To convert an electric screwdriver to work from the mains

How to turn a cordless electric screwdriver into a corded machine

There are two ways to make an adapter: use an old battery pack because it already has a connector that fits the screwdriver, or connect the wires directly to the handle.

By connecting the old battery pack

To connect the old battery pack, proceed as follows:

First you need to disassemble the battery pack, to do this unscrew the screws as shown in the picture.

Take out the old nickel cadmium batteries.

Then separate them from the connector pins.

Connecting the wires directly

Connecting the wires directly to the screwdriver is done as follows:

To connect the wires directly, you must first disassemble the screwdriver, that is, unscrew the screws that fasten the two halves of the housing.

Examine the connections, find the plus and minus, remember the polarity of the connection. For convenience, it was decided to remove the bottom wide part of the handle.

Next, you need to connect the wires, this can be done with a soldering iron or good old duct tape.

And the final touch is to wrap the wires at the exit of the handle for extra security and insulation.

Wanted to know how to make a screwdriver directly from the charger?

Congratulations! Now that you know how to convert your screwdriver into a cordless screwdriver, you can put this knowledge into practice

And it doesn’t matter if your screwdriver is charged or not. You won’t have to worry about how long the battery will last

Instructions for conversion

Let’s take a closer look, step by step, at how you can convert a cordless electric screwdriver to a corded screwdriver.

Disassemble the battery

In order to convert the tool to a corded tool that receives voltage from the native charger or computer power supply, you need to follow simple steps.

First we disassemble the old battery. Remove the fixing screws. An important prerequisite will be the preservation of all terminals.

Remove the innards

Remove the batteries and carefully release the terminals. Then a wire with a cross-section that can withstand the operating current is soldered to these terminals. Choose a wire with a cross section of at least 2.5 mm² and the length required for comfortable operation of the electric screwdriver. Remember which color wire we are soldering the minus and plus pins to.

Connect the wires

Take apart the computer power supply case. Remove the board and unsolder the wires on the power cable. To the wires coming out of the power supply unit, instead of the yellow and black wires, solder the wires with terminals from the battery. The black wire is the minus conductor and the yellow wire is the plus conductor.

You can increase the power produced by connecting the black wire to the black wire and the yellow wire to the yellow wire. This will improve the performance of the electric screwdriver because there will be less loss.

Connect the green wire from the 20-pin connector to the black wire to start the computer power supply. This can be done right on the power supply board. For convenience, you can connect the switch to the green and free black wire.

For ease of use, you can solder a special connector to the wires, allowing them to disconnect. It is necessary to observe the polarity, otherwise you can damage the electric screwdriver. To do this, the connector must be keyed (a special tab on the housing, preventing it from being connected incorrectly).

Assemble everything back and connect the electric screwdriver to 220 V mains

It is necessary to assemble a “modified” battery. Insert the terminals with wires into it and lead them out through the drilled hole. Inside the body of the former battery is recommended to put a capacitor of 10000 uF capacity at 16 V or 25 V and connect it to the terminals in parallel. Choose a capacitor with a voltage of 1.5 or 2 times the nominal voltage of the tool.

Such a capacitor will compensate for the high starting current. If you do not put it, the likelihood of tripping the power supply by the built-in protection is greatly increased. It is also recommended to place a weight inside the tool to balance it out. It will reduce the load on your hand while you work.

Put the computer power supply together and connect the electric screwdriver to 220 V mains. If you find during the test that the tool lacks power, you can replace the low-voltage wire.

How to convert an electric screwdriver to 220 V

After the battery of an electric screwdriver fails, it can be switched to 220 volts. This requires only an adapter and a power supply unit. This is a very simple improvement that does not require much time or money.


It is necessary to disconnect the battery of an electric screwdriver, disassemble it, and remove the batteries.

It is important to retain the original terminal blocks and terminals.

The latter are neatly stripped from the batteries, and a 4 kV wire is soldered to Then the terminals are inserted into the holders.

convert, electric, screwdriver, work

Next, you need to drill the battery housing, remove the chamfer from the hole to screw the terminal holder through it with a screw M3, because without batteries it will not hold.

convert, electric, screwdriver, work

A capacitor is soldered to the terminals before installation so that the PC power supply does not go into inrush current protection.

Since the capacitor will interfere with holding the nut when tightening the screw, it is better to glue it to the terminal holder. On the side of the battery case, a hole is made for the wire.

Then the terminal holder is screwed on and everything is put back together. It is important to remember which terminal is soldered to which color wire.

According to the sticker on the power supply, you need to determine which of its wires have a 12 V output, and connect to them. If there are 2 such lines, then they are twisted together.

To make the PSU turn on without the computer, you need to connect any black wire to the green. This can be done with a paper clip jumper.

