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How to check screwdriver batteries with your own hands. Restoring a screwdriver battery. Battery compartments for different numbers of batteries

Hello! Today we will repair the screwdriver battery. Do you know that the history of the creation of a screwdriver goes back to the deep Middle Ages - all the way back to the 15th century, when knights put on armor before battle, and squires helped them twist parts of the armor with guess what? With a screwdriver!

This went on for a long time until, in 1907, Canadian inventor Peter Robertson patented a Robertson screw with a standard square hole into which the tip of a screwdriver was inserted. Since that time, screws began to be produced on an industrial scale and used in household. Later, in 1934, inventor Henry Phillips modified the screw head and a screw with a Phillips notch appeared, into which a corresponding screwdriver was inserted. By that time, the engine had already been invented and the idea of ​​​​creating a “rotator of screws and screws” was in the air. However, there were big problems with batteries - their weight and dimensions. The problem was solved only in the 1980s, when the first nickel-cadmium Ni-Cd and lithium-ion Li-Ion batteries appeared.

The USA and Japan were the first to master the production of household and professional products. All this happened thanks to the advent of new energy-intensive electricity batteries. We will urgently change them inside the Interskol DA-10/10.8 ER cordless drill/screwdriver that fell into my hands. The problem was this: When you press the button, the engine simply does not turn, but the LED lights up, though the light was weak.

Disassembling the screwdriver battery

Let's start repairing the screwdriver battery. We remove the battery from the screwdriver handle and unscrew the three screws that are located under the sticker at the bottom.

After unscrewing the screws, carefully move the hooks of the latches, as in the photo. And remove the bottom part of the plastic battery case.

Inside we see lithium-ion banks Chinese company HighStar model ISR18650-1300 Li-Ion. This means that the batteries have never been changed. Because it is known that Interskol purchases batteries from this company and inserts them into almost all of its products.

The photo below shows the insides of the screwdriver battery in all its glory with three cans, which were produced back in 2011. These lasted five years with active use at a construction site. So the result is very worthy. They usually die earlier, probably they were not used in cold weather.

To replace the battery banks you need to disassemble it further. I advise you to remember the location of the plus, minus and charging contacts so as not to confuse the wires during reassembly.

Pay attention to the voltage control board on the batteries - especially often they fail. It is imperative to ring suspicious radio elements on this board.

We check the voltage at the battery output - it turned out to be 4.4 volts, but it should be 3.7 x 3 = 11.1 volts normally and 10.8 volts with minimal charging. In general, the banks are dead - they definitely need to be changed.

We continue to disassemble the Interskol screwdriver battery

This can be done in several ways - you can unsolder the wires that go to the board.

You can also simply remove the contacts from the top battery cover. The photo shows what shape the curved contacts have, so you can easily remove them yourself.

Under plastic cover We see how the batteries are connected to each other. Their spot welded. This solution is used in almost any battery of another tool. This is a reliable and gentle battery connection. At the same time, the destructive heating of the lithium batteries themselves is minimal.

Carefully tear off or bite off the metal tape with pliers to disconnect the cans from each other. On the board side, they were also connected to each other with tape and placed on a cardboard spacer with glue. This is done so as not to short anything on the board. You must remember to return it to its place when reassembling the battery.

Due to the lack of a spot welding machine, we will solder new lithium-ion batteries with a well-heated, powerful soldering iron very quickly. We remember that heating reduces their service life and is generally explosive.

Pay special attention to the condition of the wires inside the battery. They may be broken or frayed. They need to be properly insulated or replaced with fresh ones. Since I was repairing a screwdriver battery on the go in the field, I had to use a brilliant invention of an engineering mind. I took out blue electrical tape.

Solder the batteries

It can be done in different ways, for example with thick wires. I decided to solder some torn metal strip taken from old cans. First, I tinned the tapes in the places of future contacts on both sides. After Using a well-heated soldering iron with a drop of solder, I tinned the battery contacts. But so that they do not heat up too much - let them cool. Then I pressed the tape to the contacts of the cans and soldered the tape, again without severe overheating.

The most difficult thing to solder is the negative terminals, but it goes very quickly. True, it is better to wash the flux later to clean the insides of the battery.

