Self-powered screwdrivers from a 12V battery are a very popular tool on production lines and at the household level. Its advantage is considered to be that it is not connected to the electrical outlet; it is very convenient to carry out work on drilling and fastening screws. As a disadvantage, we can note the high cost of rechargeable batteries and their relatively short service life - from 3-5 years, with intensive work it can be even shorter. Therefore, many people think about how to make a power supply for a screwdriver with their own hands. When purchasing and replacing batteries, financial costs can range from 50 to 80% of the original cost of a new screwdriver. Given their financial capabilities and needs, many consumers are looking for a more economical way to continue using old screwdrivers. One of these ways is to remake its power circuit for a 220V outlet network.

How to convert a cordless screwdriver into a corded one

Let's look at two of the most available methods how to convert a screwdriver with 12V power supply direct current do it yourself quickly and with minimal financial costs:

• Use the original charger of the screwdriver;
• Use the power supply for the screwdriver from the PC system unit.

There are other methods of alteration, but they require more practical skills and knowledge in electrical engineering; these are accessible even to amateurs.

Using a screwdriver charger

This is the simplest and least expensive method, except for the cost of electricity and solder when soldering contacts.

Sequencing:

• The housing mounting screws are unscrewed charger, remove the top cover;
• The conductive wires of the power cord are soldered to the output contacts of the charger. The wires must be flexible, stranded, with a cross-section of at least 2.5-4 mm2 in order to withstand current loads during operation, the cord length is 3-4 m;

• You can solder wires to the output terminals of the charger, to which the contacts of the battery pack are connected when you install it for charging. This method has certain difficulties - the terminals are made of brass alloy, and copper wires They are not soldered with ordinary solder;
• It is necessary to clean the soldering area with a file or sandpaper until the metal appears yellowish;
• Warm up the terminal well with a 40-60 W soldering iron, lubricate it with a special paste (solders for soldering non-ferrous metals are sold in radio parts stores), then the tin solder will reliably adhere to the brass;

• After the soldering points are ready, you can solder tinned copper wire ends to them, with red insulation for +, with blue or black insulation for minus;

This entire procedure can be avoided if you remove the terminals from the board and solder wires to the board in their place. You can remove the power cord from the charger output through the holes in the case where the charging contacts were located, or make an additional hole commensurate with the diameter of the power cord.

Some people are confused by the third contact at the output of the charger; you only need to use two: “+12V” and “-12V”. The polarities of the contacts are indicated on the case or on the board; for reliability, you can plug the charger into a power outlet and use a multimeter to check the presence of 12 V DC voltage at the output and the polarity of the contacts. The remaining contact is for the sensor for automatic control, disconnecting and connecting charging; when the battery reaches its full charge level, the sensor turns off the charger. In our case, this function is not needed; the terminal can be left or cut off from the board. If you are going to use this charger for its intended purpose, then you do not need to remove the terminals; solder the wires from the bottom side of the board to the conductive tracks.

• After soldering the wires, the cord is brought out and the charger case is closed. The opposite end of the cord is stripped, the copper conductors are tinned with solder.

The next stage of work is preparing the input power contacts on the screwdriver itself:

• Remove the battery container from the screwdriver handle;
• Open it and remove the battery cells;

• We drill a hole in the body of the battery container for the power cord;
• We solder the ends of the wire coming from the charger output to the contacts in the battery container from the inside, observing the polarities;
• The terminals on the container are also brass alloy, so strip and use brass solder if necessary;
• Secure the wire inside the container to the wall of the case so that it does not come off when pulled. This can be done with a flexible plastic plate, screwing it to the body inside the compartment with two screws. Lay the power cord under the plate, so it will be securely pressed from the inside;

Important! Do not use metal plates as clamps to secure the wire in the charger and on the screwdriver, or use a dielectric spacer (plastic, rubber, cardboard or other) between the wire and the plate. insulating material). Otherwise metal plate may crush the cord and cut through the insulating layer, resulting in a short circuit.

• The battery container is closed and installed in the screwdriver handle;
• The charger is plugged into the outlet; if everything is done correctly, the screwdriver will function.

It should be noted that if the polarities are reversed, no disaster will occur; the screwdriver chuck will rotate counterclockwise, in the direction of unscrewing. But each product has a reverse switch, so in order not to solder the contacts, just switch the rotation in the other direction. It is recommended to observe polarities in order not to mislead users, and rotation was carried out in the direction in which the arrows near the switch point.

