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How to check screwdriver batteries with your own hands. How to restore a lithium battery from a DeWalt screwdriver? Charges and discharges quickly

Hi all! Today I will touch on the topic of construction and summer dacha activities. I’ll tell you how to repair or restore a screwdriver battery with your own hands. I must say that the screwdriver is very convenient thing. Charge the battery and run without wires, turning it here and there. Only over time, such a twist turns less and less. This is due to loss battery capacity. We will talk about them.

How does a screwdriver work?

Everything is quite simple here. The simplest screwdriver consists of a plastic case, a battery (1), a speed controller (2), a plastic button (3), a motor (4), a gearbox (5) and a chuck (6).

Screwdriver battery insides

The battery inside of the screwdriver is very simple. The battery banks are connected in series with each other using metal foil using spot welding. In the simplest case, everything ends with sliding contacts.

More complex batteries include charge and discharge controller boards that monitor the temperature of the cans. Most often, such boards are installed in screwdrivers from branded companies with lithium-ion battery sections.

Types of battery cells

Over the past 20 - 30 years, many portable battery technologies have been developed: Ni-Cd, Ni-Mh, Li-ion, Li-Pol, Al-Ion, Li-S, Mg-S, Li-O2, LiFePO4 and even lithium- nanophosphate. Let's look at the most popular of them.

Nickel-cadmium batteries

This is the most popular type of battery section for .

Advantages: They are cheap and can work well in sub-zero temperatures. They are also not afraid of discharge and storage in this position.

Flaws: Cadmium is toxic and such batteries must be disposed of in a special way. There is self-discharge and memory effect, low specific volumetric capacity.

Nickel-metal hydride batteries

Nickel-metal hydride ones are a little more expensive, but in general they are about the same level, maybe a little better than nickel-cadmium ones.

Advantages: non-toxic, less memory effect and self-discharge, larger number charge/discharge cycles.

Flaws: are more sensitive to negative temperatures, are afraid of being stored in a discharged state - they lose capacity.

Lithium-ion batteries

Lithium-ion batteries are increasingly used in even budget-class screwdrivers.

Advantages: no memory effect - can be charged and discharged at any time, large capacity with smaller dimensions, low self-discharge, big number charges/discharges.

Disadvantages: high price, danger of excessive heating during intensive charging and discharging.

Lithium polymer batteries

So far, lithium-polymer batteries are rarely used in screwdrivers, but with the development of technology, most likely they will begin to be installed there en masse.

Advantages: larger capacity with smaller dimensions than Li-ion, can take any shape, holds voltage better during discharge, low self-discharge.

Disadvantages: high cost, heating during operation and risk of fire.

Battery cell recovery

Here I will give a story from Master Sergei on the restoration of a nickel-cadmium screwdriver battery. The owner began to complain about the short operating time of the electric screwdriver and that “the battery doesn’t hold up.” Disassembling the battery case showed that there are factory Ni-Cd banks from Liang with a capacity of 1000 mAh.

It is possible to restore a Ni-Cd battery sufficiently in a simple way. You need to do several deep discharge and charge cycles. In such extreme modes, hard-to-reach areas of battery charge accumulation begin to operate, the output of which has deteriorated due to the memory effect, violation of operating or storage conditions.

Such problems arise not only with screwdrivers. Industry radio controlled models battery-powered technology has long ago solved the problems of automated discharge/charge. There are special chargers for this.

Master Sergey had a Vista Power AK610AC. This is a charger with a charge function of 90 W and a load discharge of 20 W. This is a wonderful professional device with a touch screen! This can be found on Avito for about 5,000 rubles.

Instead of such a charger, you can use something more Chinese, for example, at a price of about 2000 rubles.

It is best to start cyclic battery recovery by deeply discharging the battery and then immediately charging it.

After the first cycle, the discharge capacity was 707 mAh, and the charging capacity was 879 mAh. As you can see, the capacity decreased by 30% relative to that declared by the manufacturer.

The second discharge/charge cycle showed figures of 781 mAh / 937 mAh. As you can see, this is 10% more than the previous values.

The third battery recharge cycle showed minor deviations from the previous second recharge. So this is enough. If you see on your batteries that the capacity is increasing, then you can continue.

All cordless devices, including screwdrivers, have a significant drawback - limited period battery service.

