How to turn a cordless screwdriver into a box screwdriver

The cordless electric screwdriver was created primarily to provide mobility. It is much more convenient to work with the tool without thinking about whether the wire is long enough or whether it is snagged, etc. д.

But without batteries, such a handy tool as an electric screwdriver becomes a simple piece of iron, although it is fully functional. Batteries have a service life of about 3 years, and it is often impossible to find complete or similar batteries on sale. For example, the manufacturer has already stopped producing such a model, and other batteries do not fit according to various parameters.

It can be very unpleasant to throw away a tool that you have paid money for, sometimes quite a lot of money. Besides, the cost of batteries often makes up to 80% of the price of an electric screwdriver, and it would be more reasonable to buy a new tool. As a rule, the old tool is sent to a distant shelf and lies there without any use. But there is a way to return it to work. to convert it to power from 220 volts.

Is mobility important?

Once the rechargeable battery becomes unable to hold a charge, the electric screwdriver becomes a completely useless tool. Buying a new charger is not reasonable, because its price is often up to 50% of the cost of a new model. So the idea of converting the tool to mains power is a perfectly justified decision.

It is possible to restore the characteristics of the battery, but this option is still a half-measure, because in the future the situation will be repeated. However, before choosing a solution, you need to consider what to do with the mobility of the tool. Is it so necessary? There are 2 options for the potential modification of an electric screwdriver:

  • A tool with an external power supply. In this case, a separate unit is made. It is not so terrible, because even a bulky design can be placed in close proximity to the outlet. But you have to accept the length limitations of the power supply cable and the power cord.
  • An electric screwdriver with a power supply built in place of the battery. This way of modification will make it possible to avoid the assembly of a dimensional construction, significantly limiting the use of the tool. But in this case, the problem of access can also create the length of the mains cable. But you can use in such a capacity compact devices. They can be a purchased or existing power supply, if they fit the characteristics.

Methods of “revival” of an electric screwdriver are very different. Nevertheless, each of these options finds supporters, as it meets the different needs of owners of cordless tools, whose operation has suddenly become impossible.

BP for an electric screwdriver with their own hands

In order to perform the conversion of a cordless electric screwdriver in the mains, you must first make a step-down transformer. It is made on the basis of the one used in TV sets of older models. When powered by an electric screwdriver from an electronic transformer, the latter must be rated at 160 watts. In order to prepare one that is necessary for a screwdriver, you need to do the following:

  • The prepared transformer should be disassembled.
  • The secondary winding needs to be removed completely.
  • Wind ten turns on the transformer.
  • Now the transformer is ready, all that is left is to assemble it.
  • Next you need to measure. Now connect it to the mains and measure the voltage obtained on the secondary winding. Now divide the number of turns, which in this case is ten, by the voltage now measured. Multiply the obtained value by the required voltage for the instrument, and obtain the number of required turns.
  • Now disconnect the transformer from the network, it is disassembled again and wound the required number of turns. Then it needs to be assembled.

For the winding take a wire with a cross section of 1 square millimeter. mm.

After the current has passed through the transformer, the output will be an alternating voltage. The circuit diagram of the power supply for an electric screwdriver provides that in order to get a DC from it, you will need to make a diode bridge. It is made with the use of diodes on radiators, designed for 20 V and 10 A.

The converter, made in such a way, is placed in the case. Its output will produce the voltage necessary to operate the electric screwdriver. The input will be the mains voltage of 220 V.

The wires coming from the PSU are connected to the pins through which the tool is powered.

Such a power supply for an electric screwdriver from the mains is usually installed in the case, where previously was a battery cell.

PSU for an electric screwdriver with their own hands

In order to perform the conversion of a cordless electric screwdriver into a mains one, you must first make a step-down transformer. It is made on the basis of the one that was used in TV sets of older models. When powering an electric screwdriver from an electronic transformer, the latter must be rated at 160 W. In order to prepare one that is needed for a screwdriver, you need to do the following:

  • The prepared transformer should be disassembled.
  • The secondary winding must be removed completely.
  • The required number of windings should be ten turns.
  • Now the transformer is ready, now it needs to be assembled.
  • The next step is to measure. Now connect it to the mains and measure the voltage obtained in the secondary winding. Now the number of turns, which in this case is ten, divide by the voltage now measured. Multiply this value by the required voltage for the instrument, and you will get the number of necessary turns.
  • Now disconnect the transformer from the network, take it apart again and wind the required number of turns. Then it has to be assembled.
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For the winding, a wire with a cross section of 1 sqm. mm cross-section.