Using a power supply from a PC system unit

This method is used if there is no original charger for the screwdriver, or it is faulty and cannot be restored.

We are considering a switching power supply LC 300-ATX P4, the output of which is three types of DC voltage: +3.3V; +5V and +12V. The 12 volt line can withstand loads up to 15A, this is a power of up to 180W. This is no less than what batteries provide, but, as practice shows, it is quite enough to screw screws into dense wood.

Sequence of operations during rework:

• The power supply is removed from the old PC system unit; to do this, you need to disconnect all the buses with connectors going from it to other boards, and unscrew its case;

• The cover of the metal case is opened;
• Connectors with wires are bitten off at a distance of 15-20 cm from the board;

Important! Do not cut the wires going from the board to the fan - there will be no cooling, and the power supply will quickly fail.

• On all power supply models of this series, the colors of the wires are soldered according to the standards, black - body, yellow +12V, orange + 3.3V, red +5V;
• We connect the green wire for turning on the power supply to the case (black wire) through the switch;

• It should be noted that a switching power supply works effectively when all its outputs are under load, so you can solder a light bulb, black and red wires, even a 12 V car one to the +5V output. It will not glow brightly, this is not required, the main thing is that the chain was under load. We do the same with the 3.3V line - solder an orange and black wire to a 5-10V lamp. One of these lamps can be displayed on the front panel as an indicator that the power supply is turned on and power is supplied;

• Using a screwdriver, we run the black wire to the negative in the battery compartment and connect the yellow wire to the positive. Removal of galvanic cans from the battery compartment and soldering of wires is carried out according to the method described earlier;

• The remaining excess wires can be bitten off or, for reliability, run parallel in one line;
• After connecting all the wires, turn on the power supply; if everything is done correctly, the screwdriver will work.

It should be noted that there are other ways to assemble power supplies on a transformer that deliver a full power of 300-400W. In our case, we considered options that did not require capital investment and great knowledge. In other cases, when you make a power supply for an 18V screwdriver with your own hands, a power supply for a 12V screwdriver from a PC will not work. It is possible to increase the voltage to 18 volts with certain modifications, but this requires detailed consideration in a separate article; other options, knowledge of electrical engineering and practical skills will be required.

Video

A mobile battery-powered screwdriver has become widespread in construction. One of the significant disadvantages of the model is the wear and tear of the battery, when it wears out you have to buy a new screwdriver or look for a battery. Radio amateurs offer a non-standard solution - make your own power supply for an 18 V screwdriver.

Easy tool restoration

The main advantage of a cordless screwdriver is its mobility. These tools use a lithium-ion battery, which is protected from overload and complete discharge. In addition, there is protection against overcharging in the form of a separate circuit built into the element itself. The main power source (primary) is 220 V, and the battery is also recharged.

Depending on the model of the screwdriver, the battery receives a charging voltage from 14 V to 21 V. The battery output produces a supply voltage from 12 to 18 V. This type of battery lasts a long time, but if the tool is not used for a long time, the built-in discharge protection will not help battery cells: discharge occurs constantly.

To increase service life, it is necessary to constantly discharge and charge the battery. If for some reason it was not possible to “keep track” of the tool, a specific battery element often fails. There are basic ways to solve this problem:

1. Replace the battery with a new one.
2. Buy a new tool.
3. Convert a mains-powered screwdriver.

When replacing the battery, please note that a new one is quite difficult to find. The tools are made in such a way that it is difficult to find spare parts for them. It is not profitable for a company to produce its product with high repairability, since it needs income from the purchase of products. You can only find a new battery at dealers. In addition, another option is possible: disassemble the battery and replace the faulty battery.

When purchasing a new tool, the user tends to buy a model of a higher quality, forgetting about the rules for using lithium-ion batteries. Basic rules that will help preserve the service life of the tool for a long time:

1. When purchasing in winter, it is strictly forbidden to “launch” the tool immediately. You need to wait about an hour until it “warms up” to room temperature.
2. Place the battery on charge.
3. Perform the battery charging and discharging cycle about 3 times.

