What does the charging look like for a screwdriver. How to make a charger for a screwdriver
Do.It.Yourself screwdriver charger. Scheme and principle of charging
The battery is an assistant for the autonomous operation of a screwdriver and other household tools. ZU is designed to recharge the battery. The charger scheme for a screwdriver differs in different devices depending on the voltage of the power supply. They are at 12, 14 and 18 volts.
The principle of operation of the charger for different batteries of screwdrivers is as follows:
- When connecting the device to the network, the voltage of 220V passes through the fuse.
- Alternating voltage goes to a reduction transformer. The value of Voltage is converted to 18.
- The charge falls on the diode bridge.
- There is a straightening and transition to the capacitor C1, its capacity is 330 μF. Voltage is converted to 24V.
The relay closes after turning on by pressing the button. The battery begins to charge at the outlet of the network rectifier. The average time of full charge of battery in a screwdriver is 50-60 minutes. These are average indicators that apply to batteries 12, 14 or 18 volts.
Charger schemes for screwdrivers
In the same screwdrivers, various types of batteries that differ in parameters and technical characteristics can be used. In this regard, they require different chargers. Therefore, before you purchase or make a charger for a screwdriver with your own hands, you need to determine the type of battery and operating conditions. In addition, it is recommended to study the main schemes most often used in charging devices.
Charging on a microcontroller. It is placed in a regular case, equipped with a sound and light alarm about the beginning and end of the charge. This scheme provides the correct battery charging. At the beginning of the work, LEDs light up and then go out. Indication is accompanied by a sound signal. Thus, the performance of the device is tested. After that, the red LED begins to flash evenly, which indicates a normal charging process.
Upon reaching the battery of a full charge, the red LED stops blinking, and a green, accompanied by a sound signal, lights up instead. This means that charging is over.
Setting the voltage level, which should be with complete charging, is carried out using a variable resistor. In this case, the input voltage value is equal to the voltage of a fully charged battery plus one volt. The diagram uses any field transistor with a P-channel and the most suitable in the current characteristics.
In order to ensure charging at the level of 14V, the voltage supplied to the input should be at least 15-16V. The threshold of the operation, turning off the charger, is installed using a variable resistor at 14.4V. The charging process itself proceeds in the form of pulses displayed at the LED. In the intervals between pulses, the voltage on the battery is controlled and, upon reaching the desired value, the sound signal is supplied together with the flashing of the LED on the end of the charging.
There are other chargers. For example, charging for a drill-sprayer works with a voltage of 18 volts. When charging a battery for 14.4V, a charging current is selected using a resistor.
Homemade charge devices
Independently make a charge for a 12.Volt screwdriver with your own hands, by analogy with the one used in the OS intercol is quite simple. To do this, you will need to take advantage of the ability of the thermallane to break off contact when a certain temperature is achieved.
In the circuit R1 and VD2 are a charge current sensor, R1 is designed to protect the diode VD2. When the voltage is supplied, the transistor VT1 opens, the current passes through it and the LH1 LED begins to glow. The voltage value falls on the chain R1, D1 and is applied to the battery. The charge current passes through the thermallane. As soon as the temperature of the battery to which the heat relay is connected will exceed the permissible value, it works. Relay contacts are switched, and the charge current begins to leak through resistance R4, the LH2 LED lights up, reporting the end of the charge.
Scheme on two transistors
Another simple device can be performed on available elements. This scheme works on two transistors KT829 and KT361.
The value of the charge current is controlled by the KT361 transistor to the collector, which is connected by the LED. This transistor also controls the state of the compound element KT829. As soon as the battery capacity begins to increase, the charge current decreases and the LED accordingly goes out smoothly. The maximum current is set by resistance R1.
The moment of the full charge of the battery is determined by the necessary voltage on it. The required value is set by a variable resistor for 10 kOhm. To check it, you will need to put a voltmeter on the terminals of the battery, without connecting it itself. Any rectifier unit designed for a current of at least one ampere is used as source of constant voltage.
