How to connect a charger to a screwdriver

Can an electric screwdriver be plugged directly into the charger

An electric screwdriver is convenient for its ubiquity. Independence from limiting wires makes it possible to get into hard-to-reach areas. A set of two power modules allows you to power one while working with the other. However, each battery pack has a finite number of charge/discharge periods, failing once they are used up. In low-cost tools, the blocks break faster, and the user gets a gadget with a functioning motor, but no power. Then there is the dilemma of “can an electric screwdriver be connected directly to the charger”.

Such an electric screwdriver can be powered by connecting it to the mains via a power hub, because its motor runs at 220 volts.

General circuit and current consumption of 12, 14 and 18V screwdrivers

Screwdrivers of different manufacturers are constructed on different element base, but the structural electric scheme at all approximately identical. The power tool consists of:

  • The battery is removable;
  • control board;
  • trigger switch, combined with the speed regulator;
  • frequency control range switch (may not be present);
  • an electric motor (collector or brushless).

When making a power supply for an electric screwdriver with your own hands, you should pay attention to two parameters:

The voltage is simple: the new power supply must have an output voltage equal to the rated voltage of the power tool. Decrease leads to loss of torque, increase. to reduction of service life. Under-voltage operation is not guaranteed, over-voltage operation may cause damage to the control card.

It is more difficult to determine the necessary operating current. Power tool manufacturers very rarely indicate the current consumption. Slightly more power in watts. But on the nameplates of the screwdrivers you can find the following data:

This data looks sufficient to calculate the operating current.

The name plate with the electric characteristics of the electric DEKO DKCD20FU screwdriver.

In fact, everything is not so rosy. If we take the data from a real electric screwdriver and try to calculate the rated current, we get an absurd result.

First, the output power is calculated using the formula:

  • P. power, kW;
  • T. torque, N/m;
  • RPM. rotational speed, rpm;
  • 9550 is a factor that combines the conversion from one unit to another.

This power to be developed must be divided by the efficiency factor (about 0.8), resulting in a power consumption of about 7 kW. At 20 volts, the batteries should give a current of 350 A. At 2 Ah capacity, the battery will discharge in 20 seconds (if even theoretically the battery will provide this current). This is the promised absurdity. This can be caused by misleading rpm or torque declarations. Perhaps the highest torque is only produced at a certain speed, but even if you know it, there is little practical sense. After all, an electric screwdriver works at different frequencies.

Therefore, you should be guided by the following figures obtained experimentally:

  • No-load current of 1.2 amperes;
  • average load. 4.6 А;
  • the maximum load is 8.11 А;
  • current surges at full braking. up to 30A.

To specify these figures for a particular electric screwdriver, you can measure real current consumption in different modes, making a simple circuit and driving the power tool under different loads.

Consumption current measurement diagram.

Or, instead of specifying, refer to the above figures. The power supply unit is needed on the maximum current of 10 A (but not less than 5 A).6), preferably with overcurrent protection.

What is needed for conversion

To remake an electric screwdriver, you should briefly familiarize yourself with the wiring diagram of the tool. Tool is driven by an electric motor. Depending on power and class of tool, voltage may be 12, 14, 18 volts. Electric motor is powered by a battery of accumulators with corresponding voltage.

The motor transmits the torque to the chuck through a mechanical gearbox. Engine speed is controlled both by a geared gear system and a reversible electronic speed regulator, combined with a pushbutton.

The main difficulty in converting an electric screwdriver to work from 220 volts is that it needs a lot of power. Nickel-cadmium or lithium batteries will do it without any problem. But not every AC adapter will be able to supply the required power.

How much power do you need and how much does your electric screwdriver draw from the power supply??

To calculate the required power supply capacity is easy. multiply the current consumed by the electric motor of the tool by the voltage. For example, the tool is powered by a 12 volt battery. The current the electric motor needs to work is 10 amperes. That’s 120 watts. But this is the minimum value.

To ensure normal operation under loads, for example, when driving a screw into hard wood, the power supply unit power must be chosen with a margin of 30-40%. Otherwise the electric screwdriver will not be able to work properly under load or the power supply will fail.

The amperage depending on the model can be 7-10 A for domestic screwdrivers and 30-40 A for professional models. Battery voltage may be 12 V, 14 V, or 18 V, depending on the particular model.

Important! The current the screwdriver needs to operate depends on the load. The no-load current is minimal and increases greatly during startup or when tightening a screw.

The required voltage, output and battery capacity are usually found on the label on the tool itself or in its technical documentation.