After the current has passed through the transformer, the output will be alternating voltage. The power supply circuit for an electric screwdriver provides that in order to get a permanent one out of it, it will be necessary to make a diode bridge. It is made with the use of diodes on radiators, designed for 20 V and 10 A.

The converter made in this way is placed in the housing. Its output will produce the voltage needed to operate the screwdriver. The input will be the mains voltage of 220 V.

The wires coming from the PSU are connected to the contacts through which the tool is powered.

Such a power supply for an electric screwdriver from the mains is usually mounted in the housing, where the battery cell was previously.

How to make an electric screwdriver from the mains video

The procedure for converting an electric screwdriver can be viewed in detail at

If, after the batteries are out of use, the electric screwdriver is converted to be powered by 220 V, then this will allow the tool to continue to be used without significant cost.

When the batteries stop working, many people wonder how they can convert a cordless electric screwdriver to a corded. It is impossible to repair batteries with destroyed cells. The cost of new power supplies is almost equal to the price of an electric screwdriver. It is not always possible to find suitable elements, the models are often removed from production. But for the prudent and skillful owners there is a way out. to power the electric screwdriver from the mains.

The disadvantage of a converted tool is one: it is tied to a socket. But for indoor work it is not so essential. But the advantages are more. Now you don’t have to worry about recharging the battery, no downtime. Current remains stable at all times and does not depend on low battery power, which means constant torque.

Before you go in search of the power supply (hereinafter. PSU), look at the parameters of an electric screwdriver, which are listed on the case or in the data sheet. Note the voltage. often there is a 12-volt tool, it is not difficult to find a power supply for it. If the voltage is higher, the search may be delayed. It is required to find out the current consumption, which is not specified in the technical specification. The unit to be purchased must deliver an average current value (between the battery capacity and the regular charger). You can read the information on the markings.

There are two main options for converting a cordless electric screwdriver to 220 volts. The first is to use an external PSU. Any rectifier, capable of delivering the necessary DC voltage, will do. Even if it is large and bulky, there is no problem. After all, you don’t have to carry it around the room. The unit is installed near the socket, and the cord to the tool makes the required length.

Remember that as the voltage decreases, the amperage increases, if the power remains the same. This means that the cross section of the low-voltage cord must be larger than that of the 220 V mains.

The second option is that the PSU is mounted in the case from the battery. The only obstacle in choosing this method can be the size of the transformer. Mobility is preserved, the radius of use depends on the length of the power cord. It is important to remember that the tool is powered by 220 V, so the cord must be reliable, and the input itself is made neatly, carefully insulated.

Available power supplies can be used as an external power source:

You can buy an old battery charger inexpensively at the market. Now mostly impulse chargers are used, and the old units are often sold for lack of use. This particular charger with the ability to manually adjust the voltage and current is ideal for any electric screwdriver, regardless of its operating voltage. The whole rework is to connect the low-voltage cord to the output terminals of the charger.

The power supply of the computer is purchased from older models, it should have a shutdown button. You won’t need it, but it’s exactly the “AT” format option you need. At the radio market choose a 300-350 watt power unit, which will provide reliable operation of low-power and medium screwdrivers. All technical specifications are indicated on the sticker on the housing. The unit has a cooling fan and overload protection. To remake a computer PSU with his own hands on an external power supply for an electric screwdriver, perform simple operations:

  • disassemble the housing;
  • on the large square connector, find the green wire and any black wire;
  • connect the two wires together, insulate them;
  • on the other smaller connector remove all the wires, leaving the yellow and black;
  • They solder a low-voltage cable cord.
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To observe the polarity, you must know: yellow wire is positive, black is negative. Your computer power supply is running the tool at up to 14 volts.