That is why every owner of such a tool at any time may face the question of replacing the batteries in a screwdriver. But before you get started, it’s worth understanding the variety of batteries and their features.

Types of Power Tool Batteries

There are a huge number of battery production technologies, but the most common and popular among them are the following:

1. Lead-acid batteries are the most popular for automotive production due to their ease of manufacture and low cost. But further, for use in power tools, they did not show themselves very well, since they have low power with large dimensions and heavy weight.
2. Nickel-cadmium batteries are significantly superior to lead-acid cells. After all, they produce great power with light weight and compact size. But, of course, there are also negative aspects, in particular, the toxicity of the battery. Since the production of this kind of battery cells is harmful environment. For example, in the countries of the European Union this type of battery is considered prohibited.
3. Nickel-metal hydride cells are considered a more advanced version of the previous type of battery. After all, they are completely safe for the environment. But there is also a drawback in the form high performance self-discharge current.
4. Lithium-ion batteries, although they have almost ideal parameters, since they have a high capacity, small size And little weight, are not very popular. This is because such a progressive element has a high cost, and therefore is not affordable for every average person.

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What is a screwdriver battery?

Any battery is presented in the form of a small number of batteries, in other words, cans. The latter mostly have standard dimensions. Distinctive feature Such batteries are considered to have a SUB-C capacity.

The battery is characterized by the presence of four main contacts:

1. Currents pass through the power contacts, of which there are two units, during the process of charging and discharging the entire battery of the screwdriver.
2. At the top there is always a control contact, which is continuously connected to the disconnecting temperature sensor and is used to prevent overheating of the tool during the charging process. since at this moment the device absorbs currents of enormous value.
3. The last but not least important contact is called the service contact. It is used to equalize the charge in all banks at the moment of the deepest discharge in the most structurally complex battery cells.

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How to calculate a non-working battery cell?

Since the battery is presented in the form of a certain number of cans connected to each other, current completely flows through it. To find a dead battery cell, you must initially fully charge the entire battery until it is clear that charging is complete.

Next, it is recommended to measure the voltage on each individual bank. The voltmeter should not show values ​​below 1.2 Volts. If such readings are available, it means that the battery cell is not receiving proper power or is not charging.

Important! In order to verify your measurements, you need to put a mark on the questionable element and reassemble it.

So, after several periods of operation of the instrument, it is necessary to reconnect the banks again and measure the voltage. Practice shows that the previously mentioned can will have even less voltage than before, since it begins to lose its performance and “slow down” the screwdriver.

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Stages of the process of replacing the battery in a screwdriver

Considering the fact that in the post-Soviet space the tools most often used are nickel-cadmium battery-type screwdrivers, this option will be considered in more detail using the Bosch GSR 14 4 ve-2 professional screwdriver as an example. In our case it will be done complete replacement elements of individual screwdriver batteries.

1. Remove the cover and remove the battery cells in the assembly.
2. Unscrew a few bolts on the red upper body.

First, you should disassemble the screwdriver battery. It is as follows:

1. Prepare new battery cells.
2. Next, you need to apply tin to all cans on one side and thoroughly wipe the soldering areas with distilled water.
3. To connect each battery element of the screwdriver, you can use a previously tinned piece of copper foil. In this case, it is necessary to make U-shaped cuts at its edges for further soldering.
4. So, attach the foil with a U-shaped cut to the battery contact, to which liquid rosin was previously applied, and solder. After a few simple manipulations, all battery cells will be assembled and ready for replacement.
5. Install the assembly into the original screwdriver box. Ready!

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Types of restoration of previously used battery cells

A method of reanimating previously used batteries is very often used, since during the operation of a screwdriver, in other words, during constant high loads, some elements lose their tightness and become unusable. In this case, it is necessary to briefly apply a strong current to the required battery cell (cell), and it may be possible to restore the battery’s functionality.

You can also try gently squeezing or slightly deforming the battery housing of the screwdriver. Because this can extend the battery life for a short period of time. But in most cases, this method does not guarantee the battery life of the screwdriver and is temporary.

Nickel-cadmium batteries have significant endurance because they can for a long time do not lose charge or discharge, but very slowly. But in the case when it was not possible to restore their functionality, it is worth carrying out a process such as replacing the batteries in the screwdriver device.

