How to Charge the Drill Battery without a Charger?

About How to Charge the Drill Battery without a Charger, Cordless drills come in handy when your work site has no power outlets nearby. 

They also help in drilling in places where you may not reach with ordinary drills. 

To work, these drills will need rechargeable batteries so that plugging the system with the wire is not a problem for you. 

Every cordless drill comes with its battery charger by default. But what if you forgot to pack it during travel or lost it somewhere? 

You need alternative methods to charge the battery.

In this article, we will look into the concept of a drill battery power along with other methods you can opt for to charge it. Let’s dig into the details. 

Understanding Cordless Drill Battery Charging

Cordless drills use batteries for power rather than using electric plugs. 

These batteries can be either Nickel Cadmium (NiCd), Nickel-metal Hydride (NiMH), or Lithium-ion (Li-ion) type.

 Also, they can be in different shapes, sizes offering voltage of either  12V or 18V. 

To get the correct version of the battery for your cordless drill, you must understand each type. 

Moreover, as the type changes, the way of charging will also change.

How to Charge the Battery with its package charger?

To charge the battery of a cordless drill with a charger that comes with the product, follow these simple steps.

  • Press the rectangular red button on the front of the battery and hold it down. Slide away the battery from the drill. 
  • Connect the charging lead to the battery using the socket on it. Plug its other end into the nearby 13A electric plug and turn the switch on.
  • As the battery starts charging, the light on the battery will turn red. The red light indicates that the charging is low and as it gets full, it will turn green.
  • After full charging, put the battery pack back into the drill base and set it. As you hear the sound of a click, leave it as the battery is fixed properly.

The science behind charging a battery

Rechargeable batteries can be charged to their full potency by providing 12V to both ends. 

For that, you can use charging leads and attach the positive to the positive terminal and the negative to the negative terminal. 

However, if you are using a variable voltage source with less potential difference than required, the battery will not start charging. 

As the potential difference rises to the rating of the battery, then the battery will start to pick up charges. 

If you look more into the concept, you will see that applying a higher voltage to a battery than its current value makes the charging process faster until both reach the same level. 

For instance, if the battery is now at 6V, it needs charging; connecting it with a charger that provides 12V will fasten the charging process until the battery reaches 12V. After that, the process slows down. 

The concept of “Fast Chargers” use the same phenomenon. They provide a voltage higher than the needed of a rechargeable battery and decrease the speed of energy transfer as soon as the potential difference is lower.

Man holding cordless drill

Caption: Man holding cordless drill

Standard Un-Balance Charge vs. Balance Charge

One Lithium-ion battery has a rating of 3.7V. The highest charging voltage it can endure is 4.2V, while the lowest discharge is 3V. 

It means the cells are not supposed to charge beyond 4.2V. While discharging, the cell should not be less than 3.0 in voltage.

Lithium-ion batteries in cordless drills can provide up to 12 to 18V. How? By using the 3.7V cells in series or parallel.

The combination of cells in series affects the voltage aspect of the battery, while when in parallel, it affects the amp-hour rating of the battery and the time it will last.

Moreover, multiple pins on a battery connect the charger to each cell stack to charge it properly. 

That way, every cell group has access to the incoming voltage. 

Standard Charge

Standard charging refers to the process where you apply the voltage to the terminals of the battery and wait for it to charge. 

This is a simple process and requires the correct assembly of wires.

For proper connection, make sure to attach the positive of the battery to the positive of the voltage source and the negative of the battery to the negative of the voltage source.

Additionally, for safe charging, use a 12V voltage source with a Lithium-ion battery. Although 12.6V won’t hurt the battery, it is still not recommended.

Balance Charge

Balance charging uses a different method from standard charging. To achieve this method, you will need a special balance charger with control features for balancing many parameters.

You can use these chargers for multiple battery types, including Nickel Cadmium, Nickel Metal Hydride, and lead.

The balance chargers charge each cell stack and keep them on the same level until the whole battery has full charging ( 4.1-4.2V).

This is not possible to attain by yourself as such batteries have difficult infrastructure to understand. Thus, you will need a balance charger at any cost.

How to Charge a Drill Battery Without a Charger?

