In this topic, we will look at a screwdriver malfunction, learn how to check a screwdriver, and more. An explanation will be given based on personal photographs, which will allow you to learn some details in checking the circuit of the power tool. Let's start with powering the screwdriver.

Batteries for screwdriver

The battery of a screwdriver consists of separate electrochemical elements, which, unlike primary elements, are capable of restoring their chemical composition electrolyte. How to repair a screwdriver battery if your screwdriver fails (broken). First of all, let's look at what the principle of generating electricity from such individual battery cells is based on. The example shows a manganese-zinc element (Fig. 1).

The zinc vessel in such an electrochemical battery is an electrode with negative charge. The positive electrode here is a carbon rod. The carbon rod is in a medium of active material - manganese dioxide, and a condensed solution of ammonia is used as an electrolyte.

That is, the fundamental principle here is the use of reversible electrochemical systems. The substances of electrochemical batteries formed during the discharge process seem to return to their original state as a result of exposure to electric current(during the battery charging process). The screwdriver is powered by a battery - a group of electrically interconnected elements located in a common housing, as can be seen in the photograph (photo 1).

Serial and parallel connection of elements

The screwdriver battery consists of individual elements. The electrical circuit of such elements can have both parallel and serial connections (Fig. 2).

The serviceability of the elements can be checked after a certain time of charging them, that is, the presence of voltage on each element or the battery as a whole is checked. If, when measuring the voltage of an element, the value on the display of the multimeter device is less (for example, not 1.2V, but 0.8V), it means that this element has lost its electrochemical properties during operation. Such elements are subject to replacement. Electrochemical cells for the battery (photo 2)

need to be selected in accordance with their technical characteristics, that is, by voltage and current. For example, the indicator on the body of the removed battery cell is:

• voltage: 1.2V;
• current: 1200mA - 2900mA,

- therefore, it is necessary to select elements with precisely such indicators. Connecting elements together

performed with jumpers (photo 3). For such a replacement, you will need a soldering iron, soldering tin and soldering acid.

How to check a screwdriver

This topic provides an example from my own practice.

So, the photograph in front of us shows a Bort screwdriver.

Initially, to find a screwdriver malfunction, you can check the total resistance of its electrical circuit.

Before checking, the start button must be turned on, that is, the button must be secured, as shown in the photograph (photo 4).

Then, use a Multimeter to measure the resistance of the electrical circuit of the screwdriver (photo 5).

To do this, set the Multimeter device in the resistance measurement range, then use the probes of the device to touch the output contacts (on the handle) of the screwdriver, as shown in the photograph (photo 5). When measuring, the display of the device indicates a resistance that is not comparable for the operation of this power tool. The resistance value here is an indicator of a short circuit. The display of the device shows that this screwdriver is faulty. But we need to establish a specific reason - what is the malfunction?

To find the cause of the malfunction, you need to disassemble the screwdriver and check the circuit electrical connections(photo 6).

Screwdriver diagram

In this electrical circuit, as we can see, there is a transistor.

The transistor is mounted on a metal plate (photo 7), which serves to remove heat when heated. The transistor is checked for the presence of resistance between the transitions (emitter - collector - base). To check the transistor and not focus on the type of transistor (n-p-n, p-n-p), any two legs of the transistor are checked in both directions.

In this way, the absence of conductivity between the collector and the base of the transistor was established. But what could cause the transistor to fail? We carry out diagnostics for individual electrical connections, namely, for the screwdriver motor (photo 8).

The photo shows an unacceptable resistance value for the electric motor (photo 8). What exactly is the cause of an electric motor malfunction? Let's look further.

The electric motor of the screwdriver is a commutator motor, powered by direct current. There are graphite brushes on the end part of the electric motor cover (photo 9). Graphite brushes in in this example, V good condition. Here you also need to check the conductivity of the contact connections (wire - brush).

The rotor of the electric motor consists of windings (photo 10) connected to each other in series. The stator of an electric motor is permanent magnet with two poles, that is, the stator of the electric motor does not have windings.

You can verify this - the motor housing attracts metal objects (photo 11).

From this we can conclude that a malfunction of the electric motor causes an insulation breakdown between the wires of the rotor windings.

Well, the reason for the breakdown of the screwdriver has been established, which consists of a malfunction:

• transistor;
• electric motor rotor windings.

All that remains is to replace the relevant parts.

That's all for now. Follow the section.

How to repair a screwdriver battery yourself?

• Device and types
  • Advantages and disadvantages
• Malfunctions
• Repair features

The cost of a new screwdriver is approximately 70% the cost of the battery that comes with it. It happens that the battery of a screwdriver fails. In this case, you will need to purchase a new battery or repair the screwdriver yourself, saving some money.

Cordless screwdriver contents: screwdriver, 2 batteries, charger, flashlight, 1 set of bits with magnetic holder, plastic suitcase.

Device and types

To repair a battery, you first need to know its design. It is worth knowing that, regardless of the screwdriver model and manufacturer, the batteries have the same design. View of the battery pack assembled.

If you take it apart, you can see that it consists of small-sized elements that are assembled in a certain sequence. From physics lessons at school we know that elements that are connected in series add up potentials. Their sum can give the final voltage at the battery contacts.

In most cases, the assembled parts have typical dimensions and voltage, the only difference is in capacity. Battery capacity is usually measured in Ah and is indicated on each cell.

The following types of elements are used to assemble screwdriver batteries:

• nickel-cadmium elements, the voltage of which is 1.2 V;
• nickel-metal hydride cell, the voltage of which is 1.2 V;
• lithium-ion cell with a voltage of 3.6 V.

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Advantages and disadvantages

Table of characteristics of screwdrivers.

You should know the advantages and disadvantages of each type of element.

Advantages of nickel-cadmium elements:

1. Low cost. For this reason, these batteries are most often used.
2. They are not afraid of low temperatures, which cannot be said about Li-Ion batteries.
3. Can be stored uncharged without losing the main characteristics.

Disadvantages of nickel-cadmium batteries:

1. Due to toxicity during production, they are manufactured exclusively in developing countries.
2. They discharge on their own.
3. Memory effect.
4. Small capacity.
5. Not large number charge/discharge cycles, and therefore they will not be able to work for a long time in case of intensive use.

Advantages of nickel metal hydride cells:

Cordless screwdrivers operate on lithium-ion, nickel-cadmium batteries.

1. Environmentally friendly production.
2. Availability of high quality battery.
3. Low memory effect.
4. They practically do not discharge on their own.
5. High capacity compared to nickel-cadmium cells.
6. More charge/discharge cycles.

Disadvantages of such elements:

1. High cost.
2. If stored for a long time in an uncharged state, some of the characteristics may be lost.
3. They are afraid of low temperatures.

Advantages of Li-Ion cells:

1. No memory effect.
2. They practically do not discharge on their own.
3. The battery has a high capacity.
4. There are a large number of charge/discharge cycles.
5. In order to gain the required voltage, fewer cells will be needed, as a result of which the weight and size of the battery will be significantly reduced.

Disadvantages of Li-Ion batteries:

1. High cost. These batteries cost almost 3 times more than nickel-cadmium cells.
2. After 3 years, significant loss of capacity may occur.

Diagram of a cordless screwdriver.

You should also become familiar with the remaining components of the battery pack. In order to repair the screwdriver battery, you need to disassemble the unit. This is done as follows: all existing screws are unscrewed and the housing is disconnected.

The case most often has 4 contacts:

1. Two power ones, which are used for charge/discharge.
2. One manager, who is located at the top of the structure. This contact is activated via a temperature sensor. The sensor is needed to protect the battery; it is capable of turning off or reducing the charging current if the specified temperature of the components exceeds. Most often the temperature is between 50-60°C. Heating will occur due to high currents during accelerated charging.
3. “Service” contact, which is switched on through a 9 kOhm resistance. It is used for complex charging stations that will equalize the charge on existing battery components. Such stations are very expensive, so they are practically not used in everyday life.

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Malfunctions

You should know that all battery components cannot fail at the same time. It must be remembered that the circuit is sequential, therefore if one of the elements fails, the entire structure will not work. It is necessary to identify where in the chain the non-working element is. To do this, you will need to use a multimeter and a 12 V lamp, if the battery is also 12 V. The sequence of actions in in this case will be like this:

1. The battery is charged, after which a signal of full charge is expected.
2. The case is disassembled and each battery cell is measured. In Ni-Cd cells the voltage should be 1.2-1.4 V, in Li-Ion - 3.6-3.8 V.
3. All batteries in which the voltage does not correspond to the nominal voltage are noted. For example, most Ni-Cd has a voltage of 1.4 V, and a few have a voltage of 1.0-1.1 V.
4. The battery is assembled and turned on until there is a strong loss of power.
5. The device is dismantled, disassembled, after which the voltage drop in the batteries is measured. The voltage on the identified components should “sag” more than on the others. For example, the voltage on them will no longer be 1.2 V, but 1.0 V or even lower.

