[NintendoKD]

Originally Posted by jkeller1ca

I agree, you'll probably want a Lion pack. Keep in mind that the MR2 Spyder is a lightweight rear-wheel drive car. The stock weight distribution is 44/56 (front/rear) and is very sensitive to weight distribution. Look up "snap oversteer" and "lift-off oversteer" for some cautions about the MR2 design. I was able to push the distribution forward a bit from stock, 48/52 which seems to help keep the car in-line even at more neutral tire alignments. But, yeah, take your time and have fun.

spyderchat member bro, look me up, guy smiley is on here too surprise.

what are your specs? power? total power avail. motor output? controller, DC setup right? I am going with A/C so for now I need to find a good re-winding service. good to finally hear from someone.

[PStechPaul]

Just a quick note about the motor rewinding. Depending on the winding pattern you might be able to reconnect the existing belts in parallel rather than series. I know that it is a fairly common practice to rewire from star to delta in order to get 138V rather than 240, but for higher pole numbers, AFAIK, each pole consists of several identical sequences wound in series. But if you separate them, you might be able to wire them in parallel, which will eliminate a total rewind and will allow use of thinner wire which is easier to work with, and also may have a higher fill factor.

And the other thing to consider is that the usual reason for rewinding is to run on a lower voltage battery pack. But if you can make a battery pack for 288V or even as much as 640V, you can use standard 480V drive components and still get V/F boosts up to 3x, which may be the practical limit before core losses predominate.

[NintendoKD]

thanks for the heads up

[NintendoKD]

A123 3.6vdc @ 24ah
for 650vdc 181 are needed @ 24 ah each pack
4 packs are 724 batteries total @ 76 ah total
A123 32113
$8.00 each $5,792.00 for the packs
discharging current at 2.5C or 5 A making for 20 A total.
46.5 g each 33.666g total 33,666kg
http://www.batteryjunction.com/oneli18322ma.html ~74 lbs

Looking at the lithium route, it looks very promising. The weight is very low, but the price is not really that high considering it wouldn't move at all with lead acids at this voltage. I will be building my own custom controller with igbts, and the fro board. I will also be using a BMS for the lithiums to protect my investment. Building a charger shouldn't be too much trouble, 220 in at half an amp or so should do the trick without taxing the packs.\
the motor will be turned by three phase 460vac and about 20A, so no big deal I have some room for overages minus the losses...... I think. how do I figure for range? I want to use a rear end from a rav 4 and am not sure of the gearing I should use. I am using a straight baldor industrial motor hooked to te diff 20 hp, can be overdriven about three times safely for short periods so 60~hp max and the car still stays right around its stock weight.

[PStechPaul]

It seems your proposed battery pack is about 724*3.6*24 = 62kWh.

So if you can achieve 250 Wh/mile you might get as much as 248 mile range, but realistically and depleting to about 75% and with losses you will probably safely get 150 miles. Pretty good!

But I question how you can get 62kWh for under $6000.

So I check the link and the batteries are actually 2.4 Ah. Now all the calculations are off by a factor of ten. So you might get 15-25 mile range. And you are paying $5792 for 6.2 kWh. If you use 200*20Ah*3.2V cells from http://www.electriccarinternational....-Batteries.php at $25 each you will get 12.8 kWh for 30-50 mile range for $5000, so twice the range for the same cost, and a lot easier to use than the cells you are considering.

[NintendoKD]

I'm a dummy, I looked again and you are right. Guess I got a little hasty and didn't move the decimal enough. The object is to drive the igbt three phase circuit with enough juice to put out 460 @ 20 a but if I so desire run @ 220 at the higher current. For the most bang for the buck out of the batteries.

[PStechPaul]

We all make mistakes.

Still, for the same cost, the batteries I found will give you twice the energy for the same cost. At 20 Ah and 650V you can get 13kW or almost 20HP at 1C, and 60 HP (45 kW) at 2.5C. 200 pieces would be 366 lb which is not excessive. But the batteries are shipped ocean freight with 8-12 week delivery. If you could spring for 20 kWh they offer free shipping. Or you can get 2-4 week air shipping but at unknown cost.

You could also just get 100 pieces for 325V and run the motor on 240 VAC and then upgrade later to get the power and range you want. Not a bad deal for $2500.

[NintendoKD]

thanks paul, back to the drawing board, I have to figure out how, and where I am going to put those things in the car at the dimensions described. Planning, planning, and more planning, I'm not complaining, but it gets old quick. one little mistake, and you are back to the ol drawing board