Welcome to the forum.I try to figure out most of the problems I have on my own through research and that can be such a PITA at times. There is a gentlemen on YouTube who installed his 8 fun Middrive unit with a Nuvinci Hub.He was explaining gear ratios of sorts.In my opinion when your out having fun you forget all things and run your pack down.I believe in Murphy's law and if I could I'd get a backup. Now for solar panels......You just gave me food for thought.