If the power supply turns out to be weak for your electric screwdriver, it will go into protection even with the capacitor. Then you need to connect a separate load to it. It can be an old hard drive. It also helps to install a 5W 6V light bulb on a line for a 5V trimmer unit. By modifying your electric screwdriver in this way, you will retain the ability to disconnect the modified battery case from it at any time, and put a conventional battery.

Electric screwdriver battery design

Conversion of an electric screwdriver for lithium batteries 18650

Battery design is brand-independent. In all devices, the battery design is similar and differs in appearance, housing, and contacts.

Design of the rechargeable battery

The case contains several cells connected in series. Their number depends on the voltage of each cell and the battery as a whole. When using the most common, nickel-cadmium cells with a voltage of 1.2V, to power a device rated 12V you need 10 pcs. Battery capacity is specified in ampere hours.

Interesting. When connected in series, the output voltage increases, and the capacity does not change and is equal to the capacity of the individual cells.

convert, electric, screwdriver, work

Domestic or professional

Professional screwdrivers are known to be more expensive, but this is no accident. They are made with a large margin of safety, for which higher quality and more expensive materials are used. In addition, they have more power, which allows you to screw in longer screws and/or work with tougher materials.

The difference between a professional and a domestic electric screwdriver in life span

To decide whether you need a domestic or professional electric screwdriver, assess the amount of work that will need to be done. If you’re starting a construction or major renovation project, you probably need a professional or semi-professional model. If the tool will be needed periodically. to unscrew/screw something from time to time, a household tool is more than enough. With this kind of work, the resource of the tool pro is simply not going to be used. So it is not very difficult to choose an electric screwdriver by this criterion.

How to convert a cordless electric screwdriver to 220 V

Over time, the battery of a cordless electric screwdriver wears out, so it has to be charged more often and longer. In order not to change it, you can switch the tool to mains power, thus ensuring its uninterrupted operation. If you have a power supply, this can be done in literally half an hour.

Basic Materials:

To transfer the power of an electric screwdriver from the battery to the mains, you need to get to its power contacts. For this you need to disassemble the housing of the battery pack. The batteries it contains are removed.

Since the battery terminals remain on the removed batteries, you need to rework them in order to return them to the housing. For this purpose, from the 20-th polypropylene pipe cut 2 short tubes. Their length should match the height of the battery pack removed. It is necessary that the segments fit into the battery housing of an electric screwdriver.

Most likely one of the edges of the tubes will have to be trimmed a bit, as it will rest against the ledge on the cover.

Next, you need to remove the contact plates from the batteries and move them to the tubes. To make them fit tightly, each tube should be wrapped with duct tape, thus increasing the seating diameter. After that, a cable of a convenient length is soldered to the contacts and they are finally attached to the tubes.

Now you need to connect the cable from the terminals of the electric screwdriver to the wire of the power supply. It is important that the polarity is correct. The plus of the block must connect to the plus terminal, and the minus with the minus. For reliability, it is better to solder the twist. It can be insulated with electrical tape or heat shrink.

Next, the contacts with the tubes are placed in the battery case. To do this, a side hole is made in it right at the junction with the cover to enter the wire. To prevent the tubes with contacts from slipping and falling out, everything is fixed with hot melt glue. To be reliable, it can also be applied to the joint between the case and the lid, so that the lid does not open.

The electric screwdriver can now run on the mains for as long as you like without recharging.

The device device

The screwdriver consists of several basic elements:

  • Cylindrical electric motor powered by current. Inside the housing are permanent magnets that enable the construction to gather sufficient torque. They are also handy when repairs are needed. The motor shaft contains the planetary reduction gear.
  • Torque limiter. Required to limit the gain when operating the screwdriver. Transmits torque through hinges pressed by an internal spring.
  • Planetary reduction gear. Named after Honor Solar System, which it resembles when assembled. Located in a separate housing and composed of several gears and other parts. Acts as a force on the load controller. Works harder in drill mode.
  • Speed regulator with reversing function. It works by reversing the polarity of the connection.
  • The battery of the device. Represents several individual power cells in a single casing. Voltages in different devices range from 9 to 25V.

The device in disassembled condition Source stroy-podskazka.In case of battery failure, there are options for replacement or repair. These batteries are usually expensive to change, because in a cheap device the replacement will be about equal to the full cost of the screwdriver. Repair is not always possible, in addition, as in the first option, its cost will be close to the full price of the device. But there is also a third option, such as to convert the screwdriver to work on the mains, which allows you to use the tool further without much cost and effort.

Tips for Using a Electric Screwdriver

When the 12-18 volt power supply is assembled, the electric screwdriver becomes a mains. You have to use it correctly:

  • Every 20 minutes of work take a 3-5 minute break so that the unit cools down;
  • If operating an external unit, keep it clean. It must not be dusty, dirty. This will cause the unit to heat up faster and work less efficiently;
  • Do not use the upgraded tool at heights over 200 centimeters;
  • Provide the element with a protective shutdown device. In case of problems with the network RCD will save the equipment from breakage;
  • all wires must be securely soldered.

