along the sides of the two motor, with one quarter inch plate holding the motors in place. Seeing their's hold up was encouraging considering mine is (i think) strongr.


----------



## Joey (Oct 12, 2007)

I do not think it is a safe bet that your motors will survive without damage if your mount fails. It really depends on what goes wrong. What happens if a motor suddenly goes unloaded under heavy acceleration and over revs if the coupling breaks? The motor shaft or bearings can get damaged if the motor drive shaft comes out of alignment. If it were my project, I would err on the side of overdoing the design of the mount, or having it reviewed by an engineer.


----------



## Wild (Aug 19, 2011)

Powerhouse If you want to keep the aluminum pan as protection for the motors that will be fine as long as airflow is not restricted. You will need to fabricate proper vertical motor plates as many others have done either aluminum or steel and bolt them directly to the motors front & back as an example http://memimage.cardomain.com/member_images/3/web/2559000-2559999/2559239_1144_full.jpg 

Don't kid yourself, your design will end in costly failure no arguments accepted. So consult with the motor's manufacturer for mounting recommendations before going any further.
http://memimage.cardomain.com/member_images/3/web/2559000-2559999/2559239_1144_full.jpg


----------



## Yabert (Feb 7, 2010)

Hi Powerhouse

If it's too much trouble for you to build something strong enough, you can think about sold the Warp motors and buy and a dual Kostov motor. 
That would be smarter than destruct both motors when you push the throttle.

But IMHO, build a motor support is way more easy than build a powerful 500-1000 cells battery pack. Think about that before continous to invest in your project.

Good luck!


----------



## TigerNut (Dec 18, 2009)

powerhouse said:


> I completely agree with you on the strength of the aluminum. While is is somewhat rigid, I do feel as though it isn't strong enough. The main reason I chose 1/8" aluminum was because that is the thickest metal local shops can bend around here. So I basically said hell, why not, and figured I would try it out.
> 
> I think I am going to try to finish up the car with the current motor mount, and see how it goes. If any noticeable vibration arises in the car, I will have to tear down the drivetrain and inspect.
> 
> ...


What makes you think that a piece of 1/8" aluminum is stronger than 1/4" steel angle? Steel has three times the tensile strength and infinitely more fatigue life than whatever aluminum you were able to find that the local shops could bend. 
Before you say "my mount is bigger and it spreads the load" consider that your motors bolt to the mount in three or four places, and your motor mount bolts to the chassis in only three or four places. That is where the stress concentrates, and that is where it will break because the 1/8" aluminum sheet isn't strong enough and because it will work harden and crack.

You should buy "Engineer to Win" by Carroll Smith and read it cover to cover before you spend any more time in your garage.


----------



## powerhouse (Apr 1, 2011)

Hey everyone

You guys are freaking me out on the motor mount! 

I will find some engineer and ask them about it. It feels strong to me, but I am sure steel would be exponentially stronger. 

The primary reason that this motor mount has been so difficult to build is because I can only go to the metal shop friday afternoon, directly after I get out of school. So it takes another week until I can pick it up, and bla bla bla. 

Time to design another motor mount! :I

Also, an small update on the batteries. 

Anyone who has followed my build has seen my previous battery plans. Initially, I had anticipated using 10Ah Headway cells. Then I switched to the blue 8Ah cells, since they yielded a lower internal resistance meaning less losses to heat and inefficiencies. Then, I switched to 8Ah cells with an even lower resistance, red 'high power cells'. 
The game plan was to mate 972 of these cells together, 9p/108s, for a nominal voltage of 345ish and 2000A bursts. 
I was almost certain the headways were the route I was going to take, however I decided against it in favor of some of the highly acclaimed A123 20Ah pouches. 

Alright, why? Because the cells are pretty awesome. Although their origins are unknown, they still boast some pretty impressive specifications. 

To get the same performance out of this battery pack, I will a 4s/416s setup, for 343v nominal, and 80Ah capable of 2000A bursts. 

Not only that, but the headway pack would weight about double what the A123 pack should weigh.

