Gateway Laptop Battery Charging LED Blinking

Hi
Just recently while I was on the laptop, the screen started to blink dimmer and brighter. The charge light was blinking on (charging/purple light) and off (no color). So the screen light settings adjusted accordingly per my settings. The charge light was blinking such that it wasn’t charging so the laptop died 1-2 hours later. But once it was off, the laptop charged normally. I made sure that the charger was connected at all parts and i tried to remove and reinsert the battery while off. Nothing works. It charges when off but blinks and doesn’t charge when on.
Do i need to buy a new battery or something…this one is like 5 years old.
Thanks