Tool progress charger for screwdriver diagram. Charger for screwdriver batteries. Power supply elements

How to make a homemade screwdriver charger? In the construction business, the main assistant is a screwdriver. Without it, it is very difficult to work on assembling furniture, when tightening all kinds of bolts and nuts. And if it stops working, then problems immediately arise.

You can, of course, go to the store and buy a ready-made charger, but the price sometimes bites a lot. Sometimes the price is fine, but the right model There is no battery, and then there is only one way out - to create the charger yourself.

What types of batteries are there? Nickel-cadmium batteries are most commonly found on the market. They attract buyers with their size and reasonable price.

This type of battery is very effective in that it can be charged very often, only until it is fully charged. But it has one drawback, this kind is toxic, so it was abandoned in Europe.

The next type is nickel-metal hydride, from the point of view of ecology, it is quite safe. These batteries can be left unused for a very long time, but must be constantly recharged if necessary. Another popular type is a lithium-ion battery, the disadvantage of which is that this type does not tolerate low air temperatures well, and the price is very high for given view goods.

How to make a screwdriver charger

For a homemade charger, you will need the following materials and tools:

charging glass;
damaged battery;
two wires 15 cm long;
soldering iron;
screwdriver;
drill;
thermal gun.

Start assembling the battery:

They take a charging glass and carefully open it, use a soldering iron to paste over the terminals and all the electronics.

Then they take the damaged battery and use a soldering iron to solder the terminals from the plus and minus. For further work do not forget to mark the plus and minus points with a marker on the battery cover.

In the prepared glass, marks are made where the postings will take place.

With the help of a drill, holes are made, if necessary, then with the help of a blade they are adjusted to size.

The wires are passed through the finished holes, take a drill and solder the wires to the glass (it is very important to observe the polarity).

To prevent the battery connector from falling apart, a previously made imitation of a cardboard battery is inserted inside.
The battery cover is attached to the charging glass with a heat gun.

And the very last action will be to attach the bottom cover to the charging glass.

The charger is ready, now you need to insert it into the adapter, and the adapter into the battery.

Back to the table of contents

Device for a screwdriver from a USB source

You will need the following materials and tools:

screwdriver;
socket or cigarette lighter socket in the car;
usb charger;
fuse from the machine for 10 A;
detachable crimp connections;
dye;
insulating tape;
Scotch.

Getting started:

To begin with, disassemble the screwdriver into all the small parts, you do not need a stator, an anchor, a gearbox and the entire upper part.
Using a knife, cut off the upper body from the handle.

The next step is to work with a drill, you need to drill a hole in the side of the handle and sharpen it a little. There will be a fuse.

Take the crimp wires and connect them to the fuse.

In the housing from the screwdriver handle, you need to fix the fuse with wires using glue from a gun.

When all this is done, connect to the battery connector.
At the top of the screwdriver, mount the crimp wires to the cigarette lighter outlet and use a glue gun to secure everything well.

To fix everything well, wrap the entire body of the handle with tape.
Collect the entire screwdriver and connect everything well with electrical tape.

For an aesthetic look, you need to grind the putty part and cover everything with paint.

No repair is complete without a drill. This electrical appliance is powered by mains or battery. If a cordless drill is chosen for the work, you will also need a charger for it. It is sold complete with the device. However, such an element will fail sooner or later. To avoid an unfortunate circumstance, you should study the design capabilities and description of the charges. It is especially worth getting to know the charger circuit of the drill-screwdriver. This will help you know how to properly repair it.

Types of chargers

There are many types of charging tools for cordless drills. They differ in price, operating principle and repair features. Each of the types of screwdrivers should be considered in more detail.

Analog devices with built-in power supply

Such devices are quite popular due to their low cost. If the drill will not be used for professional purposes, do not focus on the duration of the work. The main condition that the simplest charger must meet is that it must provide a sufficient current load to charge the screwdriver battery.

Important! To start charging, it is necessary that the voltage at the output of the power supply is higher than the nominal indicator of the device battery.