IN Lately rechargeable electric tool is becoming increasingly popular. This is understandable - in some cases you simply cannot do without such a tool. One of the most important elements in the design of a screwdriver is the battery. Without it, the tool will be useless.

The battery produces direct current through the process of electrolysis. It consists of several elements (cans) connected in series. Each jar includes:

• Electrodes (anode and cathode).
• Electrolyte.
• Battery case.

Current is generated due to the appearance of a potential difference at the anode and cathode. Batteries have many important parameters, but the main ones are:

• Type, that is, the material from which the poles and electrolyte are made.
• Voltage.
• Capacity.

The battery voltage depends on its type and number of cells. One bank has a voltage from 1.2 to 3.9 V, depending on the type of battery. The banks are connected in series, due to which their voltage is added.

The battery capacity or maximum operating time depends on the current consumed by the tool and the final voltage when completely discharged. Let's consider all these parameters using the example of a battery for a Bosch D 70 745 screwdriver. This lithium-ion (li-ion) battery has a voltage of 11.1 V and a capacity of 1500 mAh. Lithium-ion battery has a cell voltage of 3.7 volts and, as can be seen from the total voltage, the battery consists of three cells. Typically, the battery voltage for a screwdriver does not exceed 18 V.

Types of batteries and their features

As can be seen from the above, almost all of its parameters depend on the type of battery. In hand-held power tools they are mainly used following types Battery:

• Nickel-cadmium (Ni-CD).
• Nickel metal hydride (NiMH).
• Lithium-ion (Li-ion).
• Lithium polymer (Li-Pol).

Learn more about each type.

Nickel-cadmium

The anode of the NI-MH battery is made of nickel, and the cathode is made of cadmium. The poles are separated from each other by a separator. The electrolyte is a solution of potassium hydroxide.

Pros:

• A large number of charge-discharge cycles (operation cycles).
• Work well when low temperatures.
• Low cost.

Minuses:

• Strong memory effect.
• High self-discharge.
• Big sizes.
• Toxicity of materials.
• The need to periodically perform a complete discharge-charge cycle.

Nickel metal hydride

Nickel metal hydride batteries have been developed for partial replacement nickel-cadmium. Their anode is made of nickel-latanium or nickel-lithium, the cathode is nickel oxide, and the electrolyte is potassium hydroxide. The cathode and anode are separated from each other by a separator. The case is closed with a lid with a valve that is activated when the battery malfunctions.

Pros:

• Higher energy intensity (compared to Ni-CD).
• Complete absence of memory effect.
• Environmentally friendly.

Minuses:

• Fewer charge-discharge cycles.
• The need to control temperature during charging.
• High self-discharge.

Lithium-ion

The anode and cathode in this type of battery are lithium salts of various acids deposited on foil. Copper is used for the anode, and copper for the cathode. aluminum foil. Electrolyte is a gel-like liquid based on lithium salts. The poles are separated by a separator, and the housing is built into safety valve excess pressure.

Pros:

Minuses:

• Explosive spontaneous combustion.
• Low operating temperature range.
• High price.
• Strong discharge, overcharging and heating are unacceptable.

Lithium polymer

Li-Pol batteries are an improvement of lithium-ion batteries by replacing the liquid electrolyte with a polymer one.

The pros and cons of this type of battery are similar to the pros and cons of lithium-ion batteries. But unlike them, Li-Pol batteries are safer in terms of spontaneous combustion, provided that the charging regime is followed.

Do not try to replace a failed battery of one type with another. If lithium-polymer and lithium-ion batteries are interchangeable to some extent, then lithium batteries with nickel batteries are completely interchangeable.

• Monitor the level of discharge. Try to charge the battery immediately after it runs out. Otherwise, due to the self-discharge effect, the voltage may drop below permissible level, and the battery will fail.
• Charge the tool only with the charger included in the kit. If it breaks, replace it with a similar one or select one that matches the parameters. Violation of at least one of the charging mode parameters will lead to battery failure.
• As a rule, lithium batteries have an overcharge and overdischarge protection circuit installed, so be careful not to damage it when repairing. Otherwise, you will have to use a special device when charging, manually controlling all parameters, and charge the battery before it is completely drained.
• Monitor the battery temperature during operation and charging.
• Do not damage the battery.
• Store the battery in a partially or fully charged state, and when long-term storage You need to charge the battery at least once a month.

