Thyristor circuits for screwdriver Interskol 14.4. Design of a charger for a screwdriver. Using BC847 transistors

Almost all screwdrivers are battery operated. The average battery capacity is 12 mAh. And in order for it to always be in working condition, it needs constant recharging. To do this, you need a charger specific to each type of battery. However, they differ greatly in their characteristics.

Currently releasing 12–18 V models. It is also worth noting that manufacturers use different components for chargers of different models. To figure this out, you should familiarize yourself with the standard circuit diagram of these chargers.

Standard charger circuit diagram

basis standard scheme is three-channel type microcircuit. In this version, four transistors with very different capacities and high-frequency capacitors (pulse or transition) are mounted on the microcircuit. To stabilize the current, thyristors or open-type tetrodes are used. Current conductivity is regulated by dipole filters. This electrical circuit easily copes with network overloads.

Schematic diagram

The purpose of power tools is primarily to make our daily work less tedious and routine. In home life, a screwdriver is an indispensable assistant in repairing or disassembling (assembling) furniture and other household items. Self-powered screwdriver makes it more mobile and convenient to use. The charger is a power source for any cordless power tool, including a screwdriver. As an example, let's take a look at the device and circuit diagram.

For circuit diagrams of 18 V screwdriver chargers, we use transition type transistors several capacitors and a tetrode with a diode bridge. Frequency stabilization is carried out by a grid trigger. The conductivity of the charging current at 18 V is typically 5.4 µA. Sometimes, to improve conductivity, chromatic resistors are used. The capacitance of the capacitors, in this case, should not be higher than 15 pF.

Design of a battery device for a screwdriver

The battery “banks” are enclosed in a housing that has four contacts, including two power contacts, plus and minus for discharge/charge. Upper control contact switched on via thermistor(thermal sensor), which protects the battery from overheating during charging. When it gets too hot, it limits or cuts off the charging current. The service contact is connected through a 9 kOhm resistor, which equalizes the charge of all elements of complex charging stations, but they are usually used for industrial devices.

Standard and individual characteristics of the Interskol charger

Power supply elements

The battery is the most expensive part of the screwdriver and is approximately 70% of the total cost tool. If it fails, you will have to spend money on purchasing a practically new screwdriver. But if you have certain skills and knowledge, you can fix the damage yourself. This requires certain knowledge about the features and structure of a battery or charger.

All elements of a screwdriver, as a rule, have standard characteristics and dimensions. Their main difference is the amount of energy capacity, which is measured in A/h (ampere/hour). The capacity is indicated on each element of the power supply (they are called “banks”).

“Banks” are: lithium - ion, nickel - cadmium and nickel - metal - hydride. The voltage of the first type is 3.6 V, the others have a voltage of 1.2 V.

Battery fault determined by a multimeter. He will determine which of the “cans” is out of order.

DIY battery repair

To repair a screwdriver battery, you need to know its design and accurately determine the location of the breakdown and the malfunction itself. If at least one element fails, the entire circuit will lose its functionality. Having a “donor” who has all the elements in order or new “cans” will help solve this problem.

A multimeter or 12 V lamp will tell you which element is faulty. To do this, you need to charge the battery until it is fully charged. Then disassemble the body and measure the voltage all elements of the chain. If the voltage of the “cans” is below the nominal voltage, then you need to mark them with a marker. Then reassemble the battery and let it run until its power noticeably drops. After this, disassemble it again and measure the voltage of the marked “cans”. The voltage drop across them should be most noticeable. If the difference is 0.5 V or higher, and the element is working, then this indicates its imminent failure. Such elements need to be replaced.

Using a 12 V lamp, you can also identify faulty circuit elements. To do this, you need to connect a fully charged and disassembled battery to the plus and minus contacts of a 12 V lamp. The load created by the lamp will be discharge the battery. Then measure sections of the chain and identify faulty links. Repair (restoration or replacement) can be done in two ways.

1. The faulty element is cut off and a new one is soldered with a soldering iron. This applies to lithium-ion batteries. Since it is not possible to restore their operation.
2. Nickel-cadmium and nickel-metal-hydride elements can be restored if an electrolyte is present that has lost volume. To do this, they are flashed with voltage and also with increased current, which helps eliminate the memory effect and increases the capacity of the element. Although it will not be possible to completely eliminate the defect. Perhaps after some time the problem will return. Much the best option Failed elements will be replaced.

