Do-it-yourself restoration of a Makita screwdriver battery. How to restore a lithium battery from a DeWalt screwdriver? How to convert a screwdriver to a lithium-ion battery

Repairing a screwdriver battery with your own hands is not difficult, but you will need to correctly identify the breakdown.

Breakdown of the screwdriver battery occurs due to frequent charging and operation in unacceptable conditions.

Today, almost every man has this tool. This device is intended for various works for repair and installation. It can be used to tighten or unscrew self-tapping screws and bolts. It is known that rechargeable batteries in screwdrivers do not last long. Frequent charging and operation in unacceptable conditions can cause battery failure. In this case, many people go to the store and buy new battery. However, you should know that the battery ranks first in the cost of a screwdriver. Almost anyone can do all the steps to repair a screwdriver battery with their own hands.

Please note that it is not always possible to quickly find a battery that is suitable for a particular model. Today there is great amount various types batteries for such a device. The easiest way is to repair this part yourself.

Figure 1. The sum of all batteries will give the final voltage at the battery contacts.

Items that will be needed to repair screwdriver batteries:

multimeter;
soldering iron;
flux;
tin;
copper wires.

It is worth knowing that, regardless of the brand of the tool and the country of manufacture, rechargeable batteries have the same structure. The assembled battery pack is shown in Fig. 1. From the physics course we know that elements that are connected in series add up their potentials. The sum of all batteries will give the final voltage at the battery contacts.

Banks in most cases have standard sizes and voltage, they differ only in capacitance. This indicator is measured in A/h and is indicated on the part itself. Visually this can be seen in Fig. 2.

To assemble rechargeable batteries for screwdrivers, the following types of elements are used:

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

In most cases, nickel-cadmium elements are installed, since they are low cost. Their disadvantage is that they have a short service life. Lithium batteries can last longer. Their disadvantage is that lithium decomposes over time, and therefore they can become unusable prematurely.

How to diagnose faults?

Figure 2. Design of a battery bank for a screwdriver.

Before you start repair work, you will need to perform high-quality diagnostics of the instrument. Not in all cases it is possible to immediately determine the breakdown. Majority modern models batteries consist of parts that are connected in series. They have a specific voltage rating.

The first thing you need to do is disassemble this part. However, before disassembling it, the battery must be fully charged. Next, each element should be measured using a multimeter. On this device You need to set the nominal voltage of the battery, and then take measurements. It's very easy to do. Each element should have approximately the same performance.

Then you need to collect the battery and work with it until it completely loses power. After this, the device should be disassembled again and the voltage measured on each of the cans. If any of them shows a value 2 times lower than the nominal value, then this bank is unsuitable for use. There may be several such elements, so all parts should be replaced. It is not recommended to postpone this procedure.

What nuances should be taken into account?

If the screwdriver operates on a voltage of 12 V, then diagnostics can be performed using another method. You will need to disassemble the battery constituent elements, while they must remain fastened to each other. The chain is sequential, so it will be possible to connect a light bulb to the ends of the battery. The voltage should be 12 V. The use of car light bulbs is allowed. After this, it will be necessary to measure the voltage drops on each part. The one at which this indicator is maximum is faulty.

It is worth noting that there may be other malfunctions. For example, contact may be lost in places where parts are fastened. The reason is poor soldering. In this case, you will need to reattach the wire that came loose. The thermistor may also be faulty. This part can be checked using the same multimeter.

How to repair batteries?

Many people want to know whether it is possible to repair batteries for screwdrivers?

If out of order lithium battery, then it should be noted that it does not have a memory effect. Therefore, they are very difficult to repair. Often the problem is that the lithium in the batteries has decomposed. This cannot be eliminated. However, the problem may also lie in the control circuit.

In order to perform the test, you can use a similar circuit, which is removed from the same device. If the device functions normally, then the problem is a malfunction of one or more batteries. If the part rating is 3.6 V, then you will need to apply 4 V to it at a current of 200 mA. If the battery is charged to the nominal value, then it is suitable for use. If it cannot be fully charged, then it will need to be removed from the chain. In this case, it will not be possible to restore the element, so you need to replace it.

If the screwdriver has nickel-cadmium batteries, the device can be repaired. It is worth noting that such batteries are most often installed on household appliances. The faulty part is subject to a compression effect. If it contains electrolyte, this will help solve the problem. If not, then another method should be used. You will need to charge the battery with a powerful charge. To do this, apply a voltage to the element that greatly exceeds the rated voltage. Then you will need to increase the current.

If these methods do not help, then the battery will need to be replaced. The problem is the electrolyte boiling away. If this happens, then individual elements of the tool will need to be replaced.

How to repair and replace batteries?

