Completly normal. The method that seems to be employed for the battery percentage is read the voltage itself and make a guess :)
This high voltage drops down quite quickly both as a "load" is applied to the battery,. Plus there is not a lot ...
sometimes the charge goes up to 376mA down to -21mA while doing one time charge.
So it probably is not your battery, it is probably the rate of charge.
This is a similar quantity that I will see when the "fast charge" is not going ...
I have been facing constant battery drain for sometime now. Even while charging, battery keeps on draining without much of heavy use.
Your battery sounds like it sucks.
I am using a method on my phone that shows me (about) how...