How to convert a cordless electric screwdriver from the mains

How to turn a cordless electric screwdriver into a mains

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

Connecting the old battery pack

Connecting the old unit is done as follows:

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

Take out the old nickel cadmium batteries.

convert, cordless, electric, screwdriver

Next, separate them from the connector pins.

Connecting the wires directly

To connect the wires directly to the screwdriver, proceed 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 fixation and insulation.

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

Congratulations! Now that you have learned how to convert a screwdriver to a corded tool, you can put this knowledge into practice

And it doesn’t matter if your screwdriver is charged or not. No need to worry about battery life

Instructions for rewiring

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

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, disassemble the old battery pack. Unscrew the fastening screws. An important condition will be the preservation of all terminals.

Remove the insides

Remove the batteries and carefully loosen the battery terminals. Then a wire with a cross section that can handle the operating current is soldered to these terminals. Choose a wire with a cross section of at least 2.5 mm² and with the length you need to use your electric screwdriver comfortably. Remember which color wire we solder the minus and plus terminals to.

Connect the wires

Disassembling the computer power supply case. Remove the board and solder the wires on the power supply stub. To the wires coming out of the power supply, instead of the yellow and black wires, solder the wires with terminals from the battery. Black wire is for the minus terminal, yellow wire is for the plus terminal.

You can increase the wattage that your power supply puts out by connecting the black wire to the black and the yellow wire to the yellow. This will improve the performance of the electric screwdriver because there will be less loss.

To start the computer power supply you need to connect the green wire from the 20 pin connector to the black wire. This can be done directly on the PSU board. You can connect a switch to the green wire and the free black wire for convenience.

For convenience, you can solder a special connector to the wires, allowing them to disconnect. Be sure to respect the polarity, otherwise you can damage the electric screwdriver. To do this, the connector must have a key (a special tab on the housing that prevents it from being connected incorrectly).

Reassemble the battery and connect the electric screwdriver to a 220 V mains supply

It is necessary to assemble a “modified” accumulator. Insert the terminals with wires into it and lead them out through the drilled hole. We recommend that you put a 16V capacitor (10,000 uF or 25V) inside the former battery case and connect it to the terminals in parallel. Choose a capacitor with a voltage that is 1.5 or 2 times the rated voltage of the tool.

A capacitor like this would compensate for a large inrush current. Failure to do so will greatly increase the likelihood of the power supply being cut off by the built-in safety device. It is also recommended to place a weight inside the tool to balance it. This will reduce the strain on your hand while you are working.

Assemble the computer power supply together and connect the electric screwdriver to the 220 V mains. If the test reveals that the tool does not have enough power, you can replace the low-voltage power cord.

Options for making a power supply

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.

We use the charger from a laptop

You can make a 12-volt power supply for a screwdriver with your own hands, even without any 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 that the output voltage corresponds to the sought (12-14 volts).

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

  • We take the charger from a laptop.
  • Cut the output connector, bare it and tin the ends of the wires.
  • Strip the wires and solder to the battery input wires.
  • Insulate the soldering points to avoid short circuits.
  • We make a hole in the housing so as not to squeeze the wire, and assemble the construction.

The basis. the power supply from a computer

For the manufacture of such a device you will need a block from a personal computer of format A. Т. It is not difficult to find, 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 300-350 W block with a current of 12 V at least 16 A.

It is the AT format blocks that meet these parameters. On the body of this device there is a power button, which is very convenient for work. A cooling fan and overload protection circuit are installed inside.

The order in which the unit is rebuilt:

  • Removing the lid of the B housing. П. Inside we will see a board with a lot of wires going to connectors, as well as a fan.
  • The next step is to disable the power protection. Find the green wire on the big square connector.
  • Connect this wire with the black wire of the same plug. You can make a jumper from another piece of wire, or you can just cut it short and leave it in the case.
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Then we find the smaller connector (MOLEX) in the output bundle, and do the following things with it:

  • We leave the black and yellow wire, and cut the other two short.
  • For convenient location of the PSU during work, solder an extension cord to the black and yellow wires.
  • Attach the other end of the extension cord to the contacts of the empty battery compartment. This should be done by soldering, you can make a good twist, it is necessary to observe the polarity.
  • Make a hole in the case, so as not to squeeze the wire during assembly. The device is ready.

If you have the desire to ennoble your construction, i.e. е. Hide it in another housing, drill holes for air intake to prevent the PSU from overheating.

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 the power supply of the electric motor.

If there is a device for charging with continuously adjustable output voltage, you can use it as a power supply of 18 volts for a screwdriver.

Electric screwdriver battery design

Converting an electric screwdriver to lithium 18650 batteries

The design of the battery does not depend on the brand. In all devices, the battery design is similar and differs in appearance, housing and contacts.

Battery construction

In the case there are several elements connected in series. Their number depends on the voltage of each cell and the battery as a whole. If you use the most common, nickel-cadmium cells with a voltage of 1.2 volts, to supply a device rated 12V you need 10. The capacity of the battery is indicated 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.