The operation of an analog device with a power supply is quite simple. Such a charger is used as a stabilizer. As an example, you need to consider a charger circuit for a battery from 9 to 11 V. It does not matter what type of battery is used. Cordless drills are quite common among DIYers, so knowing the features of their repair will be useful to everyone.

Many home craftsmen assemble such a power supply with their own hands. Soldering the circuit can only be done on a universal board. To ensure heat dissipation of the stabilizer microcircuits, it is necessary to find a 20 sq. cm square.

Attention! The stabilizers are operated according to the compensation principle. Excess energy can be dissipated in the form of heat.

Thanks to the output transformer, the alternating voltage is reduced from 220 V to 20 V. It is possible to calculate what the power of the transformer will be by the voltage current at the charging output. AC rectification is carried out by a diode bridge.

After rectification, the current turns out to be pulsating. However, this feature of the current negatively affects the functioning of the circuit. The ripple can be smoothed out with a filter capacitor (C1). The KR 142EN microcircuit is used as a stabilizer. Radio amateurs call her "krenka". To get a voltage of 12 V, you must have a microcircuit with an index of 8B. The control is collected on a transistor VT2. In addition, trimmer resistors are used. Automation is not installed on such devices. How long it takes to charge the battery depends on the user. To control the charge, a fairly simple circuit is assembled on the VT1 transistor. There is also a VD2 diode in the circuit. When the charge voltage is reached, the indicator goes out.

In more modern systems there is a switch. Thanks to him, the voltage is turned off at the end of the charge. When you buy a cheap screwdriver, it comes with a simple charger. This explains why such devices break very often. When buying such a screwdriver, the consumer runs the risk of being left with a new, but inoperative device. However, the charger is easy to assemble with your own hands. The main thing is to have a diagram.

A homemade device can last much longer than a purchased one. To select the value of the drill-driver battery, you will need to experimentally adjust the transformer and stabilizer.

Analog devices with external power supply

The charger circuit itself is pretty simple. Complete with such a device comes network block power supply and charger. It makes no sense to inspect the power supply. Its circuit is standard. It includes a diode bridge, a transformer, a rectifier and a capacitor filter. Typically, the output is 18 V.

The control is carried out using a small board, which has the dimensions of a matchbox. Such assemblies do not have a heatsink system. For this reason, such devices quickly fail. Therefore, users are often interested in how to charge the cordless drill without a charger.

This problem can be solved quite simply:

One of the main conditions is the availability of a power source. If the "native" block is working properly, you can create simple scheme management. If the entire kit fails, a laptop power supply can be used. The output is the desired 18 V. Such a source can have a power that is enough for any battery.
The second condition is the ability to collect electrical circuits. Parts are usually soldered from old household appliances. In addition, most of them are sold on the radio market.

The control unit must have a diagram as in the photo:

An 18 V zener diode is installed at the input. The circuit that will control the charger operates on a KT817 transistor. To provide amplification, a KT818 transistor is installed. At the same time, it is equipped with a radiator for heat dissipation. Depending on what the charge current will be, it can dissipate up to 10 watts. It is necessary that the radiator has the required area - from 30 to 40 sq. cm.

The unreliability of Chinese batteries is explained by the manufacturers' savings on matches. To establish the exact charge current, you should have a 1 Kom trimmer. A 4.7 ohm resistor is installed at the output. It must also provide sufficient heat dissipation. The output power does not exceed 5W.

Assembled circuit quite simply fits into a standard charging case. The radiator does not have to be removed. The main thing is that there is sufficient air circulation inside the case. At the same time, the power supply from the laptop is still used according to its intended purpose.

Important! One of the main disadvantages of analog chargers is the lengthy charging process. In the case of a household cordless drill-screwdriver, this is not a big deal. On the simple work it's enough. It is enough to put it on charge the night before work. A simple Chinese battery in a screwdriver usually lasts 3 to 5 hours.

Impulse

Professional screwdrivers are designed for intensive use. Therefore, downtime during work is unacceptable. It is worth remembering that every serious device has a high price. Therefore, the price issue should be omitted. In addition, there are usually 2 batteries included in the kit.