Basic faults and checking batteries

Subject to operating conditions In handheld power tools, the battery most often fails. Signs of a bad battery:

• Significant reduction in operating time.
• Doesn't charge or charges very quickly.
• External damage.

Depending on the type and parameters of the battery, their price can vary greatly. Powerful lithium batteries can be comparable in cost to a new tool; in this case, you can try to repair the screwdriver battery yourself.

Before you begin repairing the battery at home, you need to determine the type of fault. Main types of faults:

• Broken contacts.
• Mechanical damage to cans.
• Natural aging.
• Degradation due to improper use.

To check the integrity of the contacts, it is necessary to disassemble the battery case and visually inspect all solder joints. At the same stage, it will be possible to inspect all the battery elements and make sure there are no mechanical damages.

In the event of natural aging or degradation of the cells, the total voltage of a fully charged battery decreases. This can be detected using a multimeter, but not all owners hand power tools keep it handy.

Battery repair and restoration

General principles of repair various types The batteries are similar. For example, methods for restoring Ni-CD screwdriver batteries are similar to methods for repairing nickel-metal hydride batteries. But more on that below.

To repair the battery, you must perform the following basic operations:

Full discharge-charge cycles are necessary to eliminate the accumulated memory effect and attempt to equalize the voltage between the battery cells. Wherein good option There will be the use of special universal chargers that allow you to set the charge-discharge voltage. We set the voltage 2-3 times less than that indicated on the charger included in the kit, and perform cycles. At the end we get a fully charged battery.

We disassemble the battery. There may be two options: either you will need to unscrew the screws holding the battery case together, or, using a small hammer with rubber pads, carefully separate the parts of the case. In the second case, it is important to find the junction of the body halves. At the end of the procedure, remove the soldered battery elements from the case.

At the next stage, we perform a visual inspection of the elements, paying special attention to the integrity of the contacts and soldering points.

After that, we move on to the whole and each element separately. Depending on the type of can and their number, the total voltage may be different. For nickel-cadmium and nickel-metal hydride batteries it is 1.4 V per cell, for lithium - 3.6 - 3.9 V. We measure the voltage when the battery is fully charged for each element. For convenience, it is better to write down the readings.

Then we discharge the battery (supply power) until there is a noticeable loss of power and repeat the voltage measurement procedure. A Ni-CD and Ni-MH type element must be replaced if its voltage is below 1.2 V when fully charged and below 1.0 V when discharged. For a lithium can, these figures are 3 and 2.2 V, respectively.

Let's move on to troubleshooting. Swollen cans or cans with damaged casing seals cannot be repaired and must be replaced. The fallen contacts must be soldered again.

Elements with low voltage readings are best replaced with new ones. To save money, you can take cans from another used battery, but it is important to remember that after some time these cans will also require replacement.

On some resources you can find information about restoring Ni-CD and Ni-MH cans using electrolyte renewal. To do this, you need to make a hole in the jar, pour water into it and solder the hole. But the problem is that the density of the electrolyte must be in a certain range and it will be very difficult to “get into” it at home.

Violation of the tightness of a lithium can usually leads to its complete failure. Therefore, lithium banks cannot be repaired. If the overcharge control circuit for lithium batteries breaks down, it can be re-soldered.

Considering the cost of nickel cans, the most the best way Replacing failed elements will involve purchasing new ones. Some new elements are available for free sale, but in this case it is important to pay attention to the manufacturer. Factory-made cans usually have markings; if they are missing, you should consider purchasing.

After eliminating the identified malfunction, it is necessary to assemble the battery, fully charge it and check the total voltage. If everything is done correctly, the screwdriver will work like new.

As you can see, it is not difficult to restore and repair a broken battery for a screwdriver; it all depends on your skills and the availability of a soldering iron and a multimeter. If they are not available, their cost may be higher than the cost of the battery itself. On the other hand, a soldering iron and a multimeter are always useful around the house.

If you doubt your abilities or simply do not want to repair the battery yourself, it is better to take it to a specialized workshop. Such workshops or service centers are always located in large stores that sell tools. On the other hand, service center specialists do not always carry out repairs efficiently and often delay deadlines.

