The electric cordless tool is equipped with a factory-made charger to recharge the battery. If the unit is lost or broken, the owner has a question about how to charge a screwdriver without a charger. In addition to acquiring the original unit, there are several methods for recharging a current source from domestic or automotive equipment.
Basic safety requirements when charging power supplies to the instrument from non-standard charging units:
- To charge the battery of the instrument, direct current is used.
- The connection is made with cables with a protective insulator, it is necessary to provide for a reliable fixation of the wiring on the battery connectors.
- When the capacity of the elements is replenished, heating occurs, accompanied by the release of gases. Battery cells are equipped with emergency valves, but the leaked component is not suitable for further use.
- It is recommended to carry out work in a ventilated room, eyes and hands are protected by personal protective equipment. When the case overheats, the appearance of smoke or traces of electrolyte on the can body, charging immediately stops. Reconnection is carried out after determining the causes of the malfunction.
- Connecting power adapters that are not designed to charge a screwdriver battery is a last resort. Due to the mismatch of the current parameters, the circuit components operate with overload, which causes increased heating and fire. Continuous use of non-original charging units is not recommended.
How to charge a screwdriver battery without a charger
Three types of power sources are used in the construction of an electric tool:
- Nickel-cadmium elements, characterized by the ability to withstand high loads and work at freezing temperatures.
- Batteries are characterized by a pronounced memory effect and accelerated self-discharge. Before connecting the battery to the charging station, a full discharge of the jar is necessary.
- Short-term connection of the battery jar to a non-original charging unit is allowed.
- Nickel metal hydride elements have a reduced memory effect and increased capacity. Connecting batteries to non-original chargers is not recommended.
- Lithium-ion power sources that prevent deep discharge and overheating. For charging, special blocks are used with microprocessor control that monitors the state of the elements. The use of charging units from car batteries or other power sources is prohibited.
Before connecting the external unit, you need to find out the type, capacity and charging current of the power source. Information is indicated on the factory label located on the battery can body. If the sticker is lost, you will need to open the casing and find out the operating parameters by marking on the elements.
Video: How to Charge a Screwdriver Without a Charger
To replenish the capacity, it is possible to connect an external charging unit via a self-installed USB port. It is recommended to use adapters rated for a current of 5-7 A. It is not recommended to use computers or laptops to supply current, since the increased current in the circuit overheats the controller and destroys the node.
Algorithm for equipping a screwdriver battery with a USB connector:
- Remove the battery jar, and then separate the sections of the case (the elements are held on the screws and additional plastic clips).
- Cut a hole in the housing section for installing the USB connector. The port installation location should not impede the placement of the power source in the instrument handle or in a standard charging station. The channel configuration depends on the appearance of the prepared plug. The block is installed in the resulting socket and is fixed with a special hot glue.
- Place a 10 A fuse in the circuit connecting the standard charging controller and the USB connector. A hot-melt adhesive is used to secure the protective element and the wiring. Cables are connected by soldering with lead-tin solder, fixing points are protected by insulating materials.
- Connect the housing sections using standard screws. If you were cutting a one-piece construction, then the line of the joint is covered with a strip of fabric or masking tape coated with liquid epoxy. After the material has hardened, the surface is ground and painted in the color of the battery can body.
- To conduct the test charging DC source. Since the voltage in the charging circuit is 5 V, the replenishment of the capacity takes up to 6-8 hours for batteries with a capacity of 1-2 A h.
Using a car charger
The use of a charging unit designed to service a 12-volt car battery can permanently damage the power source for a power tool.
Before connecting devices, it is necessary to bring the operating parameters of charging to the necessary requirements.
If the equipment is equipped with stepless voltage and current regulators, then you need to set the parameters identical to the standard unit. To reduce the current load, ballast resistance is used (for example, a car marker light).
If the information on the operating parameters of the standard charging is unknown, then for a nickel-cadmium battery with a capacity of 1.3 A h, the charging current is set within 50-100% of the nominal capacity. The voltage is set to the minimum level. Then the polarity of the battery can is determined (according to the factory marking), the location of the minus and plus, if necessary, is specified by the test device.
For measurements, it is necessary to drill a plastic casing of the can and install a sensor inside (for example, from a household test device). Depending on the current parameters, charging lasts from 30 minutes to 2 hours, when the threshold temperature is reached, the external unit is turned off.
Universal battery charging equipment supports step or stepless adjustment of voltage and current in the output circuit. The unit is equipped with devices and indicators that allow you to control the progress of charging.
If the design of the device has a battery type switch, then you must select the appropriate value. Universal charging equipment is recommended for maintenance of worn-out items.
Using an external power source
The technique involves connecting the instrument to a car battery or charging station using cables. The voltage of the external power source must match the parameters of the electric motor. When the tool is operating, the load on the motor changes, which leads to a change in the current strength in the circuit. An external power supply should ensure the operation of the engine and not overheat during prolonged use.
A fuse is provided in the power circuit, the rating depends on the motor power and operating voltage. For example, when installing a 200 W motor and a voltage of 18 V in the supply circuit, it will be necessary to install a fuse with a rating of at least 200/18 = 11 A. The use of a fuse with overestimated parameters leads to overheating and destruction of the motor windings. In the manufacture of the connecting wiring, the current strength in the power circuit is taken into account.
The cables are equipped with a junction box, made independently or removed from the standard faulty battery banks. Fixing the plug with adhesive tape is provided. It is not recommended to glue the block, since there will be difficulties with opening the parts.