Most laptop chargers have characteristics that allow them to be used as a power source for an electric screwdriver. Chargers with an output voltage of 12-19 volts are suitable. The only changes you need to make are about the output plug. It should be cut, stripped the wires and soldered to them a cable of the right length.

Those who know about electrical engineering can make a homemade power supply. Its circuit is quite simple and includes a step-down transformer, diode rectifier and two capacitors. You can buy all the parts or get them from old radios. You can use a transformer from a tube TV with a 24-30V output. The rectifying diode bridge is necessary. Capacitors are used non-deficient, from old equipment: one of 0.1 uF and the other of electrolytic 4700 uF.

Warning! The design must be enclosed. For short-circuit protection it is necessary to install fuses on the input and output.

The power supply for an electric screwdriver can be placed in the battery case or in the handle. Possible Options:

At the radio market pick up a PSU with the right parameters. At home it should be carefully removed from the case and placed in your electric screwdriver, fixing all components securely. If the wires are short, lengthen them so that they do not touch metal parts. Separate the transformer and the circuit board. Lay additional heat sinks on the microcircuits for better cooling. Also not superfluous would be holes in the case to circulate air and heat dissipation during operation.

Adapted from a computer power supply

The AT power supply standard is suitable for conversion. The average output voltage is 14 V, and the average power does not exceed 400 watts. These values are ideal for a 14V electric screwdriver power supply. You can take one from an old computer. The computer PSU comes with a built-in fuse, cooler. The main disadvantage is the size of the PC component.

Computer PSU

Power supplies for ATX standard computer system units will not work. They are more complicated, and creating a power supply for an electric screwdriver requires a thorough knowledge of electronics. ATX standard power supplies require extensive modification before they can be built into an electric screwdriver. To modify a standard AT power supply you should:

  • Disassemble the computer system unit.
  • Disconnect the power supply, for which the green wire is responsible.
  • Desolder the black and green wire.
  • Connect black wire to black and green wire to yellow.
  • Solder one end of the green wire to the unsoldered black connector.
  • Connect the other end of the green wire to the pins of the electric screwdriver power supply.

If your computer power supply has a red wire, then unsolder it. This is for monitoring the 5V rail load. Next, check the voltage of the incoming current. If there is a value of 14 volts, the finalized power supply is going to. After that, connect the pad to the black and yellow wire. The electric screwdriver will be connected to it. It is important to observe polarity when soldering. The black wire is for “-” and the yellow wire is for “-“.

It is important to make sure the power cord and wires are not twisted during rewiring.

How to properly use a converted electric screwdriver?

A converted electric screwdriver can be used much like a conventional mains-powered screwdriver. But it is still advisable to observe certain precautions.

  • Do not operate the device without a break. Make small rest intervals every 20 minutes.
  • Clean the power unit regularly to remove accumulated dust inside.
  • Do not use a converted electric screwdriver too high off the ground or floor (above 2 m).
  • Check the condition of the wires. they should not be pinched or too tight during operation.

Follow the rules for using a converted electric screwdriver That’s how relatively easy and simple it is to give a second life to your favorite screwdriver with a finally dead battery. This is a good way to extend its life and save money on the purchase of a new device. The main thing is to have patience and carefully follow all the recommendations given in the instruction above.

The mobility of the device

When converting battery-powered equipment to mains power, one of its main distinguishing features. mobility. is lost. So if you decide to do a power conversion on your screwdriver, you need to determine exactly what kind of device you want to use in the future.

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

  • Power supply (PSU) will be external. This version provides a separate device. But do not let this scare you, even a heavy and large rectifier can simply be near the power outlet. You will still be limited by the length of the power cable either to the outlet or to the power supply unit. According to Ohm’s law, reducing the voltage at the same power increases the current. That’s why the 12-19 volt power cord of the device must have a larger cross section than the 220 volt mains cable.
  • The power supply is built into the battery case. With such a device mobility is almost completely preserved, only the length of the mains cable can limit the movement of the operator. One problem may arise when it is necessary to install a high-power transformer in a screwdriver battery case. 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 method finds supporters because it has a certain set of features.