If none of the options for solving the problem are suitable, you need to start converting the screwdriver to a network one with your own hands. It's easy to do. There are many simple and complex ways. Changing the tool model has several positive aspects:

1. There is no need to recharge the battery.
2. Lots of power supply options.
3. Increasing the quality characteristics of the product.

Other Upgrade Methods

Radio amateurs offer many options for upgrading the instrument. Some of them are very simple and boil down to the use of ready-made power supplies, while others require knowledge in the field of electrical engineering and give the device versatility. Classification of methods:

1. Power adapter for laptop.
2. Connecting a computer switching power supply (power supply).
3. Application: 12 V car battery.
4. Assembly homemade source nutrition.

Using a laptop charger is the best solution to the problem. In addition, you need to know the parameters of the screwdriver and charger (available for 12 V and 19 V), and also take into account the dimensions of the latter (for installation in the battery compartment). You need to solder the output of the laptop power adapter, to the terminals of which the battery is connected.

When using a switching power supply (power from 350 W and above) for a personal computer (AT form factor), you need to find a 12 V supply voltage on the connectors powering the hard drive or CD drive. Remove the wires, and carefully cut and insulate the rest. You can assemble a housing for the power supply, which will allow you to obtain a current of up to 16 A. In addition, you need to remove the start-up protection. To do this, you need to connect the green wire to the black wire from this connector. These two methods are very simple and do not require additional description.

The car battery is the optimal source electrical energy. When upgrading the model, nothing changed except connecting a different battery. A significant drawback is its weight. In addition, you need to assemble a charger or purchase it at a specialized store.

Assembling your own power supply is the optimal solution for those who maintain quality. The previous options are good, but do not allow for flexibility of use. For example, they only apply to screwdrivers with a voltage of 12 V, not 18 V. There are chargers rated for 19 V. Getting 18 V is achieved by serial connection rechargeable batteries, for example, 12 and 6 V. Please note that the characteristics of the batteries should differ only in terms of voltage. This is why it often becomes necessary to assemble a power source yourself.

Schemes and their description

The option of self-assembly of the power supply must be carried out subject to knowledge in the field of radio engineering. In addition, before assembly you need to think carefully about everything, find a housing for installation and the corresponding radio elements.

A simple power supply option

A simple circuit of 1 power supply (screwdriver from a 220 volt network), consisting of a power transformer (diode bridge input), a rectifier and a capacitor filter.

Scheme 1 - Power supply for 18 V screwdriver

The transformer must be selected with a power of 300 W and above, the voltage on winding II must be in the range from 20 to 24 V and the current strength is over 15 A. For the diode bridge, powerful diodes should be used, selected for the current of the secondary winding. It will be more difficult to select the appropriate power supply for the screwdriver. At the output of the rectifier, it is necessary to install a capacitor with a capacity of 2000 μF (you can limit yourself to a capacity of 470) and a voltage of 25 V and higher. Parts must be taken with a reserve of current and voltage. All radio elements are mounted on a getinaks board, which is mounted in the housing.

Universal power adapter

The proposed version of the universal power supply has excellent characteristics and can withstand a load current of up to 10 A. The output voltage is 18 V, although you can make calculations and make a power supply for a 12 V screwdriver. This power supply can be used as a battery charger and backup power source in case of network blackout (Scheme 2).

The adapter is assembled on a voltage stabilizer consisting of transistor VT3 and VD2-VD5 (zener diodes). Using toggle switch SB1, the power is turned on and relay K1 closes its contacts. The power goes to a transformer, which converts alternating current to the required rating. The output current from the transformer goes to the rectifier. Next, the rectified voltage is supplied to the stabilizer. There is also a current amplifier in the circuit, assembled on transistors VT1 and VT2. A load is connected to this amplifier. The battery recharging mode (backup power source) is carried out through VD6 and a limiter in the form of resistor R4. Using SB2 you can disable battery charging.

Scheme 2 - Universal power supply for a screwdriver and battery charging

In the absence of a 220 V supply voltage, the relay is de-energized, and voltage from the battery is supplied to other relay contacts (powered directly from the battery). Fuses are used to protect against short-circuit currents and overloads. Such a system can be used without a backup power source. No additional setup required.

The list of radio components is indicated in the corresponding diagram 2, however, replacement with analogues is also possible, for example:

After assembly, the product is installed and brought to the appropriate form; the design is chosen independently.