You should know that a difference of 0.5-0.7 V is considered significant. This means that the element will soon become unusable.

In this way, it will be possible to identify the “banks” that should be repaired or replaced.

If the screwdriver operates on a voltage of 12-13 V, then the search for the faulty element can be done in another way. The charged battery must be disassembled, after which a 12 V lamp should be connected to the “+” and “-” contacts. This lamp will gradually discharge the battery. Next, measurements are taken on the elements. The faulty component will be where the voltage has dropped the most.

Instead of a lamp, resistance can also be selected, but for this you need to know the basics of electrical engineering.

Other malfunctions are quite rare. For example, contact may be lost in places where elements are soldered or power contacts of the unit. The temperature sensor may also become unusable. This problem is most often found in fakes.

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Repair features

Items needed:

You should know that Li-Ion battery cells cannot be restored.

They have no memory effect. In most cases, lithium decomposes, and nothing can be done about it. In this case, it will be necessary to determine whether the element itself or the control circuit is faulty. There are two options:

1. You can install a control circuit from a working battery.
2. 4 V is supplied to the element with a current of approximately 200 mA. In this case you will need adjustable device for charging. If the voltage on the battery rises to 3.6 V, this means that it is working.

Screwdrivers most often contain Ni-Cd elements that can be restored. There are 2 ways to restore items:

1. Compaction method. Will work in cases where the electrolyte is available, but the volume is lost.
2. “Firmware” with high current. Using this method, you can eliminate the memory effect and restore lost capacity. This method will not completely solve the problem of faulty battery components. It can only delay the replacement of faulty elements.

Repairing a screwdriver battery yourself is best done by replacing faulty components. When purchasing a new element, you need to ensure that its capacity and dimensions match the original components.

You will need to cut off the faulty component, and then solder a new one in its place.

You need to know the following nuances:

1. You need to solder quickly with a soldering iron so that the battery does not heat up.
2. The connection must be made using plates.
3. The connection is serial, therefore the “-” of the previous element will go to the “+” of the new component, and the “-” of the new one will go to the “+” of the next one.

The potentials on the batteries will be different, so they should be equalized. A charge/discharge cycle should be carried out: the battery is charged for 12 hours, after which it cools down for a day. Finally, the voltage in the batteries is measured. The multimeter should show 1.3V across all components.

Repairing a screwdriver is not difficult, you just need to know all the nuances.

How to repair a screwdriver battery

A cordless screwdriver is a fairly common tool in the home craftsman’s arsenal.

BOSCH screw driver before battery repair

As a rule, it is used not only for its intended purpose. This is both a portable drill and grinder, and even circular saw. With such intensive use, the screwdriver batteries are constantly under extreme load, and their service life is reduced.

An additional factor that accelerates the failure of screwdriver batteries is the poor quality of the included chargers. As a rule, this is a primitive power supply without charge level control. memory inexpensive models simply supplies a given voltage or current to the battery, without being able to trigger the discharge or recovery modes of the screwdriver battery.

Screwdriver device

Everything is quite simple - an electric motor, a power button with a primitive regulator and a battery. Three quarters of the cost of an electrical appliance is the battery itself, so replacing batteries in a screwdriver is not economically feasible. Yes and find finished item The correct power supply for your model is often not possible. There are three options left:

1. Manufacturing (purchasing) an appropriate power supply and turning the tool into a network one.
2. Using a remote battery, for example from a car. Suitable only if the screwdriver supply voltage is 14.5 volts.
3. Screwdriver battery repair.

The battery circuit is simple - a number of elements connected in series and arranged in the shape of the battery case.

The insides of the battery consist of small batteries (also called banks)

The main thing you need to know is which elements are used in your instrument.

Types of batteries for screwdrivers

Battery cans. used in household power tools, are only alkaline, with a voltage in each element of 1.2 volts (or 3.6 volts - which corresponds to a three-section unit). There are three main types of work element material:

Nickel-cadmium (designation – Ni Cd)

Due to the low cost, manufacturers equip most models of screwdrivers with just such batteries. The price determines the performance properties, and they are low. The operating voltage of a serviceable and charged element is 1.2 volts.
Advantages:

• Of course - price
• They tolerate low temperatures well - this allows you to keep the instrument not in a warm pantry, but on the balcony or in the garage
• When stored for a long time in a discharged state, it practically does not lose its factory characteristics. This property is especially useful for home use of the device - when it is used occasionally

Nickel metal hydride (designation – Ni MH)

Such battery cells can be found both on economy class models and on affordable versions of famous brands. Just like nickel-cadmium, they are installed on household electrical appliances with low intensity of use. The operating voltage of a serviceable and charged element is 1.2 volts.
Advantages:

• Produced in developed countries, since the production is environmentally friendly
• Virtually no self-discharge
• Small memory effect, you can recharge by 30-50% and continue to work quietly
• Sufficiently high capacity, this allows you to work at a distance from a stationary outlet, for example in a garage or when building a summer house
• Such elements are designed for a large number of charge-discharge cycles, which compensates for their high cost.

• Higher (compared to nickel-cadmium) cost
• When stored in a discharged state, it loses some of its working properties.

This forces the owner to regularly recharge, even if the tool is not in use.

Lithium-ion (designation – Li Ion)

Installed on professional or semi-professional screwdrivers with high intensity use. Such batteries are used by famous manufacturers in models in the middle and high price segments. The operating voltage of a serviceable and charged element is 3.6 volts.
Advantages:

• No memory effect

Recharging can be done at any percentage of discharge.

Battery refurbishment

If your screwdriver “goes silent” due to battery failure, this is not a reason for despair. You can repair the battery yourself, spending an amount that is several times less than buying a new one. There are three ways to repair a screwdriver battery:

1. Replace battery cells (banks) in the battery

If you decide to do the repairs yourself, then you need to understand that the cans are selected similar, preferably of the same chemical type, so that they fit your charger.

Most manufacturers (this is especially true for economy class models) simply put cells (cans) in the battery case, best case scenario securing them with insulating tape.

Such blocks are the easiest to repair. Before disassembling, sketch out the connection diagram on paper to ensure that the new batteries are installed correctly. It is necessary to remove one element from the block and select the appropriate size in a specialized store or on the radio market.

IMPORTANT! Be sure to comply with the labeling of the cans. Otherwise, when charging, you can quickly damage them, since the standard charger is configured for a specific type of battery.
Then you need to solder all the new batteries into the battery in series, plus to minus.

All battery banks must be soldered together in series

It is better to solder with a powerful soldering iron to reduce the heating time of the cans. Use aggressive fluxes when working with aluminum or iron. Then you need to wash the soldering area with isopropyl alcohol. The first few charge-discharge cycles must be completed completely so that the battery “remembers” its maximum capacity. This is especially true for nickel-cadmium batteries.

There are more economical option, but it will take longer. Not everything can be replaced, but only those banks that are guaranteed to fail. To do this, you will need a “donor” - a damaged battery with the same elements. You can purchase it at a service center or at the same radio market. It is necessary to fully charge both batteries and measure the voltage on each bank with a tester. Select from both sets the elements that produce the value closest to 1.2 volts.

We check the charged battery with a tester, determine the damaged jar

From them assemble a restored set. The effect of such a solution is not comparable to a complete replacement with new banks, but at least your instrument will be brought back to life.

Using the method described above, we identify the most damaged elements and solder them. Then, using a charger with a current and voltage regulator, we produce a shock charge for 3-5 seconds on each can. The voltage value during charging should be three times the nominal value (in our case, 3.6 volts).

We check with a tester - the voltage after charging should be about 1.4 volts. If not, we send the item to scrap.

IMPORTANT! Shock charging may cause a faulty battery to burst. Work must be carried out wearing rubber gloves and safety glasses.

If we are unable to revive the elements, we return to replacing them.

New battery in old case.

If you were unable to restore the old battery, you can make your own battery for a screwdriver. To do this, you will have to pick up a new battery (or a set of cells), perhaps a higher class one, and a charger for it. The main thing is to keep within the dimensions of the battery case.

If the total rating of the battery and the new charger are the same, it is enough to make an adapter using the old charger, especially since you won’t need it anyway.

If you have a charger for individual cells, you will have to remove them from the case each time to charge them.
There are also more extreme methods - for example, attaching a battery to a screwdriver that does not fit the form factor.

