How to Power a Cordless Screwdriver
In the economy of modern man, a screwdriver is not a rare tool, in fact this tool is an analogue of an electric drill. The advantage of this type is considered to be autonomous power from a portable battery built into the bottom of the handle. The battery must be periodically charged from the mains through a special charger, during prolonged use the battery fails, replacement is required, and they cost a lot. Therefore, many users are thinking about how to remake a cordless screwdriver so that it works on a 220-volt network.
General view of one of the options
Sometimes consumers decide that a screwdriver needs to be converted to a regular electric drill powered by a power outlet. The question arises how to do this with less time and money. If you have some knowledge in electrical engineering and practical skills, then powering a screwdriver from a 220V network is not difficult. There are several ways using various devices to convert electricity to the appropriate form for rotating the motor of a screwdriver.
Ways to remake a cordless screwdriver
Converting a screwdriver to power from the network consists in converting 220V AC voltage to 12 or 18V DC. One of the most reliable and easiest ways to convert a screwdriver into a network version is to use its standard components.
Alteration with a standard battery and charging
Converting a cordless screwdriver to a network one in this case suggests that the circuit is assembled on the basis of a standard charger. The following materials will be required:
- Accumulator battery;
- 2-3 meters of flexible stranded copper wire, with two conductors, cross section 2.5-4 mm2;
- A common set of tools and supplies, a soldering iron, solder, insulation tape or heat-shrink tubing of the appropriate diameter to the wires. To disassemble a screwdriver, you will need a screwdriver, side cutters and an assembly knife for cutting and stripping wires.
The sequence of operations in the process of remaking a screwdriver in a network:
- The cover is removed from the charger;
- At the output contacts of the charger board, which are connected to the battery during charging, the ends of the wire are soldered in accordance with the polarity. A core with red insulation. To the terminal “”, with blue insulation. To the minus terminal;
- Polarity can be identified by the inscriptions on the board or the body of the product. For reliability, you can turn on charging and measure with a multimeter at the 12 V output, and determine the contacts by polarity;
- Galvanic cells are removed from the battery housing;
How galvanic cells are removed from the battery compartment
- The wires from charging are connected to the contacts inside the battery case in compliance with the polarity.
Thus, the screwdriver is converted to a network. When you turn on the device into the outlet, the corresponding voltage of 12 or 18V DC will be supplied to the input circuit of the screwdriver.
Polarity is recommended, but not required. When the polarity changes, the motor shaft will rotate in the opposite direction, all modern screwdrivers have a polarity reversal switch, in fact, the rotation of the screwdriver chuck is reversed.
Important! The terminals on the charger board are usually made of brass alloy, they must be soldered to the copper wires with acid solder or removed altogether, and the wires soldered to the tracks of the printed circuit board.
Before soldering, holes are made in the battery and charger cases through which the wire is drawn. For a more rigid fixation, it can be tied into a knot within the body and wound electrical tape so that the diameter of the winding exceeds the hole diameter.
Replacing a faulty charging board with a PSU from a computer
In the case when the charging board is faulty in the set of the screwdriver’s set, in order to make a network version, a power supply with parameters suitable for voltage and power is installed. Sometimes the power supply comes from a personal computer. It must be taken into account that the power supply is converted to 12 volts of direct current, the idle screwdriver consumes current up to 4A, for a short time at the moment of tightening. than 40A, then the peak value of power consumption can be up to 480 watts.
You can install the PSU from a laptop, they are compact and convenient for operation, but the maximum power of these models is within 100W, a little more than this is not always enough.
Laptop power supply
The output voltage is 19V, there are screwdrivers with this power supply.
Power (P) = 19 A x 6.15 A = 117 W, then you can add a 12V converter, and the screwdriver will idle and tighten the bolts with little effort. When screwing the screws into a dense wooden surface, such a power supply may not last long. It will burn.
