# Batteries for a Chevrolet Sprint



## dtbaker (Jan 5, 2008)

do not even consider lead! way more expensive in the long run. I'd suggest you take a close look at CALB, and at least read thru design considerations regarding $/mi on my site... on top of weight implications for accel, braking, space, and suspension.

also, forget the 6.7" and go at least to an 8"... WAY better.


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## migreig (Aug 5, 2011)

I am using the 6.7", I already have it. Does anybody have a Sprint/Metro and know how to achieve the 50k range?


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## madderscience (Jun 28, 2008)

I don't have a geo, but my MR2 is another compact, efficient chassis. I have been driving it as an EV for over 4 years now at the rate of about 3000 miles a year. Here are my numbers, given that my car has about 1200 pounds of lead acid batteries and a 9" ADC motor:

In winter driving conditions I am seeing about 250wh/mile battery-to-wheels on a 25 mile or so route I drive along highway 99 fairly frequently. It is about 1/2 flat and 1/2 with steady but not very steep grades (hwy 99 south and north of seattle, respectively). Speed limits range from 30mph with stop lights every few blocks to 50mph highway. In the summer it is more like 200wh/mile on the same route. So assuming your driving conditions are similar then with a car of similar weight and similar motor you would get similar efficiency. a 50km or 35 mile route would require about 9Kwh of usable battery capacity. 

However the 6.7" is considerably less efficient overall in a full sized car. Many conversions I've seen with that motor need forced air cooling and don't have much power. That is one reason why a larger motor (8" is the biggest that fits in a sprint/geo apparently) was recommended. Reliability and better torque are the others. But since you are staying with that motor, just take a 20% or so reduction in motor efficiency (guessing here, but in an educated way) to offset this and keep the revs up when driving. However if you have a lithium pack and a geo / sprint your car will weigh around 2000lbs while mine weighs 3400lbs. So overall the efficiency loss in the motor vs. my car might be made back in the weight savings, perhaps and then some.

A 120V, 90 AH lithium pack would be the minimum recommended. That gives about 11kwh total capacity. this would keep you to no more than 80% DOD. Better to give yourself a bit more margin and go to either 100Ah or 144v. 

To back up the claim, I know a fellow with a converted S-10 and a 144v, 100Ah lithium pack. He can get 35-40 miles of range if he doesn't drive aggressively. Given that, your sprint should be able to easily do the same with a similar and even somewhat smaller pack.

Another data point: I just got home from the drive I described, Using 5.3 kwh in 22 miles of driving. Near freezing, windy night but dry roads and minimal traffic.


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## Ziggythewiz (May 16, 2010)

I'd second the recomendation for 144V 100ah lithium, assuming your motor handles 144 well.

The 6.7 motor just means you will need to add forced air cooling if you drive much in 3rd or 4th. (For my bug that's over 45 mph)


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## dtbaker (Jan 5, 2008)

migreig said:


> I am using the 6.7", I already have it. Does anybody have a Sprint/Metro and know how to achieve the 50k range?



50 k (35mile) range with 120v x 100ah prismatics like CALB is a slam dunk with a decent motor and controller. I will say again that you are not going to be happy with the 6.7", and really should consider getting an 8".

The older pre-2000 Metro is the same as suzuki swift and pontiac firefly... MANY conversions have been done on these. Mine is a '97. I now have a stock weight, 50 mile max build that is great to drive... WAY better than original build with lead that struggled to get 38 miles max when batteries were new and dropped from there...


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## tomofreno (Mar 3, 2009)

migreig said:


> I am using the 6.7", I already have it. Does anybody have a Sprint/Metro and know how to achieve the 50k range?


I have a Swift, http://www.evalbum.com/3060. Over two years I have averaged 216 Wh/mile from the wall with mixed highway and secondary road driving. I use a bit over 200 Wh/mile from the batteries at 50 mph on level ground, or about 1.8 Ah/mile. If you use lead acid remember you have to estimate range based on the capacity at the average discharge current you will have, not the 20 hr rate that is typically given.


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## dtbaker (Jan 5, 2008)

tomofreno said:


> I have a Swift, http://www.evalbum.com/3060. Over two years I have averaged 216 Wh/mile from the wall with mixed highway and secondary road driving. I use a bit over 200 Wh/mile from the batteries at 50 mph on level ground, or about 1.8 Ah/mile. If you use lead acid remember you have to estimate range based on the capacity at the average discharge current you will have, not the 20 hr rate that is typically given.



Tom, its important to note that you have an AC motor, which probably lowers your net consumption per mile 'from the wall' compared to DC with regen during driving. i.e. you and I have pretty much the same car, but my net consumption 'from the wall' averages around 275-290 whr/mile depending on use of headlights and heater. The difference probably being I have DC motor with no regen, do not make much effort to hyper-mile with easy starts from the lights, and have a cheapo Elcon charger that is not terribly efficient and kicks out a fair amount of loss (heat) while charging.


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## migreig (Aug 5, 2011)

Ziggythewiz said:


> The 6.7 motor just means you will need to add forced air cooling if you drive much in 3rd or 4th. (For my bug that's over 45 mph)


I chose the 6.7 because...well, I got an awesome deal on it with the controller, but also because it came out of a comparably sized car that performed quite well with it. It was a 1980 Renault LeCar.

No issues with highway driving or anything and on that vehicle, the motor is mounted behind the transmission, making it quite enclosed and not in the path of ay direct airflow. I will likely upgrade in the future but this thing is sitting in my garage now and I don't want to upgrade before even giving it a shot.

I should mention that I'm not looking for a power machine. I do need a certain amount of range but this wasn't a powerful car as an ICE, and I don't need to it be as an EV.

I will take the advice on the forced air cooling, anybody know how to do this?


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## Ziggythewiz (May 16, 2010)

Mine's a 6.7 (D&D) It gets hot in 3rd gear and quite toasty in 4th without the forced air. There are some kits out there for around $150 or $200, but I made my own for about $50.

Here's a pic of cruisin's setup when he was running DC. Mine is similar, but doesn't look as nice.

Mine's made out of an air filter from Oreilly's, hooked to a 4" marine bilge blower, hooked to flex gutter downspout and coupler, and sheet aluminum (from oil pan).

You can get more air flow using a centrifugal (squirrel cage) fan.


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