Bosch screwdriver after repair with a battery from another tool

But this is rather a temporary solution, it is better to use it anyway old building and select new batteries of the appropriate size.

Many people use the “garage option” - using an old starter battery from a car. This method is quite applicable, but there are some limitations. Many screwdrivers have an operating voltage of 18 volts. This corresponds to 15 cans battery.

A fully charged car battery produces 12 volts; the screwdriver will not work. If your electrical appliance has a voltage of 14.5 volts - that is, the battery consists of 12 elements, the engine will work. In that case, this is your solution to the problem.

As you can see, failure of the screwdriver battery is not yet a reason to buy a new battery. If you have patience and basic electrical skills, you can repair the battery at home. Or entrust this procedure to a service center. It will be a little more expensive - but still cheaper than buying a new battery.

How to repair a cordless screwdriver

Here's mine Screwdriver Skil(photos 1 and 2) after three years of active use, both batteries became unusable. As a result, even after being fully charged, they only had enough energy to tighten a couple of screws. It’s not so easy to find a new replacement battery, and it costs one and a half thousand rubles, which is a pity to spend on “reanimating” an old screwdriver. Especially if you live in the provinces, then it is generally useless to look for an outdated battery model.

The first, simplest solution to the problem is to sort out the battery that has lost its capacity. It is not difficult to disassemble the battery, but not a single screwdriver fits into the deep and narrow grooves holding it together. Only the screwdriver from the “Proxxon” set helped me out (photo 3). After opening the case (photo 4), it turned out that each of the two batteries included in the drill kit consists of ten separate small battery cells connected in series to each other by spot welding.

Since the voltage of this battery, in accordance with the marking on the nameplate, is 12 V, and the capacity is 1300 mAh, the voltage on each individual bank should be 1.2 V (when the batteries are connected in series, the voltage is summed up), and its capacity should be the same , like the entire battery. At the same time, even if only one bank fails, its high internal resistance will not allow you to receive full current from the battery during discharge and charge all other serviceable battery cells to full capacity. It is better to search for faulty elements after charging the battery.

Having opened the battery, first check the voltage on each bank with a voltmeter. If the voltage on any bank is lower than the nominal one, then it is rejected (in photo 5 - the voltage on the bank is only 0.99 V). Lack of my battery old drill a device that provides the same voltage on each battery cell is precisely what leads to such phenomena. During the verification process, we select jars whose voltage is not lower than 1.2 V (photo 6).

But cans also have a second parameter - capacity. Battery capacity is measured in ampere-hours and characterizes the charge provided by the battery within the operating voltage limits.

Of course, we will not be able to check the capacity, that is, the amount of energy contained in the banks at home. But there is another way to find bad cans, which is to measure their internal resistance. To do this, first measure the voltage without load, and then with load (photo 7 and Fig. 1). As a load, I used a 10 Ohm resistor with a power dissipation of 25 W. Then, also using the load resistance, we measure the current flowing through the jar (photo 8 and Fig. 2).

After measurements, you can use Ohm's law to calculate the internal resistance of the battery. For a new can, this value is approximately 0.06-0.1 Ohm, and over time it increases. Thus, the lower the internal resistance of the can, the better quality it is. It is calculated by the formula r=U/l-R, where: U - voltage, I - current, r - internal resistance of the can, R - load resistance (in our case = 10 Ohms). For example, measurements showed that in one can the voltage without load was 1.2 V, the voltage with load was 1.19 V, and the current with load was 112 mA.

And the other bank has a voltage without a shunt of 1.2 V, but with a load – no more than 1.1 V. The current strength with the load is only 70 mA.

Thus, the first bank has r = 0.63 Ohm. and the second (faulty) has r=5.71 Ohm. The obtained values ​​of the internal resistance of the battery banks clearly indicate that the second bank is not suitable for further use.

The load fork, a device for testing batteries, operates on the same principle (photo 9). But we still need to purchase it, and we got by with the tester.

So, after taking measurements, I selected 10 cans with the lowest internal resistance. Now they need to be connected into a battery. Of course, spot welding at home is difficult to do, so I decided to limit myself to soldering (photo 10). However, under no circumstances should batteries be overheated. They may even explode. Therefore, you should tin the contact pad very carefully. For soldering cans stainless steel you need to use soldering acid, but preferably active fluxes, for example, FIM. In any case, the soldering area should be washed with water.

Of course, old cans may no longer be in perfect condition, but the battery that results from a preventive overhaul will still serve well for some time. To prepare for use, the battery must be subjected to several training cycles of charging and completely discharging. During training, charge the battery for about 10 hours to provide it with the maximum possible energy. In this case, the battery gets quite hot, and before using the drill, you should wait until the temperature of the battery pack drops. The easiest way to discharge it in the training cycle is by connecting a 12 V light bulb.

So, one working battery out of two faulty ones was assembled. And to use the screwdriver while the battery is charging, you can do network adapter. After all, when working in a city apartment, the energy independence of the tool is not so important - the power outlet is always nearby anyway. As a network adapter, I used a 300 W power supply from the system unit of an old computer (photo 11). The modification of the power supply required the most minimal: I cut off the extra leads - 3.3 and 5 V, leaving only 12-volt ones. Then I supplemented the power supply with an E 8021 ammeter, an LED to indicate power on, and a toggle switch.

Photo 12 shows the power supply connector, in Fig. 3 - pinout diagram.

Rice. 3. Network adapter diagram: PSU – power supply; A – ammeter; ХР – connector; SA1 and SA2 switches; HL – LED; R – resistor.

The ammeter in this case performs an informative function. It shows that the starting current when this screwdriver is turned on reaches 26 A (photo 13). If excessive load occurs and the current increases to maximum values ​​(more than 30 A), the power supply protection is triggered and it automatically turns off. The LED on the front panel of the network adapter goes out when overloaded. For restart It is enough to turn off both of its toggle switches and turn them on again after a few seconds, and the power will be restored. In operating mode, when drilling or tightening screws, the current is approximately 5 to 8 A.

This is the network adapter I ended up with (photo 14). The only drawback is that the screwdriver has an additional and rather bulky part. But with a well-sharpened drill, it’s easy to drill even a thick steel corner (photo 15).

And this one screwdriver "Interskol"(photo 16) another problem arose. It was not used for about a month, and then when it was turned on, the engine began to smoke and refused to rotate.

To make a diagnosis, I had to disassemble the screwdriver. To unscrew screws from narrow and deep grooves, “Proxon” screwdrivers were again required (photo 17-20). Then I unsoldered the wires from the motor and, bending the ears, removed the back cover (photo 21).

Attention! Before removing the back cover, it is necessary to secure the brushes with a rigid wire spacer, otherwise, after removal from the shaft, they will hit each other and may fall apart. The same spacer is useful for moving the brushes apart before installing the back cover back (photo 22, 23).

After opening this “patient”, the cause of the malfunction was revealed. It turned out that the oil in the gearbox had liquefied and leaked onto the rotor shank and under the brushes. This led to the appearance of smoke. This can happen when working in a hot shop or during prolonged heat, or if the tool is left in the sun with the chuck facing up. By the way, screwdrivers generally do not like elevated temperatures.

In order to bring the tool back to life, it was enough to thoroughly rinse with alcohol (or overshoe gasoline) the rotor shank (where the brushes come into contact with the rotor), the brushes themselves and the spacer washers on the shaft shank (photo 24-26).

If desired, you can also disassemble the gearbox, thoroughly wash all the gears and put fresh thick lubricant in it (Litol or CIATIM). And one last subtlety: when assembling the screwdriver, it is important not to crush the wires with protruding elements of the case.

So, two faulty screwdrivers have been restored, and I hope they will serve me for a long time.

The screwdriver battery has several contacts - two power contacts (“+” and “-”), as well as a control contact that connects the temperature sensor inside the battery to the charger. This sensor monitors the temperature of the battery cells during charging.

If the permissible temperature is exceeded, the sensor breaks the electrical circuit and thereby prevents the destruction of the elements. In photo A we see a temperature sensor in a Skil screwdriver. In more advanced models today, a thermal relay is installed (photo B).

Temperature control is absolutely necessary when charging quickly with high currents, which will heat up the cells and can destroy the battery. In addition, batteries from leading companies today include a device that allows each battery cell to be evenly discharged and charged. Inexpensive tool batteries do not have these protective options.

DIY screwdriver repair - photo

Do-it-yourself improvement and modification of a screwdriver

I bought this screwdriver at Leroy Marlene. It cost only 590 rubles. For such a price you can only buy on the market screwdrivers without battery .

