[valerun]

Hi All,

Opening a new build thread here. After converting a Fiat Spider convertible (haha, such a wordplay), EVs are a way to go for me. Fiat thread: http://www.diyelectriccar.com/forums...der-51822.html

So we are taking one of my other cars (2001 330Ci) and making it high-octane electric. In doing so, we will plan to develop bolt-on designs that can be easily replicated on other E46 bodies.

Target parameters:

0-60 below 5 sec. It just HAS to be faster than stock (which is not super-easy to do with a 330...), EDIT: EVcup qualifier is <5 sec 0-60
125 mph top speed. EDIT: EVcup qualifier is >200km/hr top speed
100 mile city range

Configuration options we decided on so far
Battery: 90 CALB 100Ah cells for a 288V nominal 800A peak pack
Controller: 1000A DC (most likely Soliton1 but if I can get 1400A WarpDrive in less than 4 weeks, I'd try it)
Motor: Kostov 11" 250V SFM, with space left for dual 11" setup later.
Charger: our own design (open-source, http://www.diyelectriccar.com/forums...rce-59210.html) - 10kW, 60A
Drivetrain: not a direct drive (see below)
Coupler/transmission plate: from ElectricCarInternational. Can't beat the price and no design fee. Plus good discounts on subsequent orders of same design.

Open Questions:
1. Mechanical drivetrain setup. I definitely want to have a transmission. The question is: do I keep stock manual 5 speed or swap it for one of the automatic sets like http://www.grassrootsev.com/tranadapt.htm. Benefits are: even higher drive-ability and ability to use idling to belt-drive accessories
2. Accessories. How to best set up heating, AC, power steering, vacuum, etc. In a Fiat, I have ignored all of these - after all, it's a small convertible so braking is fine without assist, heating is a joke anyway with top open, no power steering / AC. In a beemer, all 4 of these will have to work. Now, if you do that in a 'traditional EV DIY' way, that's 4 electric motors and subsystems you have to mount somewhere, etc. Why not keep all the original pumps and pulleys and just mount then on the backplate of the motor and drive all from idle of the main motor (if using automatic tranny) or one small high-voltage DC motor?
3. EV management system choice (or build) - I want a big color screen displaying everything I want about the vehicle at all times. It has to look like a production electric car, without any ammeters on the dash, etc. At this point, the thinking is to build our own system based on Arduino for data gathering and Android tablet for display. If anyone knows any other systems available on the market today, please let me know.

Comments / suggestions?

Let the fun begin! (again...;-)

Valery.

[Yabert]

Hey! be careful.

You don't have enough battery power because your voltage is too low!

800 x 0.0009 = 0.72 - 3.2 = 2.5v x 90 = 225v.
800A x 225v = 180Kw from cells and roughly 200 hp at motor shaft....... so, not enought!

You probably need at least 250 hp....

[valerun]

Originally Posted by Yabert

Hey! be careful.

You don't have enough battery power because your voltage is too low!

800 x 0.0009 = 0.72 - 3.2 = 2.5v x 90 = 225v.
800A x 225v = 180Kw from cells and roughly 200 hp at motor shaft....... so, not enought!

You probably need at least 250 hp....

Thanks Yabert! I was thinking of going to 100 cells which would take care of that. But then again,
1. pure hp rating matters more for top speed than acceleration
2. My latest shipment of CALB cells lists 0.3-0.5 mOhm IR (each cell is tested separately). So the sag should be lower (at least on new cells).

V

[Yabert]

Excellent news! Calb 100Ah at 0.5 mhom... seem awesome!

Originally Posted by valerun

pure hp rating matters more for top speed than acceleration

It's barely true, because a different gear ratio can give the advantage. An high torque isn't enought alone, you need to keep this high torque to high RPM to have a powerful car.
It's why higher voltage is important.

Especialy because having a good torque at high speed can give you the important advantage of having a single Kostov motor to acheive your goal performance instead having two engines that provide more torque, but lower rpm and roughly same power.
96 or 100 cells seem really good to acheive your goal... 270v x 800A = 216 Kw.

After all, If Crodriver managed to generate 500hp from its Warp 11 HV, I do not see why a Kostov 11 250v could not produce 250-300 hp at lower amps.

Good luck..., your car will be awesome. I can not wait to see him finish.

[rwaudio]

sounds like a fun build, for the power level you are looking for you might want to look into higher power density cells to shed some weight unless you need it all for the range you are looking for. Headway/A123 etc.

I really like your display ideas, nothing like taking a step towards a Tesla model S and away from an obvious garage creation.

I kind of like the idea of a higher end automatic, I know the transmission in my G35 shifts faster than a stick, and it doesn't have the typical automatic lag. The only thing I'd complain about is it's always in the wrong gear, but with the wider power band of an electric it would be much easier to keep it in the right gear.

Using the idle feature in the Soliton1 has been very helpful while setting up my belt driven A/C even though the car is a manual.

[valerun]

Originally Posted by rwaudio

I really like your display ideas, nothing like taking a step towards a Tesla model S and away from an obvious garage creation.

thanks rwaudio. I have started a separate thread on this at http://www.diyelectriccar.com/forums...075#post246075 - please post any comments / suggestions you might have!

V

[piotrsko]

you'll probably beat the build time on the ranger, Let me know how the kostov works out.

[valerun]

80 100AH CALB cells are in! Another copy of our 10kW charger is built and tested on the pack - ready to go!

ICE coming out this weekend (I hope). Will post pics soon.

[valerun]

Originally Posted by piotrsko

you'll probably beat the build time on the ranger, Let me know how the kostov works out.

Kostov was great on my Fiat. Plenty of power. Couple of notes though:
1. You need a high-voltage pack for it. Seems like a very obvious need but for some reason did not get through to me initially so I was running a 250V motor with a 192V pack and it didn't work very well. 256V nominal is getting there.
2. Pros say that you can't overload Kostovs for as long as NetGains (lower thermal mass) but that is likely to be relevant only for racing.

I still can't get over the fact that you can get dual Kostovs for less than 2 motors bought separately!! ;-) Direct drive with dual 11" in series on a 340V pack and 1000A controller, anyone? 1800lbs (0.5G) push at the wheels from 0 to 70-80mph? mmm... ;-)

V

[Bowser330]

Originally Posted by valerun

Kostov was great on my Fiat. Plenty of power. Couple of notes though:
1. You need a high-voltage pack for it. Seems like a very obvious need but for some reason did not get through to me initially so I was running a 250V motor with a 192V pack and it didn't work very well. 256V nominal is getting there.
2. Pros say that you can't overload Kostovs for as long as NetGains (lower thermal mass) but that is likely to be relevant only for racing.

I still can't get over the fact that you can get dual Kostovs for less than 2 motors bought separately!! ;-) Direct drive with dual 11" in series on a 340V pack and 1000A controller, anyone? 1800lbs (0.5G) push at the wheels from 0 to 70-80mph? mmm... ;-)

V

yes please!

I want to do a similar conversion as you maybe into a newer E92 or a porsche 911... very excited for your results, good luck!