Axle generator

I am thinking of trying to prototype a charging system for a towable rv. Concept is using a generator connected to one of the axles of the trailer to generate power while turning to recharge onboard batteries. I understand the electrical side of project with exception of power generation capabilities. Does anyone have any pointers or links to a suitable generator that could be integrated or attaches to a wheel axle to generate power while trailer is rolling.

Thanks

Is trailer towed by a vehicle? If yes? That vehicle most likely has a alternator that generates electricity when vehicle is moving. Usually 12V DC. Use that to charge batteries.

Ditto to what Marty said.

If the alternator of the towing vehicle is insufficient to do the work, just upgrade it to a better one.

It'll be more efficient than having to drive around at a specific speed to make the axle-driven generator work. Plus you can recharge without actually driving.

If you use an axle-driven generator, then if you're not at a constant speed, you don't get a constant voltage. If you're not at the right speed, you don't get the right voltage. If you're not driving around at all, you don't get any voltage.

There's some ways around that, but they can get complicated, and complications generally impact reliability.