First, you should buy several cans or disassemble another battery that contains working cans. Batteries today are sold in many specialized stores, so you can try to find the right model.

A soldering iron is needed to repair the screwdriver battery.

To work, you will need to prepare a soldering iron. In this case, a low-power household appliance is suitable. In order to perform soldering, you should prepare flux and tin.

The replacement process is quite simple. You will need to remove the faulty part and attach a new one in its place. If you have at least minimal experience in this matter, then the replacement work will take no more than 2-3 minutes.

During the soldering process, you must work as quickly as possible, otherwise all the parts that are planned to be replaced will overheat, which often leads to their failure. In the process of fastening elements, it is important to use original plates or perform soldering using copper wires. Soldering must be done efficiently, otherwise there may be poor contact. This is not recommended, as the bonding areas will overheat. This may negatively affect the functioning of the screwdriver battery.

In the process of fastening parts, it is important not to confuse plus with minus.

All battery components must be connected in series: the plus of the previous can must be connected to the minus of the next one.

This should definitely be taken into account.

When all the parts are installed, you will need to equalize the potentials of each battery. To do this, you need to perform a charge/discharge cycle on the battery. During this, potential equalization will occur on all parts, and this is prerequisite for the correct functioning of a device of this type.

When talking about how to restore a screwdriver battery, you should know that not all types of batteries can be replaced. Everything will depend on what kind of battery is installed in the existing screwdriver.

The ability to work with a tool such as a screwdriver without connecting it to an electrical outlet is convenient, practical and, most importantly, necessary. After all, you often have to do some work in places where you can reach network cable almost impossible. In shops construction tools We offer a wide selection of screwdrivers, including Bosch, as well as the popular Hitachi and Makita. But, unfortunately, the service life of the battery of any drill or similar tool is short - a maximum of 5 years. It happens that after a shorter period of time. It is not profitable to buy a new battery immediately. For the same amount you can buy a new screwdriver. Therefore, it is worth trying an option such as restoring the screwdriver battery yourself.

Types of batteries used in screwdrivers and their differences

As you know, the battery of any screwdriver includes several batteries that are connected in one chain in a certain sequence. There are (Ni-Cd), nickel-metal hydride () and elements.

Nickel-cadmium batteries, in this case, are the most popular and frequently used. The voltage of each individual cell is 1.2 Volts and the capacity is 12000 mAh if we have a 12 Volt tool. It’s worth noting right away that, unlike lithium ones, they can be restored because they have the so-called “memory effect” in the form of a reversible loss of capacity.

As for batteries that contain lithium, it is unlikely that it will be possible to restore their capacity using the popular Imax B6 charger - due to the fact that lithium tends to decompose over time.

Restoring a screwdriver battery in a similar manner may also not be successful for cadmium batteries. Such a battery differs in that the electrolyte in them sometimes completely boils away. However, in the case of cadmium batteries, the chances of “reanimating” them are much greater. But at the same time, it is important not to rush and not to rashly use common methods " quick recovery» Ni Cd batteries.

How to restore a screwdriver battery

There is a a large number of videos in which, for example, battery recovery is clearly shown Hitachi screwdriver using Imax B6. It consists in “reanimating” nickel batteries by supplying high currents. Proponents of the express recovery method suggest reviving the battery using the simple settings of the Imax B6. The mode is set to nickel-cadmium, and the battery can be revived in this mode.

However, warming up with pulsed power and subsequent charging are rather risky methods for nickel-cadmium batteries. A broken connection in an element cannot be restored by high currents. In addition, if there is little or no electrolyte inside the battery, high currents will finally “kill” the battery. Therefore, in order to prevent irreversible damage to the batteries, it is recommended to first replenish their electrolyte supply with distilled water and only then charge them using Imax B6.

There is an extreme option for how to restore a nickel-cadmium battery in a screwdriver - you can “jerk” them with a high current. They will start charging, but not for long. Electronics enthusiasts who criticize this method claim that there has not been a single case where a pulsed current restored the battery capacity for a long time. As a rule, it will rise by a very a short time, and then, a few days later, the battery runs out again.

Whether it is possible to use the pulse current method is up to the owners of the batteries to decide. There are many videos on the Internet on how to restore a Ni Cd battery from a screwdriver. But there is an opinion that in reality quick ways They don't work very long. For example, if the electrolyte inside a battery has boiled away or dried out, the pulsed current will “kill” the element completely.

If possible, you can carefully disassemble each nickel-cadmium battery and see what condition the electrolyte is in. If it turns out to be dry, you can use the method of adding a small amount of distilled water through a syringe.