Using a specialized chip
Shuruzerte manufacturers try to reduce for their products, often this is achieved by simplifying the struggle scheme. But such actions lead to a quick failure of the battery itself. Using a universal microcircuit designed specifically for the ZU MAXIM MAX713, you can achieve good indicators of the charge process. This is what the circuit of the charger for a screwdriver for 18 volts looks like:
The MAX713 chip allows you to charge nickel-cadmium and nickel-metall-hydride batteries in fast charge mode, current up to 4 c. She knows how to track the parameters of the battery and, if necessary, reduce the current automatically. At the end of charging, the circuit based on the microcircuit practically does not consume energy from the battery. Can interrupt his work in time or when the thermal attemptor is triggered.
HL1 serves to indicate nutrition, and HL2 to display fast charge. The setting of the scheme is as follows. To begin with, a charging current is selected, usually its value is 0.5 C, where C is the battery capacity in amperes. PGM1 output is connected to the plus of the supply voltage (u). The power of the output transistor is calculated according to the formula p = (UB. Ubat)Izar, where:
The resistance R1 and R6 is calculated by the formulas: R1 = (UVH-5)/5, R6 = 0.25/Izar. The choice of time through which the charging current will be turned off is determined by connecting the contacts PGM2 and PGM3 to different conclusions. So, for 22 minutes, the PGM2 is left unconnected, and PGM3 is connected with U, for 90 minutes the PGM3 is switched with the 16th foot of the Ref chip. When you need to increase the charging time to 180 minutes PGM3 is shaken with the 12th foot Max713. The greatest time for 264 minutes is achieved by the PGM2 connection with the second foot, and PGM3 with the 12th chip.
Charging with a faulty battery
Sometimes it happens that the screwdriver itself works, but the battery broke. There are several solutions to the problem:
- Buying a new one.
- Repair of the old. If you do it yourself, special knowledge will be required. In addition, not everyone wants to work with harmful substances.
- Connection via a power supply. For example, if there is a common “Chinese” at 14.4 V, a car battery is suitable. You can assemble your own from the transformer by 15-17 in. A diode bridge (rectifier) and a thermostat to combat overheating will be required. The remaining components. Only to control the voltage at the input and output. The stabilizer is not needed.
- “Native” battery or its substitutes can generally be excluded from the structure. Screwdriver will eat from the network directly.
Charger for a screwdriver battery
The voltage was set, now you can configure the charge current. To do this, first, using the tuning resistor of the current adjustment, set the minimum charge current, rotating it counterclockwise and when clicks appear, you need to do a turn or two clockwise. This is necessary to configure the minimum current so as not to damage the power supply.
Next, with a multimeter in the current measurement mode, set the charge current. Install the probe of the multimeter on the terminal terminals DC-DC of the converter and set up the charge current of approximately 1A. You need to do this as quickly as possible so as not to damage the current inner shunt of the multimeter.
Everything, the charge current is configured. The voltage and charge current of the assembled charging device are configured for the desired battery and now you can connect the plow plug directly to the screwdriver battery.
On the DC-DC DC-DC board, the current restriction LED lit up and the battery charging process went. The charge current is about 1A, as was previously configured. The batteries are gradually charging and their tension increases.
At the end of the charging process, the battery protection board will turn off the battery connection with charging and on the DC-DC board of the converter will light up the LED near the terminal.
As a result, the collected charging turned out to be very universal and, if necessary, it can be redesigned in the same way for charging two, three or damn battleships.
Charger scheme for a 12 volt screwdriver
Devices designed for 12 volts operate with a maximum voltage up to 30 Ohms. Most often they are designed for 10 mAh batteries. Makita manufacturer is a common example of this. The circuit of the charger for a 12 volt screwdriver looks as follows:
12 volt voltage circuit
Field resistors may be present in the chain. Their maximum container in this case is 4.4 PF. The chain conductivity is about two times less than that of the 18-volt analogue and is 9 μ. The capacitor acts the role of a tact frequency controller. Some ZU have a phase resistor that supports the frequency of oscillations.
Modernization of charging devices
In the first example (analogy), an electrical circuit for a 12V battery is given. You can install other electrical parameters at the output by current and voltage by changing the parameters of the transformer and the microcircuit. The revision is based on preliminary calculations.
