How to convert a cordless electric screwdriver into a networked one with your own hands
The power supply for an electric screwdriver can be housed in the battery case or in the handle. Possible options:
At the flea market a power supply with the right parameters is chosen. 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 the metal parts. Place the transformer and the board separately. On microcircuits for better cooling install additional heat sinks. Also not superfluous would be holes in the housing for air circulation and heat dissipation during operation.
Converting a cordless electric screwdriver into a cordless screwdriver
At the hardware store, buy a 24V, 9A PSU. Screwdrivers are powered by 12 or 18 volts, so it is a challenge to reduce the voltage to the required level. Minimal knowledge of radio engineering is required to do this job. The output voltage is supported by the 2320 Ohm resistor R10. It should be replaced with a 10 kOhm trimmer resistor. How to make the tuning of the power supply is described below:
- solder out the permanent resistor;
- set the device resistance of the trimmer resistor to 2300 ohm;
- The trimmer resistor was soldered in place of the constant resistor;
- Adjust the voltage while the PSU is on.
At the heart of the construction of a homemade PSU will be an electronic transformer Feron or Taschibra 60W. You can buy them in electrical stores, they are designed for halogen lamps. They do not need any modification. Taking the secondary winding away from the center point allowed to use two Schottky diodes instead of the usual four. BPP work can be controlled by LED HL1. You can see all the necessary parts in the schematic.
The T1 transformer is wound by itself. A 28×16×9 non-deficient NM2000 ferrite ring is used. Deburr the corners with an emery cloth and wrap the ring with FUM tape before winding. The made unit is mounted on an aluminum plate with a thickness of 3 mm or more, placed in the battery case. It also serves as a common wire.
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 using an intermediate source.
Using a laptop charger
To make a 12 V power supply for a screwdriver with your own hands is possible, even without technical knowledge. You only need to find an unnecessary charger from a laptop, which has specifications similar to the parameters for powering a 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:
- Take the charger from a laptop.
- Cut off the output connector, bare and tin the ends of the wires.
- Strip the wires and solder them 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
To make such a device you will need a block of A-format PC. 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
It is the AT format blocks that meet these parameters. On the body of this device is a power button, which is very convenient for work. Cooling fan installed inside and overload protection circuit mounted.
The order in which the unit is rebuilt:
- Removing the lid of enclosure B. П. Inside we will see a board with many 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 large square connector.
- Connect this wire to 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 find the smaller connector (MOLEX) in the bundle of outputs and do the following operations with it:
- Leave the black and yellow wire, and cut the other two short.
- For the convenience of the PSU location, solder an extension cord 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, at the same time it is necessary to observe the polarity.
- Make a hole in the housing, so as not to squeeze the wire during assembly. Your device is now ready.
Power from the car charger
With a car battery charger, 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 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.
It is necessary to disconnect the battery of an electric screwdriver, disassemble it, and remove the batteries.
It is important to keep the original terminal holders and terminals.
The latter are neatly detached from the batteries, and to them soldered wire section of 4 kv.mm. The terminals are then inserted into the holders.
Next, you need to drill the body of the battery, remove the chamfer on the hole, so that through it to screw the terminal holder with a screw M3, because without power cells it will not hold.
Before installation, a capacitor is soldered to the terminals, so that the power supply from the PC does not go into inrush currents 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 shined through for the wire.
Then the terminal holder is screwed on, and everything is put back together. It is important to remember which terminal of what color wire is soldered to.
According to the label on the power supply unit, you need to determine which of its wires have a 12 V output, and connect to them. If there are 2 lines, they are twisted together.
To make the power supply turn on without a computer, you need to short any black wire to the green. This can be done with a jumper made out of a paper clip.
If the power supply turns out to be weak for your electric screwdriver, it will go into protection even with a capacitor. Then you need to connect a separate load to it. This can be an old hard drive. It also helps to have a 5W 6V light bulb installed on the line for the 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.
To power 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 housing of the battery pack. The batteries present in it are removed.
Since the battery contacts remain on the removed batteries, you need to rework the battery to get them back into the housing. To do this I cut two short tubes from a 20-gauge polypropylene pipe. Their length must match the height of the removed battery pack. It is necessary that the pieces fit into the battery case of the electric screwdriver.