Electric screwdriver battery design

Converting an electric screwdriver to lithium 18650 batteries

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

Battery design

In the case there are several cells connected in series. Their number depends on the voltage of each cell and the battery as a whole. If you use the most common, nickel-cadmium cells with a voltage of 1.2 V, then to supply the device rated 12V you will 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.

Household or professional

As you know, professional screwdrivers have a higher cost, but this is not accidental. 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 makes it possible to screw longer self-tapping screws and/or work with tougher materials.

The difference between a professional and a home electric screwdriver is in the life span

convert, cordless, electric, screwdriver

To decide whether you need a domestic or professional electric screwdriver, assess the amount of work that will need to be done. If you are starting a construction or major renovation, you probably need a professional or semi-professional model. If you will need a tool from time to time, for example, to unscrew/screw something from time to time, a household tool is more than enough. In this kind of work, the resource of the tool profile will simply not be in demand. So it is not very difficult to choose an electric screwdriver according to 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. To avoid changing it, the tool can be converted to mains power, thus ensuring its uninterrupted operation. If you have a power supply, you can literally do it in 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. To do this, you need to disassemble the battery pack housing. The batteries present in it are removed.

Since the contacts of the batteries remain on the removed batteries, in order to return them to the case, it is necessary to refine it. For this purpose, from a 20-th polypropylene pipe I cut 2 short tubes. Their length should correspond to the height of the block of batteries removed. It is necessary that the segments fit into the battery housing of an electric screwdriver.

It is likely that one of the edges of the tubes will need to be trimmed a bit as it will fit into the tabs 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 electrical tape, thus increasing the seating diameter. After that, a cable of a convenient length is soldered to the contacts, and they are finally fixed on the tubes.

Now you need to connect the cable from the terminals of the electric screwdriver to the wire of the power supply. The important thing here is to keep the polarity. The plus side of the block must be connected to the plus terminal, and the minus side to the minus terminal. It is a good idea to solder the twist together for safety. It can be insulated with electrical tape or heat shrink.

Next, the contacts with tubes are placed in the battery case. To do this, a side hole is made in it right at the joint with a wire entry cover. To keep the tubes with contacts from slipping and falling out, everything is secured with thermal adhesive. Can be securely applied to the joint between the housing and the cover to prevent it from opening.

Now when you plug in the power supply, the electric screwdriver can operate for as long as you like without needing to recharge it.

The device device

The screwdriver consists of several basic elements:

  • Cylindrical electric motor powered by current. There are permanent magnets inside the housing that allow the structure to gain sufficient torque. They are also handy when you need to repair. Motor shaft contains a planetary reduction gear.
  • Torque limiter. Needed to limit the tightening torque of the screwdriver. Transmits the torque through the pivots supported by an internal spring.
  • Planetary gearbox. Named after the Honor Solar System, which is similar in assembly. Housed in a separate housing and composed of several gears and other parts. Acts as a force on load regulator. Works harder in drill mode.
  • Speed regulator with reversing function. It is used by reversing the polarity of the connection.
  • The battery of the device. Represents several separate power cells in one package. Voltages range from 9 to 25V.
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Instrument in disassembled condition Source stroy-podskazka.When a battery malfunctions, there are options for replacement or repair. It is usually expensive to replace these batteries, because in a cheap device, the replacement will be approximately equal to the full price 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 will allow you to use the tool further without much cost and effort.

Tips for using an electric screwdriver

When the 12-18 volt power supply is assembled, the electric screwdriver becomes mains. It should be used according to the rules:

  • Every 20 minutes of work, take a break for 3-5 minutes to let the block element cool down;
  • If you operate an external unit, make sure it is clean. It must not be dusty, dirty. This way the unit will heat up faster and work less efficiently;
  • The upgraded tool may not be used at heights greater than 200 centimeters;
  • equip the unit with a ground fault interrupter. If there are problems with the mains RCD will save the equipment from breakdown;
  • all wires must be securely soldered.

The mobility of the device

When transferring cordless equipment to power from the mains one of its main distinguishing features. mobility. is lost. Therefore, if you have decided to make a conversion of the screwdriver power, you need to determine exactly what kind of 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 (PSU) will be external. This version has a separate unit. But don’t let that scare you, even a heavy and large rectifier can just be near a power outlet. You will still be limited by the length of the power cable either to the socket 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 the device for 12-19 volt should have a larger cross-section than the 220 volt power cord.
  • The power supply unit is built into the battery housing. In such a device, mobility is almost fully preserved, only the length of the power cord may limit the movement of the operator. One problem may arise when it is necessary to install a transformer of high power in the battery housing of the screwdriver. But the modern radio industry allows us to solve this problem, there are a large number of compact rectifiers on the radio equipment markets.

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

The variants of making a power supply

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

Using a laptop charger

Make a 12 V 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 a screwdriver. The main thing is that the output voltage corresponds to the desired one (12-14 volts).

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

  • We take the charger from a laptop.
  • We cut the output connector, bare it, and tin the ends of the wires.
  • Solder the stripped wires to the battery input wires.
  • Insulate the soldering points to avoid short circuits.
  • We make a hole in the housing, so as not to squeeze the wire, and reassemble the construction.