Note. If only repairs of charging screwdriver are carried out, the pictures should be taken during disassembly. They will help subsequently correctly install the functional components of the structure.
What can you assemble a power supply
The power supply unit for charging a screwdriver can be made according to various schemes. It all depends on the qualifications, the availability of devices and available materials.
From a computer BP
A good supply unit for a screwdriver with a voltage of 12 V can be obtained from a BP for a computer. First you need to check whether it is suitable for parameters.
In the above example, the BP has two 12-volt channels-at 11 A and 13 A. Each channel is enough to power the selected power tool for 12 volts. On the Internet you can find tips on the parallel connection of the channels until the total current is obtained (in the given case. 24 A). It is not recommended to do this, because due to the difference in stresses, one channel can become a consumer for another. The whole risk of choosing the owner. A loop of wires comes out from the power supply. Everything must be cut off except:
Sometimes you need to leave a red wire. Some schemes require the basic load. To do this, between red and any black, you need to connect a 12.Volt light bulb. If in its absence the PSU does not turn off, then it can be removed. The green wire must be connected to any black. And 12 volts remove from yellow and black (any) conductors.
From the transformer
If there is a suitable transformer, you can build a power source on it. The general scheme of an unstabilized power source is shown in the figure. Such a device consists of:
If there is a ready.Made industrial transformer, you need to find his data according to the directory. If they arrange, BP can be assembled on it. If not, it can be redone by first checking its suitability for work in the required conditions. The suitability of the transformer is determined by its power. If you set the output current of 10 A, a voltage of 14 V and the efficiency of the system (from the transformer to the output shaft of the screwdriver) equal to 0.5, then a transformer with a power of P = 10 A14 V/0.5 = 280 W is required (you can round to 300 Tue).
To determine the power of the transformer by iron, you need to find the area of the cross.Section of its core in centimeters (in most cases you can remove the dimensions without disassembly). The resulting area in square centimeters SC must be substituted in the formula:
If the result is exceeds 300 W, the transformer is suitable for the manufacture of a power supply. Next, you need to remove all secondary windings and wind up a new. The number of turns can be determined experimentally. To do this, you need to wind any known number of turns with any wire and measure the output voltage. Suppose, having wound 10 turns, the output is 5 volts. So, one volt has two turns, and to obtain 14 volts you need to wind 28 turns. For 10 ampers, the cross.Section of the wire must be at least 2.5 kV.Mm, this corresponds to a thickness of 1.8 mm.
After the manufacture of the transformer, you need to choose diodes capable of working at the selected current. They must be put on radiators. And the last is to install a smoothing capacitor. It should be designed for a voltage of at least 25 volts and have a capacity of 4000-10000 μF (more can increase, but the dimensions will increase). For such tasks, the transformer power supply is quite bulky and heavy.
It can be supplemented with a voltage stabilizer, then it will maintain torque at any load (but this is not necessary. After all, in the normal mode, the batteries also sit at a large current).
You can assemble a stabilizer on an integrated chip of the 78xx series (79xx for a negative shoulder), destroying it with an external transistor.
The finished source must be placed in the case. It can be done on your own or pick it up with ready.
From the laptop
A good result can be obtained by applying the side of the power from the laptop. Such devices are designed for the output voltage of 19 volts and for various load currents. You can choose source that issues a current up to 6 amperes, this is enough for most homework. You should not overload such source. The protection will work or the self.Healing fuse at the input will turn off (it is not always restored independently, and you have to replace it).
To power a screwdriver, you can use adjustable and unregulated DC power sources used, for example, in laboratories. Their advantage is that the output voltage can be adjusted and installed, depending on the power tool model, both 12 V and 18 V. The problem is that it is difficult to find a laboratory voltage source designed for an output current 10 A. So, the block presented in the photo for each channel has a current limitation of a slightly more than 3 A. The voltage is about zero, so the screwdriver cannot work in this mode. At best, this power supply will provide an idle power tool.
The best option is the impulse power source. Light, compact, does not contain a powerful heavy transformer due to the fact that the transformation of the voltage level occurs at a higher frequency. The disadvantage of such a solution is a complex circuitry. To make a pulsor with your own hands, a certain qualification will be required.
