I have some background with electronics, but that was in the "old days", so my knowledge of lithium battery types and charging processes is very limited.
I have a bunch of gadgets with one of those baggie-type lithium batteries. Some of them are size/weght restrained, but with a couple, size is no issue, so i was wondering if I could replace the provided battery with a (lot) larger ones. Those gadgets also have charging circuits (i've read the charging is voltage-controlled, so in theory, the capacity shouldn't matter for the charger, atleast in theory). All batteries are single-cell.
So, is this possible at all, and what should I be extra careful about, when selecting batteries (eg. when ordering cheap large ones from ebay), and what are the limitations?