So you have cordless batteries that have died out. Is it time to buy new batteries? Not necessarily. If your cordless batteries are nickel metal hydride (NiMH) or nickel cadmium (NiCad) then there is a more practical solution available to you. Cordless battery reconditioning can save you a lot of money and make your NiCad and NiMH batteries work again like new. Here's how:
Remove the battery pack from the drill and then identify which of the leads is positive and which is negative. Place a distinctive mark on the positive lead to make it easier for you to put your battery back together after reconditioning is completed. Remove the screws from the battery case to get to the battery cells. Take note that the inside spring tends to pop out as you open the case, so be very careful not to lose it. Keep the screws and inside spring in a small container while you are reconditioning the battery.
12 Volt Drill
Once the battery cells are revealed, pull them completely out of the casing. Mark the points where the wires need to go, so you won't have problems in reassembling the battery. Use a pair of needle-nose pliers to remove the battery's terminal piece. Be careful not to let any of the wires touch during this process as this poses a risk of explosion or electrical shock. Place the terminal piece into the container holding the screws and inside spring.
The metal band you have just exposed will become hot when you start reconditioning the battery, so be sure to insulate it with electrical tape. Remove the cardboard insulation that covers the battery cells and set it aside. If the cells are shrink-wrapped together, cut the wrap such that you expose the bottom and top of the battery leads. Once the battery leads are exposed, test each battery cell to see which ones need reconditioning.
Now that you have identified the battery cells to be reconditioned, you may prepare a 12-volt power source and put on protective gear and eyewear. Position the alligator clamps of your power source; black clamp against the negative and red clamp against the positive end of the battery. Hold the clamps in their respective positions for about two seconds and then remove them. Check to see if the battery took the charge before moving on to the next cell. You may have to zap a cell more than once before it takes the charge. If you have zapped a cell ten times and it still does not take the charge, it will have to be replaced.
After all the dead cells have been reconditioned, you may reassemble the battery pack and then place it into the cordless drill battery charger. Overnight charging should serve to get your battery pack back into shape and working like new. So, you see, buying replacements shouldn't be your first option when your cordless batteries die out. Cordless battery reconditioning is an easy DIY project and a much less expensive option to boot.