I’ll be using my electric golf cart ($600) batteries come from local junk yard ($30 each has 4) my RV friend is getting me 4 solar panels to mount on roof to keep them charged up. For the price of those bikes (which I like) one big 48 volts lithium batter can be had cheaper and it last 20 miles on a charge. Maybe something to think about (I dislike having to put gas in one)