LiFePO4 Cells

GEM Forum
1

Hello all,

Has anyone any experience or insight into retrofitting LiFePO4 cells into GEM vehicles?

My lead acid batteries in my 2005 GEM e2 are needing replacement and I’m considering making the change.

Craig

2

Look at my thread at http://www.electricforum.com/cars/neighborhood-vehicles/3005-new-gem-owner-converting-lithium-batteries.html

Feel free to ask any questions in that thread or in this one.

3

Hi CPseudonym

I would be interested to hear how you get on with the change of batteries if you have time to post an update?

4

[QUOTE=Editor;15292]Hi CPseudonym
I would be interested to hear how you get on with the change of batteries if you have time to post an update?[/QUOTE]Don’t the 2005 models use the Delta-Q? Those models can’t be reprogrammed for use with lithium cells, so needs to be replaced with another charger (either onboard or offboard).

You might be a able to use fewer cells (23 or 24) and try to manually disconnect the Delta-Q charger when the cell voltage reaches the charged voltage, but good luck always remembering to do that. One time forgetting, and potentially there goes one or more cells in the pack

On the older models with the Zivan chargers, these can be reprogrammed to work with lithium cells for about $100, but the temperature compensation still throws off the voltage setpoint (lithium doesn’t need TC). To address this issue, I cut off the TC probe end and replaced it with a soldered to the leads temp-stable resistor from Mouser. This seems to have fixed the problem with my voltage adjustment constantly changing with temperature, but more testing is still underway to make sure.

The ultimate solution is to replace the processor in the Zivan with this $40 programmable version so you can have full programming ability of the Zivan. I have one, but have not yet experimented with programming it to work on the NG1 (it works as-is on NG3 models but should work on all the Zivan models). I also don’t know if they are still being offered.