Is it worth the switch to the mains

Many may not understand why a tool should be switched to the mains. In fact, over time, the battery weakens and sooner or later the power cell must be replaced. As practice has shown, it is expensive, and the selection of quality parts can take time and finances. If you switch the electric screwdriver to work from the mains, you can:

The latter depends directly on the battery charge. If you work from the mains, then the power of the apparatus will be at the same level. The only disadvantage of working from the mains is the dependence on the length of the cord. Therefore, in the following design we will consider the version with a removable element.


Before proceeding to the task at hand, you need to review whether everything is there to “upgrade” the tool. In the process, you will definitely need:

  • Power supply from a computer;
  • 12 V electric screwdriver;
  • Condenser;
  • Soldering iron;
  • Drill;
  • Duct tape;
  • XT60 power plug;
  • A 6 watt bulb or two 3 watt bulbs.

These tools and materials are helpful in converting an electric screwdriver to mains power without harming the tool. And then we will consider the option of a removable cord.

The mobility of the device

When converting cordless equipment to power from the mains one of the main distinctive properties is lost. mobility. Therefore, if you have decided to make a conversion of the screwdriver power supply, you need to determine exactly what device you want to use in the future.

There are two concepts on how to convert battery-type equipment to mains power:

  • The power supply unit (PSU) will be external. This version requires a separate unit. But don’t let this scare you, even a heavy and large rectifier can simply be near a power outlet. You will still be limited by the length of the power cord either to the outlet or to the power supply unit. According to Ohm’s law, reducing the voltage for the same power increases the amperage. Therefore, the power cord of a 12-19 volt device should have a larger cross-section than a 220 volt power cord.
  • The power supply is installed in the battery case. In such a device, mobility is almost completely preserved, only the length of the power cord can limit the movement of the operator. One problem may arise when you need to install a transformer of high power in the battery housing of the screwdriver. But the modern radio industry allows you to solve this problem, there are a large number of compact rectifiers in the radio equipment markets.

Each of the methods finds supporters, as it has a certain set of characteristics.

Power Supply Options

There are several options on how to convert the screwdriver to work from the mains. The task is to power the electric motor of the device with an intermediate source.

Using a laptop charger

To make a 12V power supply for a screwdriver with your own hands is possible, even without technical knowledge. It is only necessary to find an unnecessary charger from a laptop, which has specifications similar to those for powering the screwdriver. The main thing is that the output voltage corresponds to what you’re looking for (12-14 volts).

To achieve this goal, you must first disassemble the battery and remove the defective elements. Then follow these manipulations:

  • Take a laptop charger.
  • Cut off the output plug, strip and tin the ends of the wires.
  • We solder the stripped wires to the battery input wires.
  • Insulate the soldering points to avoid short circuits.
  • Make a hole in the housing, so as not to squeeze the wire, and assemble the construction.

The basis. a power supply from a computer

To make such a device you will need a block from a personal computer of format A. Т. It is not difficult to find it, this is an old model of the power supply, which is easy to buy at any market for radio components. It is important to know that you can use a 300-350W unit with a current of 12V not less than 16A.

Exactly the AT format blocks meet these parameters. On the body of this device is a power button, which is very convenient when working. There is a cooling fan inside and an overload protection circuit.

The order of the rearrangement of the unit:

  • Let’s take off the cover of the B case. П. Inside we will see a board with a lot of wires going to the connectors, as well as a fan.
  • The next step is to disconnect the power protection. Find the green wire on the big square connector.
  • Connect this wire with the black one from the same socket. You can make a jumper from another piece of wire, or you can just cut it short and leave it in the case.

Then we find the smaller MOLEX connector in the outputs and work with it as follows:

  • Leave the black and yellow wire and cut the other two short.
  • To make it easier to position the PSU when working, solder an extension wire to the black and yellow wires.
  • Attach the other end of the extension cord to the pins of the empty battery compartment. This should be done by soldering, you can make a good twist, and it is necessary to strictly observe the polarity.
  • Make a hole in the housing so as not to squeeze the wire during assembly. The device is ready.

If you feel like refining your setup, t. е. Hide it in another housing, drill holes for air intake to avoid overheating the PSU.

Power from the car charger

Having a charger for a car battery, it is quite easy to make a device to power a screwdriver. To make the conversion, you only need to connect the power terminals of the charger output to power the electric motor.

If you have a battery charger with continuously variable output voltage, you can use it as a power supply for a 18 volt screwdriver.

