DIY battery repair from a screwdriver

In detail: do-it-yourself battery repair from a screwdriver from a real master for the site my.housecope.com.

The battery life is relatively short, on average 5 years. After a set period, the battery abruptly stops working. In such a situation, it is not always possible to quickly acquire a new power source, so the home craftsman has to solve the problem of how to restore the screwdriver's battery, at least for a short time. In some cases, after a successful recovery, the batteries work normally for quite some time.

The screwdriver is rightfully considered an indispensable universal tool. The modern screwdriver market is represented by a large number of models equipped with batteries. Despite the variety of brands and modifications, all batteries have the same structure and only slightly differ from each other.

Each of them includes separate elements connected in series with each other. They are all made to standard sizes and have the same voltage level. Certain types of elements differ only in capacity, measured in A / h and indicated in the marking.

There are 4 contacts in the tool body that perform various functions. Including, two are power, designed for charging and discharging. In addition, in the upper part there is a control contact included in the circuit together with a special temperature sensor. It protects the battery, disconnects the charging current and limits it to the set value by changing the temperature.

A fourth contact is separately located, connected together with a resistance. It is necessary when using charging stations of increased complexity, capable of equalizing the charges of all battery cells. Such stations are rarely used in everyday life due to their high cost. A conventional 12-volt screwdriver does not require such stations.

Video (click to play).

One of the reasons for the failure of a screwdriver is a malfunction of the battery, that is, its separate element. In such cases, the daisy chain breaks down the entire circuit. Therefore, it is very important to pinpoint the faulty location. As a rule, this happens after the expiration of the established service life. This problem can be solved in two ways: purchasing a new battery or repairing and restoring an old battery.

Correct diagnostics requires knowledge of the main types of batteries used in screwdrivers and the design features of each of them. Each battery consists of mini-batteries connected in series in a single chain. Depending on the material of manufacture, they are nickel-cadmium (Ni-Cd), nickel-metal hydride (Ni-MH) and lithium.

The first option, Ni-Cd, is the most widely used. In these batteries, each cell has a voltage of 1.2 volts for a total of 12 volts with a capacity of 12,000 mAh. They differ from lithium ones in the possibility of recovery, since they have the well-known memory effect, which is a reversible loss of capacity.

Due to the design features of batteries, not all methods are suitable for their recovery. For example, lithium cells cannot be recovered using Imax B6 charging, since lithium gradually decomposes, loses its quality and does not hold 18 volts. The same method is not always suitable for Ni-Cd batteries, since in some cases the electrolyte can completely boil off in them. Nevertheless, there are many options for recovery.

Different types of batteries also differ in their own operating voltage. This difference is due to the materials used to make a particular battery. This factor also affects the capacity, which ensures long-term operation of the tool without additional charging. Therefore, at the initial opening of the case, first of all, the type of elements placed inside is determined. The fact is that it is not allowed to replace lithium mini-batteries with nickel-cadmium ones, since their operating voltages differ significantly. The repair and restoration methods will differ accordingly.

To repair the battery, you will need measuring instruments - a 2 A ammeter, a 2 and 15 V voltmeter, a tester, an ohmmeter and a milliammeter. The body is manipulated with a screwdriver, scissors and pliers. A magnifying glass may be needed to detect defects.

While solving the problem, can the battery be repaired, the faulty element is searched for and its further replacement. For verification, a standard scheme is used, and on the basis of the data obtained, the state of individual parts is analyzed. It should be remembered that not only mini-batteries may be faulty, but also the terminals of the screwdriver itself.

Determining the causes begins with measuring the voltage with a tester on each individual battery. All non-working elements are marked and separated from non-working ones. If the battery is rapidly discharging, do not immediately disassemble it. First, you can try to restore the battery capacity of the screwdriver. For this purpose, the battery is fully charged and deeply discharged over several cycles. In most cases, capacity is almost completely recovered.

Often the screwdriver stops working due to the failure of the terminals. During operation, they gradually unbend, as a result, the contact is broken and the battery is not fully charged. To repair the charger, you must first disassemble it, and then carefully bend each terminal. After that, you need to check the quality of charging using measuring instruments.

If the measures taken did not help, you just need to replace the defective part. If you find a specific cause of a malfunction, it is recommended to use the recovery methods below.

When a battery very often experiences insufficient charging and subsequent discharge, it has a so-called memory effect. That is, the battery gradually, as it were, memorizes the minimum boundary of charging and discharging, as a result, its capacity is not fully used and gradually decreases more and more.