In the arsenal of any good owner there will probably be a power tool that is common in everyday life - a screwdriver. Its main advantage is mobility. After all, this device runs on removable batteries, which makes its use as convenient as possible, since it does not require connecting to a power outlet. But what if the battery of the screwdriver fails? Buying a new one will be quite expensive, because its cost in some models reaches 50–70% of the price of the screwdriver itself. It would be much more practical to buy it right away. new tool, which includes two batteries. But you can still extend the service life of an old screwdriver by repairing a failed battery.

What is a screwdriver battery?

In any models of electric screwdrivers this important element, like the battery, looks about the same. It is a plastic box containing up to a dozen (and sometimes more) batteries. They are connected to each other in a serial chain and are arranged in such a way that the conclusions of the first and last can in the circuit are closed to contacts that provide power to the tool and connection to the charger.

A screwdriver battery is a chain of rechargeable batteries connected in series

The batteries of any type of screwdriver have quite simple design, which anyone with at least a little knowledge of the basics of electrical engineering can easily understand. In addition to batteries, the battery housing may contain:

Depending on the type of batteries used, screwdriver batteries are of the following types:

• nickel-cadmium, designated NiCd and designed for a nominal voltage of 12 V;
• nickel metal hydride (NiMh) with the same rated voltage as the first type (12 V);
• lithium-ion (Li-Ion), the voltage of which, depending on the number of elements used, can range from 14.4 to 36 V.

Different types of batteries provide different nominal voltage and power for the screwdriver

Rechargeable batteries the first type (NiCd) are most common in modern instruments, first of all, due to their lowest cost. Batteries based on nickel-cadmium alloy can be found especially often in budget models screwdrivers. They are not afraid of low temperatures and can be stored in a discharged state without losing their characteristics. The disadvantages of such batteries include:

• a pronounced memory effect, when, when the charge is not fully developed, the battery seems to remember to what value its capacity was used, and in the future it is no longer charged above these parameters;
• small capacity and small number of charge and discharge cycles;
• susceptibility to self-discharge, when an unused charged battery gradually loses its charge;
• high toxicity when opening the can due to the cadmium contained in the battery.

To ensure that a new battery for a screwdriver does not lose capacity, it must be charged for 10–12 hours the first few times, even if an indication appears that it was charged much earlier. During operation, it is better to use the battery until it is completely discharged, and then immediately connect it to the charger until it is fully charged.

Nickel-metal hydride elements are also common in modern screwdrivers. They consist of environmentally friendly elements, but are more expensive than nickel-cadmium batteries. They have lower self-discharge and memory effect and a higher number of charge cycles than NiCd cells. But they are afraid of low temperatures and, when discharged, also lose their characteristics.

The most expensive are lithium-ion batteries, which, compared to the first two types, have noticeable advantages:

Among the disadvantages of batteries of this type, their short service life should be noted. After three years, lithium begins to decompose and the battery loses its capacity beyond recovery.

Typical screwdriver battery malfunctions

Despite the fact that the screwdrivers are equipped different types batteries, they all have the same design and similar faults. The most common failures of this device are:

• loss of capacity of one or more batteries;
• mechanical damage to the battery pack circuit (separation of the plates connecting the banks to each other or to the terminals);
• drying out of the electrolyte;
• Lithium decomposition in Li-Ion cells.

Loss of battery capacity is the most common defect in screwdriver batteries. Its essence is that the loss of the charge capacity of at least one battery does not make it possible to fully charge the remaining banks. When receiving a low-quality charge, the battery quickly discharges.

Such a malfunction may be a consequence of the memory effect or drying out of the electrolyte in the banks due to their heating during charging or under load. This defect in batteries of any type can be eliminated independently, without contacting service center. In this case, you can try to restore faulty elements or replace them. It will not be possible to restore only lithium-ion batteries that have lost capacity as a result of lithium decomposition. Such banks can only be replaced with new ones removed from a non-functioning battery pack.

A screwdriver battery malfunction can be caused by loss of capacity of one or more batteries, so it can be easily eliminated by replacing them with new ones or ones that are known to work.

DIY screwdriver battery repair

Most defects in the battery pack of a screwdriver can be eliminated yourself if you know the cause of the malfunction and how to deal with it.

