Which Batteries Do You Use? in General geocaching topics Posted June 26, 2005 · Edited June 26, 2005 by CharlieP Hmmmmm! I'm always hearing about school budgets and the problems with not enough money. So, why doesn't this school use rechargeable batteries? Many devices made for children are not recommended for rechargeable batteries because things get really hot if there is a short circuit. Alkalines cannot deliver enough current to get very hot. In other words ... lawyers. I use off-brand NiMH rechargeable batteries in my GPS. I have analyzed the economics, and if you are using your GPS more than 20 hours per month on average, the rechargeable are cheaper.