Ryobi Battery Not Charging - How To Fix

My Ryobi battery is not charging normally, it would flash both red and green light on the charger.

As per the indication on the Ryobi charger, flashing red and green light means the battery is bad.

To solve this issue, first I used a multimeter to measure the output voltage of the battery. For healthy ryobi battery, it should output around 18V - 20V for the 18V ryobi battery.

If the Ryobi battery is bad, in my case, the voltage is far below the 18V, measured at only around 1V - 2V.

Obviously something is wrong in the battery.

To fix this issue, I have to reset the ryobi battery.

I used another healthy battery to connect it the bad ryobi battery,

Connect the positive terminal to positive terminal and negative to negative terminal.

Let it stay connected for around 15 seconds.

Now, try to charge it again and the ryobi charger should start charging normally.