Restoration with water

In order to drill a neat hole in the battery, you will need a small drill. The hole should be made away from the center, preferably in the upper side of the element, where there is a small recess. Then fill the battery with distilled water using a syringe to the last.

After this, the battery can be fully charged Imax B6 and allowed to “settle”. The procedure is long. Restoring 8-, 12-, 14-battery “cans”, depending on the voltage, can take a long time. Ideally, you should not charge them immediately, but give the “jars” of water time to sit for a day. You cannot charge batteries one at a time; it is better to have at least three or four of them in a bunch to distribute the voltage evenly.

Short-term current pulses through a 40 Ohm resistance at 12 V should be applied after water has been poured into the element to be reanimated, and not “dry”, as is often done.

After the batteries have stood for a day, you can start charging them. Do not close the holes yet. Connect to Imax so that the device “sees” them. Charge and let it sit again if any one battery is not restored. Find the weak element in the bundle using a multimeter and add water to it again.

The main essence of this meticulous method is to restore the connection of the battery plates with their contact-adapter buses (internal organization Ni-Cd is similar to the scheme by which solar panels are made). main reason When batteries stop working, the positive contact is separated from the inside of the battery.

Do not close the holes drilled in the batteries until the battery charge remains stable. Once the charge has stabilized, carefully seal the holes with silicone. Water can be added periodically at any time.

As has already become clear, this method is not intended for the lazy and for those who do not want to delve into the intricacies of electronics. However, the method with distilled water helps save a lot of money and is the answer to the question of how to restore a screwdriver battery using the most gentle method. Typically, a screwdriver comes with two batteries. One can be used, and the other can be gradually restored. This method, despite its duration, seems to be more humane and safe for batteries.

Battery restoration by replacing several elements

Restoring a screwdriver battery by replacing several elements can be successful for all types of batteries. It also does not pose any risk to them, as does manipulation with distilled water, provided that care is taken during soldering.

First, the output voltage of each “can” is measured using a multimeter, which in total should be 12-14 V. Accordingly, the voltage of one “can” should be 1.2-1.4 V. The U indicators are compared with each other, the most weak elements.

After this, the battery is inserted into the screwdriver and works until the moment when the power begins to noticeably decrease. The voltage readings are taken again, and those “banks” whose voltage difference is 0.5-0.7 V compared to the “stronger” ones should be removed and replaced with new ones, similar to the old ones, having previously ordered them from the online store.

It is recommended to solder the battery chain using spot welding, but if this is not available, there is nothing left to do but use a regular soldering iron and do everything as quickly and accurately as possible, in order, if possible, to prevent the battery from overheating.

"Native" connection plates The batteries should not be lost; they must be soldered back without reversing the polarity. In addition, all elements of the chain must have the same capacity.

After soldering is completed, insert the battery back into the screwdriver and carry out 2-3 complete charge-discharge cycles to equalize the energy potential of all batteries. In order for the updated battery to last longer, it should carry out such training 2-3 times a month.

Restoring a screwdriver battery by purchasing new Ni-Cd cells

In this case, we are talking about complete and so-called “erasing of the memory effect” from new batteries in order to ensure their more productive operation. The memory effect is that the battery “remembers” all possible charging cycles that it could theoretically be subjected to in production before it falls into someone’s hands. The more such cycles in its “memory”, the more likely it becomes that the capacity will begin to decrease much earlier than expected. Also, nickel-cadmium batteries love similar “boosting” processes. If they are carried out immediately before use, they will work much better.

The required number of batteries can be ordered online, for example, on Ali-Express. You need to keep in mind that they already have a certain factory charge, which it is advisable to “remove” in order to “save” the battery power during operation. This can be done using the same Imax B6 charger, the menu of which is easy to understand.

Let's say the battery of a screwdriver should consist of 10 elements with the following indicators: the output voltage of each is 1.2 V, and the capacity is 1200 mAh, which is a total of 12 V. Advantage complete replacement battery with the subsequent “erasing” of the factory “memory effect” is that in any online store you can order elements with higher capacity than the old ones. For example, 1800 mAh. And the battery will last an order of magnitude longer. Of course, such batteries will be more expensive. But their price always justifies itself.

First, the voltage on each “bank” is checked with a multimeter. This will immediately help determine what quality the new batteries have and whether there is dishonesty of sellers who could sell old elements instead of new ones. The voltage level on each battery should be approximately 1.3 V. When taking measurements, it is important not to confuse the terminals.

Next, “memory erasing” is carried out with each element in turn. On charger The following charge parameters are set: if the capacity is 1800 mAh, it can be set a little more - 1900, a little with a margin. Then you should switch to the charging mode for nickel-cadmium batteries. The charge parameters should be as follows: current indicator 0.9 A (half of the capacity of 1800).