Now the most important thing. What batteries were used when repairing the battery of the Interskol DA-10/10.8 ER screwdriver, you ask? Well, I won’t hide it. These were the most Chinese of the cheap cans that the owner of the device honestly bought in the store. from Bailong with a fictitious capacity of 8800 mAh. This is of course a laugh and God forbid they have 2200 mAh. Judging by how long the screwdriver worked after the repair on a full charge. I would reduce this figure by half. But nevertheless, the screwdriver was urgently repaired and it makes the owner happy.

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, as a 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 larger number charging 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 screwdrivers are equipped with different types of 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 a 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 faulty battery from the battery circuit. Considering that they are all connected to each other by spot welded plates, 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.

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

Cordless screwdriver – what power sources are used?

The cost of batteries is about 70% of the price of a new tool, so it is logical to try to repair the screwdriver battery. Before you begin the operation, you should familiarize yourself with the features of the voltage sources and 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 elements connected in series standard size. On each element there is an indication of the type and capacity in ampere-hours (A/h).

Screwdriver battery

The batteries are equipped with the following types of elements:

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

Evaluation of lithium-ion power supplies in terms of quality and service life puts them beyond competition. They are practically resistant to self-discharge, have a high capacity, and can be charged many times, several times more than other types of batteries. The cell voltage is three times greater than that of other types, which allows batteries to be equipped with fewer cells, reducing weight and dimensions. They do not have a memory effect, which makes them an ideal device of this kind.

But ideal does not exist in nature, and lithium-ion power supplies also have some disadvantages. They cannot be used when sub-zero temperatures, as the manufacturers honestly state. But practical use revealed another drawback: when the service life of such a battery expires (three years), lithium decomposes, no way to reverse the 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 due to their low cost. They are not afraid of negative temperatures, like lithium-ion voltage sources. If the screwdriver is rarely used, such elements are ideal, because they can be stored discharged for a long time, maintaining their characteristics. These batteries have a lot of disadvantages: they are small in capacity and toxic, so their production is concentrated in underdeveloped countries. The tendency to self-discharge and short life expectancy during intensive use are also disadvantages of these batteries.

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

Nickel-metal hydride batteries are environmentally friendly, high-quality, produced by leading global companies. Compared to Ni-Cd they have clear advantages:

• slow self-discharge;
• the memory effect is small;
• resistant to numerous discharge-charge cycles;
• relatively large capacity.

But during long-term storage without operation, some of the characteristics are lost; they do not like low temperatures, and besides, they cost quite a lot. And the main drawback is that they cannot be repaired.

We determine the malfunction - can it be repaired?

If your screwdriver has elements installed in the battery that, in principle, can be repaired (except for nickel-metal hydride), we proceed to disassembling the case. It has two parts connected with screws or glue. In the first case, no difficulties are foreseen - unscrew the screws and separate the parts. If the connection is adhesive, insert a knife between the parts at the joint, then screw a self-tapping screw into this place. Carefully, so as not to damage the elements, we pass the knife along the joint, separating the parts of the body.

We check the elements on a fully charged battery.

Having disassembled the case, we will see banks connected in series, which means that the malfunction of even one bank can lead to poor battery performance. The main task during repair is to find the weak point in the circuit. We remove the cells from the housing and lay them out on the table so that there is easy access to all contacts. We use a multimeter to measure the voltage of each element and write down the readings on paper or directly on the case. The voltage indicator on a nickel-cadmium battery should be 1.2–1.4 V, on a lithium-ion battery – 3.6–3.8 V.

Types of malfunctions and ways to eliminate them

Having measured the voltage, we assemble the cans into a housing, turn on the screwdriver and work until it loses power. We disassemble again and take the voltage readings again, fix them again. The cells with the lowest voltage will again show a significant drop in voltage after being fully charged. A difference 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, you can use more than one simple method, eliminating double disassembly and assembly. First, we also measure the voltage value of each fully charged element and record the indicators. We connect a load to the jars 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 drop is observed is the weak area.