Diagnostics of screwdriver battery faults

Before you begin repairing the battery, you need to diagnose it and identify the cause of the malfunction. To do this you need:

1. Fully charge the battery pack. A nickel-cadmium or nickel-metal hydride battery must first be discharged to zero to avoid memory effect.
2. Disassemble the battery case by removing its cover. It can be fastened with screws or glued, which will make disassembly somewhat difficult. In the second case, to remove the cover, you need to use a sharp scalpel or knife to walk along the adhesive joint, and then, carefully prying it off with a thin screwdriver, disconnect the cover.

   The battery pack cover can be attached to the battery housing with screws or glue

3. By visual inspection, determine the presence of mechanical damage, broken circuits, as well as swollen or leaking battery cans.

   After disassembling the battery pack, perform a visual inspection of the contents for obvious defects.

4. Measure the voltage on each battery with a multimeter. For batteries such as NiCd or NiMh, it should be in the range of 1.2–1.4 V, and for lithium-ion banks - 3.6–3.8 V. It is better to write the measured value on each bank with a pencil to avoid confusion.

   By measuring the voltage on each bank, you can find all the faulty elements

5. Load the battery by connecting a regular car light bulb or resistor to the output contacts.

   By connecting the lamp, we let the batteries work to show the voltage drop under load.

6. After holding the battery under load, measure the voltage on each bank again and find the batteries on which the maximum drawdown occurred. These are the defective elements.

Video: how to completely discharge a screwdriver battery

Having found faulty batteries, you need to decide on how to repair them. There are two possible options here. The first is to revive defective batteries by flashing them with a current with more high voltage or add distilled water to the jars if the electrolyte dries out. But these measures are temporary; in the future, the malfunction may appear again. Another repair method that is more effective is to replace defective batteries with new or used ones that are known to be good.

Video: searching for defective batteries in a screwdriver battery

Battery recovery

Restoring the lost capacity of a battery is possible only for batteries with a memory effect. These are nickel-cadmium and nickel-metal hydride batteries. To do this, you will need a more powerful charger with adjustable voltage and current settings. Having set the voltage to about 4 V and the current to 200 mA, we apply this current to the batteries in which the maximum voltage drop is detected.

You can try to restore defective batteries by compressing or compacting them. This procedure is a dilution of the electrolyte, the volume of which in the battery bank has decreased. To do this you need:

The procedure described in paragraph 5 can, under certain conditions, restore the functionality of the battery if the cause of its malfunction is the memory effect.

Video: the process of restoring the capacity of screwdriver batteries

Replacing batteries

The most in an effective way Repairing a screwdriver battery involves replacing a defective battery. To do this, you can use a new battery, which can easily be found on sale today, or remove a working jar from a non-functioning battery pack. Replacement work must be carried out in the following sequence:

1. Remove the battery from the circuit faulty element nutrition. Considering that they are all connected to each other by plates mounted on spot welding, it is best to use side cutters for this purpose. In this case, you need to leave a sufficiently long shank on a working can in order to be able to solder it to a new battery.

   On working cans, you need to leave the shanks so that they can be soldered; on a faulty can, this is not necessary

2. Solder the new battery in place of the removed defective can, observing the required polarity. The positive terminal is soldered to the negative terminal of the “neighbor”, and the negative terminal is soldered, respectively, to the positive terminal. To do this, you will need a soldering iron with a power of at least 40 W and soldering acid. If it was not possible to maintain a sufficient length of the plate, you can connect the cans with a copper conductor.

   For soldering, use a soldering iron with a power of at least 40 W and soldering acid.

3. Assemble the batteries into the case according to the same pattern in which they were placed before repair.

   After installing a working can, the entire chain must be put back into the battery box

4. Equalize the charge on each bank by repeating the charge-discharge cycle several times. Then check the voltage potentials on each bank with a multimeter. They should be at the same level - 1.3 V.

It is important not to overheat the can when performing soldering work. Therefore, you cannot hold the soldering iron tip on the battery for too long.

Repair of battery packs with lithium-ion type banks is carried out in the same way. The only thing that complicates the repair task is disconnecting the batteries from the control board. In this case, only one repair method is applicable - replacing the defective can.