Pulse block power supply is complemented by a "smart" control scheme. Thanks to this, the battery is charged to 100% in just one hour. You can build the same analog-type charger with your own hands. However, its dimensions will be equal to the dimensions of the screwdriver itself.

Pulse devices good because they are devoid of many disadvantages. They are quite compact, have high charge currents and are equipped with a well thought-out protection system. There is only one problem - the circuit of such devices is rather complicated, which affects the cost of the device.

However, even such an apparatus can be built on your own. The savings come out about 2 times.

It is worth considering the option for nickel-cadmium batteries, which are equipped with a third signal contact. A diagram of the device is assembled on the MAX713. This controller is quite popular. The output voltage will be 25 V. The current will be constant. Assembling such a power source is quite simple.

The charger is equipped with several functions that make it smart. After the voltage level is checked, it is necessary to start the accelerated discharge mode. This will prevent the memory effect. In this case, the charge is carried out in an hour and a half. The main hallmark circuit is the ability to select the type of battery and charge voltage.

When a proprietary charger of a professional device comes out, you can save a lot on repairing the charger for a screwdriver. The circuit can be assembled by yourself.

Power supply for screwdriver

Quite often, the owners of screwdrivers are faced with a situation when the device itself is working properly, and the battery pack is out of order. There are many ways to solve this problem. However, not everyone will work with toxic parts.

To continue working with the screwdriver, you must connect an external power supply. If you have a standard Chinese instrument with 14.4V batteries, you can use car battery... However, there is another option - to find a transformer with an output voltage of 15-17 V in order to assemble a full-fledged power supply.

At the same time, the necessary parts are cheap. First of all, you need a thermostat and a diode bridge. Other structural elements perform service functions - to show the input and output voltage. You do not need to purchase a stabilizer. This is due to the undemanding electric motor of the screwdriver.

conclusions

As you can see, assembling the cordless drill charger is pretty straightforward. The main thing is not to decide to throw away the appliance right away. In the event of a complete failure of the batteries, the device can be converted to a power supply. This kind of work also has many subtleties that you should get acquainted with.

To build your own charger for a screwdriver, you need to find out the diagram of such a device and the characteristics of the main parts. The assembly process itself is pretty simple. The main thing is to be able to work with a soldering iron.

Even if the power supply unit of a professional model of a screwdriver fails, it can be made networked. If you decide to repair the device yourself, you don't have to worry about the price of parts - they cost a penny on the radio market. Knowing these features of repairing cordless screwdrivers will help you do the job yourself.

Hello dear visitors. I want to offer a simple circuit diagram of a charger for sealed screwdriver batteries. The diagram is shown in Figure 1.

The basis of the circuit is the KR142EN12A three-output integrated adjustable positive voltage regulator. The stabilizer allows operation with a load current of up to 1.5A. This parameter limits the maximum battery charging current.

The circuit works in the following way... An alternating voltage of 12.6 - 13V, taken from the secondary winding of the network transformer, is rectified by a diode bridge VD1 - D3SBA40. It can be replaced with RC201, RS201, KBP005, BR305, KBPC1005 or assemble a bridge from individual diodes with a direct rectified current of at least two amperes. At the output of the rectifier there is a filter capacitor C1, which reduces the ripple of the rectified voltage. The capacitor already has a constant voltage equal to the amplitude value of the alternating voltage 12.6 ... 13V. Those. 12.6 √2 ≈ 17.7V. Such a voltage will be if ready-made filament transformers are used as a network transformer, for example, TN17, TN18, TN19 with the corresponding connection of the secondary windings. I have a transformer - rewound TVK-110L1. The effective voltage of its secondary winding is 14V.

From the rectifier, the voltage is supplied to the integral stabilizer DA1, the output voltage of which is set using the resistor R4 at the level required for your specific battery. For example, you know that the voltage of a fully charged battery is 14.1V, then this voltage must be set at the output of the stabilizer. The resistor R3 serves as the charging current sensor, in parallel with which the trimming resistor R2 is connected, with the help of this resistor the level of limiting the charging current is set, which is equal to 0.1 of the battery capacity. The power allocated to the resistor R3 is equal to I2 of the charge R3 = 1.52 1 = 2.25W, so you can use a two-watt resistor with a nominal value of 1 Ohm, but the charging current must be slightly reduced. In general, this circuit is a voltage regulator with a load current limitation. At the first stage, the battery is charged with a stable current, then, when the charging current becomes less than the limiting current, the battery will be charged with a decreasing current to the stabilization voltage of the DA1 microcircuit.

