First Ever - Tesla Powered GEM Car

As many of you know I have been working on building out my 16’ GEM E4. Last night I was able to drive it for the first time. To the best of my knowledge this is the first GEM car EVER to be powered by a Tesla battery. Still lots more to do but making it move for the first time was awesome.
Here are some pics and a video, big thanks for all the help from @Inwo @grantwest @bundcur @LithiumGods - I could not have done it without their help.

16’ GEM E4
17:1 Gears
8kw AC induction motor
240Ah/99v Tesla Model 3 battery - 6.5ft long
Sevcon Size 6 controller

First Drive Video:


Sounds smooth. That motor sounds like it spools up super fast. With thoes light weight wheels and tires and the 17:1 transmission I bet it whips up to speed in no time. When will you have it on the road for the first speed test?

1 Like

Should be able to get it out on Thursday, however with these 17:1 gears I think about 35 will be my max as David found.
You on the other hand … will be much different with 12:1 gears.
Time to call Rodney.

1 Like

504 lb lighter.


The real question is gonna be. Will the12:35 gears with my heavy wheels big down the 8k motor with a 80v lithium pack?

Will this combo have enough power and torque to push this car up to the 50Mph mark.

Gears & wheels are the big “unknown” as far as how they will effect performance. Dave has set my expectations low to start with. Once I get my car rolling fingers crossed his File in the controller is magic. But I think Dave is gonna be proven right once again. That programming Varys from car to car and weight and gears have everything to do with it.

May i ask how did u get a bms for the model 3
Did you remove the bms because i would love to use one

I am not using the BMS from a Model 3, this is a single module from a whole tesla pack.
The BMS board is still on the module, but it is not hooked up or technically doing anything with the pack.
I am going to install cell balancers to keep things leveled out, but I am not charging the batter enough to worry about over charging, I am charing to 98.6 (3.9x per cell) it will take 4.2 per cell.

I have a 23s Tesla3 module wired to a smart bms.
Tried an active balancer, but it didn’t like the balance wire resistance.
@LithiumGods has had good luck with them. I find them buggy as heck.
Also the smart balancers only go to 24s without cascade.
Smart bms does 32s for the 25s modules.

Good job @MikeKC. I know there was lot of obstacles and challenges to overcome on this project. Ready to go for a ride.

1 Like

Got the BMS wires on today - it was a little bit of a nail bitter with a live 100v battery. But I got it.


Any new updates on this or any similar conversions? been a while since I’ve seen anything similar… This project seems to have the most potential for GEM greatness.

And here I thought that would be achieved with combo SAE & SI self centering lug nuts.