Repair of a rechargeable battery for a screwdriver. How to repair a battery for a screwdriver: fault determination and restoration. Correct use of the device
Repairing a screwdriver battery with your own hands is not difficult, but you will need to correctly identify the breakdown.
Breakdown of the screwdriver battery occurs due to frequent charging and operation in unacceptable conditions.
Today this tool Almost every man has one. This device is intended for various works for repair and installation. It can be used to tighten or unscrew self-tapping screws and bolts. It is known that rechargeable batteries in screwdrivers do not last long. Frequent charging and operation in unacceptable conditions can cause battery failure. In this case, many people go to the store and buy a new battery. However, you should know that the battery ranks first in the cost of a screwdriver. Almost anyone can do all the steps to repair a screwdriver battery with their own hands.
Please note that it is not always possible to quickly find a battery that is suitable for a particular model. Today there is a huge number various types batteries for such a device. The easiest way is to repair this part yourself.
Figure 1. The sum of all batteries will give the final voltage at the battery contacts.
Items that will be needed to repair screwdriver batteries:
- multimeter;
- soldering iron;
- flux;
- tin;
- copper wires.
It is worth knowing that, regardless of the brand of the tool and the country of manufacture, rechargeable batteries have the same structure. The assembled battery pack is shown in Fig. 1. From the physics course we know that elements that are connected in series add up their potentials. The sum of all batteries will give the final voltage at the battery contacts.
Banks in most cases have standard sizes and voltage, they differ only in capacitance. This indicator is measured in A/h and is indicated on the part itself. Visually this can be seen in Fig. 2.
To assemble rechargeable batteries for screwdrivers, the following types of elements are used:
- nickel-cadmium, the nominal voltage of which is 1.2 V;
- nickel-metal hydride, the voltage of which is 1.2 V;
- lithium-ion with a voltage of 3.6 V.
In most cases, nickel-cadmium elements are installed, since they are low cost. Their disadvantage is that they have a short service life. Lithium batteries can last longer. Their disadvantage is that lithium decomposes over time, and therefore they can become unusable prematurely.
How to diagnose faults?
Figure 2. Design of a battery bank for a screwdriver.
Before you start repair work, you will need to perform high-quality diagnostics of the instrument. Not in all cases it is possible to immediately determine the breakdown. Majority modern models batteries consist of parts that are connected in series. They have a specific voltage rating.
The first thing you need to do is disassemble this part. However, before disassembling it, the battery must be fully charged. Next, each element should be measured using a multimeter. On this device you need to set the nominal voltage of the battery, and then take measurements. It's very easy to do. Each element should have approximately the same performance.
Then you need to collect the battery and work with it until it completely loses power. After this, the device should be disassembled again and the voltage measured on each of the cans. If any of them has a value 2 times lower than the nominal value, then this bank unsuitable for use. There may be several such elements, so all parts should be replaced. It is not recommended to postpone this procedure.
What nuances should be taken into account?
If the screwdriver operates on a voltage of 12 V, then diagnostics can be performed using another method. You will need to disassemble the battery constituent elements, while they must remain fastened to each other. The chain is sequential, so it will be possible to connect a light bulb to the ends of the battery. The voltage should be 12 V. The use of car light bulbs is allowed. After this, it will be necessary to measure the voltage drops on each part. The one at which this indicator is maximum is faulty.
It is worth noting that there may be other malfunctions. For example, contact may be lost in places where parts are fastened. The reason is poor soldering. In this case, you will need to reattach the wire that came loose. The thermistor may also be faulty. This part can be checked using the same multimeter.
How to repair batteries?
Many people want to know whether it is possible to repair batteries for screwdrivers?
If out of order lithium battery, then it should be noted that it does not have a memory effect. Therefore, they are very difficult to repair. Often the problem is that the lithium in the batteries has decomposed. This cannot be eliminated. However, the problem may also lie in the control circuit.