The only drawback to the A123 cells is their inability to be put into a pack easily. I originally designed a rather primitive pack, consisting of bus bars separating the cells, and the entire pack would be compressed via a threaded rod that would go through the cells. 










While this design would work, I had two issues;
1. The threaded rod would have to be some sort of nylon or ceramic. The nylon rod would stretch under heat, and the ceramic rod would be fragile.
2. The cost of the copper needed for the bus bars would be ridiculous. I calculated about $700 worth, using bars of 1/4" and 3/8" copper.

With that in mind, I went about designing another pack. In order to combat the expensive copper necessary for the first pack, I needed to design a pack that didn't rely on the cells connecting directly to each other, since that would call for thick copper to space the cells. I had always wanted to do something along the lines of the white zombie's pack, having the tabs bend over a copper bus bar, and then another bus bar being clamped down on these tabs. However, this wasn't practical using 4 cells in parallel. After a little finicking with my A123 test cells, I figured I would cheat, and treat two 20ah cells as one 40ah cell. Now I need 2 parallel (which is 4 cells), which would allow me to use the clamping system. 4 cells would need 8 slots, and I dont think the cell's tabs farthest from the central copper mounting bars would reach.

A couple of minutes in CAD got me this 










Simply by changing the design, I was able to reduce the cost of the copper significantly. With the new clamping design, I can use 1/8 copper bus bars, with more surface area. The total copper price for all eight packs will be around $223 (according to onlinemetals.com). 

I then optimized the design, and entered some more accurate dimensions for the final battery pack file. 
I decided to make the pack with a 1/4" polycarbonate top, so that I can see the batteries. It also isn't much more expensive than other plastics. I wanted to use 3/8", however the cell tabs would not be long enough to go through the plastic slots, and attach to the copper bus bars. 
The sides of the box will be 3/8" on the short sides and 1/4" on the longer sides. There will be half an inch of space between the cells and the edges, so there is some room for error. Foam padding will be placed in these gaps to secure the cells. 

Here are some pictures of the final design, with one of the box sides removed so you can see inside.





























I still need to add some copper bus bars to the pack, but I just needed the box dimensions for now. 
The hole drilled through the center of the copper bars will hold them to the polycarbonate top plate, while two more holes will be drilled on the sides of the same bus bar to secure it to the larger bus bar which will hold 2 groups in series.

Let me know what you guys think, constructive criticism is good!! 

From there, I contacted a couple of engineering schools around where I live, and found a place to CNC the top plate and the individual sides of the battery box.

I still have more to update, I will update soon!


----------



## TigerNut (Dec 18, 2009)

Hey,
You should buy this motor coupler.
http://www.diyelectriccar.com/forums/showthread.php/electric-blue-motor-coupler-71715.html
It might look like overkill, but unless the two motor shafts are held in exact axial alignment under all conditions, your shaft coupler and the motor bearings are not going to last you more than a few minutes. And you can't make something like this for the price he's asking (no, I have no interest in the sale, I just noticed it's a part that you really need).


----------



## drgrieve (Apr 14, 2011)

Hi,

You might want to have a look at Ian Hoopers (Zeva) RX7 conversion

http://zeva.com.au/Projects/RX7/

This is his 2nd direct drive conversion and is using dual impulse 9".

I like his plan of joining to to the tail end of the transmission instead of directly to the shaft.

Cheers.


----------



## powerhouse (Apr 1, 2011)

drgrieve said:


> Hi,
> 
> You might want to have a look at Ian Hoopers (Zeva) RX7 conversion
> 
> ...



Great looking car !
He looks very anal about all the parts and work done on the car.

I went ahead and got some advice from an engineering friend, and redesigned the entire motor mount out of 1/4" steel. 

It should be significantly stronger, and stiffer.

I also have gotten tired of this car not being finished, so I dropped the sketches off on monday and told them to have the entire thing completed by this Friday. I will pick it up that night, and see if I can get the motors in the car by Saturday.

BTW All the materials for the batteries have come in. As per my fathers agreement, once the motors are in I can order the batteries. I anticipate the batteries will take about a week to arrive, since that is the amount of time it took my samples to get here. 