Charging screwdriver without charger
It is not difficult to restore the battery without the help of it. You can charge a screwdriver of a screwdriver without a charger using any power supply with a constant voltage. Its value should be equal or slightly larger than the voltage of the charged battery. For example, for 12V batteries you can take a rectifier for charging a car. Using terminal clamps and wires, connecting polarity, to each other for thirty minutes, while controlling the temperature of the battery.
And you can finalize and power supply with greater voltage using a simple integral stabilizer. The LM317 chip allows you to control the input signal up to 40 volts. You will need two stabilizers: one is turned on according to the voltage stabilization scheme, and the second is current. Such a scheme can also be applied when remaking a memory that does not have components of control of the charging process.
The scheme works is completely easy. During operation, the voltage drop is formed on the resistor R1, it is enough to light up the LED. As it is charged, the current falls in the circuit. After some time, the voltage on the stabilizer will be small and the LED will go out. RX resistor sets the largest current. Its power is selected at least 0.25 watts. When using such a scheme, the battery cannot overheat, since the device is automatically turned off with a full battery charge.
Universal charging for a screwdriver
Chargers for tools are always in the arsenal of masters who regularly work in conditions of power supply. Compact devices help to replenish the power supply level of batteries, due to which a screwdriver, drill and other technique function. On sale are devices compatible with accumulators of different types, so before buying it is necessary to study all technical nuances. Famous brands have created reliable and durable chargers for tools. Most of the models are equipped with systems of protection against voltage drops, incorrect connection of polarity and other negative factors. An undoubted advantage will be the built.In cooler for cooling both the device itself and the battery installed in the nest. Management does not require special knowledge and skills from the user. The presence of LED sensors that notify the end of reloading will save you from the need to continuously control the process. If you use a lot of equipment, take a closer look at the models with branches for 2 or more batteries. The rate of replenishment of the power level depends both on the maximum current of the charger itself, and on the battery capacity. The DNS online store presents devices of different brands. You can familiarize yourself with detailed descriptions, photos of each model, and then buy charger for tools online.
When using a screwdriver, users often encounter damage to the charger (ZU). This is primarily due to the instability of the parameters of the electrical network, to which the charge device is connected, and in the second. With the failure of the battery. This problem is solved in two ways: by buying a new charger for a screwdriver or its independent repair.
Types of charging devices
This section discusses typical electrical circuits. Choose a suitable charger for a screwdriver taking into account the following factors:
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- Type of battery;
- Number of cells;
- The possibility of thorough control of the charging process;
- The presence of skills and knowledge for high.Quality assembly (settings) of a certain design;
- Additional requirements for weight, size, other individual criteria.
Analogue with a built.In power supply
The popularity of such engineering solutions is explained by comparative simplicity and low cost. The device presented in the next drawing provides stable maintenance of the voltage for charging a 12 volt unit with a sufficiently high current.
- The KR142en microcircuit performs the main function. Stabilization;
- For the above example (12V), a modification with the “8B” index in the designation is suitable;
- This element heats up, so it is mounted on a metal radiator with a scatter area of 20-25 cm square.;
- The winding of the transformer (cross section of the conductors) is calculated according to the required current at the output;
- The condenser C1 is removed residual pulsations after straightening with a diode bridge;
- The extinguished LED (HL1) signals the completion of the charging cycle, there is no automatic shutdown.
Analogue with external power supply
The principal scheme in this version is similar to the examined example. The main difference is the separate execution of the rectifier block:
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Electric circuit of the control unit of the charger
Such a device can be made with miniature. It can be connected to a standard rather powerful rectifier (this is a laptop power supply, tablet, other equipment). Explanations for assembly:
- A large power disperses on the KT 818 transistor, so it is installed on an effective radiator (area. From 35 to 45 kV. Cm);
- The tuning resistor set the optimal current current, taking into account the features of the battery;
- As in the previous version, the completion of the procedure is the extinguished LED.
Previous devices are able to restore the functionality of the standard screwdriver battery in 4-6 hours. The scheme presented below will complete the similar task much faster (45 minutes.-1,5 hour). The main advantages are minimum sizes and lightness.