12V adapter

The adapter is assembled on a 7912 chip and is a linear regulator. The transistor increases the power of the power supply (scheme 3). This homemade product can also power an 18 V screwdriver, for which you need to calculate the transformer.

Scheme 3 - Power supply for 12 V screwdriver

The secondary power supply is a transformer that outputs 16V (for 12VDC model) or 22V (18V powered screwdriver). The rectifier is assembled from ordinary diodes with a reverse voltage of over 50 V (it is possible to use ready-made options). The anti-aliasing filter is a high capacitance capacitor of about 10,000 µF, but the larger this value, the better.

The microcircuit must be purchased at a specialized radio parts store. In addition, the circuit uses LEDs that allow diagnostics in case of power supply failures. The radio element 2N3055 is pnp transistor structure and can be replaced by any (an analogue must be selected from reference literature with a voltage of about 50 V and a current of more than 5 A). It is possible to use LUT for manufacturing circuit board. The manufacturing process is described in detail on the Internet. printed circuit board using laser ironing technology (LUT).

Adjustable modification

The adjustable power supply is very easy to use and versatile. Thanks to the adjustable voltage values, you can power any equipment and use it to charge the battery. The main element is an LM317 type microcircuit. Amplification occurs using two transistors of the 2N3055 type, but more powerful ones can be used, because this increases the power of the power supply and allows you to obtain a current of up to 20 A. The transistors are installed on a radiator, and it is advisable to also use a fan in the design for cooling (a cooler from a personal computer at 12 V).

Scheme 4 - Adjustable power supply

Parts list:

When assembling, you need to insulate the transistors using heat-conducting pads. In addition, thick wires should be used for any assemblies of powerful power supplies.

Operating rules

If the screwdriver has relatively little power, you need to install a homemade power supply in the battery compartment. When assembled separately, all power supplies must be provided with cooling using a fan or motor with an impeller. The case should not be sealed, as overheating will occur (hot air will have nowhere to escape). When the power supply is ready, you need to check the screwdriver in combination with the power source. Basic requirements for using the tool to extend its service life:

1. Working time: 30-40 minutes, after which you need to pause until it cools completely.
2. Avoid working at high altitudes.
3. Monitor the condition of the power cable, battery (if used), temperature of the tool and homemade power supply.

Thus, if the battery of an 18 V screwdriver fails, you can avoid unnecessary costs. If mobility is important, then it makes sense to purchase a new battery or the tool itself. There are many options proposed by radio amateurs to extend its service life. It is necessary to select the optimal one for the specific application of the device.

Cordless screwdriver for sure useful tool, the main advantage of which is mobility. But when the original batteries die completely or partially, buying new ones costs a tidy sum, comparable to half the cost of a new tool. Many people simply buy a new screwdriver, but I propose, at the expense of loss of mobility, to make a reliable power source for it, which will forever remove the problem of constantly charging half-dead batteries.

Let's look at the pros and cons of such modernization

Let's start with the cons. The biggest and only problem is connecting the screwdriver to the socket with wires, which is more than covered by the advantages listed below:

• The screwdriver is always ready for work, the problem of uncharged batteries (or discharged at the wrong time) disappears.
• Feels great in low and negative temperatures, unlike a battery.
• If the original batteries are dead, and the toad is choking on buying new ones, then the power supply completely replaces the batteries.

If you are satisfied with these conditions, then let's get started!

The power supply can be made pulse or transformer. Why I chose the transformer version will become clear as you read the article. If your screwdriver runs on 12 or 14 volts, then I advise you to choose a switching power supply from your computer. This option requires minimal rework and costs.

Patient #1

Reason for modernization: Batteries run out quickly, even when when they were new.

Purpose of modernization: Get a hybrid that runs on both batteries and mains power.

Power supply requires a current of about 10A. Here the question of application arises computer unit power supply, but bad luck - the screwdriver runs on 18V. When 12V is applied to it, it turns very sluggishly and you can brake it by hand with almost no effort. Although some claim that a screwdriver turns normally even on 12 volts, but now, so to speak, the myth has been verified and destroyed.

There are 2 options left - redo the PWM control of the pulse unit so that it produces the required voltage, or use a transformer with the required voltage.

Another disadvantage of a switching power supply is that it is designed to operate at room temperature, and it is not known how it will behave at a lower temperature. In principle, a transformer practically does not care under what conditions it is operated. Although these are all assumptions that have not been tested in practice.

