What Jump-Starting a DeWalt Battery Means
Jump-starting a DeWalt battery is a technique to revive a battery pack that has lost its charge so completely that the charger won't recognize it. When a lithium-ion battery drains entirely—often from sitting unused for months or from a charger malfunction—the internal protection circuit can lock the battery in a dormant state. A jump-start bypasses this by forcing a small amount of current back into the pack, waking up the internal electronics so the charger can take over again.
This is different from straightforward recharging a dead battery. A truly dead battery will sit on the charger with no lights, no response, and no sign of life. Jump-starting it takes about 10 to 15 minutes and uses another working DeWalt battery or a basic power supply to send current through the pack's terminals. After that, the charger should recognize it and begin a normal charge cycle.
Key Takeaways
- A completely dead DeWalt battery will not respond to the charger until you send current through its terminals to wake up the internal protection circuit.
- You can jump-start using another working DeWalt battery of the same voltage, a 12-volt power supply, or a bench charger designed for this purpose.
- The process takes 10 to 15 minutes and involves connecting the positive and negative terminals of the dead battery to a power source in a specific order.
- If the battery still will not charge after jump-starting, the cells inside may be damaged and the battery cannot be revived.
Gather the Right Equipment Before You Start
You will need a working power source that matches your battery's voltage. If you have a second DeWalt battery of the same voltage (20V, 60V, or whatever your pack is rated for), that is the easiest option. Alternatively, a 12-volt power supply, a car battery with jumper cables, or a bench charger with a jump-start function will work. Do not attempt to use a higher-voltage source—jumping a 20V battery with a 60V pack will damage it.
You will also need two pieces of wire or two jumper cables with alligator clips on both ends. If you are using a car battery, you likely already have jumper cables. If you are using a power supply, you may need to strip about half an inch of insulation from each end of two wires so they can make contact with the battery terminals. Wear safety glasses and work gloves—battery terminals can spark, and lithium-ion batteries can be hot if they have been recently in use.
Identify the Battery Terminals and Prepare the Connection
DeWalt batteries have two metal terminals on the bottom or side of the pack. The positive terminal is usually marked with a plus sign (+) and is often slightly raised or a different color. The negative terminal is marked with a minus sign (−). Before you connect anything, inspect both terminals for corrosion, dirt, or damage. Wipe them clean with a dry cloth if needed.
Lay the dead battery on a flat, non-conductive surface—a wooden workbench or rubber mat is ideal. Position your power source (the working battery or power supply) nearby so the wires or cables can reach both batteries without strain. If you are using a car battery, position it so the cables can reach comfortably. Do not let the metal clips or wire ends touch each other or any metal part of the tool or charger while you are setting up.
Connect the Positive Terminal First, Then the Negative
This order matters because it reduces the risk of a spark. Take the positive wire or cable and connect it to the positive (+) terminal of the dead battery first. If you are using jumper cables with alligator clips, clamp it firmly so it makes solid contact. Then connect the other end of that same wire to the positive terminal of your power source (the working battery or power supply).
Next, take the negative wire or cable and connect it to the negative (−) terminal of the power source first. Then connect the other end to the negative terminal of the dead battery. This reversed order for the negative connection—power source first, dead battery second—is the standard safety practice and reduces sparking. You should now have a complete circuit: positive from dead battery to power source, and negative from power source back to dead battery.
Wait and Monitor the Jump-Start
Leave the connection in place for 10 to 15 minutes. During this time, current will flow into the dead battery and begin to wake up its internal protection circuit. You may see a small light on the battery pack illuminate, or you may hear a faint click inside the pack as the circuit comes to life. These are good signs. Do not touch the battery or wires during this wait—they may become warm, which is normal.
If the battery becomes very hot to the touch (too hot to hold for more than a few seconds), disconnect when ready. This can indicate an internal short circuit or cell damage, and continuing could be unsafe. If the battery remains cool and you see no signs of damage, proceed to the next step after 10 to 15 minutes have passed.
Disconnect and Test with Your Charger
Disconnect the negative wire from the dead battery first, then disconnect the negative wire from the power source. Next, disconnect the positive wire from the power source, and finally disconnect the positive wire from the dead battery. This reverse order prevents sparking and is the safe way to break any electrical connection. Set the power source aside.
Place the jump-started battery on your DeWalt charger. If the jump-start worked, the charger should now recognize the battery and show a charging light or indicator. The battery may charge slowly at first, especially if it was deeply discharged. Let it charge for at least 30 minutes before removing it. If the charger still shows no response—no light, no sound, no sign of recognition—the battery's internal cells may be damaged beyond recovery, and jump-starting will not help.
Prevent Future Deep Discharge
Once your battery is charged and working again, avoid letting it drain completely in the future. Store DeWalt batteries in a cool, dry place with at least a partial charge. If you know a battery will sit unused for more than a month, charge it to about 50 percent and store it that way. Chargers left plugged in with a battery on them can also slowly drain the pack over time, so unplug the charger when the battery is fully charged.
If you use your tools regularly, rotate between batteries so no single pack sits dormant for long periods. A battery that is used every few weeks is far less likely to enter the deep-discharge state that requires jump-starting. If you have multiple batteries, label them by date so you know which ones have been sitting longest.
Frequently Asked Questions
Can I jump-start a DeWalt battery with a different voltage?
No. A 20V battery must be jumped with a 20V source, and a 60V battery with a 60V source. Using a higher voltage will damage the internal circuits and may cause the battery to fail permanently or catch fire. If you do not have a matching-voltage power source, take the battery to a DeWalt service center or retailer—many will jump-start it for you.
What if the battery gets hot during the jump-start?
Disconnect when ready. Excessive heat during jump-starting usually means there is an internal short circuit or cell damage. Continuing could cause the battery to fail or become unsafe. Let it cool for at least an hour, then try again with a fresh connection. If it heats up a second time, the battery cannot be revived and should not be used.
How long does it take to jump-start a battery?
The jump-start itself takes 10 to 15 minutes. After that, place the battery on the charger and let it charge for at least 30 minutes before using it. Full charging may take several hours depending on the battery size and charger model.
Will jump-starting damage a battery that is not completely dead?
No. If a battery still has some charge and the charger recognizes it, you do not need to jump-start it—just charge it normally. Jump-starting is only for batteries that are so deeply discharged the charger will not respond at all. If you jump-start a battery that still has charge, no harm will come to it.
What should I do if the battery still will not charge after jump-starting?
The internal cells are likely damaged. A battery that does not respond to jump-starting and does not charge afterward has reached the end of its life. Contact DeWalt customer service or visit a retailer to discuss replacement options. Some retailers offer recycling programs for old batteries.