The screwdriver was the simplest: single-speed, with an operating voltage of 12 V, a reverse button, a torque of only 10 Nm and a quick-release chuck. The maximum drill diameter is 10 mm. The capacity of the standard battery is 1 Ah. For comparison: a similar model of a Bosch screwdriver has a battery capacity of 1.5 Ah, but such a two-speed screwdriver costs about 4,000 rubles.

The insides of the screwdriver can be removed quite easily, just unscrew a few screws (photo 1-2). The screwdriver is equipped with a double-sided bit (photo 3). The battery is also disassembled (photo 4).

Before work, I charged the battery for about 8 hours (photo 5). My main concern was the alignment of the chuck, since I often have to drill small holes of 00.9-1.2 mm. If the chuck was poorly centered, the small drill easily broke, and it was difficult to drill holes according to the markings. The centering of the chuck in this screwdriver turned out to be acceptable, and I easily drilled several millimeter holes in wood and plastic (photo 6).

The next stage of verification was brick wall, in which I easily made a hole with a 05 mm drill with a carbide tip.

It's time to test the screwdriver in full.

For the test I took a package of 35 pcs. the most common self-tapping screws 03.5×25 mm. In about five minutes I drove all the screws up to the head into an inch pine board - the screwdriver continued to work (photo 7). I unscrewed all the screws, tightened them a second time on the other side of the board and unscrewed them back - the screwdriver worked (photo 8)!

Then I decided to check how the screwdriver copes with drilling holes. I drilled a 010 mm hole in the board with a wood drill, but somehow I didn’t like working with it (photo 9).

Then I installed a 06 mm drill for metal and continued testing (photo 10). At the 20th hole my arm was already tired and a short break was taken. The screwdriver began to slow down only at the 50th hole. At the last hole, the drill had difficulty entering the board.

So, let's summarize. One battery charge was enough to: tighten and unscrew 70 screws, drill a 010 mm hole, drill 55 06 mm holes. According to the test results, this screwdriver is quite a “workhorse”.

But the thought does not stand still, and I decided to convert this screwdriver to be powered by a lithium polymer battery. I borrowed the idea from a friend of mine, an aircraft modeller, Konstantin. He converted his screwdriver to use a lithium-polymer battery for model airplanes.

I ordered the battery, connectors and buzzer from Hobby King (Hong Kong). I waited for the parcel for more than a month. As soon as I received the parcel (photo 11), I immediately began upgrading my “Practyl-R” screwdriver.

The components for converting the screwdriver to fit a new battery cost me about 600 rubles, i.e. an amount close to the cost of the device itself. A Li-Po 1500 mAh 11.4 V battery sent from China can, of course, be bought here, but it will cost 2-3 times more.

Replacing the connector on the battery was necessary due to the lack of a mate. Therefore, I carefully cut off the old one and soldered a new connector (photo 12).

Then I soldered the connector to the tweeter (photo 13). The beeper is needed to indicate the minimum charge of the lithium-polymer battery in case the lithium-polymer battery is completely discharged, it will lose its functionality and can be thrown away.

The wire was brought out through a sawn hole in the screwdriver handle (photo 14). I collected it. I stuck the new battery into the handle, wedging it with a piece of dishwashing sponge. Of course, it would be more correct to insert it into the case of a standard battery - it fits there perfectly. I glued the tweeter to the battery with double-sided tape (photo 15).

The main disadvantage of lithium-polymer batteries is that they require special charging. I had it, so there were no problems in this regard (photo 16). Cool device with a lithium-polymer battery - ready!

And now - the test. First I screwed in 32 short screws. According to tactile sensations, the power of the screwdriver has even increased slightly. Then - 11 long ones and... (photo 17-20).

Test results. Halfway (!) charging the new lithium-polymer battery: 96 screws 03.5 × 25 mm and 21 screws 04.2 × 65 mm were screwed into the pine beam and 35 holes were drilled in the same beam 06 mm and 60 mm deep.

We draw conclusions: a cheap tool is not always so bad. And if you are smart and invest a little money, then the tool can rightfully take its place in your workshop!

Do-it-yourself modification and improvement of a screwdriver - photo

1. We unscrew just a few screws...
2. ...and the insides of a screwdriver in his hands.
3. A double-sided bit is included.
4. The battery can be disassembled using a regular screwdriver.
5. The standard battery charges in about 8 hours.
6. The alignment of the cartridge is quite acceptable.
7. To start the test, I used short self-tapping screws.
8. The screwdriver showed amazing endurance when tightening screws.
9. The 010 mm wood drill somehow didn’t work very well.
10. The 06 mm metal drill did its job perfectly.
11. The lithium polymer battery had to be ordered from China.
12. Resoldered the connector on the battery.
13. I soldered a deep discharge alarm beeper to the battery.
14. The leads were brought out through the cut made in the screwdriver handle.
15. I stuck the battery into the handle (for the duration of the test) and secured it with a piece of sponge. I attached the tweeter to the battery with double-sided tape.
16. Charging for lithium polymer batteries.
17. Test for tightening short self-tapping screws.
18. Long screws 04.2×65 mm.
19. The screwdriver coped with long screws with a bang.
20. Drilling holes for a lithium polymer battery is also not a problem.

Improvement of the screwdriver - conversion to a lithium-polymer battery

Below are other entries on the topic “How to do it yourself - for a homeowner!”

DIY screwdriver battery repair

The cost of a new screwdriver is approximately 70% the cost of its battery. Therefore, it is not surprising when, faced with a battery failure, we ask ourselves the question - what next? Should I buy a new battery or screwdriver, or maybe there is an opportunity to repair the screwdriver battery with my own hands and continue working with an already familiar tool?

In this article, which we will roughly divide into three parts, we will look at: the types of batteries that are used in screwdrivers (Part 1), their possible reasons failure (part 2) and available methods repair (part 3).

Screwdriver battery: design and types

It should be noted that regardless of the brand of screwdriver and the country of manufacture, the batteries have an identical structure. The assembled battery pack looks like this.

If we take it apart, we will see that it is assembled from small elements that are assembled sequentially. And from the school physics course we know that elements that are connected in series balance their potentials.

Note. The sum of each battery element gives us the final voltage at the battery contacts.

Set parts or “cans”, as a rule, have a standard size and voltage; they differ only in capacity. Battery capacity is measured in Ah and is indicated on the cell (shown below).

The following types of elements are used to assemble screwdriver batteries:

• nickel - cadmium (Ni - Cd) batteries, with a rated voltage at the “banks9raquo; 1.2V;
• nickel-metal hydride (Ni-MH), element voltage - 1.2V;
• lithium-ion (Li-Ion), with a voltage of 3.6V.

Let's take a closer look at the advantages and disadvantages of each type.

• The most common type due to its low cost;
• Low temperatures are not scary, for example, like Li-Ion batteries;
• It is stored in a discharged state, while retaining its characteristics.

• Produced only in third world countries due to toxicity during production;
• Memory effect;
• Self-discharge;
• Small capacity;
• A small number of charge/discharge cycles means they do not “live” for a long time; with intensive use.

• Environmentally friendly production, it is possible to purchase a high-quality branded battery;
• Low memory effect;
• Low self-discharge;
• Large capacity compared to Ni - Cd;
• More charge/discharge cycles.

• Price;
• Loses some of its characteristics when stored for a long time in a discharged state;
• At low temperatures it does not “live” for a long time.

• No memory effect;
• Almost no self-discharge;
• High battery capacity;
• The number of charge/discharge cycles is many times greater than that of previous types of batteries;
• To set the required voltage, a smaller number of “cans” are needed, which significantly reduces the weight and dimensions of the battery.

• High price, almost 3 times compared to nickel-cadmium;
• After three years, a significant loss of capacity occurs, because Li decomposes.

We got acquainted with the elements, let's move on to the remaining elements of the screwdriver battery pack. Disassembling the unit, for example, to repair the battery of a Hitachi screwdriver (shown below), is very simple - unscrew the screws around the perimeter and disconnect the case.

The housing has four contacts:

• Two power ones, “+9raquo; and “-9raquo;. for charge/discharge;
• The upper control is switched on via a temperature sensor (thermistor). The thermistor is necessary to protect the batteries; it turns off or limits the charging current when a certain temperature of the elements is exceeded (usually in the range of 50 - 600C). Heating occurs due to high currents during forced charging, the so-called “fast” charge. charger;
• The so-called “service9raquo; contact, which is connected through a 9Kohm resistance. It is used for complex charging stations that equalize the charge across all battery cells. In everyday life, such stations are useless due to their high cost.

That's the whole design of the battery. Below is a video on how to disassemble the block.

Troubleshooting

We have figured out the purpose of the battery design elements, now let’s look at how to determine the malfunction, this is part 2 of repairing a screwdriver battery. Let us immediately note that all elements cannot fail at once, and since our circuit is sequential, if one element fails, the entire circuit does not work. This means that our task is to determine where the weakest link is in our chain.

