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