Most likely one of the edges of the tubes will have to be trimmed a little, because it will be 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 electrical tape, thus increasing the seating diameter. After that, a cable of convenient length is soldered to the contacts, and they are finally fixed on the tubes.
Now you must connect the cable from the electric screwdriver terminals to the power supply wire. Here it is important to observe the polarity. The plus side of the power supply has to be connected to the plus terminal and the minus side to the minus terminal. For safety, it is better to solder the twist. 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 directly at the joint with the lid for the entry of the wire. To prevent the tubes with contacts from shifting and falling out, everything is fixed with hot melt glue. To be sure, it can also be applied to the joint between the housing and the lid, so that it does not open.
Now, when you plug the power supply into the socket, the electric screwdriver can work from the mains as long as you want without recharging.
How to make an electric screwdriver from the mains video
The procedure for modifying an electric screwdriver can be viewed in detail at
If, after the batteries are out of use, the electric screwdriver is converted to power from 220 V, then this will allow you to continue using the tool without significant cost.
When the batteries stop working, many people wonder how they can convert a cordless electric screwdriver to mains power. It is impossible to repair batteries with destroyed cells. The cost of new power sources is almost equal to the price of an electric screwdriver. Finding the right elements is not always possible, models are often removed from production. But for the prudent and skillful owner there is a solution. to power the electric screwdriver from the mains.
The converted tool has only one disadvantage: it is tied to a power outlet. But this is not so important for indoor use. But the advantages are more. Now you don’t have to worry about recharging the battery, no downtime. The current strength at all times remains stable and does not depend on the battery discharge, which means a constant torque.
Before you go looking for a power supply (hereinafter. PSU), study the parameters of the electric screwdriver, which are listed on the case or in the passport. Pay attention to voltage. 12-volt tools are more common, so it’s easy to find a power supply for them. If the voltage is higher, the search may take longer. It is required to find out the current consumption, which is not specified in the technical specification. bought unit should give the average current value (between the battery capacity and regular charger). The data can be obtained from the marking.
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 do not 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 so does the amperage, 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 a case from the battery. The only obstacle in choosing this method can be the size of the transformer. Mobility is maintained, 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 neat, carefully insulated.
Available power supplies can be used as an external source:
You can inexpensively buy an old battery charger on the market. Pulse chargers are mostly used now, and older units are often sold out of necessity. This is the charger with the ability to manually adjust the voltage and current is ideal for any electric screwdriver, regardless of its operating voltage. The entire modification is to connect the low-voltage cord to the output terminals of the charger.
Computer power supply is purchased from older models, it should have a button to turn off. It will not be needed, but it is the “AT” format version that is needed. At the flea market you choose a 300-350 watt power unit, which will ensure the reliable operation of small and medium screwdrivers. All technical specifications are listed on a sticker on the housing. The unit has a cooling fan and overload protection. To remake a computer PSU with his hands on an external power supply for an electric screwdriver, perform simple operations:
- disassemble the case;
- on the big square connector, find the green wire and any black one;
- Connect the two wires and insulate them;
- On the other smaller connector remove all wires, leaving the yellow and black;
- We solder a low voltage cable to it.
To observe the polarity, you should know: the yellow wire is positive, the black one is negative. From the computer power supply works tool with a voltage of 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 12 to 19 volts output will work. The only changes you need to make are related to the output plug. It should be cut, stripped wires and soldered with a cable of proper length.
People with some know-how in electrical engineering can make a home-made power supply. Its circuit is quite simple and includes a step-down transformer, diode rectifier and two capacitors. All parts can be bought or borrowed from old radio equipment. A transformer from a tube TV with a 24-30V output will work. The rectifying diode bridge is a must. Capacitors are used non-deficient, from old equipment: one of 0.1 uF and the other of electrolytic 4700 uF.
Attention! It is necessary to enclose the construction. To protect against short circuits, fuses must be installed on the input and output sides.
The power supply for an electric screwdriver can be placed in the battery case or in the handle. Possible variations:
Find a power supply with the right parameters at a radio market. 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. Place the transformer and circuit board separately. Put additional heat sinks on the chips for better cooling. Holes in the case are also useful to allow air to circulate and heat to dissipate during operation.
