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Existing build and want to change battery chemistry

Posted: Jun 22 2018 12:02pm
by FarFromStock
New to the board and wanted to see if I could get some advice for my existing build. About 9 years ago I decided to have RebirthAuto (St. Petersburg Florida) do the actual conversion on my 1975 BMW 2002. For the first few years, I drove it to work daily on a 30 mile round trip. However, since my work location changed, I wasn't able to make the round trip on a full charge anymore, so the car has been sitting in the garage with the exception of an occasional weekend run within the 30 mile range of the lead acid batteries. Now that the battery chemistry and technology has advanced, I am looking at replacing the LA batteries with newer chemistry batteries. I'd appreciate some advice on how best to proceed.

So here are some of the basics on the build:

- NetGain WarP9 motor.

- EVnetics Soliton1 controller with liquid cooling.

- 11 Deka Deep Cycle GEL 12VDC 97.6AH batteries (8 are mounted in the trunk and 3 in the engine compartment along with a service battery).

- Elcon PFC1500 charger.

-Iota DLS-30 DC/DC converter.

We kept the 4-speed manual transmission and Rebirth made an adapter from a single block of aluminum to mate the transmission and the Warp9 motor through the stock clutch/pressure plate.

Here are links to videos of the initial road tests:

Since RebirthAuto and EVnetics are no longer in business, I can't go back to them to do the battery conversion. Any suggestions on where to start would be appreciated.

Re: Existing build and want to change battery chemistry

Posted: Jun 22 2018 1:15pm
by fechter
Do you know what the maximum current is?

There are quite a few possibilities with used lithium EV batteries these days.

Re: Existing build and want to change battery chemistry

Posted: Jun 29 2018 4:35pm
by JoeG
Chevy Volt batteries from a wreaking yard seem to be the low cost option right now. There is a lot of info on the web on how to re-purpose them for an ev. Check for packs in your area. Near me, in Los Angeles, CA there are a couple in the $1650-1700 range, which is pretty cheap for about 23 KWH of batteries.

Re: Existing build and want to change battery chemistry

Posted: Jul 25 2018 4:47am
by unklegrumpknee
Excellent project.

A couple reasons come to mind.

Because of the Puekert sp effect, you can expect longer range from the exact same kilowatt hr of capacity if the weight were the same.

It be much lighter extending the range even further.

You should have enough room, that you can get even more capacity.
a higher capacity battery with a decent C will give you the current and functionality of a smaller extremely high C battery, while yet extending the range even more.
The guys here have used massive amounts of laptop batteries. Low C each cell, large number of cells, a high overall and usable C. I do not recommend used laptop batteries. But you could use LiFePO4 chemistry. I do agree that salvaged batteries from wrecked E-vehicle probably is your most effective choice by both cost and performance but the LiFePO4 might let you use your existing charger.
Very worthwhile project.
I wish you the best of luck.