I purchased a spare battery for an LG G4 on Amazon that was better than the original. I've also purchased several UPS batteries from UPS Battery Center that are very good as well as Harmony remote and camera batteries on eBay. Can't say I've ever had a real dud but a couple of the camera batteries from a few years ago didn't seem to hold a charge as long as they should. But then they cost $10 and the local stores wanted $60 for the OEM version. The $60 batteries failed quite fast which is why I tried eBay.