Forgive our ignorance here, will update this ad as we go along and learn more and can provide more info.
Basically, bought a GEM with a bunch of mods, including this battery upgrade, and one of the cells has gone bad. Doesn’t appear that these batteries are easy to get a hold of anymore, so looking to just do a newer EV battery upgrade, and will part out these individually for anyone that needs them. Looking for $80 each with the balancing board, here’s a couple pictures 20200506_175625|666x500
I can get you spares.
those are great cells. If you can get a replacement that would be good.
Thank you for the reply. How much are spares? I feel like for the amount of space that these take up, VS just getting newer Chevy Volt packs (Or equivalent), I’ll be much better off in the long run, it can all live under the rear seat, and I’m not forever chasing down random packs going bad in the future…
Definitely would be good, but what’s to keep another one from randomly going bad, then another…? Think I’d rather pull the trigger and just get newer/higher capacity/smaller footprint new gen car batteries and call in a day…
Then these are available for anyone with this conversion that needs them and wants to keep the split pack system/higher weight/less free space arrangement they already have. Pretty much the way we are leaning, just need to look into what it takes to get some Volt batteries or equivalent.
Chevy volt batteries are an older discontinued battery , ok for used inexpensive install . But I would look for a newer version battery if I was buying new . For NMC chemistry you need MINIMUM 20 cells upto 24 for a high performance setup.
$50 each. Your’s may have been abused, as I have not seen failures other than doa occasionally.
Lifepo4 are heavier but safer. And no bms needed if top balanced with shunt boards.
It will take two Volt modules to give more run time than a single green pack. I make parallel harness for Volt packs. It’s difficult to configure Volt for 72v. 24s is 88v high performance. Need 2p24s IMO.
Depending on your budget, I have some E-Golf 112ah test modules. Prewired for 20s, 22s, or 24s. Upgradeable from 20s later.
@LithiumGods has 75ah BMW batteries.
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GEMs need weight over the front axle for traction. Be aware if you put all the batteries under the seat you’ll be burning rubber every time you start. Even with 15 green cells up front, I had to add 4” of steel plate 6x10 in front battery tray to gain reasonable traction.
yes if you have a pre2005 you need weight upfront. Add 125 or so pounds or put the lithium up there.
Thank you for the info! We do “A little” Mustang work here, and have already been playing with the rims and suspension here. We went from a 16x7 rim to a 17x7 rim now, so there’s enough meat to keep loss of traction from being an issue. We also did the Progessive Suspension air shock front conversion which definitely helps wheel hop from being an issue from the previously grossly oversprung stock front shocks, and have done the same for the rear, which makes the GEM night and day better at any speed. With the instant roll center characteristics of this 4 seater chassis with at least 2 people in it, removing weight from the front where it’s also a higher center of gravity will be ideal, (For our specific combo, anyway).
Thank you for the info, definitely different things need to be done for every specific GEM combo 
Definitely possible, I can’t speak for them, since we just got them, but the guy we got them from had another GEM with the same set up, and said it’s been a solid runner since he did the swap. His main warning was to NOT run them low, that once the dash shows under 100% charge left, there is a problem. Of course we were out, and made it back while it showed 99% left, all cells but one charged back up. Tried to shock it back to life with my RC charger in both NiMH and NiCd mode, so far-no go.
The GEM was running well over 72v with these packs, the T1 controller was already reprogrammed for the RFF motor and speed control was raised, this GEM would go into an overheat mode, (Forget the code now), and would need to cool down before it would run again. Strange thing is, we also made it overheat literally just going 2mph alongside someone walking on a sidewalk and talking, so it’s not just a wide open motor overheating thing, (In our limited experience/opinion) Need to look deeper into that…
I guess we need to spend more time with this cart learning more about it and understanding what we “Truly” need.
It’s an afterthought at this point, and a time waster, in reality. It’s barely used, and making any kind of priority out of “Upgrading” it is really not the best use of our time, but it looks cool, and when we take it out on the streets around here, people trip out, and my kids love it-so the money pit will continue if for no other reason than “Just because”… 
After looking at that video 8 months ago on youtube of the modified blue one that had a simple pack set up under the rear, it “Seemed” like the way to go. Looking for a “Simple” and reliable set up, clean and as uncomplicated as possible, and lightweight.
where are you located ?
We’re in Thousand Oaks, CA.
Simpler setups are available but considering your comment on not using it much a single cell swap seems easiest and cheapest. Majority of my experience is with 2005 and up but multiple people do use lithium with earlier Gems. R4F motors dont have temp sensors so wondering if it is a controller overheat?
41 code is Controller Overheat. Look for dragging brakes which is probably #1 cause of reduced performance and overheat. T1s are more prone to this than later units. Greasing the back of the controller when mounting and using all the mounting bolts helps a lot, These controllers radiate heat thru the back so good contact with the mounting surface is important, If your controller is getting hot quickly for no good reason it NEEDS service.
Thank you for the info. There’s no dragging brakes, I did the disc brake conversion at the same time as the battery upgrade, and I regularly push the cart around the shop a few feet here and there if the keys aren’t in it-no issue with brakes.
The strange thing is… even with that code 41, the motor is HOT, and smells hot, too.
It never smelled or radiated this much heat with the 12v gel batteries, but of course this new battery array was around 90v, with the 15 up front, and 10 under the rear seat. After the one up front went below threshold charging voltage, I just removed it and jumped over to the next pack. Haven’t taken it out much since then, since I’m reasonably sure there is prob some kind of issue now with charging all the rest of the cells “Evenly” now?
Not sure, ideally need to wire up each battery to a multitap rotary switch and an LED voltmeter, so I can monitor the voltage of each on the fly.
One of these days…
a $100 bms will monitor all cells , balane them and report all voltages to your phone.
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Hmmm
When you removed the pack did you reset the charger so it doesn’t over charge the remaining?
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