Yeah, batteries. I find that these small batteries, like a small charge. Anything more than the 750ma charging output that a Battery Tender JR. puts out can prematurely kill them. Also, a new battery should be fully charged on the bench before it even goes in to help extend life. To each their own on which type of battery to buy. I've been running a $25 ebay sealed battery for 3 years without issue. Best of luck to you.