That thing should take just about anything within reason. It's just a simple little DC motor. NiMH will run slower and if you go the Li-ion route it would run faster.
There used to be C and D cell NiMh available. I have a charger thst has the slots for them. They were always very expensive. Beware of C/D cell bodies thst just have a AA hidden inside…
There used to be C and D cell NiMh available. I have a charger thst has the slots for them. They were always very expensive. Beware of C/D cell bodies thst just have a AA hidden inside…
I have C on hand, although in flat top. I've sort of fallen into a business of rebuild batteries for obscure camera flash equipment, and have one application that takes C cells. Sub-C and 4/5 Sub-C are far more common, though(and I normally buy 50-100 of those at a time in both NiCd and NiMH-I think I have around 200 4/5SC NiMHs on hand now as they're getting hard to find and I use a lot of them).
Tenergy makes a standard C size button top, and they're not terribly expensive
There's a lot of older information out there about Tenergy not making great batteries, but I use a lot of them and I've had good luck. I test my stuff pretty extensively before selling/sending it back out. I never ship a battery pack that hasn't been through at least 5 charge/discharge cycles(3 bench tests, including an initial break-in slow charge and two standard charges), one complete cycle installed to make sure it's performing at or better than spec, and at least one "real world" test where I actually use the thing the way it's meant to be used. The AA and 4/5SC Tenergy cells I use are rated at 2000mAh, and I see a range of 2050-2200 as actual capacity. I check other specs too like internal resistance and self discharge, and every thing is dead on where it should be.