You did not say what kind of battery they are. Most lithium batteries will die if they go lower than a certain voltage. Going to zero volts will do that. That can happen when you leave the drill in the garage, where its not only hot which is not good, but not using the battery for long times it will drop in voltage until it stops working altogether. There are ways to try and repair the batteries but it is a dangerous thing to do if you do not understand. I can't share that with you because it can be dangerous. You may need to search Ebay for a new battery, and be sure to keep it charged and out of the heat of a garage. The battery charger should not indicate that the batteries charged, it should indicate and error. So your question did not give enough details for me to give you anymore information.
Answers & Comments
You did not say what kind of battery they are. Most lithium batteries will die if they go lower than a certain voltage. Going to zero volts will do that. That can happen when you leave the drill in the garage, where its not only hot which is not good, but not using the battery for long times it will drop in voltage until it stops working altogether. There are ways to try and repair the batteries but it is a dangerous thing to do if you do not understand. I can't share that with you because it can be dangerous. You may need to search Ebay for a new battery, and be sure to keep it charged and out of the heat of a garage. The battery charger should not indicate that the batteries charged, it should indicate and error. So your question did not give enough details for me to give you anymore information.