A powerful 18 volt transformer is quite difficult to find, but for me it has become impossible. At this point, I wanted to return to the option with a computer power supply, but suddenly, as the 7th discharge masters say, a toroidal transformer with a wound primary winding accidentally fell into my hands. All that remains is to wind the secondary, I got about 90 turns with 1.5 wire.

If you decide rewind the transformer to a different voltage, then the program will help you Power Trans.

The power supply is made in a housing from an AT unit. The role of the rectifier is played by 10 ampere Schottky diodes connected in a bridge circuit. 220 goes to the unit’s native connector, 18V comes out of the connector intended for connecting a monitor. The toggle switch is a power switch, and the LED signals the presence of 18V.

For ease of use and carrying, the unit is equipped with a folding handle:

Since I need a hybrid, I had to install a separate power line to connect the unit:

At the same time, do not forget to disconnect the batteries when working from the unit.

Taking advantage of the opportunity, when disassembling the screwdriver, I added illumination of the working area:

The result was a mutant like this:

Patient #2

Reason for modernization: The original battery died, restoration is not justified.

Purpose of modernization: Replace the battery with a power supply.

Here I came across a 12-volt unit, and I connected it to the computer power supply. But that was not the case - the block began to go into defense. I connected it to a more powerful power supply, the picture did not change. The reason for this was a short-circuited motor winding. The brushes on the motor turned out to be quite large, and I decided to make a transformer power supply, it has no protection. In any case, the engine will work for a while, and then it can be replaced (they work great with other screwdrivers and car pumps).

This is where the transformer from the UPS came in handy, which had conveniently lain under my table for half a decade, waiting for its finest hour. Just under the required 12v.

Everything was assembled according to the same principle, only instead of Schottky diodes I used 3 Schottky diode assemblies obtained from computer power supplies.

In the previous block, I used a whole cord to connect the monitor, but you shouldn’t do that. The cross-section of the original cord is small and causes heating and losses. It is more correct to use only the connector. To it I soldered a two-core PVS 2.5 square:

It is better not to use a very long low-voltage cord; there will be losses. It is better to make the power cord longer.

I took the cans out of the battery case and connected the power:

The car is ready

Cordless screwdrivers provide mobility and freedom of movement when performing various tasks. However, a common problem with all power batteries is that their efficiency decreases over time. After a certain number of cycles, they begin to hold a charge worse or fail altogether. This often becomes the reason for purchasing a new expensive tool. Experienced craftsmen recommend making a power supply for a screwdriver, which will allow you to use it unlimitedly at full power.

Design features of the screwdriver

Any modern screwdriver has enough simple design.It consists of several basic elements present in each model:

• electric motor,
• accumulator battery,
• start key,
• force regulator,
• rotation speed controller,
• planetary reductor,
• lever for changing direction of movement.

For the upcoming rework, only the first three elements are important - the engine, the battery and the start button, and the rest will not be affected in any way. The task is to convert the battery into a power supply to operate from a regular electrical outlet. Batteries are the most expensive element - they take up up to 75% of the total cost of the tool, so this decision is justified.

Preparatory stage

First you need to take into account the dimensions of the tool body so that the new element fits inside. The power supply can be placed in the body of the screwdriver itself or in the battery body, depending on the specific model. It is difficult to determine the dimensions externally, so it is advisable to open it and remove all internal components. If the body is glued at the seams, then you need to carefully separate it with a knife. Most often it is attached only with small screws. Main actions at the preliminary stage:

1. 1. Carefully study the dimensions and look for a place to install a new component.
2. 2. Find the marking indicating the supply voltage (remember it).
3. 3. Calculate the required current strength.

The last point is difficult because manufacturers usually do not write this parameter. To calculate, you need to divide the power (total electrical load) in watts by the voltage of the electrical circuit in volts. The calculation can be done by eye based on capacity and charging time.

If the first value is 1.2 A/h, and the second is 2.5 hours, then the current strength (A) will be approximately equal to the average value, i.e. about 1.9 A.

If the assessment is incorrect, you can spend a lot of effort and time creating a power supply, but not get the desired result.

• sizes,
• minimum required current,
• the required operating voltage to power the electric motor.

