Glenn, This is very trival to find between 12v and 13v sources at least 1 to 2amp DC. Polarity, dunno because I had mine stored but others could answer this. Do favor for us, disconnect that bad battery! Someone left the bad battery connected too long, ruining a spot near power switch where the charging regulator got too hot in mine. When rebuiding a pack, either sub-C or C (C is better and you can remove pair of spacers found in battery cavity of your luggeable. (it's stuck on with double sided tape, they're there to prevent the sub-C Cut open the old pack, save all and silver thingy, that's resettable thermal cutout switch, wires and connector, taking care to keep the original circuits intact, dispose the old cells at recycler. Sub-C is appox 2/3 shorter in length of a C cell size. The mAh rating determines how long you can keep things going before the host machine dies from weak working battery. Sub-C is about 2K mAh max if you can hunt for it or C about 2.8K to 3K mAh. Rechargeables are always expensive except for sealed gel lead-acid batteries (loads of mAh but pealty in weight/bulk!) Jason D.