Battery for cordless drill

Caption: Battery for cordless drill

Suppose your cordless drill doesn’t come with a battery charger, or you have lost it somewhere. Then, you can opt for the following methods for charging the battery. 

Assemble a homemade Charger.

For making a charger at home, all you need is a pair of jumper cables, a voltage source, wires, and a heat shrink tube. 

With those, you can start making your charger with these steps.

  • Attach one end of the positive and negative jumper cable with the corresponding terminals of the voltage supply. Put the other end of these cables into the cordless drill battery terminal.
  • Take an electric wire and attach one end to the center terminal of the voltage supply and the other to drill the battery. Press and fix all the connections firmly.
  • Connect the voltage supply to the nearby plug, and adjust the voltage according to your battery. Let the batter charge for a few minutes. 
  • As the battery is charged fully,  unplug the voltage supply from the electric outlet and disconnect all the wires.

Use Car Battery

If you have a car in your garage, it can be the best source to charge your drill’s battery. It is because both batteries have the same rating of 12V, and thus can be a perfect match.  

Using a car battery is simple. For that, you will need a pair of wires to connect the terminals of both batteries.

Just link the positive terminal of the car battery to your drill battery’s positive and negative of the car battery to the negative of your drill battery. 

Use a Laptop Charger

Laptop chargers can provide up to 18 to 20 V of power. To use it with the drill battery with an 18 voltage, you need to get a female connector that you can solder with the inside of the laptop charger.

Cut a hole for this connector to fix; that way, you can charge the drill battery easily.

Also, you can get a two-pin external connector and align the wires by setting positive to positive and negative to negative.

Charge the battery using 1.5V AA Cells.

If any emergency occurs, you can use 1.5V AA cells and set them in series to compensate for the required.

 For example, you will need 9 cells connected in series that will give 13.5 V, sufficient for a 12V battery. Also, you will need 13 cells to make 19.5V to charge an 18V battery.

Use Cheap Voltage Adapters

If you have cheap voltage adapters laying around the house for old Bluetooth speakers etc, you can use them for battery charging.

The only thing you need is to check the rating of both the charger and the battery of the cordless drill. 

These adapters are not expensive and will help you cut the cost of buying a new charger.

Charge with another Drill Battery

Charging the drill battery with another fully charged one is a great hack in need.

For instance, if you have another drill that uses a different type of charger, then you can charge your battery directly with it. 

Again, the process is the same, connect the same polarity terminals with jumper cables. Also, see that both batteries have the same voltage and the other battery has full charging.

It may not be a solid solution, but it can work perfectly in an emergency.

Get a Solar Panel

The solar panel can provide unlimited access to power since it uses inevitable energy from the sun.

The DC voltage from the solar panel may not be constant; however, it will be sufficient for charging your battery.

Before purchasing one, ensure it is rated for charging a 12 or 18-V battery. Most solar panels with a 12V rating can provide up to 17 or 18 volts that can regulate down to charge a 12V battery. 

Additionally, using an MTTB controller can also help you regulate the voltage. Just ensure that the batteries do not get too hot and explode.

Use a Car Charger

12V charger attached to cigarette switch in the car

Caption: 12V charger attached to cigarette switch in the car

You can also charge a drill battery inside your car using a car charger that plugs into the cigarette socket and connects to the battery. 

This simple method allows you to recharge the battery anywhere you are on the go. But, for the efficiency of this method, you need to invest in car chargers from the same company as your drill. 

Many big companies like DeWalt, Bosch, and Makita have come up with branded car battery chargers with compatible plugs.

To connect the charger, plug it directly into the car cigarette compartment. This will ensure the charger gets all the juice it needs to buckle up the drill battery. 

Attach the other end of the charger to your drill battery, which is a pretty simple process. 

Now, the power socket may work if the car is off. But it is better to start the engine on since with the engine off, and the battery will charge using car battery power. 

Hence, the engine will also start the alternator so that the car battery doesn’t drain.


Charging a cordless drill battery when no charger is available may not be as impossible. 

With the above hacks on hand, you can work with the components laying in your garage and juice up the drill battery for your next use.

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