Gem lithium battery conversion advice

Hi all, new forum member here. My boss owns an e825 2002 gem and tasked me with converting it to lithium ion. After reading through the forum i realize batteries around 12v would be the conventional option, yet my boss found 3.7v cells ( adding up to 14.8v batteries) and wants me to see if they can work. Does anyone know if a gem can take such voltages in series? Any advice would be really appreciated.

There is much much more to using lithium batteries in a Gem than just connecting some cells in series for the right voltage.
It’s well that you asked first. Most do not.
3.7v cells are LFP and not well suited for traction batteries. IMO
Those who know use cells designed for the latest production electric vehicles.
That being said, one of your challenges in a 2002 is fitting battery in the front. Where the weight is needed.
Where are you located and what mileage is expected?
Use 250-300 wh/mile ballpark.

Thank you for replying. Were located in the Tri-state area and my boss says he is looking for 30- 40 mile range and wants speeds around 25 to 30 mph (I assume the wh/mile is around 300 but i’m not sure if i calculated it right.) Hes very stingy about price I even recommended to him leaf or volt cells but he said no. Thanks for your help.

Key phrases picked out that need clarification-

yet my boss found 3.7v cells

Did he already buy these? How many did he get?

He’s very stingy about price

This is generally not a good path to follow when buying batteries. Yes, cheap cells can be found all over the place. This usually leads to some tired Grade B product and disappointing performance, eventually leading to future disappointment and the need to buy something else and rebuilding again within a year.


Hello, my boss hasn’t bought the batteries yet but wants to buy either 3.2v or 3.7v cells. Also he’s convinced the batteries and seller are pretty legitimate. Yet I completely agree about using cation around cheaper priced cells. Thanks for your help. Btw nice profile pic!