Replacement of necessary circuit elements

To repair a battery for a screwdriver you will need spare battery, from which you can borrow the necessary parts or purchase new chain elements. New “banks” must meet the required parameters. To replace them you will need a soldering iron, tin, rosin or flux.

DIY universal charger

To charge the battery device, you can make a homemade charger, powered from a USB source. Necessary components for this: socket, USB charger, 10 amp fuse, necessary connectors, paint, electrical tape and tape. To do this you need:

As you can see, this the process will not take much time and will not be too ruinous for your family budget.

There is one in every home where basic repairs are being carried out. Any electrical appliance requires stationary electricity or a power supply. Since cordless screwdrivers are the most popular, a charger is also required.

It comes complete with a drill, and like any electrical appliance it can fail. So that you do not encounter the problem of non-functioning equipment, we will study the general description of chargers for screwdrivers.

Types of chargers

Analog with built-in power supply

Their popularity is due to their low cost. If the drill (screwdriver) is not intended for professional use, the duration of operation is not the first issue. The task of a simple charger is to obtain a constant voltage with a current load sufficient to charge the battery.

Important! To start charging, the voltage at the output of the power supply must be higher than the nominal value of the battery.

This charging works on the principle of a conventional stabilizer. For example, consider a charger circuit for a 9-11 volt battery. The type of batteries does not matter.

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It is advisable to spend your free time between repairs usefully. For example, tidying up a tool. This article contains a little information about the electrical part of a cordless screwdriver.

Design and diagram of a screwdriver

The tool body houses a DC electric motor, a gearbox, a start button with a regulator and a switch for the direction of rotation of the engine, and a battery. Differences in electrical diagrams determined by the motor control method used. The most commonly used is a powerful MOS transistor with a PWM controller, which provides smooth adjustment of the rotation speed.

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For better heat dissipation, the transistor is mounted on the engine housing or on the radiator. The controller board, if small, is often located inside the start button.

The electric motor has a cylindrical body with permanent magnets fixed inside it. They create a magnetic field in which an armature with a winding of copper wire, its leads are connected to the commutator brushes. The supply voltage is supplied to the commutator through carbon-graphite brushes, its polarity determines the direction of rotation of the armature. A drive gear is pressed onto the engine axis and interacts with the gearbox.

Most models of screwdrivers have a planetary gearbox, which allows you to select the speed required for work: low for screwing screws, high for drilling. To adjust the force with which the screw is tightened, the design of the gearbox provides for mechanical load adjustment.

A battery with an output voltage of 9 to 18 volts is used as a power source. Higher voltage increases the power and reliability of the tool. In modern screwdrivers, lithium-ion and lithium-polymer elements are installed instead of outdated nickel-cadmium elements. Despite their high cost, they are distinguished by their small dimensions and better performance characteristics.

Screwdriver malfunctions

Having a general understanding of the device and the interaction of its parts, you can easily determine the cause of the breakdown and carry out a simple repair of the screwdriver yourself.

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A common problem where the engine won't start can be caused by a faulty battery or charger. The performance of both is easily verified by a tester. If this is not the reason, then the next part to be examined is the button. To do this, disassemble the tool body and use an ohmmeter to determine the integrity of the electrical circuit from the battery to the button and then to the engine. A non-working button is replaced with a button of the same type.

In the electronic rotation speed control circuit, the control transistor is most often damaged due to overload. Its serviceability is checked with a multimeter.

If, when you press a button, there is voltage at the motor terminals and the shaft does not rotate, you need to inspect the brushes to see how tightly they are pressed against the commutator, ensuring reliable electrical contact. A failed engine, as a rule, is not repaired but replaced with a new one.

Battery faults

The failure of Ni-Cd or Ni-MH batteries is often associated with loss of capacity of one or more cells. Repairing a screwdriver battery with your own hands is within the capabilities of most home craftsmen. In order to determine the faulty element, the voltage on each of them is measured (a sufficiently powerful load, for example, a car light bulb, is connected to the output terminals of the battery). The voltage on the non-working element will be near zero. Batteries rejected in this way are replaced with serviceable ones, observing the polarity of the connection. When soldering connections, you should avoid overheating the body of the cans.

Unqualified repair of failed Li-ion Li-pol batteries can lead to their explosion or ignition, and therefore cannot be recommended for novice repairmen.

The design of such batteries provides for the presence of a special electronic circuit– a controller that monitors charge and discharge parameters and prevents these values ​​from being exceeded. If the battery is discharged excessively, the correct operation of the controller is disrupted. Battery performance can sometimes be restored by charging it directly, with the controller disconnected, to a level at which the controller circuitry works on its own.