​

To do this, we will need a multimeter, and for the second method of troubleshooting, a 12V lamp, if your battery for the screwdriver is also 12 volt. The procedure is as follows:

— We put the battery on charge, wait for a signal about full charge.

— We disassemble the case and measure on each battery bank. For Ni - Cd we should have 1.2 - 1.4V, for lithium - 3.6/3.8V.

- Mark all “banks” in which the voltage is less than the nominal one. For example, most Ni-Cd elements have a voltage of 1.3V, and one or more have a voltage of 1.2/1.1V.

— We assemble the battery and work until there is a noticeable loss of power.

— We remove, disassemble and measure the voltage drop on the “banks9raquo; battery On the marked elements “subsidence9raquo; the voltage will be greater than others. For example, they are no longer 1.2V, but 1.0V or even lower.

Note. A difference between the elements in a battery of 0.5 - 0.7V is considered significant, which means that the element becomes unusable.

Thus, we found candidates for “resuscitation9raquo; or “amputation9raquo; and replacement with new elements.

If your screwdriver operates on a voltage of 12 or 13V, you can search for more simple method. We disassemble a fully charged battery and connect it to the “+9raquo;” contacts. and “-9raquo; connect a 12 volt lamp. The lamp will be a load and will drain the battery. Next, we take measurements on the battery elements, where the voltage drop is greatest, there is a weak link.

There are other ways, instead of a lamp you can select a resistance, but this already requires the basics of electrical engineering, and it is doubtful that a resistor with the required resistance would be at hand.

Other malfunctions are very rare. For example, loss of contact in the soldering areas of batteries or power contacts of the unit, failure of the thermistor. This problem is more common with fakes. Due to its rarity, we will not focus on the battery elements.

With “problematic9raquo; elements have been dismantled and need to be repaired. How to repair a screwdriver battery? In general, there are 2 methods available for repair, so to speak. This is the restoration and replacement of elements that have become unusable.

Is it possible to “reanimate9raquo; elements and how?

Let's proceed to Part 3 of screwdriver battery repair and immediately make a reservation that the concept of “resuscitation9raquo; Not applicable for lithium-ion batteries. There is no memory effect in them; most likely, lithium decomposition has occurred, and nothing can be done about it. In such batteries, it is necessary to find out what is the cause of the malfunction: the element itself or the control circuit. There are two options here:

• we change the control circuit from another, but similar to ours, battery, if it helps, we find a replacement and change it;
• supply 4V to the element with a current of approximately 200mA, for this you need a regulated charger. If the voltage on the element increases to 3.6V, the element is working properly, the problem is in other elements, or in the control circuit.

Screwdriver battery repair is available primarily for Ni-Cd batteries, but they are usually the most common in household screwdrivers.

So, how to reanimate a screwdriver battery? There are two types of “reanimation”; for these types of batteries:

1. Compaction or compression method (this will work in cases where the electrolyte is still available, but volume has been lost);
2. “Firmware9raquo; voltage and current greater than the rated one. This method allows you to eliminate the memory effect, and although not completely, restore the lost capacity.

This method is shown in the video below.

Note. As a rule, in a nickel-cadmium battery the main reason for loss of capacity is boiling off of the electrolyte, and if it is critically low, no “firmware” is needed; won't help.

This method, if its result is positive, will not solve the problem of element failure. Rather, it will only delay the replacement of those that have become unusable, and in the future you will still need to repair the battery of a Makita screwdriver or any other.

Repair and replacement of screwdriver battery elements

More effective way repair of batteries for a screwdriver - replacement of elements that we have determined to be faulty.

To carry out repairs, we need either a donor battery, in which some of the elements are working, or new “banks”. It won't cost you to buy them a lot of work, even on the Internet you can easily find a dozen stores that are ready to send these items by mail. The price is not particularly bad, for example, a nickel-cadmium cell with a capacity of 2000 mAh costs around 100 rubles.

Note. When purchasing a new element, make sure that its capacity and dimensions match the original elements.

We will also need a soldering iron, low-corrosive flux (preferably alcohol flux with rosin) and tin. We are not talking about spot welding, since for a one-time battery repair there is hardly a need to purchase or assemble it...

There is nothing complicated about the replacement itself, especially if you have at least some experience in soldering. The photographs show everything in sufficient detail; we cut off the faulty element and solder a new one in its place.

Several points need to be noted:

• When soldering with a soldering iron, try to solder quickly so that the battery does not heat up, because you risk ruining it;
• if possible, make the connection using original plates, or use copper plates of the same size, this is important because the charging currents are large and if the connecting wires are of the wrong cross-section, they will heat up, and accordingly the thermistor protection will be triggered;
• Do not under any circumstances confuse the plus of the battery with the minus - the connection is in series, which means that the minus of the previous can goes to the plus of the new can, and the minus of the new one goes to the plus of the next one.

After the new elements have been soldered, it is necessary to equalize the potentials on the “banks”, since they are different. We carry out a charge/discharge cycle: set it to charge overnight, give it a day to cool down and measure the voltage on the elements. If we did everything correctly, the picture will be something like this: all elements have the same multimeter reading, within 1.3V.

Next, we proceed to discharge the battery, insert the battery into the screwdriver and load it “to its fullest.” The main thing is to spare the screwdriver itself, otherwise you will have to repair it too. We bring it to full discharge. We repeat this procedure two more times, i.e. charge and completely discharge.

It should be noted that the procedure for erasing the “memory effect” should be carried out every three months. It is carried out in a similar way to the training described above.

This not very tricky procedure will prolong the operation of your screwdriver, at least until it has to be replaced with a new one.

Shurik from Rybinsk - I also have no more capacity - changing elements is primitive - everything is very simple - I disassembled the entire battery, no cadmium - connection plates I cut it with scissors - I took one can apart, which was completely dead - it turns out it’s just dry like sand IN THE DESERT - NEXT REPAIR I TAKE A VERY SHARP PUNCH SHARPENED AT A 5 DEGREE ANGLE BUT VERY STRONG IN THE COVER I PUNCH A HOLE WITH A HAMMER - I CANNOT DRILL - DIAMETER UP TO 1 MM K DOUBLE LIVER NEEDED IN HOLE WITH A DISPOSABLE SYRINGE WATER FILL FROM 05 TO 1 CM CUBE UNDER THE LID PLACES A LOT OF 6 -8 MM TO THE PLATES BUT WATER WILL NOT GO YOU NEED TO PUMP AIR WATER THERE - WIPE FILL WITH EPOXY BUT FIRST WITH A GRAIN OF SEAL THERE'S ANSWER AND THERE'S RESIN LEAKING AND SOLDER THE TAPE ALL BACK AND ASSEMBLY—CHARGE DISCHARGE AFTER IMPREGNATION—SELF-DISCHARGE POSSIBLY WILL BE HIGHER BUT IT WILL WORK FOR A LONG TIME—PUT WATER INTO ALL CARNS WITHOUT EXCEPTION

PASHA FROM ODESSA—I COMPLETELY AGREE WITH SHURIK, NI-CD BATTERIES ARE THE MOST DURABLE, THE ELITE JUST DRY OUT, ESPECIALLY ON CHARGERS WITHOUT AUTOMATIC MACHINE (HEATING). YES, I MYSELF SPRAYED THE ELEMENTS 336 (SOVIET) WITH DIST WATER, THE EFFECT IS COOL, I ONLY DON’T UNDERSTAND WHICH COVER TO PUNCH THE HOLE IN. IN A PLUS WHATSOEVER. IT'S A SORRY THERE IS NO FEEDBACK WITH SHURIK. YES, IN 336 ELEMENTS GAVE IF THE VOLTAGE IS SOMEWHERE 0.1V—HALF A CUBE OF DISTILATE(!) ORDINARY WATER WILL KILL THE BATTERY. CHARGING, IF IT IS SIMPLE (NOT AUTOMATIC), IT IS DESIRABLE TO BE EQUIPPED WITH AN AUTOMATIC (DIAGRAM IS AVAILABLE ON MANY AMATEUR RADIO SITES) OR BUY A RELAY TIMER, PUT FOR 5-6 HOURS OF CHARGING. MEMORY EFFECT—NI-CD ARE GREAT FOR TRAINING IN THIS PLAN. IN GENERAL THEY ARE RARELY NOT REPAIRABLE, MAINLY WHEN THEY ARE SHORT INSIDE.