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Power supply of an electric screwdriver from 220 V mains

I have finally started to implement my long-standing idea, namely, to provide power for an electric screwdriver from 220 volts. Undoubtedly some of you also have a screwdriver with a worn out, unusable battery that no longer takes a charge. In my location I had two copies.

The first one (black) has a working voltage of 18 volts. That’s what I originally wanted to power it from the mains, because.к. fits comfortably in the hand and is quite powerful. But there is no button. Perhaps in the future I’ll cut the handle and make it like a drill. The second one is designed for 12 volts. Served for quite a long time. It is of course possible to buy a new battery, or as a last resort to replace the cans. But all the same I want to have always a ready tool at hand, the more that an electric drill is not always convenient to use t.к. it is heavy. To realize this idea we can use a power transformer.

I used a step down transformer TS-250-36. “250”. This is its rated power, and the number 36 means that the output will be 36 volts. It has an O-shaped magnetic core. The windings are arranged so that half of the primary is wound on the left side and the other half on the right side. The secondary winding is wound in the same way and is placed on top of the primary winding. It is not difficult to distinguish the windings from each other in a step-down transformer.к. The secondary is made of thicker wire, and the one to which the line voltage is applied is made of thinner wire. This is because it has a lower current flow.

The windings are symmetrical and the two halves of 18 volts are connected by a wire (you can see the connection point on the bottom photo). I will use one half.

But before you rewind the transformer you have to measure. I urge you to be careful when working with current, not to touch live parts, and always check if the measurement limit is correctly set on the multimeter.

On the right you measure the voltage at half of the secondary winding. As you can see, the voltage is a little higher than the rated voltage, because.к. Here no load was connected.

So I removed one half, and now for disassembly of the transformer. There was a large amount of paraffin between the layers of paper.

The secondary winding in my case is wound in two layers, separated by a layer of paper. To reduce the secondary from 18 volts I had to remove almost half of the turns.

cordless, electric, screwdriver, network, their

In determining the required voltage, you must take into account that after the transformer will be a diode bridge, which will reduce the voltage by about a couple of volts. But adding a smoothing capacitor would increase the voltage by about 1.4 times. Т.е. in absence of load, the rectified voltage on the capacitor will be equal to the amplitude value.

As we unwind the secondary, we measure. Soon, I stopped at 11.2 volts, i.e.к. was afraid of sagging when the load was connected.

When the transformer is prepared (although some can use a ready-made one with the right parameters), now it’s time to get acquainted with the schematic.

To the output of the transformer it is necessary to solder a diode bridge (VDS) to convert the AC current into a DC pulsating current. The diode bridge can be assembled from a separate diode or you can use a ready-made. When choosing it, you should consider how many amps your electric screwdriver consumes (the bridge to pick up with a reserve).

Wires from the secondary winding solder to the diode bridge terminals, where the letters AC (alternating current).

Well, after the bridge must be soldered a capacitor to smooth the ripple. Its voltage should exceed the supply voltage of an electric screwdriver at least two times. Capacitance from 470 uF to 2200 uF.

If you want, you can add a switch and fuse before the transformer in the circuit.

So after connecting the circuit I made the measurements. Idle voltage at the output of the power supply (when the load is not connected) is 15 volts. When you start an electric screwdriver, it sags to 11.5 volts, which is the norm, so it’s no big deal. A fully charged new battery gave 13 volts.

This is what the tool looks like from the inside. Here you can find the threshold parameters of the button and you can see that the motor is controlled by a powerful field effect transistor.

To make it easy to connect the power supply I disassembled the battery. From it we need the contacts. This part needs to be tinned. I soldered with rosin, but in some cases you may need flux for aluminum soldering.

Of course when soldering wires from the power supply unit do not forget about polarity, usually it is marked on the battery. The compartment has become very light. The wire was sealed with thermal adhesive.

The tests showed that the electric screwdriver, working from the power supply, coped with the task.

There is a video attached to this article that shows in detail how to build the power supply, rewind the transformer, connect it and test.

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