Each new element is subjected to training according to the “charge-discharge” principle in order to remove the factory parameters. At a current of 1A, all batteries are discharged one by one to a voltage of 1 V (the minimum permissible voltage so as not to kill the battery).

Then you should switch to the “charge-discharge” cycle mode and start it with the “start” button.
After discharging and removing the factory memory, put the batteries back into the block, focusing on how the old ones were placed there before. Therefore, when disassembling the plastic case, you need to remember how the batteries were stored before.

Thus, there are many ways to restore a screwdriver battery with your own hands. Each of them has certain nuances, disadvantages and advantages that should be considered depending on how you restore capacity. Sometimes you should try to acquire this or that instrument or required ingredient(for example, distilled water) to ensure that the restoration is as successful as possible. But this is exactly what will help you avoid additional expenses in connection with the purchase of a new screwdriver or a completely finished battery.

Most cordless screwdrivers are equipped with a standard set of batteries. If to a sufficiently reliable and durable tool There are no complaints, then it’s worth taking a closer look at its battery cells, since this is quite weakness devices. It's no secret that without proper battery maintenance, you can simply go broke buying new batteries, the cost of which can reach up to 50% of the nominal price of the tool itself.

It is reasonable to assume that if there is some option for restoring batteries for a screwdriver, then you need to use it, while saving a significant part of your material budget. Let's figure out what methods allow you to reanimate batteries with minimal effort in order to check their functionality.

If you disassemble the battery case of a screwdriver, you will find power elements connected in series inside. In most situations, the operating voltage of the electric motor is 18 volts, which are made up of 15 can batteries in the battery case. As a rule, no external signs of breakdown are detected. Therefore, the master is faced with the task of correctly identifying a link in an existing chain that has lost its energy intensity.

The performance of the entire battery will lose its effectiveness even in a situation if there is at least one element in the system that has lost its capacity. However, all power supply elements cannot fail. Therefore, by correctly identifying ineffective cells, they can either be replaced or used batteries can be restored to functionality. In other words, there are methods to revive batteries.

As a rule, to accurately determine a battery malfunction, practical use Found two main methods:

Identification of faulty units when using a tester (multimeter);
Detection of faulty power elements in the system using a load

Let's look at how these methods work in practice.

2. Quick battery check using a multimeter + (Video)

Since batteries are connected in series, it is important to know that when the batteries are in a charged state, their voltage, when tested with a multimeter, should be identical. To correctly determine the faulty link, you should switch the tester to change mode direct current, and take measurements of each battery (bank) in the system.

If in your case you use ni cd batteries, then the nominal voltage of each block should be approximately 1.2 V. In the situation of using Li Ion batteries, the voltage should be around 3.6 V.

In general, to properly initiate a fault, the entire battery pack is first subjected to maximum charging for 6 hours. Then the corresponding measurement is made with a multimeter, based on the above indications for different types batteries If no distortion is detected at this stage, then the battery is connected to the load in order to completely discharge it.

After making sure that the battery pack is discharged, you must again measure each power battery in the system with a multimeter. This will make it possible to detect unsuitable “banks” with a high degree of probability. The multimeter readings in such units will be below 0.5-0.7 V. If you have replacement battery units available, then resuscitation of the entire circuit can be eliminated by simply re-soldering, removing the used elements and replacing them with new ones.

3. Load testing

This method involves the use of several light bulbs or small electric motors that are connected to each power element in the screwdriver battery system.

First, the entire battery is fully charged. Then one 3-4 V light bulb or a low-power “motor” is connected to each “can.” The method allows, without measuring instruments, to identify inoperative elements in the system that are the earliest to lose their charge under load. Blocks that have lost capacity will certainly reveal themselves.

4. “Memory effect”, and what to do about it? + (Video)

If we are talking about ni cd batteries, then for them there is such a thing as the “memory effect”. This “painful symptom” is defined quite simply. When the battery after passing full cycle the charge is quickly discharged, and after a short pause it continues to function again, then this is a correct diagnosis, which, with proper skill, can be cured.

What needs to be done to cure the “memory effect”?

First, the battery is fully charged (preferably at low currents). A small load is then applied to it in order to achieve complete discharge. This simple technique allows you to activate the internal plates of the battery as fully as possible. As an example of a successful load, you can use a regular 220 V incandescent lamp with a power of 60 W. The process of slow charging and discharging should be repeated at least 4-5 times. The result of these measures will be the return of the original battery capacity to 80%.

By the way, if you carry out work on a disassembled battery, where “weak” batteries are already known, then shocking them with a large current can return them to service. If there is electrolyte in the battery, then you can always restore the battery using this method.

