[Mrluvaluva]

It sounds possibly like a faulty charging point.

Have a good look inside the port with a torch. Some people have found small amounts of debris caught in there which prevents proper charging. After removing the offending material the charging returns to normal. If you cannot see anything try wiggling the charger a bit when it's in there.

I have an S2 and had a problem where it kept thinking the charger was in there when it wasn't. I kept wiggling the charge connector when it was in the phone. Ever so slightly, as I didn't want to break it, just to bend the teeth a little. It settled down after a day or two and I have had no problems since. *touches wood*