Hi Norm
I havent really pulled it apart but I did read this thread on the forum below that seemed to suggest on the second page it has a charging system, Im guessing its something like those dynamos i had on my push bike when i was a kid that charged from running on the rim.
This link gets in to some heavy electronics above my level.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=53219