This scheme is designed to charge Ni-CD batteries of an improved type. They are equipped with a special contact, which is necessary to control temperature indicators. Such a device without additional commands reproduces an accelerated discharge cycle. The user can install with jumper various combinations of output parameters.
How to charge a screwdriver if there is no charger
Using a screwdriver allows you to significantly accelerate the process of installing fasteners, where self.Tapping screws and screws are used. This is especially true with large volumes of work, when the manual method looks very obsolete. However, there are situations when a charger to a screwdriver either broke or forgotten: in such cases, you have to resort to one of the folk methods.
Ways to charging a screwdriver without a charger:
One. Car charger. The main thing in this case is to avoid reloading the battery of the power tool, which in its parameters is noticeably different from the automobile analogues of lead type. A great option is to have an electronic control and voltage force control of electronic adjustment of. For a charging current, in this case, a parameter is selected within 0.5-0.1 Ah, from the total capacity indicator. For example, if the capacity of the battery1.3 ah, current indicators should be set within 650-130 mA. If there are too large current indicators on the charger for lead batteries, then they use a ballast resistance to limit them, which is included sequentially with the battery. A car lamp often acts in this role. 2. Universal charger. It is economically profitable to buy such a device if, in addition to a screwdriver, there are other household appliances on batteries. For such purposes, the use of laboratory power sources and model charges is quite suitable. In addition to universalism, a similar device is famous for the presence of many settings that allow you to organize the most optimal charging mode for the battery.
External sources. This technique is used mainly in cases where, due to wear of the power tool, the acquisition of a new charger for it is economically inappropriate.
We revive the nickel-cadmium battery
The screwdrivers equipped with nickel-cadmium batteries have practically the past. But they are still sold, found and even work, since the Ni-CD elements can “live” up to 20-25 years, although they withstand about 900 “charge/discharge” cycles. Another feature of nickel-cadmium batteries-they can be stored in a discharged state. So if you found a grandfather’s screwdriver with a Ni-CD battery in the attic, then it makes sense to try to revive it.
We will try to charge the battery. Any burden capable of providing the desired voltage and current equal to half the battery capacity is suitable.
We turn on, try to charge. If the battery takes charging, then we continue. If there is no half.Zero on it, we move on to the plan “g” and “p” (see. Below).
As soon as the voltage on the battery reaches the value of 1.37 V, multiplied by the number of batteries, we stop the process. But that’s not all. Not the fact that the battery is fully charged. Nickel-cadmium batteries suffer from the so-called memory effect. If they were constantly discharged, say, up to 60%, and then put them on charging, then they will get used to it and then they will refuse to work when discharge for all the same 60%. Therefore, we discharge our battery with approximately the same current as they charged. We discharge to a value of 1 V, multiplied by the number of batteries. As a load, you can use car lamps or a screwdriver itself.
After that, we are completely charged again. Repeat the operation “charge/discharge” 3-4 times. We fully charge and try to use a screwdriver. If even after all these manipulations, the battery capacity is significantly lower than the declared, then, unfortunately, in our hands a decrepit, outdoor old man. He cannot be resuscitation.
Plan “w”, pushing
Plan “g” consists in the “pushing” of the battery in short (0.2-0.3 sec) high current pulses. Over, the current should be much (ten times) more than the battery capacity. “Pushing” is better each battery separately. Therefore, we open the battery, find out where each battery has plus and minus. As a pusher, we will use a car battery, but any other powerful source with a voltage of 10-15 V is suitable.
We connect the minus of our element to the minus of the “pusher”, connect one end of the wire to the plus of the “pusher”, and the second end we briefly touch the plus output of the Ni-CD element. Frequency of touches-2-3 per second. As a result of such a burning, dendrites causing microsyps are eliminated, and the battery comes to life.
The operation is carried out within 5-6 seconds. We put it on charging. If the process has gone, we eliminate the effect of memory (see. Higher). Try to use.
Plan “P”, Dolnia
This plan is effective in the degradation of electrolyte, because during operation there is a process of oxidation with water consumption. And the plan is:
- Microdrel make a hole in the housing.
- Pour 1 cube of distilled water into the hole with a syringe.