In order to perform the test, you can use a similar circuit, which is removed from the same device. If the device functions normally, then the problem is a malfunction of one or more batteries. If the part rating is 3.6 V, then you will need to apply 4 V to it at a current of 200 mA. If the battery is charged to the nominal value, then it is suitable for use. If it cannot be fully charged, then it will need to be removed from the chain. In this case, it will not be possible to restore the element, so you need to replace it.
If the screwdriver has nickel-cadmium batteries, the device can be repaired. It is worth noting that such batteries are most often installed on household appliances. The faulty part is subject to a compression effect. If it contains electrolyte, this will help solve the problem. If not, then another method should be used. You will need to charge the battery with a powerful charge. To do this, apply a voltage to the element that greatly exceeds the rated voltage. Then you will need to increase the current.
If these methods do not help, then the battery will need to be replaced. The problem is the electrolyte boiling away. If this happens, then individual elements of the tool will need to be replaced.
How to repair and replace batteries?
First, you should buy several cans or disassemble another battery that contains working cans. Batteries today are sold in many specialized stores, so you can try to find the right model.
A soldering iron is needed to repair the screwdriver battery.
To work, you will need to prepare a soldering iron. In this case, a low-power household appliance is suitable. In order to perform soldering, you should prepare flux and tin.
The replacement process is quite simple. Will need to be excluded faulty part, and attach a new one in its place. If you have at least minimal experience in this matter, then the replacement work will take no more than 2-3 minutes.
During the soldering process, you must work as quickly as possible, otherwise all the parts that are planned to be replaced will overheat, which often leads to their failure. In the process of fastening elements, it is important to use original plates or perform soldering using copper wires. Soldering must be done efficiently, otherwise there may be poor contact. This is not recommended, as the bonding areas will overheat. This may negatively affect the functioning of the screwdriver battery.
In the process of fastening parts, it is important not to confuse plus with minus.
All battery components must be connected in series: the plus of the previous can must be connected to the minus of the next one.
This should definitely be taken into account.
When all the parts are installed, you will need to equalize the potentials of each battery. To do this, you need to perform a charge/discharge cycle on the battery. During this, potential equalization will occur on all parts, and this is prerequisite for the correct functioning of a device of this type.
When talking about how to restore a screwdriver battery, you should know that not all types of batteries can be replaced. Everything will depend on what kind of battery is installed in the existing screwdriver.
All cordless devices, including screwdrivers, have a significant drawback - limited period battery service.
That is why every owner of such a tool at any time may face the question of replacing the batteries in a screwdriver. But before you get started, it’s worth understanding the variety of batteries and their features.
Types of Power Tool Batteries
There are a huge number of battery production technologies, but the most common and popular among them are the following:
- Lead-acid batteries are the most popular for automotive production due to their ease of manufacture and low cost. But further, for use in power tools, they did not show themselves very well, since they have low power with large dimensions and heavy weight.
- Nickel-cadmium batteries are significantly superior to lead-acid cells. After all, they produce great power with light weight and compact size. But, of course, there are also negative aspects, in particular, the toxicity of the battery. Since the production of this kind of battery cells is harmful environment. For example, in the countries of the European Union this type of battery is considered prohibited.
- Nickel-metal hydride cells are considered a more advanced version of the previous type of battery. After all, they are completely safe for the environment. But there is also a drawback in the form high performance self-discharge current.
- Lithium-ion batteries, although they have almost ideal parameters, since they have a high capacity, small size And little weight, are not very popular. This is because such a progressive element has a high cost, and therefore is not affordable for every average person.
Return to contents
What is a screwdriver battery?
Any battery is presented in the form of a small number of batteries, in other words, cans. The latter mostly have standard dimensions. Distinctive feature Such batteries are considered to have a SUB-C capacity.
The battery is characterized by the presence of four main contacts:
- Currents pass through the power contacts, of which there are two units, during the process of charging and discharging the entire battery of the screwdriver.
- At the top there is always a control contact, which is continuously connected to the disconnecting temperature sensor and is used to prevent overheating of the tool during the charging process. since at this moment the device absorbs currents of enormous value.