Air mail sure is more expensive than by boat, but I think its kinda worth it!

Update this weekend


----------



## powerhouse (Apr 1, 2011)

I'll just put this here.... 





























Also, I realized that the motor mount was a POS so I completely redid it with some 1/4" steel.

Here is the plan 










The blue and green plates are welded to the 2 rails that are bolted to the motor's 1/2" and 5/8" lift holes. 

Then the cross bar is mounted to the front green plate, and slipped through the two mounts which will be welded to the engine bay of the S2000. 
While I have all the metal parts, the metal shop employees aren't the most intelligent, so they didn't make the central holes of the metal plates big enough (it needs to be 3", they only made them 2.5"), and my plasma cutter is not working! So I will have to wait until I fix that up...

But I was able to get it into the car









I have completed the rear motor mount as well, based off the original rear tranny mount. 

Constructed of 1/4" steel.









It fits, however I just need to find a way to fit the shock absorbers to work on the metal plate. 

I would have loved to be doing stuff these last 2 weeks, but finals are draining all my time!

I have gotten the green light to order the batteries though! I just need to wait for the credit card bill to come in the mail, to send in the money...


----------



## Wild (Aug 19, 2011)

Sorry but I don't like this mount either and you will have torque issues. Is there a reason for making such small gussets that fall short of the mounting bolts?


----------



## powerhouse (Apr 1, 2011)

Wild said:


> Sorry but I don't like this mount either and you will have torque issues. Is there a reason for making such small gussets that fall short of the mounting bolts?


Because originally the gussets were supposed to be mounted downwards. I decided to flip them, to raise the motors up into the motor tunnel a little more.


----------



## Wild (Aug 19, 2011)

powerhouse said:


> Because originally the gussets were supposed to be mounted downwards. I decided to flip them, to raise the motors up into the motor tunnel a little more.


OK but do you see the problem of the unsupported flat plate between the gussets and the mounting bolts? That is the first issue, the second being that you need to strengthen the subframe to prevent flexing, this mount will not work. And another major issue is that you have not mounted the two motors together properly.


----------



## winzeracer (Apr 3, 2012)

Great thread cool car any updates on the pack build?


----------



## powerhouse (Apr 1, 2011)

Haven't ordered the batteries primarily because Victpower stopped accepting paypal. 
Also, I am having trouble allocating the money to paypal in order to send it over.

Work on the car has been slow, unfortunately. 

I don't know if I actually updated this thread with the information, but I did order the v8 Open source charger a long time ago, but decided to exchange it for the v9 since it seems much simpler to set up.

Over the past week, I have been getting small things out of the way. I've had to go to the metal shop multiple times just to get things fixed that they messed up.. Not the best service.

I really need to update my blog and this thread, I have too much to share..

Ive also been working on my electronics box, heres a little sneak peek




















I also booted the Zilla up not too long ago, all looks well


----------



## powerhouse (Apr 1, 2011)

In this post, I will be concentrating on upgrading my drive train.

The stock S2000 differential is infamous for being weak and fragile. Even with the stock ~200Hp engine, the car has the capability of destroying its differential if you're having a bad day. Upgrading to a turbo system nearly guarantees eminent failure of the differential.










Stock S2000 Differential


Since the s2000 differential would explode after a week or so with the two warps, I had three options

1. Send my stock differential to be cryogenically treated by Puddy mod himself
2. Purchase an R32 Skyline differential
3. Purchase an 8.8" Ford Differential

I chose the third option.










S2000 Differential Vs 8.8" differential with explorer cap


Option 1 was a little too expensive for my tastes. Puddymod does amazing work, however I couldn't bring myself to pay the $2000+ for the work. Not to mention, even after I had the differential beefed up, I would have to find a way to adapt it to support Dana 1350 drive line components. However, the obvious advantage would be that I would be able to remove the differential, and put it back in with little to no trouble. This would have saved a lot of time, but its ok.

Option 2 was also rather expensive. A used R32 differential goes for ~$400 and are much more difficult to find than Ford 8.8". Another disadvantage would be that the gearing (rack & pinion gears) aren't easy to find. Lastly, the differential would have to be modified to fit the s2000, however (evidently) the axle flanges are compatible with the stock s2000 axles.