5. What additional methods for restoring batteries for screwdrivers exist? + (Video)

It’s worth noting right away that not all batteries are susceptible to restoration. In particular, with the best success it is possible to revive “banks” with a typical insignia ni cd. Most typical screwdriver models are now equipped with such batteries. Of course, on the tool market you can find screwdrivers from the Makita or Hitachi or Bosch brand, the battery of which is built on a lithium base, but there are not many of these models yet.

In general, if we talk about the serviceability of the battery pack and methods for restoring it, in any case, you need to pay attention not only to the batteries themselves inside the case, but also to make sure that the charger is working properly. It is likely that the functionality of the power supply has lost its ability to provide the required current during charging.

Many craftsmen, faced with the repair of nickel-cadmium power cells in practice, restore them by adding an electrolyte. During operation, the battery begins to lose electrolyte as it evaporates.

Physical impact on the battery “can” using a drill helps to correct the situation. It is necessary to make a small hole in the body of the battery (diameter 0.8-1mm). Armed with a medical syringe with a needle, inject a couple of drops of distilled water into the battery. The hole is then securely filled with epoxy resin. This cycle of measures will allow you to extend the operation of the power element for several more charge/discharge operations.

Of course, the simplest and most obvious way to resuscitate a battery pack for a screwdriver is to physically replace the faulty unit with a functional one. Here, even the help of a specialist may be inappropriate, since the operation can be easily performed even by a person who has at least once used a soldering iron and held a screwdriver in his hands. The main thing here is to show a little skill to prevent the cans from overheating at the time of soldering/desoldering.

Of course, there are quite a few ways to reanimate batteries, but not all of them are available to the average user. If you are unable to extend the life of your screwdriver with a standard battery on your own, then seek help from qualified specialists. They will make an error-free diagnosis and figure out how to restore the tool’s battery with minimal labor costs.

And needs replacing. Buying a new one is often difficult, and if you succeed, it is at a very high price. That’s why they say that it’s easier to buy a new tool or repair the screwdriver battery yourself.

There are a large number of videos on the Internet in which electronics enthusiasts clearly show how to repair a screwdriver battery with their own hands. If you are seriously concerned about the issue, think about saving Money and whether it is possible to repair a screwdriver battery with your own hands, watching such videos can be a good start for repairing the battery yourself in the future.

How to disassemble the battery

Battery packs for home tools are almost the same in design, regardless of the model of the tool (Bosch, Makita, Hitachi). They are packaged in a plastic case consisting of two parts. The number of batteries may vary depending on the output voltage of the tool used. All elements are soldered in a certain sequence. The lead ends or terminals at which the battery voltage is usually measured are brought out.

Most screwdriver or drill battery packs are designed so that they are very easy to disassemble, regardless of whether we are repairing the battery of an Interskol screwdriver or another model. Several mounting screws need to be removed using a regular screwdriver. There are batteries that are difficult to disassemble, but can be removed with a screwdriver and a pocket knife. The adhesive layer is removed with a knife, and the two mating surfaces are moved apart with a sharp self-tapping screw.

The difference between screwdriver batteries and each other may lie in the presence or absence of a temperature sensor, which automatically turns off the battery under critical heating conditions (above 50°C). The sensor constantly monitors the temperature not only under load, but also under the conditions of the current battery charge. The controller reads all the data and processes it, “remembers” the capacity and other indicators. As soon as the capacity reaches 80-90% and the voltage reaches 14 V, the control unit turns everything off. Such batteries last for years without losing their technical characteristics.

There are a large number of inexpensive screwdriver models on the market.
Cheaper devices do not have such technical devices, and all processes must be monitored independently.

Types of battery repairs

How to reanimate a screwdriver battery? There are three ways:

express battery repair using zapping method ;
replacing individual elements in the battery ;
replacement of all elements of the battery pack .

Express repair of nickel-cadmium batteries using zapping method

Translated from English, this means burning, applying short pulses of high current over a period of several seconds. We can say that this is a kind of emergency resuscitation of batteries. It should be noted right away that this option is quite risky, and not every battery is able to withstand such “shock therapy” with high current. It is possible to use high current only if the screwdriver has nickel-cadmium batteries installed. Other batteries ( , ) cannot be subjected to such effects.

The essence of purging is to destroy the crystals formed inside nickel-cadmium batteries with high current. These crystals are called dendrites, and due to their growth, the battery capacity gradually decreases. “Pumping” with high currents quickly destroys the formed crystals and sharply reduces the self-discharge of the battery.

