Is Cranking Speed or Duration More Effective for Charging a Hand-Cranked Radio?

[snoggerT]

hand cranked radio question (ignore - figured out)

Your two friends argued whether they should crank more cycles (e.g. 180 cycles in 1 minute) or longer time (e.g. 180 cycles in 2 minutes) to efficiently charge the internal batteries. They couldn't conclude with their knowledge and decided to ask you about this. What would be your professional opinion?

The Attempt at a Solution

I'm not really sure on this one. It seems like speed would be a factor, but I'm not sure if the generator is only reliant on the number of turns. Can someone please help?

 

[skeptic2]

They don't specify the type of battery but I'm assuming they aren't lead acid batteries. What do you know about recharging currents of non-lead acid batteries?