The base. the power supply unit from the computer

To make this device we need a block from a personal computer of format A. Т. It is not difficult to find, 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 in the circuit of 12V not lower than 16A.

AT format units meet these parameters. On the case of this device is a power button, which is very convenient when working. Inside there is a cooling fan and an overload protection circuit is mounted.

The order of the rearrangement of the block:

  • Remove the cover of the B housing. 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 disable the power protection. Find the green wire on the big square connector.
  • Connect this wire with the black wire from the same connector. 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 a smaller connector (MOLEX) in the outputs bunch, and do the following things with it:

  • Leave the black and yellow wires, and cut the other two short.
  • For convenient PSU positioning during work, solder the extension wire to the black and yellow wire.
  • Attach the other end of the extension cord to the contacts of the empty battery compartment. This should be done by soldering, you can make a good twist, and the polarity must be strictly observed.
  • We make a hole in the case, so as not to squeeze the wire during assembly. Our device is now ready.

If you have the desire to refine your design, t. е. Hide it in another housing, drill holes for air intake to avoid overheating the PSU.

Power from the car charger

With a car battery charger, it’s fairly 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 the power supply of the electric motor.

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

Safety Precautions

After converting the appliance to mains power, the safety and operating instructions must be followed:

  • Take a break every 30 minutes to extend the life of the device and avoid malfunctions.
  • It is not recommended to work above two meters high.
  • It is important to periodically clean the power supply of the appliance from dust.
  • Check the condition of the power cord. It should not be crushed or exposed to moisture and other negative factors. Ignoring this rule may cause a short circuit of the device.

Following these simple guidelines will allow your old screwdriver to last longer than the new one, while maintaining its power and ease of use.

Fault Prevention

Batteries are made of several elements stacked together, which do not malfunction at the same time, but in parts. To determine the broken part of the battery it is necessary to charge it fully and let it work at full capacity until discharged. After that, disassemble and measure the voltage of each individual cell. Parts where the voltage will be missing or inferior to other cells should be completely replaced. Repair is done with a soldering tool. All cells of the battery are soldered with the same wire strip that was used to connect the parts originally.

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The following video shows the step-by-step process of repairing the appliance:

Materials and tools needed

Materials and tools when remaking an electric screwdriver depends entirely on the type of tool and the type of power supply, as well as its features. But to summarize, a few basic tools can be identified:

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

How to remake with your own hands

Before you remake an electric screwdriver, you need to clearly determine what power and what voltage the tool needs to work. This will have to be the starting point.

It is important to choose a power supply that is not very large and relatively light, so as not to make the work of an electric screwdriver completely inconvenient. If the unit is to be installed directly into the electric screwdriver itself, it is important to observe the dimensions.

Then open the body of the tool. The two halves of the housing can be fastened with screws or adhesive. A knife can be very useful for disassembly.

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

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

A homemade power supply can be obtained in several ways. In any case, you will get a complete tool, which can be used to perform the work after you connect it to the network. It is desirable to prepare a circuit beforehand, which will help not to make a mistake when creating the block.

convert, cordless, electric, screwdriver

Rebuilding a Chinese power supply

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

Replace the original resistor R10 with a tunable resistor to achieve the desired voltage. This is done in several steps:

  • The DC resistor can be removed;
  • in its place is inserted a pre-prepared adjustable resistor, on which the resistance will be set to 2300 Ohm;
  • so far the voltage is still 24 V;
  • by adjusting the resistor to achieve the desired voltage at the contacts.

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

Modification of purchased blocks

You can also use any other pluggable power supply. The rewiring process in this case will be almost the same, but in addition to 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 remodeling, it is important to ensure good air flow into the box with the power supply. To do this, drill holes. You should not allow the device to overheat.

Using a laptop charger

An excellent option is considered to be the use of the charger from a laptop. 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 you should not neglect the output current. The closer it is to the required one, the better.

In this case, conversion of an electric screwdriver for mains power is reduced to the elementary soldering of wires from the charger to the board in the tool. It is desirable to insulate everything with 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 you can use an unnecessary power supply from a computer. There are many varieties of such devices, but almost all of them will fit an electric screwdriver. You can locate the necessary wires by color by referring to the manufacturer’s website.

Power supplies from computers are characterized by 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 when 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 connects directly to the screwdriver;
  • Insulate all exposed contacts if possible.

Thus, the computer device will turn into a power supply for a 14 volt electric screwdriver.

Power from the car charger

Power supplies converted from car battery chargers are also quite common. 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 electric screwdrivers.

Using a car charger comes down to a few simple steps:

  • it is necessary to prepare special wires with which to connect the power unit and the electric screwdriver;
  • The edges of the wire 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 fasteners or the wires themselves;
  • Now all the connections are carefully reinforced and insulated.

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

All of the above methods are effective enough to create a cordless tool from a cordless tool. But do not forget that in this case, the mobility of the electric screwdriver will be significantly reduced, which can affect the quality of work. But if the battery is out of order and the work must be continued urgently, it is logical to connect an external power source.