Changing elements is the most reliable way

You will either need cans from an old battery that still has serviceable elements, or you will have to buy new ones, they are inexpensive. When purchasing, pay attention to the dimensions and capacity - they must match the existing elements. We throw away the unusable cans and solder new ones in their place. It is advisable to connect using original plates or copper plates that are suitable in size. Compliance with the cross section is important - when charging, a large current passes through the contacts. If the area is insufficient, they heat up and the protection is triggered.

We pay special attention to the connection sequence - the minus of one can is connected to the plus of the other.

We equalize the potentials on the assembled battery, since they are different. We charge it 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 such training is necessary not only for repairs, it should be carried out every three months to extend the battery life.

Restoring capacity - flashing batteries

A method acceptable for nickel-cadmium batteries when the cells are not dry. You can verify this using the method described below; if it does not help, it means that the electrolyte has boiled away. The essence of the method is charging using high current and voltage. You will need a charger with the ability to regulate; charging for car batteries is suitable. We will charge each element separately, for which we remove the battery from the case and disconnect the banks one from the other.

We set the charging to a voltage three times higher than the nominal voltage - 3.6 V. Connect it to the charger and turn it on for 3-5 seconds. If checking the voltage with a multimeter showed 1.4 V or slightly lower, everything is in order. We assemble the battery and use it. The method eliminates the memory effect from batteries. It is not suitable for completely dead cans.

Battery resuscitation – tested in practice

As already noted, the main reason for failure of nickel-cadmium batteries is drying out of the cans. The procedure for topping them up is not very pleasant, but not so difficult that it cannot be completed. We do everything as always - we disassemble the case, take out the elements. Remove the paper that is wrapped around the jars. On some it comes off easily, whole, on others it has to be cut. We inspect the body of the cells - some without any traces of corrosion, others may be seriously damaged, but the main thing is that the shell is intact.

Using a thin drill at the top of the element, where there is a recess in a circle, we make a hole. You will need distilled water. We draw it into a syringe, insert the needle into the hole and very slowly pump in water. It is unknown how much will go in; it is impossible to determine visually. If liquid leaks from the jar from the very beginning of introducing water, throw it away; it cannot be resuscitated; it must be replaced with a new element. Some kind of reaction occurs there, which indicates that this element is unsuitable for repair. But this happens extremely rarely. Further procedures are usual - assembly, several charge-discharge cycles.

Lithium- ion batteries it can also be restored, but this operation is harmful to health due to the toxicity of the contents. The reason for their failure is most often a violation of contact between the internal filling and the exit to the body. To check suitability for repair, insert an awl into the hole at the top of the element so that it touches the inside. We connect the multimeter and look at the readings. If there is current, the reason is a broken contact, you can continue the repair.

Using wire cutters, we cut off part of the metal on the cover protruding from the top of the element. We bend it upward, and on the contrary we press the metal of the body so that it touches the inside of the element. Now comes the turn of the most important part of the operation - soldering. We use solder that has flux inside; soldering with it is faster and more convenient, especially in such a situation. We solder quickly so as not to overheat the element. If you don’t know how to do this, don’t try it - in this situation you won’t learn, but you’ll ruin everything. Then we seal the gap in the case with sealant - and off to charging.

It can be done if you use one of the above methods!

Reading time: 11 minutes. Published November 29, 2018

Skip the talk about the benefits of screwdrivers, you can go straight to the topic. The battery or accumulator is the biggest concern for screwdriver owners. It is better to handle them strictly according to the instructions. In the event of a breakdown, there is only one solution - buy a new battery. But you can temporarily try to use the problem battery, for which a number of tips are offered here. We emphasize that repairing the battery is a temporary solution, but first you need to accurately investigate the causes of the malfunction.

Types of batteries and their differences

The power source for a hand tool should provide it with energy for at least half an hour of operation at moderate load or 10 minutes at full load. And at the same time, it can quickly restore its charge. Without these conditions being met, the tool loses all commercial meaning; people simply won’t buy it. Typically, the power of a screwdriver varies between 80-160 W.

Of all the types of batteries that the industry produces, only three types fit these criteria:

• Ni-Cd – nickel-cadmium;
• Ni-MH – nickel metal hydride;
• Li-ion – lithium-ion.