The location of the power supply inside the PC system unit
It is safer to use power supplies from system units of stationary computers. They are more powerful and in all respects are suitable for connecting to screwdrivers.
The peak power of such a power supply is 500W; the rated load for long-term operation is 460W, which is exactly what you need for a screwdriver with a 12V power supply.
Ah500-A board in the case
A fan is located on the top cover of the metal case, which is connected via connectors to the board. Ventilation cooling allows the PSU to withstand large peak loads of 500 W for several minutes. Sometimes fans are located on the side walls, it depends on the PSU model.
To connect such a power supply to a screwdriver, you need to perform just a few operations:
- Disconnect all PSU connectors from the motherboard and other elements of the system unit;
- Unscrew the mounting screws on the PSU and system unit, then remove it from the system unit;
- There are no problems with connecting to a 220V network, a wire with a connector is included in the PSU kit;
- You will have to look for a 12-volt output, there are even two of them in this PSU model, you can find it by marking on the printed circuit board. On some connectors, the output voltage is written opposite the contacts;
Designation of contacts on PSU connectors
For your information. When there are no inscriptions, you can navigate by the color of the conductors, in this series of PSU 12V, the wires with yellow insulation are output from the board to the connector. Connecting the minus is done with black wires.
- To check the correctness of the selected pair, you must turn on the power supply and measure the voltage with a multimeter;
Note! In our case, a pulse power supply is used, which will not start outside the system unit circuit. Without going into the details of the operation of individual semiconductor elements, we just accept, as an axiom, that a revision is needed, which consists in a simple jumper.
- The green wire, designed to turn on the power supply according to the standard scheme, must be connected to the black conductor, this is done directly on the board. The extra piece of green wire is bitten off, the remaining end is stripped and soldered onto the circuit board to the black conductor;
Finalization in the AX500-A power supply unit, installation of a jumper
- After the revision is done, the power supply can be connected to the network and a multimeter can check for the presence of 12V on the selected pair of wires;
- The yellow and black conductor can be extended and soldered to them connector;
- In the battery case for connecting a screwdriver, as in previous cases, the old-age galvanic banks are removed, and the counterpart of the connector to the line from the power supply is installed. The options can be different, you can solder the cord to a screwdriver, and the connector can be connected to the power supply, as you wish;
The findings from the 12V power supply are soldered to the connector going to the screwdriver
- When soldering connectors and connections, do not forget to first put on heat-shrink tubing and wire them with a hot air gun, isolating the soldering spots. In an extreme case, do this with ordinary electrical tape;
- The unused leads of the wires with the PSU can be bitten off or rolled up, the ends insulated and folded inside the case.
Ah500-A block with a fan
Note! When assembling the chassis, be sure to connect the fan. If you soldered it or bit off during the installation process, you need to remember the connection contacts. The fan is powered from the 12V line, by this sign you can easily find the connection points of a screwdriver.
Transformer circuit for powering a screwdriver
One of the available ways to quickly power a screwdriver from the mains is to use the classic circuit with a step-down transformer for 220V / 12-15V and a diode bridge, an AC to DC converter.
Transformer power supply circuit
All elements are easily placed in any case, the necessary controls, controls and displays are displayed on the front panel.
Transformers and diodes with the corresponding parameters, withstanding power of more than 100W, can be taken in old household appliances (televisions, tape recorders), from voltage stabilizers and other power supplies. If necessary, we remodel the transformer, roll the secondary winding or put the output in a winding at a certain number of turns, to achieve an output of 12-15V.
Installation of transformer power supply elements in the housing
Diodes are recommended to be placed on a duralumin radiator, which effectively removes heat, prolonging the service life. Having certain practical skills and knowledge in electrical engineering, the transformer can be wound with your own hands.
There are many power supplies on sale with the right characteristics to power the power tool, but this requires financial costs. If you have an old system unit from a PC, it’s easy to remake the power supply, all the more so if it is not difficult to restore it to its original state and use it as intended.