Can You Charge DeWalt Batteries With A Generator?

The best aspect of owning cordless power tools is having the ability to use them far from an electrical outlet. But what if you wanted to use your cordless DeWalt power tools, ranked as one of the best power tool brands, completely off-grid to the point that the batteries became depleted?

If you have a generator and you're not using an old DW9106 model DeWalt battery charger, you're in luck. DeWalt says that all its battery chargers, except for the DW9106, can compensate for any variances in amperage or voltage delivered by a properly operating generator.

In the past, DeWalt has employed a few battery systems with various voltages, including 7.2, 9.6, 12.0, 14.4, and 18 volts. DeWalt's current battery voltage lineup includes those with 12, 20, 60, and 120 volts, with storage capacities ranging up to 15-amp hours.

The DeWalt 20V MAX*/60V MAX* Flexvolt Fast Charger charges batteries at 12 amps. Any gasoline-powered generator at or above an output of 1,000 watts will easily provide enough power for this or any other suitable DeWalt battery charger.

While having the ability to charge your DeWalt batteries using a generator opens up a lot of possibilities, there are some things you should know that'll help you obtain the best results. If you'll be packing your batteries for a trip to an off-grid jobsite, you'll need to ensure that the battery terminals cannot come into contact with any materials that could cause a short circuit, which could result in a fire. 

DeWalt offers a prescribed method for charging batteries to ensure optimal run-time of its power tools. First, the battery should be discharged under normal use until there is a tangible loss of power from the tool; do not continue using the battery until it is completely discharged. Next, the battery should sit out of the tool and charger for at least two hours or until the battery has reached room temperature. Finally, charge the battery at room temperature for at least eight hours to ensure each individual cell is fully charged; it's even acceptable to leave the battery on the charger for extended periods between uses.

One thing you'll want to consider, as mentioned in the charging procedure, is the temperatures at which your batteries will charge. While room temperature is best, the range of acceptable temperatures is quite broad. Charging DeWalt batteries at temperatures colder than 40°F or warmer than 105°F can result in a partial charge and/or damage to the battery cells that can lead to a loss of run-time.