Materials and tools required

Materials and tools when remaking an electric screwdriver depends entirely on the type of tool and the type of power source, as well as its features. But if you summarize, there are a few basic tools:

  • screwdriver;
  • pliers;
  • knife;
  • insulating materials;
  • A cable for the electricity supply;
  • soldering iron and soldering materials;
  • some kind of housing for the future power supply.

How to remake with your own hands

Before you convert an electric screwdriver, you need to clearly determine how much power and what voltage the tool needs to work. This will have to be the basis for.

It is important to choose a power supply that is not too big and relatively light so as not to make working with an electric screwdriver very inconvenient. If the unit is planned to be installed directly in the electric screwdriver itself, it is important to comply with the dimensions.

Then opens the body of the tool. The two halves of the body can be fastened with screws or with glue. A knife can be very helpful for disassembly.

After opening the case, the power supply unit or wire is inserted inside, whose contacts must be soldered to the charger. Soldering should be as efficient as possible, using special solutions.

The second end of the wire should be for mains feeding. So there should be a plug. It is recommended to make a hole in the case beforehand, through which the cable will pass.

You can get a homemade power supply in several ways. In any case, you will get a full-fledged tool, which can be used to perform work after connecting it to the mains. It is desirable to prepare a diagram beforehand, which will help not to make a mistake when creating the block.

Rebuilding a Chinese-made power supply

Excellent for creating a power supply for an electric screwdriver 12 volts with their own hands will approach an ordinary Chinese power supply with an output voltage of 24 V and a current of 9 A. But since the tools use a lower voltage, you must first lower it.

To achieve the goal you need to replace the original resistor R10 with a tunable resistor, with which you can achieve the desired voltage. This is done in several steps:

  • a permanent resistor is taken out;
  • in its place, a pre-prepared adjustable resistor is inserted, on which the resistance will be set to 2300 ohms;
  • For now the voltage is still 24 V;
  • With the adjustment of the resistor you need to achieve the necessary voltage at the contacts.

After all the manipulations it is necessary to check that the output voltage is the right value (12 V, 14 V, etc.).д.), and that the current exceeds 9 A.

Redesigning purchased blocks

It is also possible to power from any other purchased power supplies. The rewiring process in this case will be almost the same, but apart from the resistor, you may need to solder additional diodes. The most important thing is to achieve the necessary output parameters. And this can easily be done with a combination of components.

After the conversion, it is important to ensure good air flow to the box with the power unit. Holes are drilled for this purpose. You should not allow the device to overheat.

Using a laptop charger

A great option is to use a laptop charger. Such devices usually work with voltages from 12 to 19 V. This is quite enough to ensure the quality operation of an electric screwdriver. But do not neglect the output current. The closer it is to what you need, the better.

In this case, the conversion of an electric screwdriver to mains-powered is reduced to the basic soldering of wires from the charger to the board in the tool. It is desirable to isolate everything with duct tape or other similar materials. After that the wire is led out and the tool can be used.

Power supply from a computer

Make an electric screwdriver from the mains using an unnecessary power supply from a computer. There are many varieties of these devices, but almost all are suitable for an electric screwdriver. You can locate the necessary wires by color by referring to the manufacturer’s website.

Power supplies from computers offer durability, advanced overload protection, and a host of other advantages. They may not be too handy because of their size, but a long wire will help solve this problem.

Procedure for connecting a computer power supply to a screwdriver:

  • disassemble the unit;
  • remove the power protection by disconnecting the green wire from the board;
  • this wire must be connected to the black connector on the device;
  • Separate all wires except the yellow and black;
  • These two wires are soldered to the extension cable;
  • The other end of the cable is directly connected to the screwdriver;
  • Insulate all exposed contacts if possible.

Thus, from the computer device you will get a power supply for a 14 volt electric screwdriver.

Power from a car charger

Also quite common are power units converted from car battery chargers. The principle of conversion here is about the same as that of a computer power supply, but there are a few peculiarities.

The main feature is that usually such devices allow you to easily adjust the voltage and amperage. This greatly simplifies the procedure of use, and also makes it possible to apply the method to all screwdrivers.

The use of car chargers comes down to a few simple steps:

  • It is necessary to prepare special wires with which to connect the power supply unit and an electric screwdriver;
  • wire edges are stripped and inserted into the terminals on the tool (for better retention, you can use clamps);
  • when connecting, it is necessary to observe the polarity, which is usually marked on the fixtures or the wires themselves;
  • all connections are now carefully fastened and insulated.

After all these procedures, the user will receive a functional electric screwdriver, which is able to work from 220 volts.

All of the above methods are effective enough to make a corded tool out of a cordless tool. But we should not forget that in that case the mobility of the electric screwdriver is greatly reduced, which can affect the quality of work. But if the battery fails and you need to continue working urgently, it is logical to connect an external power source.