If the working voltage of the tool is 12 V, the number of options for choosing the power supply increases, for example, you can connect it to a computer power supply. It is possible to buy an old 300W model for a small price. In addition, you have plenty of power to spare. This has the following advantages: It is easy to rebuild and it is relatively easy to find a computer power supply of 300W or more.

Block parameters are indicated on a sticker on the wall. For example, it says that the input voltage is 220 v, the output voltage is 12 v with a current of 25 A. We get the power of 300 W.

If desired, you can use as a power supply for 12 V mains voltage:

  • LED driver;
  • An electronic transformer to power low voltage halogen lamps;
  • car battery charger.

If the tool is designed to be powered by a different voltage, say, 14 V or 18 V, there are few options for choosing a power supply. For a tool that operates at 14 V and has a maximum current of up to 25A, a universal power supply unit AIDA BS 14 PRO is available for sale. There is also power supply unit for 18V, with current up to 20A, AIDA BSh-18 PRO.

It is not recommended to consider the use of a native, complete charger or power supplies for laptops. Such power supply is not able to supply a current necessary for normal work of the tool.

You can make your own hands a power supply for the required voltage. But this requires a certain knowledge of electronics. A diagram of such a PSU can be seen here. There are circuits of power supply units that can be mounted instead of rechargeable batteries.

When connecting the power supply from the charger to the screwdriver, a wire larger than 2.5 mm² must be used. Otherwise, the wire will become very hot, which can lead to the melting of the insulation and a short circuit.

Also the length of the wire determines the level of voltage loss. The longer the wire, the greater the loss. If you choose the wrong wire length, you might find that the electric screwdriver doesn’t “pull”, you can’t drive a screw into hardwood, etc. п.

Another thing that affects the voltage loss is the quality of the wire connections. Wires stranded together will have a high transient resistance, which will significantly affect voltage loss.

Important! You can’t connect an electric screwdriver to a power source with a wire that has a small cross-sectional area. It is at risk of breaking the tool itself and causing a fire.

Connecting an electric screwdriver to the charger

It should be understood that at low voltage losses in the cable, so it must be no less than 2.5 mm cross section, and a length of no more than 1.5 meters. In order to understand whether you can connect an electric screwdriver to the charger, you need to perform a series of actions.

Sequence of conversion to power from the charger:

  • Resolder and rewire the wires to the charger, usually the contacts are in a prominent place, one is responsible for the plus, the second for the mass. When working, the charger must be unplugged from the mains.
  • Then it is necessary to disassemble the unusable battery, dismantle the old elements;
  • In the case drilled a hole for the cable, for a tight connection, the cable is wrapped with electrical tape or fixed with thermal shrink tape.
  • For a balanced weight, the remaining space should be placed a piece of dense wood or rubber, it will contribute to a competent weight distribution and the hand will not be tired when working.
  • The final step is to solder the wires to the power supply of the electric actuator, reassemble the body of the power tool after the conversion.

How to connect a wireless charger to any modern device?

Time and new technologies do not stand still. The producers do not cease to amaze their customers with new developments that make our life easier and more comfortable. Even now many modern users refuse wired devices, it is inconvenient and unaesthetic, especially since today there is a great alternative. universal wireless charging qi wireless. It turns out that to install such an innovation of modern science, you can absolutely to any smartphone, phone, tablet etc.д., and not the latest model. nbsp

To install wireless charging to any type of smartphone or any other device, you will need:

Attach the wireless directly to the back of your device if you wear your phone in its case. But the best is to install the universal receiver inside your device under the lid. You will need to open the back of your device to do this. Remember to turn the phone off while opening, it is strictly forbidden to work with the phone turned on! Be careful when installing it.к. the cover or receiver is damaged, it is no longer a warranty case. nbsp

Then we close the back panel of the device tightly, connect the battery and perform the test. If all went well, your device will charge immediately. To be sure, try it with any wireless charger, if available. nbsp

Note that the appearance of your gadget is not affected by the installation of the receiver. On the thinnest units you may feel a slight increase in thickness (approximately 1mm).), but that’s not terrible at all. nbsp

In addition to the receiver, you also need a universal QI charging station. Here also a great choice, there are expensive, branded, and inexpensive Chinese-made. nbsp

Keep in mind that your new wireless device will charge a bit slower than a wired charger (typically a 500mA to 1000mA receiver, so it makes sense to leave the gadget charging overnight. After charging ends. Two devices are disconnected at the same time. nbsp

To save battery power, you can send the device to the charging cradle after every call. If you often travel, you can connect the charging station directly in your car, but this station must be 12V.