- The last but not least important contact is called the service contact. It is used to equalize the charge in all banks at the moment of the deepest discharge in the most structurally complex battery cells.
Return to contents
How to calculate a non-working battery cell?
Since the battery is presented in the form of a certain number of cans connected to each other, current completely flows through it. To find a dead battery cell, you must initially fully charge the entire battery until it is clear that charging is complete.
Next, it is recommended to measure the voltage on each individual bank. The voltmeter should not show values lower than 1.2 Volts. If such readings are available, it means that the battery cell is not receiving proper power or is not charging.
Important! In order to verify your measurements, you need to put a mark on the questionable element and reassemble it.
So, after several periods of operation of the instrument, it is necessary to reconnect the banks again and measure the voltage. Practice shows that the previously mentioned can will have even less voltage than before, since it begins to lose its performance and “slow down” the screwdriver.
Return to contents
Stages of the process of replacing the battery in a screwdriver
Considering the fact that in the post-Soviet space the tools most often used are nickel-cadmium battery-type screwdrivers, this option will be considered in more detail using the Bosch GSR 14 4 ve-2 professional screwdriver as an example. In our case it will be done complete replacement elements of individual screwdriver batteries.
- Remove the cover and remove the battery cells in the assembly.
- Unscrew a few bolts on the red upper body.
First, you should disassemble the screwdriver battery. It is as follows:
- Prepare new battery cells.
- Next, you need to apply tin to all cans on one side and thoroughly wipe the soldering areas with distilled water.
- To connect each battery element of the screwdriver, you can use a previously tinned piece of copper foil. In this case, it is necessary to make U-shaped cuts at its edges for further soldering.
- So, attach the foil with a U-shaped cut to the battery contact, to which liquid rosin was previously applied, and solder. After a few simple manipulations, all battery cells will be assembled and ready for replacement.
- Install the assembly into the original screwdriver box. Ready!
Return to contents
Types of restoration of previously used battery cells
A method of reanimating previously used batteries is very often used, since during the operation of a screwdriver, in other words, during constant high loads, some elements lose their tightness and become unusable. In this case, it is necessary to briefly apply a strong current to the required battery cell (cell), and it may be possible to restore the battery’s functionality.
You can also try gently squeezing or slightly deforming the battery housing of the screwdriver. Because this can extend the battery life for a short period of time. But in most cases, this method does not guarantee the battery life of the screwdriver and is temporary.
Nickel-cadmium batteries have significant endurance because they can for a long time do not lose charge or discharge, but very slowly. But in the case when it was not possible to restore their functionality, it is worth carrying out a process such as replacing the batteries in the screwdriver device.
One day, when I took my screwdriver out of the closet, I discovered that it didn’t work. The batteries were dead, the first thing I thought was and put the screwdriver on charge. But as soon as I connected the charger to the battery, it immediately showed the full charge of the battery. I connected a tester to check charging and it turned out that the batteries had high resistance, which meant they were failing.
After browsing the forums, I found out that the problem of failure of nickel-cadmium batteries used in screwdrivers is by no means new, but rather very common. In general, in addition to being cheap, these batteries are a plus for the manufacturer; they have a lot of shortcomings that become apparent during operation. This is small life cycle, and low capacity, and short battery life.
All forum members who are faced with a similar problem without hesitation boldly change nickel-cadmium batteries to lithium-ion ones, which is what I will do as well. They may be more expensive, but the screwdriver will work much longer and more.
Without hesitation, I purchased. Since my screwdriver is 18-volt, and one battery produces 3.7 V, therefore, I needed 5 pieces. 5x3.7=18.5 V is what you need.
I also bought battery compartments, one for two batteries, the other for three. I connected everything in series. I took out the old batteries and replaced them with new ones.
This could be the conclusion, but as it turns out, I made a terrible mistake. The fact is that lithium-ion batteries cannot under any circumstances be charged in the same way as old batteries! This is even dangerous, as they can simply explode.
How then? It's not that complicated - you need a charging controller for lithium-ion batteries.
