I've had an LG that was a bit hard to charge, in general. I wound up retiring it because I was like, "Eh, this is getting a bit odd."
IDK if it was The First Time, and after that it behaved normally I might assume it was a bit older or from a different batch or whatever, but I probably would not freak out.
I suppose to be on the safe side you could do everything Rossum suggested, that's probably your best course of action.
Or, you could toss it NOW. God if I did everything Rossum did with a battery (he's surely probably right though) I'd just say, "I'm tired. Goodbye battery."
Anna