Experts categorically do not recommend replacing faulty lithium elements in the battery. This is due to the imbalance in the operation of the entire circuit due to differences in the parameters of the elements and the inability to adjust the precise operation of the controller.

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Repairing nickel-cadmium batteries is carried out by many craftsmen who do not want to throw away a screwdriver that is still working. As their experience shows, the cause of premature battery failure is most often a poor-quality charger. Simple charger circuits for screwdrivers maintain a fixed current in the load for a certain time, without taking into account whether the battery was discharged before the process began. After a certain number of battery cycles, its capacity decreases noticeably. This phenomenon is called the “memory effect.”

One way to significantly increase the life of a Ni-Cd battery is to completely discharge it before charging it again. For this purpose, the design of the charger is supplemented with a circuit for launching an automatic discharge-charge cycle.

It should also be taken into account that the battery capacity decreases sharply if the tool is stored or operated at low temperatures. It is also not recommended to leave a screwdriver with a discharged lithium-ion battery for a long period - a deep discharge will easily damage it. On the contrary, there is no need to recharge a nickel-cadmium battery during storage. Reducing the capacity to minimum values ​​usually does not damage it.

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When using a screwdriver, users often encounter damage to the charger. First of all, this is due to the instability of the parameters of the electrical network to which the charger is connected, and secondly, to the failure of the battery. This problem can be solved in two ways: by purchasing a new charger for a screwdriver or by repairing it yourself.

Types of chargers

The popularity of the screwdriver is due to the fact that it simplifies the process of tightening or unscrewing various fasteners A. Characterized by its mobility and small size, it is indispensable for assembling furniture structures, dismantling equipment, roofing and other construction work. The tool owes its mobility to the batteries included in its design.

The advantage of using batteries is the possibility of their repeated use. Batteries, releasing accumulated energy to the device, periodically need to be recharged. Chargers are used to restore the value of their capacity.

The screwdriver battery is charged in two ways: with a built-in or external charger. The built-in charger allows you to charge the battery without removing it from the screwdriver. The capacity restoration circuit is located directly with the battery. While remote means their removal and installation in a separate device for charging. Chargers are distinguished according to the type of recoverable batteries. The batteries used are:

• nickel-cadmium (NiCd);
• nickel metal hydride (NiMH);
• lithium-ion (LiIon).

The final cost of a screwdriver depends not least on the type of batteries used and the capabilities of the charger. Chargers are available in 12 volts, 14.4 volts and 18 volts. In addition, memories are divided according to capabilities and may have:

• indication;
• fast charging;
• different type of protection.

The most used chargers use a slow charge due to low current. They do not contain an operation indication in their design and do not turn off automatically. This is more true for built-in capacity restoration devices. Chargers built on pulse circuits provide the possibility of accelerated charging. They automatically turn off when the required voltage is reached or in the event of an emergency.

Types of batteries used

Nickel-cadmium batteries do not experience problems when charging in accelerated mode. Such batteries have a high load capacity, low price and can easily withstand work at sub-zero temperatures. Disadvantages include: memory effect, toxicity, high self-discharge rate. Therefore, before charging this type of battery, it must be completely discharged. The battery has a high rate of self-discharge and discharges quickly even when not in use. Currently, they are practically not produced due to their toxicity. Of all types they have the smallest capacity.

Nickel-metal hydride is superior to NiCd in all respects. They have a smaller self-discharge value and a less pronounced memory effect. With the same dimensions, they have a large capacity. They do not contain the toxic material cadmium. In the price category, this type occupies a middle position, so it is the most common type of capacitive elements in a screwdriver.

Lithium-ion batteries are characterized by high capacity and low self-discharge value. These batteries do not tolerate overheating and deep discharge. In the first case, they are capable of exploding, and in the second, they will no longer be able to restore their capacity. They are also capable of operating at subzero temperatures and have no memory effect. The use of a charger with a microcontroller made it possible to protect the battery from overcharging, thereby making this type the most attractive for use. They are more expensive in price than the first two types.

In addition, the main characteristic of rechargeable batteries is their capacity. The higher this indicator, the longer the screwdriver works. The unit of capacity is milliampere per hour (mAh). The battery design consists of connecting batteries in series and placing them in a common housing. For Li-Ion, the voltage on one element is 3.3 volts, for NiCd and NiMH - 1.2 volts.