PASHA FROM ODESSA. YES, THERE IS A TYPOGRAPHICAL TYPO, SIMPLE - I MEANT CHARGING. AND TO TRAIN, YOU DO NOT NEED TO DISCHARGE WITH A SCREWDRIVERS, CONNECT A 12 OR 24 V BULB. HERE HE WILL SIT. 5-6 CYCLES AND THE BATTERY IS NORMAL, I GENERALLY DISCHARGE EACH CAN SEPARATELY, WITH SMALL 1.5V BULB. THIS IS BETTER. WHAT TO DISCHARGE THE ENTIRE BATTERY WITH ONE LOAD, BECAUSE BAD CANKS CHANGE POLARITY AND BECOME INSULATORS, AND THE DISCHARGE PROCESS FOR OTHER CANKS BECOME IMPOSSIBLE.

PASHA FROM ODESSA - REGARDING THE VIDEO - NICD AND NIMH-UNCLE HAVE CONNECTED, IN MY VIEW THEIR REGIMES ARE DIFFERENT, AND IT’S NOT WORTH IT TO COMPANY EVEN NEW BANKS WITH OLD BANKS, EVEN THE SAME. EITHER CHANGE EVERYTHING FOR NEW OR COMPANY WITH ALREADY “TIRED” IF COMPANY.

PASHA FROM ODESSA - YOU NEED TO PUNCH “-” CLOSER TO THE CENTER FILL HALF A CUBE - A CUBE (IT’S NOT WORTH MUCH) I FILLED HALF A CUBE, SO NOW IT’S NECESSARY TO FULL THE CARNS THAT ARE WELL CHARGED (ALL SHOULD BE ABOUT THE SAME AND CHARGE. THEN, CONNECT THE BULB. , PREFERABLY AT 220V 60W, BECAUSE I CONNECTED IT TO 36V - A QUICK DISCHARGE OCCURS, AND WE NEED TO TRAIN OUR “MEMORY EFFECT” FOR THIS, WE NEED A “SOFT” (SLOW) DISCHARGE TO KILL NOT THE OUTER LAYER OF THE PLATE, BUT THE AF IN GENERAL YU PLANT NEXT, I DISCHARGED (NI-CD!) AND SO FOR 4-5 CYCLES NOW THE BATTERY IS A BEAST.

Isn’t it easier to do it right away on lite 18650? The original Panasonevskaya with protection of 250-300 rubles costs 3.7v 3400mah. On the modeling forums or on flashlights there are a lot of pools for purchasing cans in bulk. An 18 volt is 5 cans, but it will be a monster, not a battery. There are only three of them on my AEG and they screw from morning to night.
You can get a cheaper LG, Sanya or something else, without protection (without charge cut-off) for about 170 rubles for 3400mah, but not Chinese ones for 50-60 rubles with the 6000mah type, bullshit banks and more than 1500 in them, and they don’t last long. And the weight will immediately fall, what for these garlands.

Heh. I read about the disadvantages, and you write how much native or original nickel ones cost, lithium is already much tastier in price. Among the minuses, they forgot to write that lithium does not withstand frost and long-term storage in a discharged state, and 3 years is a normal period for any type of battery, and with such a capacity it will last for at least 5 years before the critical comment “runs out quickly”

And I usually measure the current. It happens that the voltage shows the accepted voltage, but the current shows beyond the point after zero. Today I also discovered that battery NI-CD from Shurik, Hitachi quickly sits down. I took it apart, and that’s it - one battery is dead. But I’ve only been using it for 2 years, and not often.

Screwdrivers are used in different conditions and their load levels are different. Therefore, they differ in their power, which directly depends on the battery. If an element breaks, you need to be able to carry out prompt repairs yourself.

Battery types

By design features There are batteries in the form of sliders and clips.

But these are minor differences compared to battery types. Both the slider and the clip are used in different types of batteries.

There are three types of batteries for screwdrivers:

1. Nickel - cadmium (Ni-Cd).
2. Nickel - metal hydride (Ni-Mh).
3. Lithium - ion (Li-Ion).

Lithium polymer batteries (Li-Pol) are not produced for screwdrivers. Their main areas of application: smartphones, cell phones, tablets, laptops, radio-controlled devices, electric vehicles.

Nickel - cadmium batteries the cheapest, charge quickly, have more than a thousand charging cycles. The batteries are resistant to operation at low temperatures. But they have a memory effect. That is, they can be charged only after they are completely discharged, otherwise the capacity will drop. They have a high self-discharge current. They are made from toxic materials and are difficult to dispose of. These batteries are in greatest demand.

Nickel metal hydride batteries more expensive, non-toxic, have a low memory effect. The self-discharge current is greater than nickel-cadmium. The capacity is higher, the charge cycle is more than five hundred. These batteries are less resistant to high discharge rates. They are less suitable for maximizing the power of the tool. They need to be constantly recharged.

Lithium ion batteries more expensive, more powerful, charge quickly. They have no memory effect. Low self-discharge current. The voltage of the battery cells is higher, so their number is smaller. Consequently, the dimensions and weight of such batteries are smaller than those of nickel ones. But they cannot be completely discharged, otherwise after several such cycles you will have to buy a new one. To improve the quality of lithium-ion batteries, manufacturers install a microcircuit in the case of the battery or screwdriver that controls the operation of the battery. A multi-level multi-stage protection is formed:

1. From high temperature.
2. From full discharge. These batteries are afraid of being completely discharged and cannot recover if the discharge is below the permissible norm.
3. From short circuit.
4. From overcharging, as an explosion may occur.
5. From overload currents.

A control board installed in the battery case is more efficient. When the battery is kept separate from the screwdriver and is not in use, the microcircuit monitors its condition and, in case of any problems, opens the circuit. The battery is completely protected.

Review of lithium-ion battery with chip

Problems with the battery

What problems can occur with batteries:

• flows;
• cannot be removed;
• capacity has decreased;
• not charging;
• charging and discharging times are reduced.

Nickel batteries can be refurbished. But lithium ones are not allowed, since lithium decomposes in them. Here you can only replace unusable batteries.

How to properly repair it yourself.

Be patient and start repairing.

Let's disassemble the battery.

Disassemble the battery carefully. Do not use force to avoid damaging the housing.

• Remove the battery from the screwdriver. If the buttons are stuck and cannot be removed, unscrew the screws of the tool body and remove the top half. One of the buttons has become free. Pull the battery towards you, moving it slightly in different directions, and it will also come off. Once you disassemble the battery, position the buttons so that they press easily into their grooves.
• The battery case consists of two parts and can be dismounted or non-removable. In the first case, unscrew all the screws and separate both parts.
• In the second case, the lower part of the body is tightly fitted onto the upper and glued. Therefore, to separate them, take a rubber mallet or a piece of wood like a rolling pin and lightly tap the seam around the body. If that doesn't work, use a thin, sharp knife. Insert it into the seam and carefully cut through the glue.
• Then knock again. Sometimes it happens that the battery is almost disassembled, but in a certain place it stubbornly resists. You should not strike for a long time at one point, as you risk damaging the body. Just take a chisel or screwdriver and pry it in the right place.
• When separating parts of the case, the buttons may shoot out, but this does not mean that they are broken. They need to be assembled and inserted into place. To remove the top part from the batteries, insert a screwdriver into any of the terminals and gently press the element. Pull the housing up and it will come off.

Video: How to disassemble a screwdriver battery

Inside there are several elements soldered in series. This cassette provides the necessary voltage and current characteristics for the battery. Some nickel batteries have a temperature sensor attached to the cells.

In lithium-ion batteries, everything is more complicated. There is a control board, and the elements are covered in a protective case or film.

How to increase battery capacity.

A new battery must be fully charged before use. Average temperature environment from 10 to 40 degrees. The chargers have indicator lights. When they show that the battery is charged, you must immediately turn off the process.

1. New nickel-cadmium batteries must be rocked before first use. Fully discharge and charge three times. The capacity will become maximum. If the instructions for the device say that the build-up should include a greater number of charge cycles, then follow these recommendations. During operation, fully discharge the battery before charging.
2. Nickel metal hydride batteries have less memory effect, so they can be cycled once before first use.
3. Lithium-ion batteries do not need to be pumped. They simply need to be charged to full power.

To discharge the battery, a load in the form of a 12-volt lamp is used. It is connected with crocodile clips to the terminals. If the battery is disassembled, then to the terminals of the serial battery circuit. The discharge process will take less than an hour.

Video: How to drain your battery

The second way to properly discharge is to use a “smart” charger like imax b6, which is very convenient for charging batteries. In it you can configure the current and voltage parameters for charging and discharging the battery. Set the automatic cycling mode to boost the battery. That is, you do not need to constantly monitor the capacity and voltage. The device will do this for you. Up to 5 cycles are provided. Moreover, at the end you will be able to see the current and voltage values ​​​​after each cycle and analyze the result.

