Twice I have experienced Ryobi Lithium batteries going dead. They refuse to accept a new charge from the Ryobi charger. In my case, we’re talking about the 18v batteries for a weed-whacker/leaf-blower.
I found some remedies online which did not work (plugging and unplugging the battery for 30 minutes) Are you serious? That’s not going to work for me. What does work, is warming up the battery to improve its efficiency, and then beginning a charge cycle.
Here’s how to reset your Ryobi battery easily
To reset the Ryobi battery
Total Time: 15 minutes
Turn on your oven and set it to 150 degrees
DO NOT ATTEMPT THIS IN A MICROWAVE OVEN
Place the battery in the oven
Wait for 10 to 15 minutes
Remove the battery from the oven and place it in the Ryobi charger
In my case, this is all that was needed to get the charging process going.
Good luck with this tip! Hope it works for you as it did for me.