And it took 3 years for the frustration to build up to ask?
Has it ever worked normally? And that's the battery that came with the laptop?
How long does the battery last when charged?
The average lifespan of a laptop battery is about 2-4 years under normal operating conditions. And it sounds like your battery's life hasn't been normal.
I can't see you have much choice except to think about a new battery.
The battery has never worked normally. It came with the laptop and when charged it lasts the same as a normal laptop.