It is stated that zapping can be effective for any NiСd, even if they are completely discharged to zero or have been lying unused for 10 or 20 years. The question is always about the likelihood of successful repair in such “difficult” cases - when batteries are “repaired” in this way, it will either be successful or not. However, it doesn't hurt to try to revive them. Of course, while maintaining maximum caution.

To carry out zapping you will need:

any high current charger ;
multimeter to monitor voltage ;
welding machine ;
crocodile clip ;
zapping electrode ;
protective equipment .

You should not use a regular power supply as a charger. Even if the current strength of such chargers is 10-15 A, they will not withstand high voltage. Using a double-sided clamp, tight contact is ensured on one terminal, and the electrode itself will be held on the other terminal. It is impossible to hold it with your fingers: during burning it will become hot. A zapping electrode is a piece of wire that is rolled into a tight bundle (there is no insulation). Its cross-section is maximum 1.5 mm 2, and its length is 6-7 cm.

Instead of higher quality welding machine Especially daring electronics enthusiasts repair batteries using a regular soldering iron. But a spot soldering tool will be preferable for repairs. Protective equipment (robe, goggles, special non-flammable substrate) is necessary because sparks always appear during high current blowing.

Work progress

It is better to blow through each battery separately, the algorithm is as follows:

Attach the electrode with a minus sign to its minus pole. Do not confuse the polarity, an important point.
“Blow out” the positive electrode with short pokes, their frequency is 2-3 times per second . Typically, for a can with an output voltage of 1.2 V, blowing must be done for 3-4 seconds with a frequency of 2-3 small pokes per second;
Measure voltage readings after the first stage . It should be raised to a maximum of 1.3 V. If the voltage is higher, the time of pokes or their number should be reduced.

You need to poke very quickly and carefully, not allowing the electrode to weld even for a short time to the pole of the Ni Cd battery of the screwdriver, in order to avoid completely burning the battery. It is recommended to put a protective intermediate electrode on the positive electrode, or to hook on an alligator clip to protect the surface of the battery pole.

The procedure is repeated up to 25 times until the battery capacity is restored. During the entire process, it is necessary to constantly monitor the temperature of the batteries. The intervals between zappings should be at least 15 minutes. Only in this case will the reanimated battery have a chance to extend its service life.

Replacing individual elements in the battery

If the battery capacity drops, it means that at least several of its elements have failed. All batteries cannot die at once, so first you need to find the lowest-capacity batteries in the chain, and then disassemble the battery and replace them with new ones.

New batteries can be ordered from any online store. At the same time, it is important to buy those elements whose type and capacity fully correspond to the previous ones. If the screwdriver contains nickel-cadmium batteries, then you should purchase the same ones, with a similar level of capacity. If you can get the same battery, you can remove the most capacious elements from it and put it in the one that is being repaired.

How to identify “weak links”

Searching for dead batteries in a circuit can be done in two ways:

using a multimeter ;

For the first method you only need a multimeter:

charge the battery completely ;
disassemble the battery case ;
measure the nominal U on each battery (rated for nickel-cadmium batteries - 1.2 V, for lithium-ion batteries - 3.6 V);
mark with a cross the elements where U is below nominal so as not to be confused with others;
assemble the battery ;
turn on the screwdriver ;
work until there is a noticeable reduction in power ;
disassemble the battery again, measure the U values again .

On batteries marked with a cross, the “dips” in voltage will be significantly greater than the others - most often below 1 V. As for the difference between the U values in the battery, if it is at least 0.5-0.7 V, this is quite significant.

The second method of finding dead batteries is less labor-intensive and simpler. If the screwdriver output voltage is 12 V, you will need a lamp with the same output voltage.

Procedure:

charge the battery completely ;
connect the lamp as a load to both poles of the battery ;
wait until the battery is completely discharged ;
use a multimeter to measure the voltage readings at the terminals of all elements one by one .

“Dead” batteries are easy to separate because their voltage drops the most after discharge.

Repair

So, the failed elements have been found, new ones have been purchased, and now you can proceed directly to repairing the battery.

To repair the battery you will need:

soldering iron;
low corrosive flux ;
tin;
copper plates (in case the “original” ones broke during disassembly) .

Spot welding in case partial repair It is not necessary to use a battery. But during soldering you need to be careful not to overheat the elements. It is best to connect the batteries to each other using the plates that they had. If they break during disassembly of the battery into individual elements, then new plates will need to be made from copper.

Don't forget about polarity. Each battery element for a screwdriver is connected to its neighbor according to a certain sequence. The minus of one can must be connected to the plus of another, and the minus of another can must be connected to the plus of the third, and so on.

After the chain is reassembled, care must be taken to ensure that the voltage potential of all elements is equal. To do this, you should leave the batteries on charge for the whole night, then they should cool down over the next 24 hours. After this, the voltage is measured on each element. If soldering and the charging cycle were carried out correctly, then the multimeter will show approximately the same U figure on all batteries - 1.3 V.

