How to Test a Cordless Drill Battery Charger


A drill is a machine used to create a hole through any hard surface. Usually, holes created vary in diameter depending on the blade size of the drill. Drills in the past had cords as they depended on and electricity to run. That is in the past; now, you will find that the majority of drills are cordless.

Although they do the same job, cordless drills depend on a rechargeable battery to run. Cordless drills usually experience battery issues, depending on how they are used. Sometimes that drill won’t hold a charge, or the battery will refuse to charge. In this case, you have to find out if the problem is with the charger or the battery. Below I will show you how to test your battery charger with the best automotive digital multimeter.

What you will need to test your cordless drill battery charger

You will need either a voltmeter or a multimeter. A voltmeter mainly Measures the number of volts in a given circuit. Since most cordless drill battery chargers are rated in volts, then this device can work for you.

However, I would strongly suggest you use a multimeter because it can measure a variety of things. A multimeter can measure both volts and amps. With the best automotive digital multimeter, you can also get to measure capacitance and resistance, among other measurements. When using any of the two devices, remember to set your device to AC when testing the charger and DC when testing the battery.

Other things you will need are an electrical source, rubber gloves, and the battery charger that you want to test.

How to test your cordless drill battery charger

Step 1. Check the voltage rating of your battery charger. Voltage should be indicated on the label on the charger.

Step 2. Once you determine the voltage rating, set your multimeter to the same rating, or exceed the charger voltage a little. For example, if the charger voltage rating is 12, set the multimeter to 12 as well. If it is 20, then set the multimeter to 24 volts.

Step 3. Plug the drill battery charger into your electrical source.

Step 4. Touch the red wire of the multimeter to the Metal terminal base marked plus/positive on the charger.

Step 5. Do the same with the black wire this time make it touch the metal terminal base marked minus/negative.

Step 6. Read the voltage rating shown on the multimeter. The voltage Reading should be slightly higher than that of the charger. The charger should show a higher voltage because it is what is needed for a charger to charge the battery quickly.

Step 7. Increase the voltage reading is lower than the charger’s actual voltage rating, then the charger is faulty. In some cases, there will be no reading at all.

If you find the charger is faulty, then you need to get a new one. However, if you test the charger and find out it’s not broken, then the problem is with the battery. NiCad rechargeable batteries are the most common batteries in cordless drills, and Usually, Encounter issues after a while of use. You can get to restore the battery instead of replacing it when it doesn’t hold a charge or becomes faulty.

How to repair a NiCad cordless drill battery  

Sometimes you may leave your battery charging for long hours, or you use it lightly after charging it to capacity. The cadmium in the battery will start to form crystals when such incidents happen. They continue to grow as you use the drill. The crystals have sharp edges, which will cause the battery to experience problems.

That brings us to how you can help your battery restore its original state. You can get to repair it by choosing any of the two methods. Let me take you through both ways below.

The first method

Clean and dry the battery. Once you are sure it is dry, place it in a clean and dry freezer bag. Place the bag in your freezer and let it stay overnight.

Remove the now-frozen bag with the battery from the freezer. Once it’s out, remove the battery from the pack and dry off the moisture on the battery.

Now once it’s dry, tap the battery once firmly on a workbench or any other Stables surface. Doing this will break the Crystals. Wait for the battery to reach room temperature. Then charge it and begin using it like before.

The second method

Charge your battery to full capacity.

Once it’s full, place it into the drill and then have a vice to grip the trigger in the drill so that it can continue operating nonstop. You can decide on any tool to grip the trigger.

Let the drill continue running until it stops on its own. Once it stops, remove the vise holding the trigger.

Wait a few minutes, preferably 30 minutes, and then pull the trigger again. The motor will start to run again. Pull the trigger until the motor stops running again.

Do this until you pull the trigger, and the motor doesn’t run at all. This will mean that the battery is now empty.

Once you drain out the battery completely, the crystals formed will break and go back to their original state. Charge the completely drained battery and then start to use it like before.


If you own a cordless drill, then the chances are that you have gone through some frustrating moments with the battery. To overcome such problems, you can go for the best automotive digital multimeter, which will maintain more than just your battery charger.

As you have already seen, diagnosing your battery charger is very easy. You can now get to save money than spend it on repairs or replacing the battery. I hope my guide has helped you learn a few things about your cordless drill battery charger and battery as well.

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