Howdy Dragon. I'm working on a thing to use primarily solar with a charger back up. Using 2 6Vs in series. Walmart sells a replacement 6V and charger for kids electric cars and bikes. But the reason I am doing 2 6s, I have a really cool 6V head light made from a emergency exit sign light. And using solar because the producing of electricity, takes a lot of energy. Even though a generator spins freely in your hand, when an electrical field is generated, there is a great deal more resistance. I am really just parroting what I have been told or researched, so please take it with a bit of salt. There really is a whole bunch of good info on the subject here and some amazing light rigs. Am sure some one more knowledgeable then I will have more to offer
There are a bunch of threads on this. Comes up a lot.
Post on what ya end up doing.
....And welcome to the forum! Some great folks here