Nickel-cadmium appeared earlier than all the others and showed good performance properties. Such a battery has a voltage of 1.35 V ... 1.0 V. Here and further we denote the rated voltage first, and the voltage at the end of the discharge cycle last. Ni-Cd have a number of charge/discharge cycles ranging from 100 to 900, this depends on the quality of materials and operating mode. Ni-Cd is also characterized by very low internal resistance, they hardly heat up when charging and are stored for a long time.

Flaws:

1. “memory effect” interfering with operation.
2. The toxicity of cadmium is a strong carcinogen.

Another type: nickel-metal hydride battery. These batteries have been proposed as a replacement for Ni-Cd. The justification was the disadvantages of traditional cadmium batteries. In theory, Ni-MH is good: it has high energy intensity (up to 300 Wh/kg) and is not subject to the memory effect. Voltage 1.25 V ... 1.1 V, number of charge cycles 300-800. Ni-MH of the old type completely self-discharges after a year of storage. It is recommended to store them at a low temperature, from 0 to 20 degrees Celsius. Batteries of the new type LSD Ni-MH (Low Self-Discharge), as their name indicates, have low self-discharge and heat less when charging.

Disadvantages: Ni-MH batteries have a 10% discharge rate during the first day, and generate significant heat when charging.

Li-ion batteries have a voltage of 3.7 V ... 2.5 V, but in reality it is a little more complicated, it all depends on the mode of use of the battery. The number of charge cycles is approximately 600, but this is provided that no more than 20% of the capacity is taken from the battery. Lithium-ion batteries do not like deep discharge. This causes them to quickly fail. The internal resistance of Li-ion is very small, 5 ... 15 milliOhms. Self-discharge is about 1.6% per month when fully charged and without load.

Disadvantages: high cost, limited period storage independent of use. Risk of explosion and fire if handled incorrectly.

Diagnosis of battery faults

You should not immediately suspect a faulty screwdriver battery or restore it, but first try to replace it with the second one from the kit, after charging it properly. If the screwdriver rotates poorly, this may be caused by a breakdown in its mechanics (motor or gearbox). If in doubt, replace the power supply if possible. If everything points to the battery, then you can begin to diagnose and restore it.

First of all, you need to find out the type of battery. This is written on its body and the possibility of restoration depends on it. The rated voltage must also be indicated. It usually lies within the range of 14 ... 19 V. Then, without disassembling the body of the battery pack, it is checked. To do this, you can use two methods:

• Check with a multimeter;
• Load test.

Multimeter method

The multimeter can be used in two modes: voltage measurement and current measurement. If there are two devices, then this is even better; you won’t need to make unnecessary switches.

The measurement diagram is shown below:


One multimeter switches to voltage measurement mode (voltmeter), the other switches to current measurement mode (ammeter). If there is only one device, then instead of an ammeter you will have to use just a wire. The wires from the battery to the voltmeter can be thin, and the wires from the power source to the battery can be thicker, but don’t get carried away too much; in the end, wires with a cross-section of 0.5 mm2 are suitable for the entire circuit.

If the voltage on the battery is normal, but the charging current is small, significantly less than one ampere, then for a Ni-Cd battery this may mean a malfunction of one of the battery elements. Restoring the screwdriver battery is canceled here; repairs are needed. For Li-ion, this means that either it is normal, or one of the elements is also faulty.

Let the Ni-Cd battery have a nominal voltage of 18 Volts. Then it’s easy to find out how many elements are inside without opening the case. Knowing the nominal voltage of Ni-Cd 1.2 V, divide: 18/1.2 = 15. This means there are 15 elements in the case. If the voltmeter shows an idle voltage of 16.8 V, then this may mean that one of the banks is short-circuited, or simply a discharge of a normal battery. Such a battery gives 15 V when discharged. If the charged one shows 16.8 V or so, then one of the cells is short-circuited. It won't be possible to restore either, you will have to replace it.

If the battery passes a current of more than one ampere when charging, and the voltage gradually increases, increasing by 0.1 V every 5-10 minutes, and at the end of the charge the voltage is slightly higher than the nominal value, then the battery is in order and no restoration is required.

Load method

This method is similar to the previous one and is perhaps simpler. No need to disassemble the charger, or use a laboratory power supply. You only need:

• Automotive light bulbs;
• Multimeter;
• Pieces of wire;
• Soldering iron with solder and flux.