This problem is typical mainly for nickel-cadmium batteries and to a lesser extent affects nickel-metal hydride batteries. In any case, the battery capacity needs to be restored. The memory effect does not affect lithium-ion batteries at all.

In order to solve the problem of whether the cell can be repaired, it is recommended to completely discharge and charge the battery using a 12 volt light bulb. The positive and negative wires are soldered to it, which are connected to the battery contacts. This procedure is repeated five times or more.

Distilled water only evaporates from nickel-cadmium batteries when they overheat during operation. Therefore, to eliminate the problem and restore their functions, water must be refilled.

This procedure is performed in the following sequence:

After disassembling the battery, mini-batteries will be found inside. Their number may be different, depending on the brand of the instrument. The defective element is determined by a multimeter. In a working battery, the voltage is 1-1.3 V. If this figure is lower, then the cell is defective and needs to be repaired.
Next, the faulty parts are carefully removed without destroying the connecting plates.You will need them later for reassembly.
A hole of no more than 1 mm is drilled in the side part. It is not located in the middle, but closer to the bottom or top of the battery. You only need to drill the wall, without going deep into the element.
Distilled water must be drawn into the syringe. The needle is inserted into the hole and through it the battery is completely filled with water. After that, she must stand in this position for at least a day.
After a day, the battery is charged with a special device, and then left in a charged state for another 7 days.
After a week, the capacity and voltage are checked again, and if it has not dropped, then the hole in the body is sealed or sealed with silicone.

After all the manipulations, the batteries are assembled into one piece and inserted into the battery case. The connecting plates are soldered or spot welded. Then the performance of the entire battery is checked again, after which it is completely discharged using small loads. The charging and discharging process is performed at least 3 times.

In this way, you can repair the battery of any screwdriver. The repair procedure itself is not particularly difficult and begins with disassembling the battery. Using a multimeter, faulty elements are determined, in which the voltage will be below normal. Then they are carefully removed and the exact same mini-batteries are purchased instead.

New parts are installed in their places and connected with existing plates. Soldering or spot welding is used for the connection. In this case, you need to ensure that the battery does not overheat. Therefore, the work must be done accurately and quickly using flux or rosin.

This repair method applies to lithium-ion battery cells. During the period of operation, they overheat, as a result of which electrolyte evaporates from some batteries. This causes gases to build up inside the battery, causing swelling and bending of the plate. After that, you have to restore the screwdriver battery.

The solution to this problem is carried out in the following order:

Dismantling the battery and finding a faulty battery with a multimeter. Usually, there is no voltage at all in such elements.
The battery is then pulled out and gas is released from it. In the first case, you will need some kind of flat tool, curved at the end. It is brought under the positive contact and the swollen plate is gently pressed down. The gas finds its way on its own, making a hole and going out. In this case, you restore your working capacity only for a short time, since the electrolyte will evaporate completely through the hole and the battery will stop working again.
In the second case, the positive contact is disconnected using pliers, after which it is slightly bent, but not completely cut off. After that, an awl is inserted under the curved plate and gradually pushed inward. That is, the plate separates from the edge of the battery and the gas flows out. After that, it is inserted into its place, and the hole is closed in the most convenient way. It remains only to solder the contact disconnected at the very beginning.

There comes a time when the reliable home assistant - the screwdriver - stops working. The batteries are out of order, and regular recharging no longer helps. Do not rush to buy new batteries, there may be another way out of the situation.

The cost of batteries is about 70% of the price of a new tool, so it is logical to try to repair a screwdriver battery. Before proceeding with the operation, you should familiarize yourself with the features of voltage sources, find out what type of batteries is used on your instrument. Their structure is absolutely the same and does not depend in any way on the country of production and brand. Inside the plastic box there are standard-sized daisy-chained elements.Each element has an indication of the type and capacity in ampere-hours (A / h).

Screwdriver battery

Batteries are completed with the following types of elements:

lithium-ion (Li-Ion) - with a cell voltage of 3.6 V;
nickel-cadmium (Ni-Cd) - 1.25 V on each cell;
nickel metal hydride (Ni-Mh) - 1.2 V.