Now you need to carry out at least two charge-discharge cycles for the battery in a natural way: place the repaired battery in a native screwdriver and work with it until it is completely discharged.

By the way: Partial repair of a Li-ion screwdriver battery can be carried out in a way that requires minimal financial costs. If the unit has 18650 batteries installed, you can actually borrow the same ones from an old non-working laptop, if possible.

Replacing all elements of the battery pack

The required number of elements can be ordered at any online store, depending on the number of old batteries. It is important to pay attention to the fact that they all initially have the same capacity.

You can completely replace all elements of the battery pack with new nickel-cadmium batteries. They are much cheaper than nickel-metal hydride batteries, and, compared to other batteries, they are the most durable and hardy. However, in Lately Increasingly, self-conversion of batteries “from cadmium to lithium” is being practiced, in other words, installing new lithium-ion batteries instead of old Ni-Cd.

Despite their reliability, nickel-cadmium batteries can quickly fail because they are connected in series to each other without a balancing board. If the batteries are from the same production batch, their parameters will still have a wide spread between them. With this connection, one element will charge faster, another slower, and the third may overcharge.

To make a complete switch from nickel-cadmium to lithium-ion, you will need:

amount of elements, equal to the quantity former (with the same capacity);
balancing board 5S (its amperage depends on how many volts the screwdriver is designed for);
tester or multimeter ;
soldering iron with a good tip ;
high quality flux and lead solder ;
silicone wires AVG 16 ;
heat-resistant tape and hot melt adhesive .

Before starting soldering, discharge the batteries. Remove the old batteries from the unit and release the contacts. It is better not to throw away the old temperature sensor, but leave it as additional protection against lithium overheating.

Now the main thing is to solder the lithium correctly . Cut the wires to the required length in advance, insulated, in silicone, very thick, to avoid them melting when the lithium is heated. Use a knife to clean the battery pads for soldering.

It’s good to heat the soldering iron to 300°C and start soldering using flux and lead solder. There must be flux good quality, indelible, non-conductive. Do not use acidic fluxes under any circumstances. Soldering should not take more than 2 seconds to avoid overheating of the lithium. In order for the heat to escape faster, after soldering, you can attach any iron object to the battery that absorbs heat.

Allow the batteries to cool and connect the positives and negatives as usual. Check the overall voltage. Its indicator should be on average 20.7 V if there are 15 elements.

After measuring the voltage, the board is connected. All its wiring must be laid with special gaskets so that nothing “shorts” during operation. The entire battery pack is sealed with heat-resistant tape designed specifically to insulate batteries and their contacts.

The wires and connector are soldered. If the contacts are “dangling”, they can be attached to hot glue. Now, finally, you can finally assemble the screwdriver battery pack and check its operation.

Sometimes it seems that repairing the battery of a Hitachi screwdriver (or other tool) is very difficult. But if you look into general principles, such as the basics of electronics, the inside, and the main principles correct soldering, it becomes clear how to repair a screwdriver battery yourself. This will not only save money, but will also contribute to the acquisition of valuable and useful skills.

A replacement battery for a screwdriver is a fairly expensive element, because its price share in the total cost of the tool reaches about 30%. Therefore, it is not at all surprising that many craftsmen are trying to extend the life of the battery using various methods. How to restore a screwdriver battery? - we would like to cover this topic in today’s feature article.

Design features of the battery for a screwdriver

Regardless of the type of power tool, brand and its technical characteristics, the design of batteries is not much different from each other. After all, when disassembled, the battery is a series circuit consisting of identical batteries.

Moreover, in most cases (for different types of batteries), such cells have the same size and output voltage (V), and differ only in capacity, which is expressed in mA/h and is indicated on the cell body. In addition, when self-repair The battery for a screwdriver should pay attention to the type of elements used (Ni-Cd, Li-Ion, Ni-MH), since the recovery method for each of them may be slightly different.

It should also be noted that in order to charge the cells and power the power tool, the battery design provides power contacts (“+” and “–”) connected to the terminals of the serial circuit. Well, to protect equipment from overheating (during forced charging) and equalize the charge level on all battery banks, two more control contacts are used, through which a thermistor and resistance are connected.

We recommend that the reader read about how to use a stand-alone screwdriver.

Method for determining battery failure

Considering the series connection of batteries, the primary task of the performer will be to find the “weak link”, because if at least one element fails, the battery will function with significant technical deviations. If we take into account that simultaneous failure of all components of the circuit is not possible, you should understand how to determine the deviations of individual batteries.

