Bettery/rom problem?

[uudza]

Hi everyone :)
So I have the battery problem-it`s not charging!
at start it showed all the time that it`s charging-eaven when it was unplugged!
so I searched and disabled the usb charging,through registry.
But then started another problem-it shows that it`s connected to wallcharger and so,and it shows it`s charging,and how full the battery is...BUT!
it`s all fake! it shows 100% but after few mins dies!It only charges and holds the power normaly only when i charge it through differient methods-with just ac adapter(just two wires-my brothers electrician so he knews how to..).
but it`s not the batterys fault-I just bought a new one.
So-what could be the problem,any ideas?
thanks and have a nice day
P.S.
I got it used.its G4
the info,that i found in it was:
ROM version:2.17.7.2 WWE
Radio version:02.07.10
So do you think that rom updeite could fix it?

[xardas_90]

first try replacing batery..it seems that the battery is the oubvious problem...if it still sshows the same problems...try flashing another rom...if that doesn't fix the problem it means you have a hardware problem that "eats" too much power