Re. charging 24v scooter bat. I also considered separating the 2 12v bats and charging them directly, but that requires disassembly of bat pack, etc., a tough job with my shaky hands, even tougher to do it repeatedly. I need to just "plug and play."
Found a device at Radio Sack that produces 27v DC from 12 v DC; need to change output jack to fit scooter bat recept. 'Still considering this. 'Think I'd rather use the battery maker's charger thus far, though. That needs 120v AC - the easiest for me to do alone. (Electrons are electrons, though, and bat doesn't care where it gets 'em as long as it doesn't get too many too fast and can stop 'em after it gets enough.) BTW, some smaller inverters do plug into lighter socket. Wilton