Video: Review of the imax b6 charger

Diagnostics.

Once fully charged, disassemble the battery. Inspect the elements for swelling and oxidation. Use a multimeter or tester to measure the voltage of all elements. Voltage limits for different batteries:

1. For nickel - cadmium 1.2 - 1.4 volts.
2. For nickel metal hydride 1.2 - 1.4 volts.
3. For lithium - ion 3.6 - 3.8 volts.

Diagnostics by tester.

Battery cans are wrapped in paper casing. The voltage is plotted on each element. If all banks have normal voltage, discharge the battery to half capacity. Measure the voltage again. Those elements whose voltage has decreased by 0.5 - 0.7 volts compared to the average must be restored or replaced. They say about such banks that they “leak”.

Video: How to check the battery status

Why isn't it charging?

If the charger is normal, check the contacts between the battery and the charger. The charger's contacts may have become bent. Because of this, the battery does not charge. Disassemble the device and bend the terminals. The second reason may be a faulty or unsoldered temperature sensor. It needs to be soldered or replaced with a new one.

Charges and discharges quickly.

When the contacts of the battery, charger and tool become oxidized and dirty, the battery quickly charges and discharges. Clean contacts periodically.

Electrolyte boiling away.

Electrolyte boiling occurs due to accelerated charging and overcharging. If the cells are not swollen and show operating voltage after a full charge, they can be restored without replacement. It is necessary to replenish the empty volume with distilled water.

• After identifying the defective cans, cut the connecting metal tape. Unsolder the elements.
• Take a punch no more than 1 millimeter thick. Where the minus is on the can, make a hole in the body.
• Pump out up to 1 cubic centimeter of air and pour in the same amount of water.
• Seal the elements with epoxy resin and connect them to the circuit.

If this method does not help, then replace the jars with new ones.

Video: Adding distilled water

Replacing and soldering batteries.

When you have carried out diagnostics and identified defective cans, you need to purchase replacements. New elements must match exactly in size and technical characteristics.

Video: Replacing elements in the battery

How to convert a screwdriver to use a lithium-ion battery.

Many owners of a screwdriver with a nickel-cadmium battery have encountered the problem that when they need to use it, the battery is always low. And constant charging kills it due to the memory effect. Therefore, such a battery is converted to lithium-ion.

The source of lithium batteries can be an old laptop battery or you can buy new ones. Laptops and new banks are unprotected. You cannot use them without protection, because you will not be able to charge them and control the discharge. And when recharged, they will die safely. It is allowed to connect absolutely identical batteries in parallel, then they will work as one unit. Purchase a protection module for series-connected batteries that monitors and takes care of each cell individually. Monitors voltage and current, provides short circuit protection. Such modules are available for one, two, three and four batteries.

Battery compartments for different numbers of batteries

To increase the capacity, parallel connected elements can be added. Solder lithium batteries it is forbidden. They can be placed in holders and the contacts of the holders can be soldered. Or connect with nickel-plated tape and resistance welding, which allows you to quickly heat a very small area without harming the battery.

For contact welding we will need:

1. Powerful high current source. This could be a converted microwave transformer or a lead battery.
2. Thick copper stranded wire, at the ends of which single-core copper contacts are fixed at a distance of four millimeters.
3. Metal tape. It is inexpensive, and you can connect about five assemblies with it. This is much more profitable than holders.

Place the tape on the battery, press the contacts where they are welded. Apply current briefly. On a battery, this can be done by making sharp short contact with the terminal. A button is placed at the input of the primary winding of the transformer. For ease of welding, connect the elements with glue. Cook according to the diagram, bending small pieces to attach the test leads for the module. Solder the “+” and “-” of the entire assembly to the module.

Connection diagrams with a controller for two, three and four elements

The output from the battery must be made with thick wires. If you don't have large diameter heat shrink tubing, wrap everything with electrical tape. The resulting battery will be very compact and neat.

Heat shrink tube.

Take the old battery and disassemble it. Leave only the protective thermal sensor in it, since without it the charger will not work. Solder the new battery and fill the free space with foam or cardboard.

Video: Converting a battery to lithium ion

Now the most important thing. How to charge such an assembly? You need to charge with a voltage equal to the sum of the maximum permissible voltages on each battery. The recommended charge current should be half the capacity of one battery. Such a customizable source is a complex charger like the Chinese imax B6. In it you can set the number of batteries and the required charging current.

Restoration and repair

Basic methods for restoring nickel batteries:

Compaction (compression).

Elimination of memory effect.

Adding distilled water instead of boiled-off electrolyte.

You can use pliers to compress the jar carefully and evenly over the entire surface. Be careful not to damage the contacts. The electrolyte will become denser and its storage capacity will be restored.

The memory effect is easily detected. Once fully charged, the battery discharges quickly during operation. A few hours later it is functioning again. To erase the memory effect, apply to the battery electrical impulse capacity larger than usual.

Video: Flashing a battery with a higher capacity and voltage to erase the memory effect

The elements in lithium-ion batteries cannot be restored. They are replaced by workers. It is necessary to unsolder the control board, and replace and assemble non-working elements in the same way as when converting a battery into a lithium-ion one.

Video: How to replace lithium-ion battery cells

If the lithium-ion battery does not charge using the original charger, try using the imax b6. Set the mode to “nimh” and watch the voltage carefully. When it reaches 3 volts, switch to “liion” mode. Continue charging as normal. This process needs to be done briefly. And be sure to control the tension. If you leave the battery charging and forget about it, it will overcharge and fail. If this does not help, then look for defective batteries and change them.

Video: Charging a lithium-ion battery from imax b6

How to store it correctly

Before use, be sure to read the instructions for the device.

Nickel - cadmium batteries Before storage, discharge it, but not completely, but so that the screwdriver does not work at full capacity. After long-term storage, shake the barathea in the same way as before the first use.

Video: Advantages, disadvantages, operation and storage of nickel-cadmium batteries

Nickel metal hydride batteries Charge fully before storage. If you do not use it for more than one month, recharge it periodically. After long-term storage, leave the charge for a day.

Lithium-ion batteries can be charged at any time. They have the lowest self-discharge current. The main thing is not to discharge them completely. If during operation the tool stops working at full capacity, do not take risks. Charge the battery.

As you can see, battery repair is not that difficult. If you carry out the diagnostics correctly, you can repair all types of batteries yourself.

Our workshop now has a lot of convenient and multifunctional power tools, which are difficult to do without. A screwdriver is one of them. No repairs are scary with it. Particularly convenient is a tool that runs on an autonomous power source - batteries. Charge it in advance where there is electricity, and you can work all day in any corner remote from the network.

The battery is the most important part in a screwdriver. If the tool begins to work poorly, then one of the reasons is the failure of the batteries. A new battery pack costs slightly less than the screwdriver itself. And you have to make a serious choice - buy a new unit or new tool. Not a cheap pleasure.

But, if a person created it, then a person can repair it. The main thing is that the head works and the hands have the right source. You can repair batteries with your own hands, which will then work for many more years.

Rechargeable batteries consist of several elements. They are very similar to regular batteries, but can be recharged. The number of charge cycles determines the basic price of the cells. By type of material, battery cells are divided into:

• nickel-cadmium;
• lithium - ion;
• nickel - metal - hydride.

They are arranged in the list by frequency of use. Nickel-cadmium elements (Ni-Cd) are most often found in screwdrivers of various brands. This is due to its comparative cheapness. But they have a low output voltage and the number of charge-discharge cycles is also low. The voltage on one such battery is about 1.2 V. If a screwdriver requires 12 V to operate, then the battery must consist of at least 12 such elements.

They are stored for a long time in an uncharged state and are not afraid of temperatures. But the level of self-discharge forces the battery to be charged frequently, which is the reason for failure. The environmental friendliness of the production of such batteries is not acceptable in every country in the world, but perhaps that is why they are cheaper.

Lithium – ion (Li – Ion) batteries have the best performance. The voltage on a separate copy reaches 3.6 V. High charge capacity. Four pieces are enough to operate the tool. This is very pleasing to the hands, because the instrument must be carried and held in the hands at any height. The number of charge cycles is high, but the price is also not low. But the battery has no “memory” of its charge level. And the self-discharge is small. In a word, everything is good except the price.

Nickel-metal-hydride (Ni-MH) batteries have almost all the disadvantages of previous brands. Given the quality of nickel-cadmium elements, their price is equal to the cost of lithium-ion ones. Application in practice is very low where there are low temperatures. Low temperatures The entire battery is damaged at once.