Option 3 was the winner. The Ford 8.8" independent differential was the perfect match for the s2000. Numerous reasons contributed to the choice. Gearing is abundant for the differential, the differential itself is practically indestructible, 1350 pinion flanges are easy to come by, and it is cheap! It just so happened that I was able to pick one up off craigslist for $75 about 10 minutes away. I really lucked out on that one.
However, there are some drawbacks to the differential. One major set back is that the axles are completely different, and had to be custom made for my car. Additionally, it requires custom mounting, and once installation began I realized that a major problem existed in the inability to install the axles without tearing down the entire rear end.










The (nearly) final product


In order for the 8.8" differential to fit, I needed to figure out how to adapt it to honda's existing differential mounting points. In order to simplify the process, I chose to reuse as much of the mounting hardware as possible. To do this, I ordered a Ford explorer differential cover, which greatly simplified the process of bolting the stock support arm to the new differential. With the differential back plate installed, I began fabricating.










Differential sans-rear cover


Using Autocad inventor, and Cambam, I created a simple drawing that I exported to G-code, and ran on my router. The router cut into a 1/4" aluminum plate which I had mounted on its table. I decided to get artsy with my work...

Here is the completed plate, once cut










todo completo


I ended up drilling the remaining holes on my drill press, since alignment of the differential was rather difficult. Ideally the differential would have been rectangular, with the pinion flange in the center of one end, and the mounts symmetrically placed on another end. However, the ford 8.8" is the least symmetrical piece of hardware in the entire car. Everything is lobside, uneven, and arbitrarily placed.

Eventually I got the plate drilled, and the stock mounting arm bolted onto it.
I mounted it in the car, and proceeded to make the front mounts out of some 1/8" steel. This was my first time welding anything, so I practiced a little before hand and dove right in.










Front mounts (notice minimal clearance)


Measurements were taken for the axles, and the data collected was sent to the Drive Shaft Shop, who promptly delivered some high quality custom axles to my door, big shout out to them!










Custom DSS axles


When it came time to sell the stock s2000 differential, I was contacted by a man named Ben Herne by email who was interested in my differential. Rather than giving me the full asking price, he offered to trade me an 8.8" limited slip differential, professional installation, and some cash for the differential. After looking up the name, it didn't take long to stumble upon his company, Puddymod racing. His work is revered as some of the best work in the industry. He builds the strongest stock s2000 differentials that have become parts of hundreds of cars.

I took a trip down to Bradenton Florida to have the LSD installed, and it turned out great! Can't wait to see how it works with the car.

After removing the differential, I decided that it was mounted too low in the chassis and was susceptible to touching the ground when going up large curbs etc. So, I chose to move it up about 2". I modified my 1/8" mounts, but ended up having to throw them out because I overlooked something.










A rather provocative view of the pinion flange 


The pinion flange for a 1350 setup is huge, far larger than the stock s2000 flange. The diameter of the flange almost overlaps the s2000's differential mounts. With the previously designed front differential mounts, the pinion flange had about 2 mm of clearance between the mounts. To increase the distance between the flange and mounts, I had to re-do the design. Rather than going out and up, I had to go straight up, and out.

A day or two later, I had completed the new mounts, and painted them.










New Vs old


I reinserted the differential, and made sure it did not rub or anything. Everything checked out well!










New mount
​


----------



## powerhouse (Apr 1, 2011)

The last step was to install the stock axles. Another obstacle appeared here; the wheel hubs needed to be removed in order to install the axles. 
Some hours pass, the axles are installed, and the wheels are back on.
I took some additional time to take out the torque wrench and ensure all my bolts were correctly torqued. I don't want my axle flying off on the highway!










Buttoned up :--)


Since the rear end is completed, I went ahead and reconnected the brake lines, ESC sensors, and hand brake lines that I removed when I uninstalled the rear sub frame to remove the gas tank.
Dropped the car, pushed it, and the pinion flange rotates! Success!​


----------



## powerhouse (Apr 1, 2011)

Hey guys

I know a couple of people wanted updates on the car, and I have been working diligently on it for the last couple of months!