Video: how to properly solder screwdriver battery banks

How to convert a screwdriver battery to lithium-ion batteries

Often, owners of screwdrivers with nickel-cadmium batteries want to convert their batteries to lithium-ion batteries. They are attracted by the advantages that can be acquired by such a modification of the battery pack:

• Lighten the weight of the screwdriver, the operation of which will require fewer batteries at the same battery capacity and voltage;
• get rid of the memory effect, which is not present in lithium-ion batteries;
• reduce battery charging time.

In addition, with a certain assembly scheme, you can double the charge capacity, and therefore the operating time of the screwdriver on a single charge. The advantages, of course, are obvious, but this solution also has its disadvantages, which you also need to know in order to weigh the pros and cons. From negative points When adapting a screwdriver battery for lithium-ion batteries, it should be noted:

• higher cost of lithium-ion batteries;
• the need to maintain the charge level of the element strictly within the range from 2.7 to 4.2 V, for which it will be necessary to additionally install a charge-discharge controller board in the battery box;
• large sizes of Li-Ion batteries, which will require ingenuity and imagination to place them in the screwdriver battery case;
• it is impossible to use the tool with such batteries in low temperatures.

But if the decision to replace nickel-cadmium batteries is still made, then you need to proceed in the following sequence:

1. Decide on the number of lithium-ion batteries and their electrical characteristics. For example, for the most common screwdriver powered by a battery with a nominal voltage of 14.4 V, it is better to take 4 lithium-ion cells, the total maximum voltage which will be equal to 4.2x4 = 16.8 V. Here it is necessary to take into account that immediately after starting work on new batteries, the voltage on them will drop and will be equal to 14.4–14.8 V. If the capacity of the battery pack box allows, you can take 8 such cans, forming 4 pairs of them with parallel connected batteries. This will increase the battery capacity by 2 times.
2. Select a controller board for 4 batteries. Its parameters must correspond to the discharge current and rated voltage of the selected batteries. In this case, the operating discharge current should be 2 times less than the maximum permissible value battery discharge current, which is usually 25–30 A. This means that the board must be designed for a current of 12–15 A.

   The controller board must be designed to work with the required number of batteries and be designed for their operating discharge current

3. Disassemble the screwdriver battery box and remove all nickel-cadmium cans from it. Cut the entire chain with wire cutters or side cutters, leaving only the top element with contacts for connecting to the tool. The thermistor can also be removed, since overheating of the batteries will now be monitored by the controller board.

   When connecting the control controller board to a chain of lithium-ion batteries, the polarity must be observed. Lithium-ion batteries are best placed horizontally in the screwdriver battery case

4. Close the battery with a lid, installing a battery with contacts on an old type battery on the batteries laid horizontally.

It may turn out that assembled structure You won't be able to charge using an old charger. Then you need to install an additional connector for a new charge.

Video: replacing nickel-cadmium batteries with lithium-ion ones

How to properly store screwdriver batteries

In order for the screwdriver battery to last as long as possible, it must be stored correctly, especially when it is not used very often and with long breaks. In this case, you need to follow some rules.

Cadmium-based battery packs have a memory effect, which reduces the battery capacity when the charge is incomplete. Therefore, batteries with NiCd and NiMh batteries should be stored in a discharged state, and devices with lithium-ion batteries should be charged to half the capacity of the cans. This level can be achieved in approximately 65–70% of the normal full charge time.

If the battery pack of your screwdriver begins to discharge quickly and does not hold a charge at all, do not rush to throw it away and buy a new one. Its service life can be easily extended using the recommendations outlined above. This will save you from extra costs, because the battery of a screwdriver costs more than half the cost of the entire tool.

Correctly repairing a screwdriver battery with your own hands is a rather labor-intensive and painstaking process. However, you can’t do without it, because the cost of a new tool is about 5 thousand. Moreover, 70% of the cost is the battery. Let's figure out how to repair a screwdriver battery with your own hands rationally and quickly.

Design and types of batteries

Before you start restoring the screwdriver battery with your own hands, you need to determine its type. Each type of battery has its own advantages and disadvantages.

Regardless of the brand and country of origin, the structure of the batteries is identical. Inside we can find series-connected “banks”. As a rule, they have the same dimensions and voltage, but they have different capacities.