Check scheme:


To do this check, you must first put the battery on charge and charge it in the usual way. Then the rated load is applied. It is easy to find out the current; to do this, divide the power consumption by the rated voltage. For example, if a screwdriver consumes a power of 50 W (typical case), at a voltage of 18 V, then the current should be 50/18 = 2.77 A. You can achieve this current, or something close to it, by dialing car turn signal bulbs in parallel.

If the battery supplies the rated current for several minutes, the voltmeter shows a voltage slightly below the rated value, and the lights do not dim, then the battery is working. However, it may happen that for Ni-Cd the current will soon begin to weaken. This is a manifestation of “memory”. In this case, you need to carry out a restoration. Lithium-ion batteries do not have a memory effect, although in theory it exists, in practice it is believed that it simply does not exist.

Element-by-element check

This method requires disassembling the battery case. It is used when a battery or its cell stops delivering good current, and restoration attempts fail. One bad link is enough here, since they are connected in series. But to find such an element, you need to check the internal resistance of each of them.

Of course, you need to start with a general inspection of all cans: are there any cracks, leaks, etc. Faulty element will immediately give itself away by its appearance.

Testing for current output is carried out using Ohm's law for a complete circuit (also known as Kirchhoff's first law). To do this, you need to take a resistance with a nominal value of 10 Ohms, rated for 25 W, and an ammeter. The element being tested is short-circuited to a resistance connected in series with the ammeter.

For example, let a Ni-Cd battery with a voltage of 1.2 V receive a current of 100 mA. Let's write it down and measure again, but not the current, but the voltage on the element. First, let's measure the idle voltage, without connecting a resistor, and then connect the resistor and see how much the voltage has dropped. Let the first time be 1.2 V, and after connecting the resistor it became 1.05 V. Then the internal resistance of this element:
This is not too little, if all the elements are the same, then the battery will be able to provide the screwdriver with only half the power. The lower the internal resistance, the better the element, but when an indispensable condition: it should give the nominal voltage, or close to it. If the voltage is too low, or very close to zero, then the element has shorted, it is no good and cannot be repaired. If the internal resistance is more than 3 ohms, then you can try to restore (see below) or replace.

How to restore the battery?

There are several ways to ensure normal battery operation and revive it at home. Firstly, this is the restoration of the normal charge-discharge cycle. It is also possible, in case of failure, to open the battery case as a last resort and examine the individual condition of the cells. In some cases, this allows you to completely repair the battery (if there are similar ones for replacement).

Eliminating the memory effect

This recovery method is applicable to nickel-cadmium batteries. It's very easy to do. First, the battery is completely discharged by a screwdriver or other load, such as lamps or resistance. Then it is fully charged. And this needs to be done several times. If the battery has no other defects, it will be fully restored. There is no point in restoring lithium-ion batteries in this way.

There are methods of “restoration” with asymmetrical current, when the charging current pulse is larger, and the following discharge period is smaller, so that the difference turns out to be positive. This method is incorrect; it does not take into account the fact that chemical processes proceed much more slowly. Even more wild is the method of restoration with high current pulses. They should not be used.

To restore a Ni-Cd battery, you will need:

• Charger;
• Several car light bulbs;
• Copper wire 0.5 ... 0.75 mm.sq.;
• Multimeter.

It is better, of course, to have a simple special stand for restoration, but this is more suitable for professional repairmen than for ordinary users of screwdrivers. But be that as it may, working with two multimeters is much more convenient than with one.

The recovery steps are as follows:

In practice, do from 3-4 to 7-8 cycles. If it is not possible to achieve condition 11 in the recovery algorithm, then the battery must be repaired.

Adding distilled water to Ni-Cd batteries

This is done when disassembling the case and if the internal resistance has increased (significantly more than 0.3 ... 0.6 Ohm). Using a small drill (0.5 mm), the body of the element is carefully drilled and a few milliliters of pure distilled water are injected into it with a syringe. Then the hole is sealed with a soldering iron. These manipulations require skill and may not be easy for a beginner.

After some time, about 12-24 hours, the electrolyte will return to normal condition and the element will be restored for a more or less long period.

