There's nothing wrong with Hobby King batteries, yours died because you left them fully charge for so long I'm almost positive. And for the price you get how they can batteries for you can get double the amount for the same price as getting batteries from other places most times. And realistically all batteries to come from China, you're just paying mark up on branding getting them elsewhere. I've been buying from Hobby King for years like a decade, and I think I've had maybe four batteries in all that time go bad on me, and I've probably bought well over 200 or more. Save yourself the cash and get them again just remember to properly storage charge them