The first thing you need to do to convert your electric screwdriver for mains operation is to solder the electrical wires to the charging terminals of the appliance. The connection can be tricky. the wire is largely made of copper, and the charger contains brass terminals, making them difficult to solder. Acid, which is excellent as a connecting element, is just the thing to help. To do this, it is necessary to treat the brass charging terminals and solder the power cord to the contacts. Quality soldering will ensure the screwdriver will run smoothly for a long time.
Next, it is necessary to remake the faulty battery. To do this, it is completely disassembled and all the insides are removed, contrary to the manufacturer’s recommendations. It is forbidden to throw the innards into the general trash. You don’t need to throw out the body. you can put the weight for the counterweight inside it.
The next step is to solder the pins of the cord to the battery terminals, which are placed inside the case. During the work, it is important to observe the polarity, otherwise the screwdriver will screw in the opposite direction. It is fixed with a simple switch.
After that the cord is led into the battery from the outside of the case, for which you need to make a hole for the diameter of the wire. To reliably fix the wire in the body, it is recommended to wrap it with insulating tape inside and outside, making a special lock, which securely fixes the resulting structure.
The last step is to directly install the finished battery pack into the screwdriver from the mains and then operate it.
Power supply from a PC
If the power supply itself is broken, there are several options for replacing it to operate the device. The easiest and most convenient option. to use unnecessary power supply from a PC with a capacity of not less than 250 watts.
On modern units to turn on is usually enough to short the wires, the color of which may vary. You can find out the correct sequence on the Internet or try the matching method. The connector on the power supply for the 12-volt screwdriver is located in a four-pin connector: minus for black, plus for yellow. Such models are equipped with a fan, which must be installed outside the device. To respect the aesthetics and convenience when remodeling the screwdriver from the computer power supply, the wires are hidden in the housing.
The car battery
Another interesting and practical option is how to make a screwdriver from the 220v mains using a car battery charger. The only drawback of such a solution is the rapid discharge of the automotive power supply, so you can’t work for a long time. This variant perfectly suits those whose regular power supply unit failed, which happens quite often. After spending a few hours, an experienced craftsman will be able to convert the device to run on a car battery, in which the screwdriver will work even more efficiently than the original battery.
Power Supply Options
Any electric screwdriver requires much less voltage than a conventional outlet. That is why it is necessary to have a special converter, which outputs the necessary voltage. All power supplies are divided into two large groups: pulsed and transformer. Let’s look at each of them separately.
The principle of operation of pulse systems is that the voltage is first rectified, and then converted into a special pulse signal. It is important to achieve a stable voltage. A transformer winding or resistors can help in this.
Impulse power supplies are quite effective and can be used in various conditions. And they have a high level of protection against short circuits and similar effects. However, the pulsed systems are clearly inferior to the transformer ones in terms of power. Besides such blocks are very picky about the input voltage. If it is below the set value, the element may simply not work.
common power units that have proven to be reliable and efficient in many applications. They consist of a step-down transformer and a rectifier, through which the undervoltage is fed. Rectifiers can be different, depending on the number of diodes used.
Such elements are simple to make, cheap and reliable. So they are often the preferred type. They provide a stable voltage without interference with high maximum power. But there are a few drawbacks. The main disadvantage is the cumbersomeness, with much lower efficiency than pulsed sources. This fact requires selecting a power supply for an electric screwdriver with more power than the tool needs. Since part of the power will be wasted on side processes.
Reassembling a working battery from two batteries that have lost capacity
Two defective units can be assembled into a single, serviceable unit.
Important! By plugging in the defective battery pack, the second repaired battery pack will provide mobility for small amounts of work.
Finding the defective cells
The battery pack is assembled from separate cells. They do not fail at the same time, but even a single defective cell impairs the performance of the entire battery.
To identify parts that have lost capacity, it is necessary to:
- charge the battery;
- work until the power loss
- disassemble the battery;
- Measure the voltage at each cell individually.
Batteries, which will have a noticeably lower voltage than the rest, or will be absent at all, should be replaced.
Repair the battery
After identifying and removing defective parts, the remaining parts are assembled from the device, suitable for further use. Connect by soldering, with wires of 1.5 mm² or a strip similar to the one with which the parts were connected before.
If the number of serviceable elements is insufficient, we buy missing elements or convert the tool to 220 volts mains power.
Knowing how to convert a cordless electric screwdriver into a corded one with your own hands will help save you money and avoid purchasing a new device.