Operating principle of the charger

If a memory device fails, it makes sense to first try to restore it. To carry out repairs, it is advisable to have a charger circuit and a multimeter. The circuitry of many charging devices is based on the HCF4060BE microcircuit. Its switching circuit forms the delay of the charging time interval. It includes a crystal oscillator circuit and a 14-bit binary counter, making it easy to implement a timer.

The operating principle of the charger circuit is easier to understand using a real example. This is what it looks like in an Interskol screwdriver:

This circuit is designed to charge 14.4-volt batteries. It has an LED indication showing the connection to the network, LED2 is lit, and the charging process, LED1 is lit. The U1 HCF4060BE chip or its analogs: TC4060, CD4060 are used as a counter. The rectifier is assembled on power diodes VD1-VD4 type 1N5408. PNP transistor type Q1 operates in key mode; the control contacts of relay S3-12A are connected to its outputs. The operation of the key is controlled by controller U1.

When the charger is turned on, the alternating voltage of 220 volts is supplied through a fuse to a step-down transformer, at the output of which its value is 18 volts. Then, passing through, it is straightened and falls on a smoothing capacitor C1 with a capacity of 330 μF. The voltage across it is 24 volts. When connecting the battery, the relay contact group is in the open position. The U1 microcircuit is powered through a zener diode VD6 with a constant signal of 12 volts.

When the “Start” button SK1 is pressed, a stabilized signal is supplied to the 16th pin of the controller U1 through resistor R6. Key Q1 opens and current flows through it to the relay terminals. The contacts of the S3-12A device close and the charging process begins. The VD8 diode, connected in parallel to the transistor, protects it from a voltage surge caused by the relay turning off.

The SK1 button used works without fixing. When it is released, all power is supplied through the chain VD7, VD6 and limiting resistance R6. And also power is supplied to LED1 through resistor R1. The LED lights up, signaling that the charging process has begun. The operating time of the U1 chip is set to one hour of operation, after which power is removed from the transistor Q1 and, accordingly, from the relay. Its contact group breaks and the charging current disappears. LED1 goes out.

This charger is equipped with an overheat protection circuit. Such protection is implemented using a temperature sensor - thermocouple SA1. If during the process the temperature reaches more than 45 degrees Celsius, the thermocouple will work, the microcircuit will receive a signal and the charging circuit will be broken. After the process is completed, the voltage at the battery terminals reaches 16.8 volts.

This charging method is not considered intelligent, The charger cannot determine what state the battery is in. Because of this, the battery life of the screwdriver will decrease due to the development of its memory effect. That is, the battery capacity decreases each time it is charged.

Homemade charging devices

It’s quite simple to make a charger for a 12-volt screwdriver yourself, by analogy with what is used in the Interskol charger. To do this, you will need to take advantage of the ability of the thermal relay to break the contact when a certain temperature is reached.

In the circuit, R1 and VD2 represent a sensor for the flow of charge current, R1 is designed to protect the diode VD2. When voltage is applied, transistor VT1 opens, current passes through it and LED LH1 begins to light. The voltage drops across the chain R1, D1 and is applied to the battery. The charging current passes through the thermal relay. As soon as the temperature of the battery to which the thermal relay is connected exceeds valid value, it works. The relay contacts switch and the charging current begins to flow through resistance R4, the LH2 LED lights up, indicating the end of the charge.

Circuit with two transistors

Another simple device can be made using available elements. This circuit operates on two transistors KT829 and KT361.

The amount of charge current is controlled by the KT361 transistor to the collector to which the LED is connected. This transistor also controls the state of the KT829 component. As soon as the battery capacity begins to increase, the charging current decreases and the LED gradually goes out accordingly. Resistance R1 sets the maximum current.

The moment the battery is fully charged is determined by the required voltage on it. The required value is set with a 10 kOhm variable resistor. To check it, you will need to place a voltmeter on the battery connection terminals, without connecting the battery itself. Any rectifier unit designed for a current of at least one ampere is used as a constant voltage source.

Using a custom chip

Manufacturers of screwdrivers are trying to reduce prices for their products, often this is achieved by simplifying the charger circuit. But such actions lead to quick exit failure of the battery itself. By using a universal chip designed specifically for the MAXIM MAX713 charger, you can achieve good charging performance. This is what the charger circuit for an 18-volt screwdriver looks like:

The MAX713 chip allows you to charge nickel-cadmium and nickel-metal hydride batteries in fast charge mode, with a current of up to 4 C. It can monitor battery parameters and, if necessary, reduce the current automatically. Once charging is complete, the IC-based circuit draws virtually no power from the battery. It can interrupt its operation due to time or when the temperature sensor is triggered.

