CGRetired makes a good point about charging high capacity batteries with a wall wart. However, on the other side of the coin you can cause yourself problems by charging for too long or at too high a rate. Check out the warning at [link]http://www.hangtimes.com/txpacks.html[/link] four items down the page. It seems that the high capacity Sanyo packs are sensitive to overcharging and mechanical shock and these failures are not covered by warranty.