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John Deere Gator EV conversion to LiOn

1838 Views 21 Replies 7 Participants Last post by  pottscb
Hey all,
I just bought a “for parts” heavy duty ATV for use on my place. It’s basically just a frame and bed, all the batteries were gone and most of the plastic, rubber, brakes, suspension, needs replacing, or so I thought. After getting it apart I found an aftermarket motor that is high torque (600A) and an aftermarket Curtis 600A motor controller so I can afford to throw a little money at the batteries (and I’ll have to as that motor will crush most 48V batteries, or at least the BMS of light duty batteries) I haven’t put the inrush amp load logger on it yet but I’d like to spec batteries that can handle 600A for a few seconds on startup (and 200A continuous) as I’ll be hauling/towing with it at low speed. It has a 24”x27”x12” battery compartment under the bed so I’ve got room. The battery compartment has openings on most sides and vent in front to let airflow through so cooling shouldn’t be a problem. I’m looking for enough capacity that I only have to charge 1xWk at most so probably 200Ah+. This limits my choices and makes them much more expensive, you can either have high amperage or long range relatively inexpensively, not both.

As I’m new to this, I started out looking
for the easiest PnP solution I could find, such as kilovault HLX+ 48V-300Ah but these run $6K MSR. Then I migrated to Nissan Leaf, but I’m having trouble finding them worth the money that aren’t at less than 50-70% capacity (which is when Nissan warranty replaces them). So now I’m at Tesla S modules which are the best bang for buck as far 48V-250Ah…but implementing them isn’t for the faint of heart. I’m not an engineer but I can read a schematic, the problem is, the current electrical system has been piggybacked/spiced for several small accessory switches and implementing the BMS and contactors complicate things and I can’t find a schematic for specifically what I want to do, which would be 2X 24V Tesla modules, fairly simple BMS (SimpBMS?), onboard charger with 12V shunt for lights, commercial sprayer, etc.

Anyone have feedback on this? Am I barking up the wrong tree with Tesla modules for a first time build? Anyone interested in me posting my build pics?


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Not sure what you mean by "12V shunt"?

If you can afford them, Tesla is fine. @Functional Artist uses Chevy Volt modules.

Yes, by all means, do a build thread if you're up to it. Helps anyone else that might do a similar conversion and you can think out loud before spending the money or doing something.
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The slow capacity loss is the result of very aggressive temperature management.

Few DIYers go there.
It will be in a battery compartment vented from the front and rear with airflow above & below which Tesla chose not to do.

I really don’t need all the bells and whistles on a ranch vehicle that I plan to use pretty hard…I’d rather have something PnP that is waterproof, dust proof and shockproof...

Because that genius vented box of yours isn't at least 2 of your 3 requirements.

You also want to run the batteries up to 3C without liquid cooling...bring marshmallows. Without coolant, the cells are thermally coupled and it's not a matter of if, but when you have a gator bonfire at the ranch, imo.
One approach to get more current out is to fake the BMS out by hacking its current sensor output to say it's 100A when there's really 200A or 300A flowing.

That may have other implications, so you need to do some homework.
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