Method 1. Use a multimeter

Considering the identical voltage level of all components of the circuit, you can determine the faulty element using a multimeter (switching it to the DCV voltage measurement mode). It should be remembered that the nominal voltages for different types of batteries have different values:

Ni-Cd and Ni-MH (voltage 1.2V);
Li-Ion (voltage 3.6V).

The very method for determining a failed battery is carried out according to the following algorithm:

The battery is set to fully charged;
The device body is disassembled, and voltage measurements are taken one by one (using a device) on each of the cans;
Elements with lower voltage are marked established norm(for Ni-Cd and Ni-MH batteries, the voltage should vary in the range of 1.2 - 1.4 V; for Li-Ion - in the range of 3.6 - 3.8 V).
The battery is assembled and installed in the screwdriver, after which it should be discharged until a noticeable decrease in power, for which a number of power operations can be performed using a power tool.
After discharging, the battery case is disassembled again, and voltage measurements are again performed on all sections of the circuit ( special attention should be given to marked items)
If the voltage drop across the cell is 0.5 - 0.7 V, such a battery is considered unusable.

Method 2. Use load

The technology for identifying weak batteries in this case is similar to that described above, with the only difference being that to discharge the battery, a 12-volt light bulb (for example, 40 W) is used, which will act as a load. And in order to solve the problem, you will not need to assemble/disassemble the battery pack several times.

Having completed all the above-described manipulations, all unreliable elements of the battery circuit are identified, and only after that a decision is made to replace or restore them.

Restoring battery cells

It should be noted right away that it is almost impossible to restore the Li-Ion battery of a screwdriver, and all that can be done in this case is to identify weak elements and replace them.

Sometimes the problem can also be hidden in the charger, which is why special attention should also be paid to its correct operation.

If we talk about resuscitation of blocks, then the recovery method can be applied exclusively to Ni-Cd batteries, which are the most common for screwdrivers.

Among the main methods for restoring Ni-Cd batteries are the following:

Compaction (compression);
Elimination of memory effect;
Adding boiled-off electrolyte.

How to eliminate the “memory effect”

Sometimes, the battery needs to be restored, which is associated with erasing the memory effect. Moreover, it is quite simple to recognize such a “disease”: after a full charge, the battery discharges very quickly, and can function again after a short period of time. The “memory effect” can be partially eliminated as follows:

First, the battery is fully charged (if possible) with a small current, after which the battery should be completely discharged, applying a small load and thereby ensuring a slow (soft) discharge, which will allow not only the outer layer to sag, but all the plates as a whole. In this case, it is advisable to use an ordinary lamp with a voltage of 220V and a power of 60W as a load and discharge up to 30% of the rated capacity (approximately up to 5V).

Before using the battery, the above procedure should be repeated at least 5 times. And although the capacity of such a “reanimated” battery will be somewhat lower than a new battery, still, as a temporary measure, this technique is quite successful (it can extend the work for at least a year).

Adding boiled-off electrolyte

The most common problem with rechargeable batteries for a screwdriver is the boiling off of the electrolyte (especially during forced charging), which is why we should dwell on the solution to this issue in more detail.

So, after identifying the failed cans, you should cut the connecting plates and dismantle the required elements. After that, using a thin punch (with a diameter of no more than 1 mm), a hole should be made in the body of the jar (from the minus side), through which it is necessary to add from 0.5 to 1 cubic centimeter of distilled water into the element (after having previously pumped out a similar volume of air). The final restoration work will seal the jar (you can use epoxy resin) and connecting the element to the existing circuit.

In the future, in order to equalize the potential of all constituent elements, using 1.5 V light bulbs, you should discharge all battery banks, then perform 5 - 6 full charge/discharge cycles, and only after that use a power tool.

Replacing battery cans

Most effective method Battery repair is the replacement of worn-out cells with new elements. Why, before restoring the screwdriver battery, you should purchase the required items, taking into account the technical and overall characteristics donors (must be identical).

Replacing failed components itself does not cause any particular difficulties and requires the use of a soldering iron and soldering materials (tin and alcohol flux with rosin). Moreover, in order to ensure full operation of the battery during the work process, it is advisable to adhere to the following recommendations:

It is advisable to use existing plates as elements for series connection of cans, or use copper conductors with the appropriate cross-section (due to high charging currents);
To prevent overheating of the cans (which can lead to breakage), soldering should be done quickly;
The connection diagram of the batteries must be sequential, and therefore the minus of each previous battery must be connected to the plus of the next one.

The final part of the work should be equalizing the potentials of all components that make up the battery. To do this, it is necessary to carry out a complete discharge-charge cycle of the battery, and after cooling, repeat these steps at least twice.