battery replacement

So i see a lot of posts about replacing the battery pack in the Advanced and Pro remotes but noone seems to have asked or needed a replacement for the STandard. Can i just use any 18650 Lion with the same voltage? Anyone tried fitting ay larger sized batteries in there ?

My Trackimo got wet the other day, (it still works), but to be safe charging the small Li-ion battery, I thought I'd get the battery replaced. However I'm having a hard time finding one to buy online. Trackimo has yet to respond. It looks to be a generic model branded by Trackimo, I'm guessing...