craftsman drill charger light is on but my battery isn't charging. what do i do?

First, check for poor connections or a damaged battery.

1. Disconnect the charger from the outlet.
2. Remove the battery from the charger. Inspect the battery terminals and charger contacts for dirt, grease, or debris. Clean with a dry cloth only.
3. Check the battery case for cracks, punctures, or damage. Do not insert a damaged battery into the charger.
4. Reconnect the charger to the outlet and reinsert the battery firmly.

If that didn't work: You are using an incompatible charger. You must recharge only with the CRAFTSMAN charger specified for this V20 battery pack. Using another charger creates a risk of fire.

Final cause: The battery pack is defective or completely depleted from long storage. Battery packs should not be stored completely empty. If it's damaged (dropped, stepped on, pierced), do not charge it. Return it to a service center.