The VD2 diode serves as a charging current sensor for the HL1 indicator. In this case, the HL1 LED will indicate the passage of current up to,? 50 milliamps. If the same R3 is used as a current sensor, then the LED will go out already at a current of ≈0.6A, i.e. the end of charging the batteries, judging by the off LED, would come too early. The battery would not be fully charged. This device can also charge 6-volt batteries. By the way, you can figure out if it is possible to charge batteries with a voltage of 1.25V. The voltage at the input of the DA1 stabilizer is 20V, the charge current is admissible - 1.5A. the initial voltage on the battery is equal to one volt, which means that in this case 20V - 1V = 19V will drop on the microcircuit. In this case, a power equal to U I = 19V 1.5A = 28.5W will be released on it. The maximum allowable power dissipation for KR142EN12A is 30W. Those. Provided that a suitable radiator is used, it is also possible to charge a separate battery cell with a voltage of 1.25V. The radiator area for a given power can be estimated from the diagram.

The charger is assembled on a printed circuit board, a drawing of which can be downloaded here. The specific details that I applied are shown in photo 1. Well, I think that if you have a lau board layout, you can use other components by changing the wire pattern. If you use TVK-110L1 as a network transformer, then the primary winding can be left completely, i.e. 3000 rolls. This means that in this case the number of turns per volt will be equal to W1volt = W1 / U1 = 3000/220 ≈ 13.7. The number of turns of the secondary winding will be equal to W2 = U2 W1volt = 12.6 13.7 ≈ 173 turns. Wire diameter D = 0.7√I = 0.7 √1 = 0.7mm - for a charge current of 1A. If the secondary winding is not removed in the core window, then you will have to sacrifice a small no-load current of the transformer and recalculate the number of turns of the primary winding for a different coefficient. We count. The cross-sectional area of the TVK-110L1 core is Sс = 6.4 cm2 (ШЛ20 × 32), W1volt = 50 / Sс = 50 / 6.4 ≈ 8 turns per volt, then the number of turns of the primary winding will be 220 8 = 1760 turns. We'll have to wind 3000 - 1760 = 1240 coils. Well, you can count the secondary winding yourself. If you have any questions, I have a request, ask them on the forum. Perhaps the answers to them will be of interest to other site visitors. Goodbye. K.V.Yu.
Download the diagram and drawing of the printed circuit board.

Often, the native charger that comes with the screwdriver works slowly, taking a long time to charge the battery. For those who use a screwdriver intensively, this is very interfering with their work. Despite the fact that the kit usually includes two batteries (one is installed in the handle of the tool and in operation, and the other is connected to a charger and is in the process of charging), often the owners cannot adapt to the duty cycle of the batteries. Then it makes sense to make a charger with your own hands and charging will become more convenient.

Battery types

Batteries are not of the same type and may have different charge modes. Nickel-cadmium (Ni-Cd) batteries are a very good source of energy, capable of delivering great power... However, for environmental reasons, their production has been discontinued and they will be encountered less and less. Now they have been superseded by lithium-ion batteries everywhere.

Sulfuric acid (Pb) lead gel batteries have good characteristics, but they make the instrument heavier and therefore are not very popular, despite the relative cheapness. Since they are gelatinous (a solution of sulfuric acid is thickened with sodium silicate), there are no plugs in them, the electrolyte does not flow out of them and they can be used in any position. (By the way, nickel-cadmium batteries for screwdrivers also belong to the gel class.)

Lithium-ion batteries (Li-ion) are now the most promising and advanced in technology and on the market. Their feature is the complete tightness of the cell. They have a very high power density, are safe to handle (thanks to the built-in charge controller!), Are beneficially disposed of, are the most environmentally friendly, and have low weight. In screwdrivers, they are currently used very often.

