If you have a rechargeable battery on your cordless hand drill and it no longer charges fully, you can take steps to energize your battery so it will work for you. This is a cost effective way to prevent replacing the battery with a new one or avoid buying a new hand drill.
Remove the screws that hold the battery pack housing together with a screwdriver. Place the screws off to the side and lift the top off the battery pack to expose the battery cells inside the housing. As a note, be cautious when you pull the cover off the battery pack. A small spring under the top is likely to pop up when you remove the cover.
Write down the position of the battery cells and the positive/negative terminals and where they connect to the housing. You will need this for installation.
Lift the battery cells out of the battery pack housing. They are often in a single unit.
Slide the terminals off the battery pack housing with needle-nose pliers.
Place the replacement pack of battery cells into the battery pack housing. You can purchase the cells from the battery manufacturer. Position the battery cells in the same manner as the originals were placed.
Slide the battery terminals onto the housing for the battery pack. Make sure they seat all of the way onto the housing with the pliers.
Place the cover back onto the housing and secure it with the screws.