Evaluation of lithium-ion power supplies in terms of quality and service life sets them apart from the competition. They practically do not lend themselves to self-discharge, high capacity, they can be charged repeatedly, several times more than other types of batteries. The cell voltage is three times higher than that of other types, which makes it possible to equip batteries with fewer cans, reducing weight and dimensions. They have no memory effect, which makes them an ideal device of this kind.

But the ideal does not exist in nature, and lithium-ion power supplies also have some disadvantages. They cannot be used at subzero temperatures, as manufacturers honestly declare. But practical use has revealed another drawback: when the service life of such a battery ends (three years), lithium decomposes, no way to do a reverse reaction brings results. The price of such batteries is three times higher than that of other power sources for a screwdriver.

Nickel-cadmium batteries are the most common because of their low cost. They are not afraid of negative temperatures, like lithium-ion voltage sources. If a screwdriver is rarely used, such elements are ideal, because they can be stored uncharged for a long time, while maintaining their characteristics. Such batteries have a lot of disadvantages: they are small in capacity, toxic, so their production is concentrated in underdeveloped countries. The tendency to self-discharge, short lifespan during intensive use are also among the disadvantages of these batteries.

Nickel-cadmium batteries dry up at the end of the shelf life. Those who know about this feature overfill them, but this operation is not easy, so few decide on such an action, preferring to replace individual battery banks. If the reason for the failure is the memory effect, which is considered a big disadvantage of nickel-cadmium batteries, it is possible to restore their performance by flashing.

Nickel-metal hydride batteries are environmentally friendly, high quality, manufactured by the world's leading companies. Compared to Ni-Cd, they have clear advantages:

slow self-discharge;

memory effect is small;

resistant to multiple discharge-charge cycles;

relatively large capacity.

But during long-term storage without work, some of the characteristics are lost, they do not like low temperatures, moreover, they cost a lot. And the main drawback is that they cannot be repaired.If you have battery elements installed on your screwdriver that, in principle, can be repaired (except for nickel-metal hydride), we proceed to disassemble the case. It has two parts connected by screws or glue. In the first case, no difficulties are foreseen - we unscrew the screws and separate the parts. If the connection is adhesive, insert a knife between the parts at the junction, then screw a self-tapping screw into this place. Carefully, so as not to damage the elements, we pass with a knife along the joint, separating the parts of the case.Checking the cells is carried out on a fully charged battery.Having disassembled the case, we will see banks connected in series, which means that a malfunction of even one bank can lead to poor battery performance. The main task during the repair is to find the weak point in the chain. We remove the cells from the case and lay them out on the table so that there is convenient access to all contacts. We measure the voltage of each element with a multimeter, record the indicators on paper or directly on the case. The voltage indicator for a nickel-cadmium battery should be 1.2-1.4 V, for a lithium-ion battery - 3.6-3.8 V.Types of malfunctions and how to fix themHaving measured the voltage, we collect the cans in the case, turn on the screwdriver and work until it loses power. We again disassemble and re-remove the voltage indicators, again fix them. Cells with the lowest voltage will again show a significant drop when fully charged. The difference in readings of 0.5–0.7 V is considered significant. Such elements will soon become completely unusable, they are candidates for resuscitation or complete amputation.If you have a 12-volt tool, a simpler method can be used to troubleshoot the problem by eliminating double disassembly and assembly. First, we also measure the voltage value of each fully charged element, fix the indicators. We connect a load to the banks laid out on the table - a 12 V light bulb, which will discharge the battery. Next, we are again interested in voltage. Where the strongest fall is noted, the weak area.You will need either cans from an old battery, in which there are serviceable elements, or you will have to buy new ones, they are inexpensive. When buying, we pay attention to the size and capacity - they must match the existing elements. We throw out the unusable banks, and we solder new ones in their place. It is advisable to connect using native plates or copper plates of suitable size. Compliance with the cross section is important - when charging, a large current flows through the contacts. If the area is insufficient, they heat up, protection is triggered.