However, I don't usually update this thread as much as I do on another website. I will try to transfer all the information, but for the time being I will try to provide a link to the thread

http://www.s2ki.com/s2000/topic/975497-wait-that-isnt-an-f20c/

Check it out!


----------



## rochesterricer (Jan 5, 2011)

It would be awesome if you had a thread on honda-tech as well


----------



## TEV (Nov 25, 2011)

Good work.

How is the drive shaft connected with the electric motor ?
Do you have a picture ?


----------



## jeremyjs (Sep 22, 2010)

Just a pointer as I was looking through your pics I noticed the thumb incident. It looks like you figured this out, but I just thought I'd say. NEVER EVER wear gloves while working with lathes, mills and drill presses or any other large equipment that has rotating parts exposed to your hands. If I saw someone in my shop wearing gloves while doing something like this I'd fire them on the spot. It's very dangerous.


----------



## powerhouse (Apr 1, 2011)

Lets see if I can't get this thread up to date...

Zilla box 


















A123 Batteries, about 440 of them

















Each of the cells has to have tape removed, a sticker removed, adhesive from said sticker removed, then have the tabs punched, and finally have its perimeter wrapped in kapton tape. I got a bunch of friends together to expedite the process!

















Decided to run Orion BMS, major shout out to Andrew Ewert and his support of my project. Out of all the components I have purchased for the car, the two best companies for support are Ewert Energy (Orion BMS) and Netgain motors! I can send an email out on sunday morning asking a quick question, and Andrew will usually respond in less than an hour. Super helpful!










I also began a Nike+ iPod RFID keyless ignition project, haven't touched it much but it should work in theory.


----------



## powerhouse (Apr 1, 2011)

Added an inertia switch for safety 









New motor setup!









Driveshaft, thanks to DSS


















Getting there (not really)









Redid the ugly s2000 tail lights using some LEDs









Before:









After:


----------



## powerhouse (Apr 1, 2011)

Using an Audi Vacuum Pump 









Just some cad stuff from the new mounts

















Urethane bushings 


















Rear motor mount


----------



## powerhouse (Apr 1, 2011)

Sealing :---)









Ugly A123 module prototype









Also I have decided after some thought to get one last part machined for the drive train. 

This motor coupler will be sandwiched between the two motors where the set screw coupling is located.
Reasons why:

- More rigidity
- It will take the stress off of the bearings
- It will hold the motors together
- It will prevent my death if the coupling were to explode at highway speeds

Unfortunately, as accuracy is imperative here, I will need to get the coupling machined by water jet. 
I will see what I can do get it made!


----------



## powerhouse (Apr 1, 2011)

Got featured on Jalopnik
http://jalopnik.com/5945771/meet-the-high-school-kid-building-an-electric-honda-s2000

Also received an invitation to speak at a TEDx conference !

















Everyone loves people who build electric cars 








Also got on the university's news paper!








Videos for those interested


----------



## Jesse67 (May 12, 2009)

Nice work and great job with the Ted talk, make sure you watch the recent one with Elon Musk, super inspiring of course, but you seemed way more comfortable than he did up there! 

That's going to be a very quick car. Your new motor mount looks a lot better but make sure you do a good job on that coupler between the two motors, almost all of the rear motors torque will be transferred through it because steel channel while strong in bending doesn't have much torsional rigidity. The mounting bolts for the front motor are right next to the mounting arms so that should be all right. If your coupler is steel and properly welded you should be good to go. From a design standpoint I would also tie in the rear ends of the channels to the rear motor mount and the front ends to a plate across and bolted to the front face of the front motor, but maybe you already had this in mind?

Good luck finishing up the build!


----------



## Duncan (Dec 8, 2008)

Hi Powerhouse

Just catching up on your thread - and I'm a bit worried about your diff mounts

You will have a diff ratio of about 4:1 (mine is 4.1:1) - so the diff mounts must resist motor torque around the motor axis 

And 4 x motor torque around the "axle" axis

Look at your diff mounts - you have front and rear mounts - about 2 ft apart (front-rear)
If you put 500ft lbs from your motor that becomes 2000 ft lbs - with the mounts 2 feet apart - you end up with 1000 lbs being fed into your mounts

Are your new front mounts OK for that???


