Dewalt battery packs differ between types of rechargeable cordless tools. Cordless tools come in a variety of sizes and power source needs. Cordless drills require a larger battery pack than a small tool, such as a cordless screwdriver. Regardless of the type of tool or size of the Dewalt battery, each battery pack can be reconditioned to work like new. Fixing a Dewalt battery pack is challenging, but it will prolong the life of your cordless tool.
Remove the Dewalt battery pack from the Dewalt cordless tool. Use a small screwdriver to open the Dewalt battery case. Set the screws aside for later reassembly.
Pull apart the Dewalt battery case to reveal an internal chain of linked rechargeable batteries.
Copy down the polarity pattern on how the cells are linked together on a piece of paper.
De-solder each battery connection.
Test each battery with a battery tester to determine which cells are bad. Mark each cell to be fixed.
Locate the negative end of the first battery to be fixed. This should be the flat end of the battery.
Prepare to "zap" the cell back to life using the 12-volt power source. Hold the black alligator clamp to the negative end of the battery while holding the red alligator clamp to the positive end of the battery. Hold this link for no longer than two seconds.
Remove the alligator clamps and test the individual battery cell to see if it has been recharged. Repeat the process if necessary.
Repeat this process on other cells within the chain than need reconditioning.
Reattach the reconditioned Dewalt batteries by resoldering them back into the chain.
Replace the linked cells into the Dewalt battery case. Once the batteries are in place, screw the case closed.
The battery may "spark" when it is being zapped. Take the necessary safety precautions to protect yourself, such as protective eyewear and work gloves. The battery can leak acid, catch fire or even explode if mishandled during this process.