Replacing Battery NutrientsWe pay special attention to the sequence of the connection - the minus of one can is connected with the plus of the other.On the assembled battery, we equalize the potentials, since they are different. We put it on charge for the whole night, let the battery rest for a day, then measure the voltage. Ideally, all elements should have the same indicator. We proceed to discharge the battery until it is completely depleted. We repeat the procedure twice more. It should be said that this training is necessary not only for repairs, it should be done every three months to prolong the life of the battery.Method acceptable for nickel-cadmium batteries when the cells are not dry. You can verify this using the method below, if it does not help, then the electrolyte has boiled away. The essence of the method is charging using high current and voltage. You will need a charger that can be regulated; a charger for car batteries is suitable. We will charge each element separately, for which we remove the battery from the case and disconnect the banks from one another.Battery battery firmwareWe set the charging to a voltage three times higher than the nominal - 3.6 V. Connect to the charger and turn on for 3-5 seconds. If the voltage test with a multimeter showed 1.4 V or slightly lower, everything is in order. We collect the battery and use it. The method eliminates the memory effect of accumulators. It is not suitable for completely killed cans.As already noted, the main reason for the failure of nickel-cadmium batteries is drying out of the cans. The procedure for refilling them is not very pleasant, but not so complicated as not to be performed. We do everything as always - disassemble the case, take out the elements. We remove the paper with which the cans are wrapped. From some it can be removed easily, whole, on some it has to be cut. We examine the body of the cells - some without any traces of corrosion, others can be seriously damaged, but the main thing is that the shell is intact.With a thin drill at the top of the element, where there is a depression in a circle, we make a hole. You will need distilled water. We put it into a syringe, put the needle into the hole and pump water very slowly. It is not known how much of it will enter; it is impossible to visually determine it.If, from the very beginning of water injection, liquid flows from the can, throw it out, it cannot be resuscitated, it must be replaced with a new element. There is some kind of reaction, which indicates the unsuitability of this element for repair. But this happens very rarely. Further procedures are usual - assembly, several charge-discharge cycles.

The cost of a new screwdriver is about 70% of the cost of the battery for it. Therefore, it is not surprising when, faced with a battery failure, we ask ourselves the question - what's next? Buy a new battery or a screwdriver, or maybe there is an opportunity to repair a screwdriver battery with your own hands and continue working with an already familiar tool?

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

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

If we disassemble it, 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 have a serial connection harmonize their potentials.

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

Typesetting 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).

For the arrangement of screwdriver batteries, the following types of elements are used:

nickel - cadmium (Ni - Cd) batteries, with a nominal voltage on the "banks" of 1.2V;
nickel-metal hydride (Ni-MH), voltage across elements - 1.2V;
lithium-ion (Li-Ion), with a voltage of 3.6V.

Let's consider in more detail the advantages and disadvantages of each type.

The most common type due to its low cost;
Low temperatures, such as Li-Ion batteries, are not scary;
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, which means that they do not "live" for a long time with intensive use.

Environmentally friendly production, there is an opportunity to purchase a high-quality branded battery;
Low memory effect;
Low self-discharge;
High capacity compared to Ni - Cd;
More charge / discharge cycles.

Price;
Loses some of its characteristics during long-term storage in a discharged state;
It does not "live" for a long time at low temperatures.

No memory effect;
Self-discharge is almost absent;
High battery capacity;
The number of charge / discharge cycles is several times greater than that of previous types of batteries;
To set the required voltage, a smaller number of "cans" are required, which significantly reduces the weight and dimensions of the battery.

High price, almost 3 times in comparison with nickel - cadmium;
After three years, there is a significant loss of capacity, because Li decomposes.

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

The housing has four contacts:

Two power ones, "+" and "-", for charge / discharge;
Upper control, it is switched on through a thermal sensor (thermistor). A thermistor is necessary to protect batteries, it cuts off or limits the charge current when a certain temperature of the cells is exceeded (usually in the range of 50 - 600C). Heating occurs due to high currents during forced charging, the so-called "fast" charging;
The so-called "service" contact, which is connected through a 9K ohm resistance. It is used for complex charging stations that equalize the charge on all battery cells. In everyday life, such stations are useless, due to their high cost.