Thus, it is possible to connect any modern device to wireless charging technology without much effort, time and money. nbsp

DeWalt 8V Gyroscopic Screwdriver (With Look Inside)

Power supply for an electric screwdriver in a battery case

If your tool is not too powerful. you can put the power supply in a handle or in a case of ruined batteries.

Install ready-made power supply. To do this you need to buy a ready-made unit with the right characteristics and dimensions. There’s a lot of this stuff at the market. Take the case with you and go to the fitting. When the power supply you are looking for is purchased. carefully separate it from its housing.

Place it in the battery box of the electric screwdriver. All components must be securely fastened. If necessary, lengthen the wires connecting the control board and transformer. If the circuit during operation will touch the metal parts of the transformer. a short circuit will occur.

Since the space in the case allows. separate the board and transformer for better cooling. No matter which quality power supply you choose, the load will be high and overheating is possible.

It is not superfluous to attach additional heat sinks to the power control chips. Work with an electric screwdriver for a long time, unplug it and feel the radio components on the control board.

You can see for yourself which parts need to be heat dissipated. Holes for air circulation can be made in the case.

Reworking the power supply with your own hands does not take much time, and the cost of purchased module is incomparable with the restoration of battery performance.

Homemade power circuitry. If you are good with a soldering iron, this material can be useful as a guide. The scheme is implemented on a donor, as a ballast for a halogen 150W spotlight. Added components are indicated in the schematic by colored inserts.

We added the output transformer from the old computer power supply and took the Schottky diodes from it. The middle point of the secondary winding is between a pair of 12 windings each. Since this circuit does not start without a load. at the output is permanently switched on incandescent light bulb capacity of 15W. At the same time the scheme of backlighting is implemented.

The power supply fits easily into the battery case.

The design was so successful and inexpensive. so much so that there was an idea to streamline production. With the abundance of cheap Chinese screwdrivers demand will be assured.

See video of converting an electric screwdriver to a cordless screwdriver with a matching power supply.

In any home, you can not do without a home helper, which is an electric screwdriver. This is such an electric device, with which you can not only screw in screws, but also drill holes.

Unboxing of BLACK & DECKER BD40K27 B1 4V Push and Go Cordless Smart Screwdriver BD40K27

The main advantage of such a device is its mobility, which provides a battery of 12 volts. There are even more powerful versions of wrenches with a battery that has a constant voltage of 18 volts.

If you don’t use the device for a long time the battery discharges by itself which is a negative factor. When the battery comes into disrepair, then the electric screwdriver becomes useless, so let’s find out how you can remake an electric screwdriver to be powered by 220 volts with your own hands.

Other ways to supply power

Unit inside

The solution to the problem “whether you can connect an electric screwdriver through the charger” can become an alternative to powering an electric screwdriver. the installation of a power supply unit in the empty housing of the power tool.

Before you begin, it is necessary to prevent overheating of the block, for which purpose, holes are arranged in the housing in advance, which will provide air movement, heat removal. Continuous work time with an electric screwdriver with such an improvement is advisable to reduce to 15 minutes.

A ready-made unit is purchased, it is selected according to the size of the housing, technical indicators. The pulsed version is the most suitable, it’s small and lightweight. Not recommended the use of modules of domestic production of the last century. they have a large volume at a low efficiency.

Unsuitable batteries are removed from the bed, and the power supply is put in their place. Contacts are powered and the housing is closed. The assembled hybrid gadget is ready to work from the mains.

  • Wires can be lengthened for convenience.
  • It is necessary to monitor the quality of the assembly: the design should not be able to touch the metal elements, otherwise the short circuit will not pass. It is best to leave some space between the transformer and the board, which will have a positive effect on cooling.
  • If any part of the design is very warm, you can install the module that takes away excess heat, or the device ventilation slots.

By Yourselves

For users with special knowledge, skills, will not prove difficult the problem of “whether it is possible to power an electric screwdriver from a charger without special means”, t.к. assembly of the power supply unit is possible with your own hands. The power module, assembled according to the scheme, is inserted into the case instead of damaged elements. Outgoing voltage is measured, wires are plugged, the housing is locked.

Tip: The circuit may need additional load, it can be provided by including in the system a 15W light bulb, which also provides backlighting.

Computer module will also do

Another solution to the problem of powering an electric screwdriver is to mount it to a computer power supply. This option is applicable to such modules, which are equipped with a mechanical lever. The positive aspect is that the unit is cooled by a cooler, protected from exaggerated loads by a built-in special system.