To complete the work you will need:

• Mini drill + drill 0.3-0.5 mm (as a last resort, a strong awl);
• 1 ml syringe with needle and distilled water;
• Soldering iron 40-60 W, POS-61 solder and flux.

Place to make the hole:

The sequence of actions is as follows:

1. Cut the paper cover from the element along the axis and remove it;
2. Drill a hole as shown in the picture above. The drill should go in 3-4 mm, no more;
3. Introduce 10-15 ml of distilled water into the hole made;
4. Wait 12-24 hours until the entire volume is soaked;
5. Charge the cell to rated voltage;
6. Solder the hole with a well-heated soldering iron;
7. Put on a paper cover and seal it with tape.

The recovered cells can be collected into a battery.

An example of how to do it yourself in the video:

Resuscitation by replacement

This is the most technically competent type of repair, since chemical power sources are considered non-removable and cannot be repaired; they can only be disposed of at the end of their service life.

For such repairs, you can use two faulty batteries, and the probability of making “one out of two” is very high. Elements must be the same type and size. And also preferably close in production time. During assembly, the terminals must be properly soldered, and the entire assembly must fit into the housing without interference or effort.

To work you will need:

• Sharp nippers;
• Soldering iron 40-60 W, POS-61 solder, flux;
• Stranded installation copper wire cross section 0.75 mm.sq.;
• Scotch tape or tape.

Here the order of work is as follows:

1. Disassemble the battery pack (and possibly another one);
2. Check each of the elements (see above);
3. Select the highest quality ones;
4. Remove the old tire;
5. Quickly and thoroughly tin the soldering areas;
6. Solder the connections with pieces of wire;
7. Assemble the elements and wrap once with tape;
8. Assemble the block.

ADVICE: To avoid problems with tinning of elements, which should never be overheated, you need to warm up the soldering iron well and use an effective flux. An aspirin tablet is suitable. Do the work while extracting air, as the decomposition of aspirin produces harmful and irritating substances. Wash remaining flux with acetone or alcohol.

Release of gas from Li-ion batteries

As a result of improper use of Li-ion cells (abuse of overdischarge), swelling is possible. As a result of the decomposition of salts, oxygen is released and creates high pressure in the housing of the sealed element. These gases are released using special valves, but in small elements they may not be present.

ATTENTION! Forcibly releasing gas from swollen Li-ion batteries by destroying their casing is strictly prohibited by any instructions for their operation; this is a gross violation of fire safety!

The consequences of such an autopsy can be seen in this video:

Conclusion

It is better to operate batteries for screwdrivers following the instructions. Discharge Ni-Cd batteries to 0 before the next charge, and recharge Li-ion batteries more often if possible. Only dry nickel-cadmium cells are subject to partial recovery; lithium-ion cells are not subject to recovery. Be careful when handling batteries!

Screwdrivers are used in different conditions and their load levels are different. Therefore, they differ in their power, which directly depends on the battery. If an element breaks, you need to be able to operational repair with your own hands.

Battery types

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

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

There are three types of batteries for screwdrivers:

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

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

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

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

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

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

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

Review of lithium-ion battery with chip

Problems with the battery

What problems can occur with batteries:

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

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

How to properly repair it yourself.

Be patient and start repairing.

Let's disassemble the battery.

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

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

Video: How to disassemble a screwdriver battery

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

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

How to increase battery capacity.

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

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

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

Video: How to drain your battery

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

Video: Review of the imax b6 charger

Diagnostics.

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

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

Diagnostics with a tester.

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

Video: How to check the battery condition

Why isn't it charging?

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

Charges and discharges quickly.

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

Electrolyte boiling away.

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

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

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

Video: Adding distilled water

Replacing and soldering batteries.

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

Video: Replacing elements in the battery

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

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

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

Battery compartments for different numbers of batteries

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

For resistance welding we will need:

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

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

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

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

Heat-shrink tubing.

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

Video: Converting a battery to lithium-ion

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

Restoration and repair

Basic methods for restoring nickel batteries:

Compaction (compression).

Elimination of memory effect.

Adding distilled water instead of boiled-off electrolyte.

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

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

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

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

Video: How to replace lithium-ion battery cells

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

Video: Charging a lithium-ion battery from imax b6

How to store

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

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

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

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

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

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