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

We figured out the purpose of the battery structure elements, now we will consider how to determine the malfunction, this is part 2 of the screwdriver battery repair. Immediately, we note that all the elements cannot fail at once, and since our circuit is sequential, when one element fails, the whole circuit does not work. Hence, our task is to determine where we have the weakest link in the chain.For this, we will need a multimeter, and for the second method of troubleshooting a 12V lamp, if your battery for a screwdriver is also 12 volt. The procedure is as follows:- We put the battery on charge, wait for the signal of a full charge.- We disassemble the case and measure it on each battery bank. For Ni - Cd, we should have 1.2 - 1.4V, in lithium - 3.6 / 3.8V.- Check all "banks" in which the voltage is less than the nominal one. For example, most Ni - Cd cells have a voltage of 1.3V, and one or more - 1.2 / 1.1V.- We collect the battery and work until a noticeable loss of power.- We remove, disassemble and measure the voltage drop across the "banks" of the battery. On the marked elements, the voltage "sag" will be greater than on others. For example, they are no longer 1.2V, but 1.0V or even lower.Note. The difference between the cells in the battery of 0.5 - 0.7V is considered significant, which means that the cell becomes unusable.Thus, we have found candidates for "resuscitation" or "amputation" and replacement with new elements.If your screwdriver operates on a voltage of 12 or 13V, you can search with a simpler method. We disassemble the fully charged battery and connect a 12 volt lamp to the contacts "+" and "-". The lamp will be a load and will drain the battery. Next, we take measurements on the battery cells, where the voltage drop is strongest, there is also a weak link.There are other ways, instead of a lamp, you can choose a resistance, but for this you already need the basics of electrical engineering, and it is doubtful that a resistor with the necessary resistance would be at hand.Other faults are very rare. For example, loss of contact at the soldering points of the batteries or the power contacts of the unit, failure of the thermistor. This problem is more inherent in fakes. Due to the rarity, we will not focus on the battery elements.With the "problem" elements sorted out, it is necessary to repair. How to repair a screwdriver battery? In general, 2 methods are available for repair, so to speak. This is the restoration and replacement of elements that have become unusable.Let's proceed to part 3 of repairing a screwdriver battery and immediately make a reservation that the concept of "resuscitation" for lithium - ion batteries is not applicable. 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 the cause of the malfunction is: the element itself or the control circuit. There are two options here:

we change the control scheme from another, but similar to ours, battery, if it helps, we find a replacement and change it;

apply 4V to a cell with a current of about 200mA, this requires an adjustable charger. If the voltage on the element rises to 3.6V, the element is working properly, the problem is in other elements, or in the control circuit.

Screwdriver battery refurbishment is available primarily for Ni - Cd batteries, but these are usually the most common in household screwdrivers.So how to reanimate a screwdriver battery? There are two types of "resuscitation" for these types of batteries:

The method of compaction or compression (it will work in cases where the electrolyte is still present, but the volume is lost);

"Firmware" voltage and current greater than the nominal. This method allows you to eliminate the memory effect, and although not completely, but restore the lost capacity.

This method is shown below in the video.

The ability to work with a tool such as a screwdriver without connecting it to the mains is convenient, practical and, most importantly, necessary.After all, it is often necessary to carry out any work in those places where it is almost impossible to reach the network cable. Construction tool stores offer a wide variety of screwdrivers, including Bosch, as well as the popular Hitachi and Makita. But, unfortunately, the battery life of any drill or similar tool is short - a maximum of 5 years. It happens that the screwdriver's battery is no longer charged even after a shorter period of time. It is not profitable to buy a new battery urgently. A new screwdriver can be purchased for the same amount. Therefore, it is worth trying an option such as restoring the battery of a screwdriver with your own hands.

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

Nickel-cadmium batteries, in this case, are the most popular and commonly used. The voltage of each individual cell is 1.2 volts and the capacity is 12,000 mAh if we have a 12 volt instrument. It should be noted right away that, unlike lithium ones, they are subject to restoration, because they have the so-called "memory effect" in the form of a reversible loss of capacity.

As for batteries containing lithium, the popular Imax B6 charger is unlikely to restore their capacity due to the fact that lithium tends to degrade over time.

Rebuilding a screwdriver battery in a similar manner may also fail 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 "reviving" them are much greater. But at the same time it is important not to rush and not to use rashly common methods of "quick recovery" of Ni Cd batteries. Read more about which battery is better for a screwdriver →

There are a large number of videos on the Internet in which, for example, the battery recovery of a Hitachi screwdriver using the Imax B6 is clearly shown. It consists in "reanimating" nickel batteries by supplying high currents. Supporters of the express method of recovery propose to revive the battery using the simple settings of Imax B6. The mode is set to nickel-cadmium, and the battery can be reanimated in this mode.

However, pulsing warm-up and subsequent charging are rather risky methods for nickel-cadmium batteries. The broken connection in the element cannot be restored with 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 with the Imax B6.

There is an extreme option, how to restore the nickel-cadmium battery of a screwdriver - you can "pull" them with a high current. They will start charging, but not for long. Electronics enthusiasts who criticize this method assure that there was not a single case when the impulse current restored the battery capacity for a long time. As a rule, it will rise for a very short time, and then, after a few days, the battery "sits down" again.

