Anyone that has a cordless DeWalt tool like I do is bound to run into issues with the battery sooner or later.
But, in most cases, issues related to DeWalt battery can be fixed easily by using the trick as shown in the video below.
Just try to “Reset” the battery using the two cables.
If the above trick did not work, here’s a list of some other things you should do.
DeWALT Battery Not Charging and No Light Issue
- Loose Connection or Damaged Charging Cable
First things first, I want you to check if it is DeWalt charger related problems.
If you have another DeWalt battery, try to see if it works on this charger.
If you don’t have one, at least try to inspect all parts of the charger for any visible damage, and use a multimeter to check if its drawing power.
One more thing I want to say is that you should check the connection point where the cable starts on your charger as shown in the image below.
Take the covers off and inspect the same electrical board I’ve highlighted.
The wires here should be perfectly attached to the two points below.
- Power Source Issues
This tip speaks for itself. Your DeWalt battery is not going to be charging if the power source is faulty.
Plug the charger into any other socket available and see if that works.
- Overheated Battery or Battery Charger
Another straightforward but important thing I want you to keep in mind is the intended temperature of the battery.
You can see pretty clearly how my DeWalt battery charger can only operate at temperature range of 4 to 40 degrees Celsius.
Anything below or above this will stop the battery from charging as it would trigger the Hot Cold Delay.
In that case, the DeWalt charger light would blink fast.
If you find that it overheated or is too cold, keep the battery in a suitable environment and try charging it again a day later.
- Faulty Battery
If the previous solutions weren’t much help, it’s time to start looking at the battery as a potential problem.
DeWalt batteries like the one I’ve pictured below usually only last a few years before they start going bad.
You can check the year which the DeWalt battery being manufactured as shown in the image below.
My DeWALT battery was manufactured in the Year 2021.
If you’ve had your battery for more than 3-4 years, it could be that it died. This is usually the expected lifespan of these devices, and people need a replacement afterward.
Old unhealthy battery always cause issue like unable to hold charge and cannot fully charge the DeWalt battery to full bars.
Before that, to identify if the battery itself is supplying enough voltage, you may refer to my video below on how to measure the voltage of the DeWalt battery using multimeter.
In my case, the battery used in the video above is a 20V DeWalt battery.
The voltage measured should be between 18V to 20V.
If the output voltage is much less than its designed voltage, that’s mean some individual battery cells could be in trouble.
What you can do in this case is to replace the faulty individual battery cell with a new one.
Here’s the video on how to measure and identify bad individual battery cell.
Each healthy battery cell should provide around 3.6V of voltage.
Alternatively, wiring inside of the battery could be the issue. Check the points I’ve highlighted in the image below on your own DeWalt battery after taking the covers off.
Do they look the same? Are any of yours detached?
If they are, that means this is where your problem lies. You’ll need to fix the wring so the battery can charge properly.
- Battery Contacts
DeWalt batteries and chargers work on a contact pin system. These contacts are what I’ve marked in the image here.
The battery and charger both have them, and they slide perfectly into each other.
I took another photo too, to show you the ones on the DeWalt charger itself. This is where you attach the battery to charge.
If these pins ever get damaged, the battery, or the charger, that will mean that power can’t be transferred between them properly.
The pins are responsible for making a connection between all of them, so you need them in perfect condition for the battery to charge.
- Faulty Charger Indicator
The charging indicator on my DeWalt charger has 3 different messages, as you can see here.
- The top message, where only one light is flashing, means that the battery is currently charging.
- The second message, where one light is stable, means that the battery is fully charged.
- The last message, where both lights are on and one is flashing, means that the battery’s temperature is reaching unsafe levels.
If you don’t see any of these lights at all, that means something is wrong with the indicator itself.
It could mean that your device is actually charging, but the charger indicator has no light so you can’t figure out if it’s charging or not.
Remove the cover from your DeWalt charger and check these LED lights out.
Make sure neither of them are broken or burnt out, as they’re what lighten up the indicator.
- Charger Voltage Mismatch
One last thing that comes to my mind is the voltage being transferred to the battery.
It’s possible that the charger provide too much or insufficient voltage to the battery, causing it to stop working and not charge the battery.
You can see below how my charger has limits of 22V marked for its output.
Then the suitable battery that charged on it should be able to received 22V direct current as its input voltage.
Besides, my model of DeWalt charger above can only receive 220 – 240V as input power source.
This model of DeWalt charger is not compatible to be used in countries with outlet voltage of 100 – 100V, like the United States, Japan, etc.
Make sure to get a compatible model of charger for your country!
The battery has limits, too, as you can see below, around 18V to 20V output voltage.
My battery below does not show how much input voltage it can accept to charge it.
But, around 20V to 22V voltage should be appropriate to charge it.
Before that, I would like to mention that I conducted an experiment to test whether DeWALT 20V battery is compatible with Black & Decker since they are from the same company.
The answer is No.
So, always use a compatible battery no matter on the tool itself or on the charger!
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