You can repair a battery yourself, but this does not mean that you can repair one element. You can try to restore one element, and if restoration does not help, then you just need to replace it. All battery elements can be replaced. This is the best option - buy new elements and make replacements. But this is not always fast, and the tool is needed now.

Troubleshooting

A battery malfunction may be hidden in one element or in several. Rarely do they all fail at once. This gives hope that it will be possible to repair the instrument. To find a faulty element, you will need any multimeter, which must be in the workshop, and a car light bulb with a power of about 20 W.

We charge the battery for the allotted time, then load it onto the light bulb. While the light is on, we use the device to select those batteries with the lowest voltage. Most likely, they are the cause of the failure. For more accurate diagnostics, these elements must be removed from the battery.

The battery is soldered, or rather welded using connecting plates using the spot welding method. It is necessary to carefully use side cutters or other suitable tool tear off the plates.

On the disconnected elements, we check the direct circuit current with an ammeter of the same multimeter. We simply close “+” and “-” with the probes of the device. The current on a faulty battery will be noticeably less than on the others.

What is the crime of such a phenomenon? The fact is that a “bad” element does not allow others to be charged normally. It becomes a kind of resistance in the path of current, and the entire battery becomes uncharged until desired value. After some time, due to constant low level charge, it will all fail.

Element recovery is a reality

The “memory” effect of a battery has many interpretations, but the meaning of this phenomenon is that the cell reduces its charge capacity with each charge. Restoring an individual battery means restoring the functionality of the entire battery.

Recovery methods are different, but not all give results. A repeated charge-discharge cycle often helps. A separate element is charged and then discharged into a light bulb. After complete discharge, repeat the charge. This manipulation is performed until the element begins to gain sufficient charge capacity. If this does not happen, it is disposed of, or, more simply, thrown away.

Sometimes specialists use the shock charging method. A hopeless element that has not responded to restoration measures is supplied not with 1.2 V, but with all 12 V. Such a shock shake sometimes brings results. This is one more try before the final release.

Recovery methods for non-specialists are interesting. They, of course, are similar to shamanism, but they also exist. They apply only to Ni-Cd samples. It is suggested to put the element in the freezer for 1 hour, and then put it in a plastic bag and simply tap it with some object. If you feel bad throwing it away, try it.

DIY repair and replacement

When all restoration methods have not brought success, and the rejected elements have disappeared into oblivion, it is necessary to find a replacement for them. The ideal replacement would be a new cell or set of cells, but due to the lack of such, you can select a live cell from another used battery. You can select it using the same method as selecting an element from a battery.

Replacing with a used item is not as unreasonable as it seems. If you take a new element, its qualities may get lost in the background old battery, and the old living element will work under equal conditions.

Soldering is the most difficult moment + (Video)

At the factory, batteries are spot welded. But not every home workshop has it. There are persistent opinions that the effects of high temperature on the elements disable them. There are opinions, but there is no evidence. Therefore, you can connect the elements into a battery using conventional soldering. The method was also tested on li-ion batteries.

To do this, take an electric soldering iron with a power of 40 - 60 W, a flux for soldering nickel or whatever is available, and strips of thin sheet metal. Connectors are made from tin.

Before assembly, it is necessary to tin all battery contact points and connecting plates. Then we place the plate on the contact and press it with a soldering iron. A powerful soldering iron can quickly solder the tinned layer. A split second is enough for this.

We check the soldering for physical break. The following contacts must be re-soldered in a similar manner. There is nothing complicated in this process. It takes a certain amount of accuracy and skill to do everything yourself. After soldering, we wipe all places with alcohol to remove any remaining flux, assemble the battery into the case and put it on charge. After fully charging, we perform a full discharge to equalize the elements and the battery is ready for use.

Correct operation saves your budget + (Video)

There is only one operating rule - keep the battery in working condition. Once a month, fully charge and discharge it, simulating the operation of a screwdriver - turn it on and off repeatedly. At least for idling. That's the whole trick.

When using a screwdriver for a long time or storing it, after a certain time, the battery of the screwdriver becomes unusable. Further use of the tool becomes impossible. The consumer has to consider the option of purchasing a new battery or screwdriver. This decision problem is the simplest way out of this situation, compared to replacing the batteries in the old battery.

The cost of a new battery is about 60% of the cost of a screwdriver. Each battery contains the same type of cells, which are also sold separately. You can try to repair the battery. Repairing it is not considered a very difficult process, but if the attempt fails, the user can purchase a new battery. Below in the article we will discuss in detail the issues of repairing a screwdriver battery with your own hands.

Types of batteries

Today there are screwdrivers on sale with the following types of batteries: nickel-cadmium; nickel metal hydride; lithium-ion.

Each type has its own advantages and disadvantages. Let's take a detailed look at each type.

Repairing a screwdriver battery with your own hands is not a difficult task if you listen to our advice. But first, let's figure out what this requires. Any equipment fails sooner or later. This also happens with a screwdriver. And if you are used to working with this tool, then you will no longer want to use ordinary screwdrivers. Most often the battery stops working. But don’t rush to part with the device. Repairing a screwdriver battery with your own hands is quite feasible, and it is not so difficult to do. First you need to stock up on tools.

You probably have the necessary tool. All you need is:

• soldering iron (with solder and rosin);
• screwdriver;
• tester or ohmmeter;
• connecting wires;
• low-power lamp (better if it is an LED).

We determine the type of battery and look for a breakdown

First you need to disassemble the battery case and examine its internal contents. The “filling” consists of series-connected nickel-cadmium batteries (in most cases, these are the batteries that are installed in the battery). The disadvantage of such “cans” is that they have high degree self-discharge. All you have to do is not use the screwdriver for a while, and the battery loses its charge. This is inconvenient for the user, but the majority of batteries are like this, since they are produced in third world countries.

Cheap labor force reduces the costs of hazardous production, which is why screwdriver manufacturers are striving to use nickel-cadmium batteries to make their production more cost-effective. It's a profit for them, but an inconvenience for us. But let's get back to the renovation.

So, you need to identify the “can” that has failed and broken the electrical circuit. This can be done using a tester or ohmmeter, determining the total resistance of the entire battery and dividing it by the number of “cans”. You will get the resistance of one element. If there is a mechanical break in the electrical circuit, then you will not be able to measure the battery resistance. Then all you have to do is check each element. The readings will vary, but one (or more) battery cells will have a resistance that is significantly higher than the average value. Typically, the “banks” should indicate their operating parameters.

This marking makes your work easier. You can take the same resistance measurements and compare them with the nominal value. A sharp deviation of the resistance from the declared parameters indicates that the element is unsuitable for further use. It must be removed from the circuit and replaced with a similar serviceable one. Such an element may not be at hand. Try to find a “donor” battery. IN lately There should be no problems with this issue: collection points for used electrical power supplies are gradually filled with various kinds of elements. It is quite possible to find the necessary battery. It makes sense to seek help from specialized workshops. They definitely have the item you need in stock. Naturally, it is economically feasible for the craftsmen of such companies to restore the screwdriver battery in the workshop, but they will also be able to help you get the necessary “can” for your screwdriver. All that remains is to assemble the battery from the “cans”, solder everything properly and put everything back into the case.

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How to replace the tester?

You may not have a tester or ohmmeter at hand. And if urgent restoration of the screwdriver battery is necessary, then in this case you can find the damage using a regular LED lamp. Two wires are soldered to it, the opposite ends of which are connected in turn to the poles of each battery element. In this case, it is not necessary to solder the entire circuit: the lamp will receive current from a separate element each time. If the LED does not glow, then you have found a weak link in the electrical circuit.

Don’t rush to unsolder it right away. Try to squeeze the element from all sides without damaging the integrity of its body. If the electrolyte is still left in the “bank”, then you will increase its density, therefore, the element will still last, although not for long. If the increase in density does not lead to the appearance of a glow on the LED, then the element is soldered off. In a state of urgency, you are unlikely to look for a suitable analogue, so solder the contacts in the place of the removed element, and assemble the battery case. The screwdriver will work, although it will lose power.

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Replacement with other batteries

Restoring the screwdriver battery can be done more radically.

Instead of existing batteries, small rechargeable batteries are installed in the battery case. Even finger elements that need to be connected in series are suitable. In this case, it is necessary to calculate both the total voltage and the total power of the resulting battery. Exceeding one of the parameters may cause the electric motor of the screwdriver to fail. Repairing the latter, although less expensive, will take a lot of time.

Repairing a battery for a screwdriver with your own hands is possible, but it is advisable not to go through with it.

And this can be done if you use the product correctly. U nickel-cadmium batteries there is one drawback - a high “memory effect”.

This means that if the battery is in a half-discharged state for a certain time, it will independently discharge to this level. A forced reset of this effect will help to avoid this effect.