Lithium-ion batteries are very sensitive to overcharging and being discharged below normal - all these factors quickly damage them. This is perhaps their main disadvantage. But it’s easy to get rid of it by using a controller that will take over all the functions of monitoring and limiting dangerous modes and make the operation of the battery at a high-quality level.
Purchase links:
- or specifically - .
Charging controller connection diagram
The batteries are also connected in series, except that each connection between the batteries is connected to the controller. As a result of this, the controller monitors the condition of each battery and prevents it from overcharging in the circuit.
I put together a diagram. Everything works perfectly.
Check video
Screwdriver battery assembly
Since the controller was added, from battery compartments I had to refuse because there was a catastrophic lack of space. Well, this is for the better, since the screwdriver is subject to vibration, and not tight contact could not have a very good effect in the future...I decided to solder the batteries together. In general, lithium-ion batteries are very afraid of overheating and need to be connected resistance welding. But I don't have it. So I soldered everything with a soldering iron. If you do this, then teach: use only a powerful soldering iron of 40-60 watts. Solder with acid or active flux. And under no circumstances solder one connection for more than a second. If it doesn’t work the first time, it’s better to wait five minutes and try again.
In the end I did this:
I soldered the circuit.
The task at hand is very simple: to make a battery so that it is quite easy to charge it and replace the elements inside using simple manipulations.
First, let's look at the insides of a regular screwdriver battery. Inside most screwdrivers there are many 1.2 Volt “cans” made using Ni-Cd or Ni-MH technology. There are 12 such cans in the screwdriver on top, i.e. the final battery voltage is approximately 12*1.2=14.4 V. The capacity does not exceed 1.5 A/h. The batteries themselves last quite a long time, but among 12 pieces there are often 1-2 that stop working much earlier than their colleagues. It turns out that after some time the battery dies due to a small part of its insides. There is a recipe: replace the jar that does not work, and leave the rest unchanged. But at the same time, these banks are difficult to find and if you change them, then everything is better. Another plus is that it is very difficult to solder them, you need to have welding machine. As a result, I came to the following conclusions:
It is necessary to have a larger battery capacity in order to charge less often
The cans were replaced in a couple of minutes
Don't buy a charger
Implementation
Modern technology batteries that are used everywhere are Lithium (Li-Ion). It is used in phones, laptops, players, flashlights and much more. Affordable solution is an 18650 battery. If you disassemble a regular laptop battery, you can find them there:
These batteries can be bought or taken from an old laptop. If you buy, I recommend “Sanyo 2400 Ma/h red” based on the price/quality ratio. Keep in mind that they must be unprotected. Otherwise, they will turn off when a 2A current occurs, which often happens in a screwdriver. I recently bought a bunch of them on ebay, unfortunately my seller is no longer available, because... I'm not providing a link.
To make it convenient to change them, we will also need a so-called spring holder for 18650:
Many have seen these for regular batteries AA. There are 1-4 batteries. What’s strange is that it’s difficult to find these in a radio store or on the market; it’s easier to order them online on websites with cheap Chinese items by searching for “18650 holder.” The cost of the latter is about $1-2.
The last important thing for a homemade battery is smart charging. I had one close by, I highly recommend “Imax B6” or analogues: 
Now there are two ways to connect:
1) We simply connect all the batteries in series using holders and connect the terminals of the smart charger to the ends. The advantage of this system is its simplicity. Minus: the jars must be the same, otherwise everything may go bad. The fact is that if the voltage on any 18650 bank drops below 3 volts, then it can soon be thrown away. If your batteries are different, then you will not be able to control this nuance. If something happens to one can, you will need to change everything together, otherwise there will be problems.
Any equipment breaks down from time to time. This also happens quite often with screwdrivers. No one will want to pick up an ordinary screwdriver after they have appreciated the advantages of this type of device. Batteries fail most often. Do not rush to throw away a faulty battery. Repairing screwdriver batteries with your own hands is not difficult if you follow the instructions outlined in this article. Before starting work, you need to prepare your tools.