HL1 is used to indicate power, and HL2 is used to display fast charge. The setup of the circuit is as follows. To begin with, the charging current is selected, usually its value is equal to 0.5 C, where C is the battery capacity in ampere hours. The PGM1 pin is connected to the positive supply voltage (+U). The power of the output transistor is calculated using the formula P=(Uin - Ubat)*Icharge, where:

• Uin – highest voltage at the input;
• Ubat – battery voltage;
• Icharge – charging current.

Resistance R1 and R6 is calculated using the formulas: R1=(Uin-5)/5, R6=0.25/Icharge. The choice of time after which the charging current turns off is determined by connecting the PGM2 and PGM3 contacts to different terminals. So, for 22 minutes PGM2 is left unconnected, and PGM3 is connected to +U, for 90 minutes PGM3 is switched to the 16th leg of the REF chip. When it is necessary to increase the charging time to 180 minutes, PGM3 is short-circuited with the 12th leg of the MAX713. The longest time of 264 minutes is achieved by connecting PGM2 to the second leg, and PGM3 to the 12th leg of the microcircuit.

Charging a screwdriver without a charger

Restoring a battery without the help of a charger is not difficult, but many people have no idea how. You can charge the screwdriver battery without a charger using any constant voltage power supply. Its value should be equal to or slightly greater than the voltage of the battery being charged. For example, for a 12V battery, you can take a rectifier to charge a car. Using terminal clamps and wires, connect them to each other for about thirty minutes, observing the polarity, while monitoring the temperature of the battery.

You can also modify power devices with higher voltages using a simple integrated stabilizer. The LM317 chip allows you to control an input signal up to 40 volts. You will need two stabilizers: one is switched on according to the voltage stabilization circuit, and the second - on the current. This scheme can also be used when converting a charger that does not have charging process control units.

The scheme works quite simply. During operation, a voltage drop is formed across resistor R1; it is enough for the LED to light up. As it charges, the current in the circuit drops. After some time, the voltage on the stabilizer will be low and the LED will go out. Resistor Rx sets the highest current. Its power is selected to be at least 0.25 watts. When using this scheme, the battery will not be able to overheat, since the device automatically turns off when the battery is fully charged.

You can often come across harmful advice that you can charge the battery using a diode bridge and a 100 W incandescent lamp. This is absolutely impossible to do, because there is no galvanic isolation and, in addition to fatal damage, electric shock, there is a high probability of battery explosion.

Often, drill buyers complain that the “native” charger for a screwdriver charges the battery too slowly. As a result, you have to repeatedly postpone work for 2-4 hours. There are 2 options to avoid this situation. In the first case, you will need to purchase a new charger, in the second, you will need to make it yourself.

Types of batteries

To figure out how to make a charger for a screwdriver, you first need to study the types of batteries and their charging modes. There are 3 types of batteries:

Nickel-cadmium

This type is called Ni-Cd, it is considered good source voltage, which is capable of delivering high power. The only drawback is that such batteries are included in the list of prohibited products due to environmental considerations, so this variety will now be much less common on sale.

Nickel-cadmium batteries have an energy capacity of 1200 to 1500 mAh. The total power is provided and maintained by the number of cans inside

The maximum cell voltage is 1.2 V. The battery is charged with an electric current of 0.1-1 rated capacity. It turns out that a battery with a capacity of 5 A*h can be recharged with a current of 0.5-5 A.

VIDEO: 5 rules for charging nickel-cadmium batteries

Another name is Pb with acid gel filling. They have average characteristics and low cost. The downside is that the batteries have a large mass, which makes the device heavier. The main advantage is that it can be used in any position without the electrolyte leaking out of the container.

Their main feature is high voltage and resistance, due to which even at the end of the charge-discharge cycle there is no sharp drop in voltage

The maximum cell voltage level is 2 V, while the battery charging current always corresponds to 0.1 C.

Li-ion batteries for screwdriver

The most common type due to the complete sealing of the container. This option is characterized by increased power density, safety, environmental friendliness, low weight and ease of disposal.

Lithium-ion battery for screwdriver Li-ion 18650 Samsung 12.6V (Volt) 2400mAh

The lithium-ion cell has a maximum power of 3.3 Volts. The voltage can be gradually increased at room temperature from 0.1 to 1 C. This speeds up the charging process. But this method Suitable only for batteries that have not been over-discharged.