Pulse network units are very popular because they are lighter and smaller than transformer ones. It should be taken into account that cheap Chinese models usually have inflated specifications. Old Soviet-style blocks are suitable for conversion, but they are heavy and have low efficiency. You can find the necessary components in specialized stores or markets with goods for radio amateurs. Just tell the seller the required technical parameters.

Ways to remake a screwdriver

By this point, the case should already be open, so you can begin to remodel the box in which the battery was previously located. The sequence of actions will be as follows:

1. 1. Separate the cord with leads from the plug (you must use a soldering iron).
2. 2. Place the bare AC power supply in place of the former battery.
3. 3. Connect the power cord to the power supply through a special hole in the case.
4. 4. Solder the cord to the power supply.

The main task comes down to resoldering the wires from the contacts that connect to battery, to the contacts of the new power supply. As a result, the current will flow directly to them, allowing the motor to start when the button is pressed.

The output of the block is connected by terminals with mandatory polarity. This entire structure should fit in the place of the former battery, which is no longer needed. If something does not fit in size, then it is better to build a new socket into the tool handle.

A prerequisite is to connect the power supply parallel to the supply terminals, and install a special diode at the positive wire break. If this is not done, power may go to the battery during operation. The diode, in turn, is built into the circuit with the minus pointing towards the electric motor of the tool.

Various power supplies for power tools

You can make a power supply for a screwdriver with your own hands, or you can buy a ready-made version at a flea market. Craftsmen offer power supplies with already connected connectors that are inserted into the battery socket. After this, the tool starts working from the network.

If you don't have a power outlet at hand, you can use a car battery. In this case, it is necessary to connect the screwdriver contacts to the battery contacts using special clamps. However, this option is recommended to be used only as a last resort, since the power of the car battery is not enough. Usually the output voltage does not exceed 11–12V, and to operate a screwdriver you need at least 18–19V.

A common option among radio amateurs is AT-type elements used to power computers. The advantage is that such devices come with detailed specifications, so you don’t have to independently calculate the current strength and other parameters. Inside it there is everything necessary for stable operation: diode assembly, transformers, power transistors. All that remains is to connect it correctly to the power contacts of the screwdriver.

The most aesthetic option is to connect the power tool directly to the network using a plug on a flexible cable. However, the wire cannot be routed directly from the contacts to the plug. To make a functional and safe network device, you will need a separate power supply or transformer with a rectifier. In this case, any model is suitable if its characteristics meet the required parameters. This assembly method is more suitable for experienced craftsmen, because you need to accurately calculate the number of turns and the diameter of the wire.

If you want to maintain convenience and mobility, then increasing the battery capacity is suitable. It is necessary to find a battery for any equipment, for example, a laptop. They are usually quite powerful and can maintain performance for several hours.

We perform the following actions:

1. 1. Disassemble the device case and remove the battery.
2. 2. Connect the wiring of the new battery to the old one, strictly observing the polarity.
3. 3. We fasten the wires using insulating tape or solder them with a soldering iron.
4. 4. Turn on the power tool and check its functionality.

The cable for charging the device must be supplied separately, so you need to attach the plug. If everything is done correctly, the screwdriver will be able to run on battery power, and you can charge it like a regular laptop by plugging it into the mains.

Regardless of the chosen method, you need to remember that the characteristics of the device have changed. When operating from the mains, maximum torque is not achieved immediately, but after some time. The increased power leads to rapid heating, so you should give a short rest every 15-20 minutes. When operating a converted tool, do not forget about safety precautions, so high-quality insulation and grounding are a prerequisite.

Due to the broken seal of the housing, the intensity of contamination increases, so you should regularly clean it of dust. Moisture can also get inside, especially when working outdoors. Following simple rules will protect you from unpleasant incidents and significantly extend the life of your electric tool.

If you have a screwdriver and mainly use it indoors, then I think you will find this article interesting and useful. Here we will talk about converting a 12 volt screwdriver with a ni-cd battery.

It would be a good idea to power a screwdriver for your home from an outlet. That's what we'll do today.

First, let's start with what the problem actually is. A screwdriver is quite a powerful device. Under load, even a weak screwdriver can consume up to 200 W of power. Batteries cope with this easily, but in order to record from an outlet you need a power supply that will make 220V AC voltage what we need constant pressure. Power supplies are mainly 12 or 24 V. Thus, it only makes sense to remake a 12-volt screwdriver.

The author, for example, just had one dead 12 V nickel battery left. That’s what we’ll mock today.