Whether it is possible to use the pulsed current method is up to the owners of the batteries. There are many videos on the Internet on how to recover a Ni Cd battery from a screwdriver. But there is an opinion that in reality, quick methods work for a very short time. For example, if the electrolyte inside any battery has boiled away from the bundle or dried out, the impulse current will “kill” the cell completely.

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

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

After that, the battery can be fully charged Imax B6 and let it "settle". The procedure is long. Recovery of 8-, 12-, 14-battery "cans", depending on the voltage, can take a long time. Ideally, you should not charge them right away, but give time to the "cans" of water to stand for a day. It is impossible to charge the batteries one at a time, it is better that there are at least three or four of them in a bundle to evenly distribute the voltage.

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 on the "dry" one, as is often done.

After the batteries have stood for a day, you can start charging them. Do not close the openings yet. Connect to Imax so that the device "sees" them. Charge and let "settle" again if any one battery has not recovered. Find the weak element in the bundle with a multimeter and add water to it again.

The main essence of this meticulous method of repairing a screwdriver battery is to restore the connection of the battery plates with their contact-adapter buses (The internal structure of Ni-Cd is similar to the scheme according to which solar panels are made). The main reason for the termination of batteries is the detachment of the positive contact from their inner part.

Do not cover the holes drilled in the batteries until the battery charge is stable. Once the charge has stabilized, carefully seal the holes with silicone. Water can be topped up periodically at any time.

As it 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 the electronics device. However, the distilled water method saves a lot of money and is the answer to the question of how to restore the screwdriver battery in the most gentle way. Usually, two batteries are included with the screwdriver. One can be used, and the other can be gradually restored. This method, despite its duration, seems to be more humane and safe for the battery.

Rebuilding a screwdriver battery by replacing several cells can be successful for all types of rechargeable batteries. It also poses no risk to them, as well as manipulation with distilled water, provided that care is taken during soldering.

First, using a multimeter, the output voltage of each "can" is measured, 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. Read more on how to check the battery of a screwdriver with a multimeter →

After that, the battery is inserted into the screwdriver and works until the power starts to noticeably decrease. The voltage indicators are removed again, and those "banks", the voltage difference of which is 0.5-0.7 V in comparison with the "strong" ones, should be evaporated, disposed of and replaced with new ones, similar to the old ones, having previously ordered them in the online store.

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

The "native" battery connecting plates 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 indicators.

After the end of soldering, insert the battery back into the screwdriver and carry out 2-3 full “charge-discharge” cycles to equalize the energy potential of all batteries. In order for the updated battery to last longer, such a training should be carried out 2-3 times a month. How to quickly and completely discharge a screwdriver battery →

In this case, we are talking about a complete replacement of battery cells and about the so-called "erasing the memory effect" from new batteries in order to ensure their more productive work. The memory effect is that the battery "remembers" all possible charging cycles that it could theoretically undergo in production before falling into someone's hands. The more such cycles are in its "memory", the more likely it becomes that the capacity will begin to decrease much earlier than expected. Also, nickel-cadmium batteries like these "swinging" processes. If done right before use, they will perform much better.

The required number of batteries can be ordered online, for example, on Ali-Express. It should be borne in mind that they already have a certain factory charge, which it is desirable to "remove" in order to "save" the power of the batteries 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 cells with the following indicators: the output voltage of each is 1.2 V, and the capacity is 1200 mAh, which in total is 12 V. The advantage of a complete replacement of the battery with the subsequent "erasing" of the factory "memory effect" is that in any online store you can order items with a higher capacity than the old ones. For example, 1800 mAh. And the battery will last an order of magnitude longer. Of course, these batteries will cost more. But their price always justifies itself.

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

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

Each new element undergoes charge-discharge training to remove the factory settings. At a current of 1A, all batteries are alternately discharged to a voltage of 1 V (the minimum allowable 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 unit, focusing on how the old ones were previously placed there. Therefore, when disassembling the plastic case, you need to remember how the batteries were lying 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 the capacity. Sometimes you should try to get one or another tool or the necessary ingredient (for example, distilled water) in order for the recovery to be as successful as possible.But this is exactly what will help you avoid the additional costs associated with the purchase of a new screwdriver or a completely finished battery.

Video (click to play).