Who is this and why have you hijacked @JarJarJava 's account!? No discussion of bulldozers, explosions etc with an early car??
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Thanks for your reply. Sorry should have been more specific, yes the batteries have life (very little, and very old) so I know it works, but they need to be replaced. It drove well and stopped well so assuming the trans is okay and brakes worked.
I’ve searched and have found builds but they mostly just had pics “I did a lithium conversion” and BAM pics of it done. I didn’t come across any tutorials or how to’s or step by steps which are very useful. But I’ll keep looking.
I love to build and fab things, know how to weld and work with electronics (built a solar generator battery with 18650 cells, robotics, cnc, plasma cutters etc) but I’m new to GEMs and Golf carts with bigger batteries etc. To answer your question, yes, I would like to buy the parts and build it myself but would like to follow in someone’s footsteps to make sure I do it correctly. What cells are best to use, Nissan Leaf, Samsung SDI, what BMS (does it need one) etc.?
If I missed a good lithium build write-up please let me know, as I’m sorry I’ve searched and didn’t see it.
If you want to build a 94ah SDI battery, I have a deal on cells.
20 will fit nicely in an early classic Gem.
These were sent untapped by mistake. As I don’t have time to do the work, selling for less than cost.
You should find plenty of support on forum. Sdi is one of the most widely used gem batteries.
Picture is 28 cell battery for my Tomberlin. Built from home store PVC trim boards.
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Awesome, do you recommend a certain BMS? Or will any 20s 100a one work(or what specs should I look for)? Do you feel any work better than others in your experience? Thanks for your help!
I do, I’ll pm you with Byron.
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Hi JoeA,
I’m curious, did you work through your lithium conversion with the info on this site? I have had an 04 GemE4 for several years and decided to do a lithium conversion, but i’m having trouble it seems with the motor controller and the battery packs i picked up. So I was hoping to pick your brain as to what threads were most helpful.
Also interested in some recommendations on a BMS. Looking to do a 24 cell setup. From what I have been reading, 100A would be way too small and will trip. I have picked up some locally in various stages of assembly. Trying to figure out the best way to attach them. 8 of the cells have had the tabs cut apart. They were welded on. Doesn’t anyone know the recommended way to attach? Originally were welded aluminum bus bars it would appear. Ok to drill and tap? Stud size recommendations?
I am working on a conversion right now. Not as easy as I would have liked. Battery is in and secure. Fully charged, 72V and 105AH. 2012 Gem E4 is showing turtle mode. I think because it is looking for 86V fully charged. I am going to play more with installing the new charger similar to the Delta Q. I did the SOH reset once so far. It went full speed even on turtle mode this morning.
Has anyone played with the battery setting in the hidden menu? I think I am on 57
Be very careful about changing the parameters in that secret menu. They can affect how the display works that we don’t quite expect.
Also note the key words “How the display works”.
It is just a display. Anything you do in there only affects the dash display, NOT how the car operates.
I believe the turtle is actually set by the PSDM. Usually, it is held in DL until it senses a charge cycle pass through it. If you are saying it still works, maybe you are not feeling the full potential of your car at full power (DH?).
What are you viewing as full speed? Perhaps it was still high enough and may not have triggered the turtle yet.
Depending on what battery you installed, it may not be properly designed for use in the GEM. You say is is a 72v, but sometimes this is referring to a class of battery, and not the actual charge of this battery.
If it is truly top charged to 72v, Yes, it is on the very bottom of operating limits of the controller. It is expecting ~68v on the low, and ~85v on the high from a pack.
How much do you know about this battery? Lithium packs are rated in amount of cells (20s, 22s, 24s) and what chemical type (LiFePo4, LiOn, etc.)
Make sure the new charger you are installing is compatible with whatever battery you installed and that it is wired into the Gem properly.