Such assembly can be assembled only with use of power supply modules of 300-350 W and current of 12 volt, not less than 16 A. For tools with a voltage of more than 14 volts, this charging option is not valid.

The user may wish to hide the unaesthetic unit in a beautiful case, then it is recommended not to forget to arrange ventilation in it.

Car Charge

In looking for a solution to the question “whether you can connect an electric screwdriver to the charger,” you can stop at charging car AK-block. Manually controllable current, voltage modules are applicable. Connection is absolutely uncomplicated. it is enough to connect the input channels of the motor of the tool with the contacts of the car charger.

General recommendations

All of the above methods include one step that unites them. disassembly of the housing of the power module. If the frame is attached to the bolts, it is not a problem, fixing on the glue requires careful opening of the seam by tapping on the gap with a hammer, a knife dug into it.

During installation, observe the direction of voltage. it must not be applied to the battery. Therefore, the module is mounted in parallel with the power contacts, in the plus line is built in a diode illuminator of a certain power.

Summary: The question “can an electric screwdriver work with a battery charger” has a positive answer and several solutions, but it requires caution, some scientific knowledge and skill.

Ways to charge the battery without using a charger (non-standard methods)

HAVE TO KNOW! We do not recommend that the information in this paragraph be applied in practice. This is for informational purposes only.

There are non-standard methods of how to charge the battery of an electric screwdriver without a charger:

This may be justified if you do not have a brand-name battery charger. Safety is questionable. overcharging is possible. We do not advise using these methods. they can lead to battery failure, battery breakage and are dangerous for the user. Buy a brand-name battery of the same brand or similar characteristics.

Power supply for an electric screwdriver with his own hands (PSU). mains, scheme

Mobility is not very important for a drilling and screwing tool used in the workshop or for work at home. In such cases, instead of a battery pack, you can make a power supply for an electric screwdriver with your own hands. This will allow you to use the technique at full power without restrictions.

Where to Begin

In order for the power supply to fully match the electrical appliance, the first thing to do is to clarify the technical specifications of the motor. Most operate from 12 volts. Less common are models with voltages of 14, 16, or 18.

You also need another important parameter. the current. You can roughly estimate the number of amps the motor consumes by estimating the battery capacity and charging time. For example, for lithium-ion batteries at 1.2 A/h and 2.5 hours, respectively, the amperage will be around 1.9 A. The exact value can be found by dividing the power of an electric screwdriver (total electrical load) in watts by the operating voltage in volts.

Once you have the specific figures, you can choose the right power supply. The best candidates are the most compact and lightweight devices. For this reason, it is better to give preference to equipment based on a pulse circuit.

Important! Soviet-made transformer models are less suitable: they are heavy and have low efficiency.

To place the unit it is best to use a non-operational battery case. It’s enough to take out the unsuitable batteries and measure the free space. Depending on the model of an electric screwdriver, it may be more convenient to place it inside the housing, then it is determined by the amount of available space. After you have done the work, you will know:

Now it is enough to tell the figures you received to a consultant in a specialized store or a salesperson at a flea market to quickly find the power supply.


Remodeling begins with soldering. The power supply outputs are firmly attached to the contacts of the charging compartment with solder. Creating a secure connection between the copper wire and the brass contacts is difficult. To increase the strength and reliability of adhesion, the surfaces are treated with a special acid. Because the power supply delivers DC voltage, it is important to observe the polarity.

The power cable is led to the power supply inside the battery charger through a carefully made hole and protected from bending by a special damping nozzle. Inside the case, it is desirable to fix the cable and voltage converter securely. Adhesives which form a viscous connection that does not shake or bump are suitable. Sealing elements can also be used. With this attachment, it is better to create point substrates that do not cover the surface area of the power supply and do not impede heat dissipation.

If the design of the electric screwdriver allows it, it is possible to remove the stuffing from the power supply and mount it directly inside. This will provide the best heat exchange conditions for the equipment that gets warm in the process of operation.

Important! Connecting the PSU through a battery cassette is the most gentle way to keep the electric screwdriver in a mobile version with a battery. To integrate the PSU inside a case often means a big redesign, after which the battery can no longer be used.

The proposed method of converting a cordless electric screwdriver into a mains one is simple and easy for anyone who has ever made a flashlight or a similar simple electrical appliance. This breathes new life into a long-lived device, allowing you to use it even without a used battery.

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