Charge modes

The nominal voltage of the Ni-Cd cell is 1.2 V. The nickel-cadmium battery is charged with a current from 0.1 to 1.0 of the nominal capacity. This means that a 5 amp-hour battery can be charged with a current of 0.5 to 5 A.

The charge of sulfuric acid batteries is well known to all people holding a screwdriver in their hands, because almost every one of them is also a car enthusiast. The nominal voltage of the Pb-PbO2 cell is 2.0 V, and the charging current of the lead sulfuric acid battery is always 0.1 C (current fraction of the nominal capacity, see above).

The lithium-ion cell has a nominal voltage of 3.3 V. The charging current of the lithium-ion battery is 0.1 C. At room temperature, this current can be gradually increased to 1.0 C - this is a fast charge. However, this is only suitable for those batteries that have not been over-discharged. When charging lithium-ion batteries, be sure to observe the voltage exactly. The charge is made up to 4.2 V for sure. Exceeding dramatically reduces service life, decreasing - decreases capacity. Watch the temperature when charging. A warm battery should either be limited to a current of 0.1 C, or turned off before it cools down.

ATTENTION! If the lithium-ion battery overheats when charged over 60 degrees Celsius, it may explode and catch fire! Do not rely too much on the built-in safety electronics (charge controller).

When charging lithium battery, the control voltage (voltage of the end of the charge) forms an approximate series (the exact voltages depend on the specific technology and are indicated in the passport for the battery and on its case):

The charge voltage should be monitored with a multimeter or circuit with a voltage comparator tuned exactly to the battery being used. But for “entry-level electronics engineers” you can really only offer a simple and reliable scheme described in the next section.

Charger + (Video)

The charger below will provide the correct charging current for any of the listed batteries. Screwdrivers are powered by batteries with different voltages of 12 volts or 18 volts. It doesn't matter, the main parameter of a battery charger is the charge current. The voltage of the charger when the load is disconnected is always higher than the rated voltage, it drops to normal when the battery is connected while charging. During the charging process, it corresponds to the current state of the battery and is usually slightly higher than the nominal at the end of charging.

The charger is a current generator based on a powerful composite transistor VT2, which is powered by a rectifier bridge connected to a step-down transformer with sufficient output voltage (see the table in the previous section).

This transformer must also have sufficient power to provide the required current for continuous operation without overheating the windings. Otherwise, it may burn out. The charge current is set by adjusting the resistor R1 with the battery connected. It remains constant during charging (the more constant, the higher the voltage from the transformer. Note: the voltage from the transformer should not exceed 27 V).

Resistor R3 (at least 2 W 1 Ohm) limits the maximum current, and the VD6 LED is on while the charge is in progress. By the end of the charge, the LED light decreases and it goes out. However, do not forget about precise voltage control. lithium ion batteries and their temperature!

All details in the described scheme are mounted on a printed circuit board made of foil-coated PCB. Instead of the diodes indicated in the diagram, you can take the Russian diodes KD202 or D242, they are quite available in the old electronic scrap. It is necessary to arrange the parts so that there are as few intersections as possible on the board, ideally not a single one. You should not get carried away with the high density of installation, because you are not assembling a smartphone. It will be much easier for you to solder the parts if 3-5 mm remain between them.

The transistor must be installed on a heat sink of sufficient area (20-50 cm2). It is best to mount all parts of the charger in a convenient homemade case. This will be the most practical solution, nothing will interfere with your work. But here great difficulties can arise with the terminals and connection to the battery. Therefore, it is better to do this: take an old or faulty charger from friends, suitable for your battery model, and rework it.

Open the case of the old charger.
Remove all the former filling from it.
Pick up the following radioelements:

Choose a suitable size for a printed circuit board that fits into the case along with the details from the given diagram, draw with nitro paint its tracks along schematic diagram, pickle in copper sulphate and unsolder all the details. The radiator for the transistor must be installed on an aluminum plate so that it does not touch any part of the circuit. The transistor itself is tightly screwed to it with a screw and an M3 nut.
Assemble the board in the case and solder the terminals according to the scheme, strictly observing the polarity. Lead out the wire for the transformer.
Install the transformer with a 0.5 A fuse in a small suitable housing and provide a separate connector for connecting the converted charging block... It is best to take connectors from computer power supplies, install dad in a case with a transformer, and connect mom to the bridge diodes in the charger.

