Looks like a 48V flooded lead acid rig from maybe a forklift or a golf cart… definitely an Alltrax controller. Looks like the motor is inside the little red box.
Update: Spoke with the farmer who built it, Ari, and he found everything he needed at the Flying Beet, here. It’s an Allis Chalmers G, and apparently there’s quite a cult of them growing in all parts… 100 plus, by the Flying Beet’s count. Here’s a pretty hysterical video featuring the tractor:
Here’s the Niekamp Tool Company Electric G page, too.
…more to come!