It is important to remember here that the screwdriver is charged up to 4.2 Volts, exceeding it will affect the reduction in service life, and reducing it will reduce the capacity. It is very important to monitor the temperature when charging.

When developing a charger circuit for a screwdriver with your own hands, it is very important to consider which battery you plan to charge. You also need to additionally calculate its voltage - 12 Volts or 18 Volts. When operating a charger for a screwdriver, it is necessary to monitor the process using a multimeter or a system with a voltage comparator, which has been pre-configured for a specific type of battery.

VIDEO: Rules for choosing a battery for a screwdriver

How to assemble your own charger

Creating a homemade charger for a screwdriver requires compliance with safety precautions and carrying out work strictly according to a given scheme. You can use the drawing below, which is universal, since such charging equipment will be suitable for any type of battery. The only important parameter here is the charge current.

Homemade charger

When recharging, the current value fully corresponds to the existing state of the battery, and when the process is completed, the indicator becomes slightly higher.

Diagram of the simplest memory for a screwdriver

The charger for a screwdriver acts as an electric current generator using transistor VT2. It, in turn, receives power through a rectifier bridge in contact with a step-down transformer. The charge current level is adjusted by adjusting resistor R1 when the battery is turned on. It will always remain the same. R3 works as a rated current limiter. VD 6 is an LED, it acts as an indicator that determines whether charging is ongoing or has already completed.

All components from the screwdriver charger circuit are installed on printed circuit board, domestic devices KD202 and D242 can be used as diodes. It is required to place the elements in such a way that there is a minimum number of intersections on the board; the ideal option would be if there are none. Leave at least 3 mm between parts.

The transistor is mounted on a heat sink 25-55 cm 2. The connection field for the charging components for screwdrivers must be covered with a housing. Here, difficulties may arise with the terminals and connection of the battery. Therefore, it is better to modify the screwdriver charger by upgrading the old one:

• open the case of the outdated recharger;
• remove all components and other filling from it;
• install a homemade circuit into the case.

The diagram must contain the following elements:

Stages of work:

1. Select the most optimal dimensions for the circuit, which easily fit into the case with all the listed components.
2. Draw a thread along all its paths according to the basic drawing, etch it in a copper frame and solder all the elements.
3. Install the heatsink on the aluminum plate so that it does not come into contact with any part of the board.
4. Securely fix the transistor with an M-3 nut.
5. Assemble the components strictly according to the diagram and solder the terminals to all necessary parts, observing polarity. Output the electrical wire for the transformer.
6. Install the transformer itself, together with a 0.5 A fuse, into the housing and equip it with an adapter to enable recharging.

VIDEO: How to charge a Li-ion battery using a screwdriver

Rating of chargers for screwdrivers

For those who do not plan to study self-assembly, we offer you to choose from a range of ready-made chargers from different manufacturers.

DEWALT DCB118

The FLEXVOLT DEWALT DCB118 universal device is used to restore batteries for DEWALT screwdrivers with a voltage of 54V; you can equally successfully charge any other devices with a nominal voltage of 18 volts.

FLEXVOLT DEWALT DCB118

For convenience, there is an indicator on the body, so you can monitor the process. Type of rechargeable batteries Li-ion. Weight 850 gr. The price of the equipment is 3500 rubles.

ONE+ Ryobi RC18120

It is declared as a highly specialized device intended only for charging Ryobi ONE+ series batteries. The advantage of having only one power supply - due to this, the weight of the device is even reduced (only 460 g), while the IntelliCell™ intelligent monitoring system has been introduced, when each cell is charged to maximum within 40-50 minutes, thereby increasing battery life .

ONE+ Ryobi RC18120

The voltage is 18 volts, the battery type is nickel-cadmium and lithium-ion. There are 4 positions of the level indicator - 25…50…75…100%. The case itself can be mounted on a wall. There is a light level indication. The cost of the device is 4850 rubles.

DC10WC (10.8 V) Makita

The device is used to restore lithium-ion batteries with a nominal voltage of 10.8 volts. There is a light indication, but no automatic stop. It is advisable to control the time to prevent overfilling the container.

DC10WC (10.8 V) Makita

Weight 1200 gr. with relatively small dimensions - only 20 cm in length. There is a 1-year manufacturer's warranty. Price 2200 rub.

VIDEO: How to properly charge Li-ion