----------



## Jesse67 (May 12, 2009)

I just looked at your diff mounts as well and agree with Duncan. With 2 motors and a 2000A controller you'll be putting huge loads onto those mounts. Think of your car doing a wheelie, so imagine trying to lift the nose of the car in the air by twisting on the diff case! I doubt you'll have the traction to do that but that's how you need to think of the loads. Because the front of those mounts are in flexible bushings they will try to twist down as the front of the diff is forced up, this puts a lot of bending on those bolt holes in the diff casting, I'm assuming that's an aluminum diff case? the bolt holes could actually break out being loaded like that if the mounts don't fail first!

Looking at the picture is there another set of mounting bolt holes on either side of the diff case behind the main mounting tabs? If you could have your front diff mounts start from there on each side and bolt to the main mounting tabs before extending up to the bushings in the frame your mount would be much stronger. It also wouldn't be putting a twisting force on the diff mounting tabs. Look how the stock Honda diff mount brackets attache with two points of contact some distance apart on the diff case before they extend forward to the bushings. 

It would just really suck if those mounts let go, the diff would twist up bending the rear mount, your driveshaft would pull out of the slip joint and start whipping around causing a lot of damage, and the motors would suddenly have no load, likely with your foot on the floor as the mounts would probably break when you're accelerating! The motors could over speed and grenade very quickly with that much power and that would really ruin your day. I'm a mechanical engineer who used to deal with machinery failure analysis, you don't want to risk your drive shaft letting go!

Good luck! You'll get there eventually.


----------



## powerhouse (Apr 1, 2011)

Jesse67 said:


> I just looked at your diff mounts as well and agree with Duncan. With 2 motors and a 2000A controller you'll be putting huge loads onto those mounts. Think of your car doing a wheelie, so imagine trying to lift the nose of the car in the air by twisting on the diff case! I doubt you'll have the traction to do that but that's how you need to think of the loads. Because the front of those mounts are in flexible bushings they will try to twist down as the front of the diff is forced up, this puts a lot of bending on those bolt holes in the diff casting, I'm assuming that's an aluminum diff case? the bolt holes could actually break out being loaded like that if the mounts don't fail first!
> 
> Looking at the picture is there another set of mounting bolt holes on either side of the diff case behind the main mounting tabs? If you could have your front diff mounts start from there on each side and bolt to the main mounting tabs before extending up to the bushings in the frame your mount would be much stronger. It also wouldn't be putting a twisting force on the diff mounting tabs. Look how the stock Honda diff mount brackets attache with two points of contact some distance apart on the diff case before they extend forward to the bushings.
> 
> ...


I feel kinda bad not mentioning that I was planning on finishing my updates later...
The coupler was finished about 3 months ago! 

I finally got some progress done on the motor plate and MAN IT IS SO MUCH WORK DAMN
Increasing the precision of a piece exponentially increases the price / time necessary to assemble it seems.
All the work, and a fair amount of expertise, is a result of John Wilson at Laser Logic. He has kindly sponsored the project, and has supplied all of my lasering and router needs. And hes so much smarter than me when it comes to engineering. 
THANKS JOHN!!!



MOUNTING THE 1/2" PLATE!!!









CUT THAT PLATE









WHAT









cool









And then John taught me how to use a lathe 
The most difficult part of the process was getting the stupid pipe aligned, which was impossible because the entire pipe wasn't close to true. Same thing with the plate, completely not flat / consistent.
I had to use the lathe for a couple of hours, and it was fun until I dug a little too deep into the pipe and the machine ALMOST KILLED ME by trying to swallow the pipe. Nonetheless me and the machine settled our differences and completed the pipe at around 10 pm.
I left a very fair length of pipe on the coupler assembly because I will have to throw the entire thing on the lathe once it is welded so that I can make sure it is true. Afterwards, the holes will be drilled using a mill.