Metals are used to make batteries, which give the batteries their name:

• Nickel-cadmium. These batteries have a nominal voltage in the range of 1.25 volts. Batteries of this type are the most inexpensive and can operate at low temperatures. However, they have a small capacity and discharge quickly.
• Nickel hydride. This type has a nominal voltage of 1.2 volts. It is noteworthy that only environmentally friendly materials are used for the manufacture of nickel-hydride batteries. clean materials, they hold a charge for a long time and have a large capacity. But, unfortunately, they are very expensive, on average 2-2.5 times more expensive than those described above.

• Lithium-ion. Batteries made from this material are rarely used, the nominal voltage is in the range of 3.6 volts. Lithium-ion batteries have virtually no self-discharge and memory effect. However, because lithium degrades over time, the capacity of this type of battery becomes smaller.

Battery fault detection

After you have determined the type, you must correctly identify the fault, otherwise it will not be possible to repair the screwdriver battery with your own hands. It is worth noting that all the elements can very rarely go bad at once, since our circuit is sequential. This is only possible if the battery outputs are short-circuited for a long time.

To the question of how to restore a screwdriver battery, we answer further. First, prepare a multimeter and a 12-13 V lamp (if you have a 12 volt battery), and let’s start checking it yourself:

1. First of all, put the battery on charge and wait for the full charge signal.
2. Then disassemble the case and measure the voltage on each bank. Ideally, the voltage on nickel-cadmium batteries should be about 1.2-1.4 V. The potential difference for lithium batteries reaches 3.8 V.
3. Mark all banks with voltage below nominal.
4. Then reassemble the battery and operate until there is a noticeable loss in power.
5. After this, disassemble the battery again and measure the voltage on the banks again.

As a rule, the voltage will drop the most on the marked elements. It is these banks that need to be removed for further “reanimation” or replacement.

If your screwdriver operates at a voltage of 12-13 V, then searching for faulty elements can be done using a simpler method:

1. First, disassemble the fully charged battery.
2. Connect a 12 volt lamp to its contacts. The lamp will be a kind of load and will completely discharge the battery.
3. Then take measurements on the battery cells.

The places where the voltage drops the most are faulty.

If you have a suitable resistor with the required resistance and power, then you can use it instead of a lamp.

There are other faults such as:

• damage to contacts where batteries are soldered;
• failure of the thermistor;
• power unit malfunction.

However, these defects are extremely rare and almost impossible to correct.

How to fix a screwdriver battery

Now that we have found defects in our battery, we can begin to directly revive the screwdriver battery with our own hands.

The most effective method of repair is considered to be the replacement of faulty elements. First, we need to purchase new “banks” or remove serviceable elements from the old battery.

The price for new elements (2000 mAh) does not exceed 100-150 rubles. Before purchasing them, be sure to make sure that the dimensions and capacity match the original ones.

For repairs, you need a soldering iron, 40 or 60 watts, tin, low-corrosive flux. It is advisable to use a mixture of alcohol and rosin as a flux. The replacement process is simple - just cut off the faulty element and solder a new one in its place.

However, it is necessary to take into account several nuances:

1. Solder quickly to prevent the battery from overheating.
2. If possible, use original plates for connections, because if the wire cross-section is incorrect, they will overheat. If you have copper plates of suitable dimensions, you can use them.
3. Be sure to double-check all the pros and cons of the battery cells. The connection is serial, which means the minus must go to the plus of the new can.

After soldering, it is necessary to equalize the potentials on the banks. First, fully charge the battery yourself. It is advisable to charge it overnight, then let it cool until room temperature. After cooling, measure the voltage on each element. If you did everything correctly, it will be 1.3 V everywhere.

Is it possible to restore screwdriver elements?

If for some reason you cannot restore the screwdriver battery with your own hands by replacing defective cans, then you can try to revive them. However, please note that resuscitation is not applicable for lithium-ion batteries. Refurbishment can only be produced using nickel-cadmium batteries.

There are two ways to repair a screwdriver battery

1. Compaction and compression of defective elements. Most people carry out this operation with a hammer, vice, or pliers.
2. Firmware. It must be produced at voltage and current that will be significantly higher than the rated one.

This method will allow you to restore the screwdriver battery and eliminate the “memory effect”.