- We are waiting for an hour, then “pushing” the element with high current pulses.
- We put it on charging. We are waiting for a day, measure the voltage.
- If the voltage is normal, seal the hole with a sealant or soldering.
- If it fell or the element did not want to take exercises, go to paragraph 2 and do so until there is nowhere to pour water.
If it did not help, then you can read the articles “How to redo the battery screwdriver for 12 or 18 V in the network with your own hands” and “How to make a power supply for a screwdriver”. Still better than throwing a working tool again into the attic.
We found out how to charge a screwdriver battery without a native “charging”. Now, even if the “charger” of your screwdriver burned, drowned, lost or stolen, you will find a way out.
Types of charging devices
In the kit, one or two battery with a charger is attached to the screwdriver. Now the manufacturers of the power tool have a trend for the sale of products without batteries. This marketing technique forces buyers to purchase models of manufacturers already available in their arsenal. In any case, if the battery is purchased, even separately, you can take it to it. The matter is still in the mechanical design. The charger of one manufacturer is most likely not suitable for charging another.
Almost always, the device for replenishing energy is optimized for a specific type of accumulators, charges it in the most favorable current mode, stops charging automatically at the end of the process. Therefore, when purchasing a charger and batteries of one manufacturer, you can not think about compatibility if the ZU is designed for the battery of the same manufacturer and type.
In most cases, it is sold in impulse performance. But for nickel-cadmium batteries, there are charging devices that are considered professional (appropriate cost). They are called impulso-revervation. For each positive impulse, they give out the release of negative polarity of a small amplitude. This eliminates the memory effect characteristic of the NI CD accumulators and their capacity is maintained.
What to do if the zap does not charge the battery
The reasons why the battery screwdriver stopped charging can be several:
- The fuse burned;
- The wire is broken;
- Problems with the battery;
- The battery overheated, the microcontroller forcibly limited the charge;
- Connector is contaminated.
The presence of a battery in a construction tool significantly expands the area of use, makes the work comfortable. At the same time, the user has the need to control the level of charging the battery, regularly replenish energy. It is important that the charger is good, suitable for the type of screwdriver battery, if necessary, allowed to charge a spare battery when the main one is in work.
Fundamentals for independent manufacturing
Regardless of the preferred charger, the electronic components must be placed on the board and connected according to the scheme. The easiest way is to apply a piece of the layout (it is strictly not recommended to use a blessing. It will not be able to provide reliable contact for a long time).
The only minus of the layout is a low aesthetic component. If this does not suit the future of the owner, you can make a printed circuit board at home. Good results are given by the Lut method (laser-saturation technology). Its essence is that the drawing of the board is printed on a laser printer on a special (or simply glossy magazine) paper.
Then the drawing is translated using an iron on a copper coating of a blank of foil material and poisoned.
A more complex way is with a photoresist (liquid or film). It will require an ultraviolet lamp to implement it. But the possibilities of this method are much higher.
You can etch the board in a classic chlorine solution. Another mixture is more affordable and convenient:
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After etching in any way, the board is washed in a large amount of running water, the pattern coating is washed off by a solvent. The board is dried, holes are drilled in it, and after the plunging it is ready for installation.
The drawing of the board can be developed in a free program. For example, Sprint Layout is easily mastered. Upon reaching a certain qualification, you can master more complex programs for the development of printed circuit boards, but they will have to purchase or use free versions with cut capabilities (they are enough to close 90% of the needs of the home master). When developing a fee, it is necessary to provide for the possibility of installing powerful transistors and diodes on radiators. To do this, there should be a place on the board, or the elements are located on the edge. To screw them on external heat volumes.
Recommended for viewing: charger for a screwdriver from what was in the house.
If the scheme allows you to fix power elements directly to the radiator, then transistors or diodes must be planted on thermal conductive paste. If it does not allow. Through insulating mica or elastic gaskets. At the end of the assembly, you need to make a case for the device or make it yourself. On the front panel, control and indications are placed. To connect the batteries, you can mount the seat with contacts from the failed ZU.
It is easy to assemble a device for charging batteries of screwdrivers on your own. The scheme (and, accordingly, the level of automation) must be selected for your own qualifications.