And kinda complete..









I dropped the assembly off at the welders today after school, and I will probably pick it up on Monday :/. 
Once it is done I kinda want to try anodizing it some crazy color but I dont know yet...

I also booted the controller up !


----------



## powerhouse (Apr 1, 2011)

Well the coupler is (almost) done and (almost) fits perfectly!

I spent the first 3 days of holiday at the machine shop with John Wilson, who instructed me on the best path to take for fabricating the coupler, taught me how to use the specific machines, and then set me loose! What an awesome guy.

Last time I updated, I had just completed machining the coupler to send to the welder. I picked up the welded piece on monday, and got to work on it on Wednesday. After having the coupler welded, the entire thing was warped to complete crap. About .15" of variance between the two faces which was unacceptable for my application. So I chucked it in the lathe, and worked on the faces for about 3 hours. Its a slow process, but when a giant coupler is spinning in the machine at about 2000 rpm and digging too far into the material may send it hurdling across the room its okay to work slowly. 

Here is the coupler after having it welded










and here it is in spinning death trap form









The lathe had automatic feed, so I would just make the adjustments, flip a lever, and watch is slowly make its way across the face.

A day or so of work later BAM!!!









Beautiful.

Next John taught me how to use the mill with digital read out. I got a little too caught up in the process and forgot to take pictures, but long story short I calculated the cartesian coordinates of the holes in CAD, then found bolt clearances for the specific faces, and began working on a holding plate.
Because the holes had to be in the exact same spot on the opposite side of the coupler, it was important to develop a method by which I could flip the coupler over and still have it in the same location / rotation as before. To do this, I first drilled an aluminum plate with the same coordinates as the holes that are on a 6" diameter, then drilled the coupler with the same holes as the aluminum plate, then flipped over and placed pins through the holes to hold the coupler in place. 










It was awesome!!

The result: 


















Machined to a tolerance of .005" . It was totally worth the 20+ hours of work invested!

THEN i went home and drilled some holes for the motor coupling into the aluminum motor coupler 

And then some assembly pics...




























And complete-ish










Everything is good right? WRONG. You see, I made a stupid stupid stupid mistake. When I was designing the coupler, I had my motors in CW-CW drive end field directions, which in turn causes my wheels to spin in reverse when I want to go forward. In order to fix this, one simply needs to advance the timing so that you are CCW-CCW drive end. Unfortunately, I neglected advancing my motors before I began designing the coupler, and as a result I made a bad mistake. 
Advancing of the motor involved spinning the commutator end housing, and as a result SPINS THE SECOND MOTOR 15 DEG CCW UGH!!!!
So now my holes at 15 degrees off. 
The picture above shows the motors in CW-CW DE field direction. 
Pretty stupid. 
Oh well, nothing a little milling cant fix !

Additionally, I need to route one of the faces with a 1/8" channel so that I can route the wire from the RPM sensor out from inside the assembly. 
I also want to anodize it purple or green because the bare aluminum color looks boring with all the other aluminum.
(Looking back on this I decided not to put a RPM sensor on the second motor...)


----------



## Jesse67 (May 12, 2009)

Ha, no problem! Your motor coupler looks pretty good, and there's less chance for absolute destruction if that fails compared to your diff mounts. The motors are still held in by the main mounting brackets. Have you done anything differently with the front diff mounts as well or is that still as you last had it? If so I would seriously look at changing those. 

Cheers,

Jesse


----------



## powerhouse (Apr 1, 2011)

Jesse67 said:


> Ha, no problem! Your motor coupler looks pretty good, and there's less chance for absolute destruction if that fails compared to your diff mounts. The motors are still held in by the main mounting brackets. Have you done anything differently with the front diff mounts as well or is that still as you last had it? If so I would seriously look at changing those.
> 
> Cheers,
> 
> Jesse



I redid the entire differential area, reinforced the front brackets, redid the rear bracket, changed to much stiffer bushings. 

I will post on that later tonight


----------



## Jesse67 (May 12, 2009)

Sounds good, I'll look for your post!


----------