The assembled device will work reliably if you have carefully and carefully performed

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Charger for a screwdriver - how to choose and can you do it yourself

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

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

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 the work is not the very first question. The task of a simple charger is to obtain a constant voltage with a current load sufficient to charge the battery.

This charging works according to 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.

Such a power supply unit (aka a charger) can be assembled by hand. You can solder the circuit on a universal circuit board. To dissipate the heat of the stabilizer microcircuit, a copper radiator with an area of 20 cm² is sufficient.

Stabilizers of this type work according to the compensation principle - excess energy is removed in the form of heat.

The input transformer (Tr1) lowers the 220 volt AC voltage to 20 volts. The power of the transformer is calculated from the current and voltage at the output of the charger. Further, the alternating current is rectified using a diode bridge VD1. Usually manufacturers (especially Chinese) use Schottky diode assemblies.

After rectification, the current will be pulsating, this is harmful for the normal functioning of the circuit. The ripple is smoothed out by a filtering electrolytic capacitor (C1).

The role of the stabilizer is performed by the KR142EN microcircuit, in the amateur radio slang - "roll". To obtain a voltage of 12 volts, the microcircuit index must be 8B. The control is collected on a transistor (VT2) and trimming resistors.

Automation on such devices is not provided, the battery charging time is determined by the user. To control the charge, a simple circuit is assembled on a transistor (VT1) and a diode (VD2). When the charging voltage is reached, the indicator (LED HL1) goes out.

More advanced systems include a switch that cuts off the voltage at the end of the charge in the form of an electronic key.

Complete with economy class screwdrivers (produced in the Middle Kingdom), there are chargers and simpler ones. It is not surprising that the failure rate is quite high. The owner has the prospect of staying with a relatively new inoperative screwdriver. According to the attached diagram, you can assemble a charger for a screwdriver with your own hands, which will last longer than the factory one. By changing the transformer and stabilizer, you can choose the required value for your battery.

Analog with external power supply

The charger circuit itself is as primitive as possible. The kit includes a power supply unit and a charger itself, in the battery module retainer housing.

It makes no sense to consider the power supply, its circuit is standard - a transformer, a diode bridge, a capacitor filter and a rectifier. The output is typically 18 volts, for classic 14 volt batteries.

The charge control board occupies the area of a matchbox:

As a rule, there is no heat sink on such assemblies, except that the load resistor high power... So similar devices often fail. The question arises: how to charge a screwdriver without a charger?

The solution is simple for a person who knows how to hold a soldering iron in his hands.

The first condition is the presence of a power source. If the "native" unit is working properly, it is enough to assemble a simple control circuit. In case of failure of the entire set, you can use a laptop power supply. The required output is 18 volts. The power of such a source is enough for the eyes for any set of batteries.
The second condition is basic skills in assembling electrical circuits. The details are the most affordable, you can drop out of the old household appliances, or buy on the radio market literally for a penny.

Schematic diagram of the control unit:

At the input, a zener diode for 18 volts. The control circuit is based on the KT817 transistor, the amplification is provided by the powerful KT818 transistor. It must be equipped with a radiator. Depending on the charge current, it cannot dissipate up to 10 W, so a radiator with an area of 30-40 cm² is required.

It is the “match” economy that makes Chinese chargers so unreliable. A 1KOhm trimmer is required to accurately set the charge current. The 4.7 ohm resistor at the output of the circuit must also dissipate enough heat. Power is not less than 5 watts. The end of the charge will notify led indicator, it will go out.

The assembled circuit is easy to place in a standard charging case. It is not necessary to take out the radiator of the transistor, the main thing is to ensure air circulation inside the case.

The savings lie in the fact that the power supply from the laptop is still used for its intended purpose.

For a household screwdriver, this is not scary. I left it to charge overnight before starting work - enough to assemble the cabinet. The average charging time of a Chinese cordless drill is 3-5 hours.