If we go to our favorite aliexpress, we will see that 12 V power supplies with decent power, measured in Chinese watts by the way, are very, very inexpensive. The price is a little cheaper than a good Chinese screwdriver.

A logical question arises: is there any point in redoing anything at all? So aliexpress will not help us in solving this problem. Therefore, I want to offer you another option that is several times more profitable.

Computer power supplies are pretty powerful guys. Also, finding such a power supply will not be difficult. You probably have something like this lying around at home, unused. And if not, then you can go to any computer repair shop and buy a used power supply for a couple of hundred rubles, say, 500 W.

Let it be wrinkled, dirty, covered in dust, but the main thing is that it works. There is usually a sticker on one of the walls containing detailed information on the power lines. On this block we can see the following characteristics: 25 A per 12 V line, and this is no less than 300 W of power.

Enough for a screwdriver. Such a power supply is of course quite large, but at the same time it is much cheaper even than Chinese units with lower power.

Let's start the remodeling.
The first step is to disassemble the original battery and remove all the batteries from it. Our goal is also to preserve the terminal holder and the terminals themselves, so we carefully disassemble everything and free the terminals from the batteries. The author plans to make the battery pack removable so that it can work both from batteries and from the mains. That is, you get such a universal plug with terminals and wires.

You will need to solder a wire with a cross-section of, say, 3 mm 2 to these terminals. In theory, this should be enough to ensure that the energy does not dissipate into heat, even over a wire length of about 2 m. We take a soldering iron and, having previously prepared the wires (by stripping them of insulation and irradiating them), solder them to the terminals.

I don’t know how it will work with your screwdriver; personally, the author managed to bend the terminal ears directly into the plastic and it turned out very reliably.

Now we remember that the negative wire will be, say, blue and insert the terminals according to the plus and minus symbols on the battery case.

Supporting it from below, for example, with a screwdriver, we drill a hole through with a drill with a diameter of 3 mm. Then we remove the chamfer with a large drill. Moreover, we remove it so that the m3 screw with the countersunk head does not stick out.

Well, all that remains is to tighten the nut. This option with a screw is many times better than any other fastening.

Also, it is highly advisable to place a 16 or 25 V capacitor with a capacity of about 10,000 μF in parallel with the terminals. You can buy a capacitor at any radio market, in any radio goods store, or you can also pull it out of a dead computer unit. There is a way to get such a capacitor for free. Most likely they will give it to you for free at any computer repair service. They throw them out anyway. You just have to ask. So take action.

The capacitor will serve as an energy buffer for inrush currents. This is necessary in order to reduce the load on the power supply. If this is not done, with a high degree of probability it (the power supply) will go into protection. We take it and solder it. In this case, the author recommends gluing the nut with superglue. Otherwise you simply won’t be able to tighten it.

Next, we remove the wire from the housing. At this stage it is necessary to fix it somehow. This is necessary so that it does not create a load on the terminals. Fixation can be done, for example, by wrapping the cord around required length several layers of electrical tape.
Well, we’re actually putting everything back together.

Well, it's ready. The result is a plug battery with wires to power the screwdriver from the power supply.
Now it's time to test the homemade product. First, just for fun, let's try to power the screwdriver from a Chinese power supply with 10 Chinese amps. The author has one just like this for experiments.

We monitor the operation indicator (blue LED on the power supply housing). When the screwdriver starts, the block goes into protection.

He is unable to cope with his task. So let's go back to the computer power supply. This example has two 12V lines. One is 25A on the yellow wire, and the second is also 25A on the yellow-black wire. Actually, we take one wire and two grounds and connect them in parallel.
If you only have one 12V line, then just use 2 yellow wires and 2 black ones. By the way, the author read on the forum that for people on an old two-hundred-watt power supply with one 12 V line, the screwdriver works great.

The author decided to make everything beautiful. Therefore, the wire will be disconnectable. The XT60 power connector will come to the rescue; it costs about 25 rubles on Aliexpress.

This is not necessary, it will just be more convenient.
In order to start the power supply from a computer without a computer, you need to close the PS-ON contact to ground (GND). Accordingly, the green wire to black. This can be done with a jumper made of an ordinary paper clip. That's it, the block starts.

All excess wires can be cut off, but the author will not do this, since he may still need the block for other purposes.