20-Volt DeWalt Battery Won't Charge? This Might Be Why

Lithium-ion batteries have been a game-changer in the power tool world, which is why the major brands out there have widely adopted this technology. DeWalt is one such brand that has gone all-in on wireless, battery-powered tools, finding great success in doing so. The batteries can power all kinds of tools and charge quickly, and DeWalt chargers themselves can communicate with you through lights. However, that's not to say that the brand's offerings are perfect; as with any tech, issues are bound to arise. One issue that can come with 20-volt DeWalt batteries is that, for seemingly no reason, they'll fail to charge.

Unfortunately, there isn't a one-size-fits-all explanation for why a DeWalt 20V battery won't charge when placed on the charger as directed. Over on the DeWalt Support website, many theorize that a lack of quality control is the issue. Faulty batteries make it onto the market, and folks unwittingly buy them, none the wiser that they're defective. Most lithium-ion batteries last between two and three years or 300 to 500 charge cycles, so the age and condition of the battery should be considered, too. Alternatively, the problem could lie with the charger, which could be either defective from the factory or worn out after years of use.

While these are the most likely reasons for a lack of charging, there's another factor to consider. Some have pointed out that compatibility between chargers and batteries can also lead to problems.

In the grand scheme of power tool tech, DeWalt batteries and chargers are as simple as can be to use together. All you have to do is slide the battery onto the charger, and the lights will signify to you that charging is underway. When this doesn't happen, it's easy to think either element is somehow defective, incapable of charging or being charged. As it turns out, though, according to some anecdotes from DeWalt users on Reddit, it's possible that neither component is a lost cause. Instead, a lack of charging could stem from even the slightest gap between the battery and the charger, which prevents the transfer of energy.

"The new batteries don't seat well in the charger. I had to press the battery release button and push the battery in really hard. My older non-XR batteries just slide right in and that's what I was expecting," commented u/trknik after struggling to get their new DeWalt battery to charge. Others in the thread noted that this is an issue they encountered as well, having to more consciously push their battery onto the charger to initiate charging. While this solution might not work for everyone, it seems to be common enough that it's worth keeping in mind if you're having charging issues.

Of course, this is far from the only solution when it comes to resolving charging problems. There are a few different ways you can get your DeWalt tools — and even non-DeWalt tools that work with DeWalt batteries — back up and running with a fully charged 20-volt battery.

If you've encountered a battery that won't charge or a charger that won't work, there are a few avenues to take. The first and most straightforward option is to replace the faulty item entirely. If it's covered by one of DeWalt's warranties, this should be fairly easy. Just contact DeWalt's customer service at 1-800-433-9258 or submit a request online, and go from there. 

If you don't want to go through all that hassle, though, you can try to fix the issue yourself. If the charger is the problem, try cleaning the contacts, plugging the charger into a different outlet, inspecting the cord for damage, and, if you are able, repairing it.

As for fixing a bad battery, this is where things get a bit trickier. You can try jumping the dead DeWalt battery using a live one, as demonstrated by Hammer and Home on YouTube. The principle is similar to jumping a car battery, with you attaching the positive and negative battery terminals via wires. You let them sit for a bit, then test the dead battery on the charger. With any luck, it should be revived and capable of charging again. It should be noted this process can get a bit dangerous due to the electrical currents involved, so if you do try it, make sure to wear proper eye and hand protection throughout. 

As great as they are, lithium-ion batteries have their share of problems and disadvantages. Sometimes, even batteries from a trusted brand like DeWalt won't charge. At least if you can't fix the problem, getting them replaced at little to no cost is entirely possible.