Determining the battery type
To determine the contents of the battery, it is necessary to disassemble its case. The internal components are several batteries connected in series. For the most part, these batteries are integrated, but their disadvantage is the property of intense self-discharge. The battery's charge will deplete if the battery is not used for a period of time. Most of devices are produced precisely according to this principle, despite all the inconveniences.
The creation of nickel-cadmium elements does not require special education, special skills. The cost of hazardous production is reduced due to cheap labor. This helps improve profitability. Production technology harms the environment, the health of workers, creates inconvenience for buyers, but brings profit to entrepreneurs. Essentially, battery cells for repairing a screwdriver are not anything complicated. Anyone can repair them.
Troubleshooting
You will need to determine the location of the electrical circuit break and remove the failed “can.” This can be done using an ohmmeter or tester. The total resistance of the battery is determined and divided by the number of integrated “cans”. A very simple procedure. In this way, the resistance of each battery is calculated. But this matter still has its own nuances. It will not be possible to measure resistance if there is an open circuit.
You will have to check each “can” separately. Readings will vary, but some battery cells will have significantly higher resistance than average. Quite often, “banks” indicate their operating parameters. An example is the battery for a Makita screwdriver.
What to do after identifying a faulty element?
Such markings greatly simplify the work. The indicated value can be compared with the data obtained after the measurement. The “can” will not be suitable for further use if its resistance has sharply deviated from the parameters on the marking. You will need to remove this element from the circuit and replace it with a working one. Such details may not always be at hand.
You can try to find a donor battery for a Makita screwdriver of some other brand, developed using a similar technology. Today this method will not cause problems. Various kinds Batteries constantly fill collection points for used components. It is quite possible to find the necessary battery.
It makes sense to seek help from special workshops. Required item there will definitely be one. Of course, it is financially feasible for the craftsmen at these companies to carry out repairs themselves, but they will not refuse help with finding a new “can.” Many people use this method to repair the battery for the Interskol screwdriver.
Recovery
Li-Ion batteries cannot be restored because they do not have a “memory effect”. Consider a Ni-Cd battery. The compaction method is suitable for its restoration. The battery cells are gently compressed. In this case, slight deformation of the body is allowed. The voltage flashing method makes it possible to get rid of the “memory effect” to restore the nominal capacity of the battery “bank”.
Potential equalization
Restoration allows you to temporarily improve the condition of the battery, and repairing screwdriver batteries with your own hands and replacing components will help to update them. After work on all elements, it is necessary to equalize the potentials. To do this, the battery is fully charged and sits idle for a day. The multimeter reading should be 1.2 V on each bank. Then it is necessary to eliminate the “memory effect”.
The battery is discharged and charged several times. As a preventative procedure to prevent unwanted memory from appearing, this action should be repeated once every three months. This will significantly extend the life of the screwdriver until you decide to purchase a new one.
How to replace the tester?
An ohmmeter or tester may not be included in the existing kit. measuring instruments. An ordinary LED light bulb will help identify a faulty “can.” You need to solder two wires to it. Opposite contacts are connected to the poles of all battery cells. There is no need to solder the entire circuit.
The light bulb will receive its charge from a separate element. A weak link will be detected in the electrical circuit when there is no glow. Repairing screwdriver batteries with your own hands after identifying the faulty element is not difficult. Do not rush to remove it, try to squeeze the “can” from all sides without causing damage to the case.
The cell can last for some more time when the density of the remaining electrolyte increases through squeezing. The “can” will have to be desoldered if the LED does not light up after compression. If there is no time to select and replace components, the screwdriver battery device can be repaired by soldering the contacts in place of the removed part. The tool will lose power, but will work.
Correct use of the device
In order for a 12V battery for a screwdriver to function for a long time and stably, it is necessary to charge it to the maximum once a month, and then completely discharge it during use. We need to develop its energy. Even idling can be effective. Do not overload the tool. Small natural breaks in the operating mode of the screwdriver would be preferable, which is typical for the normal process of operation. The battery is discharged to the maximum and again put on charge.
This procedure should be repeated 2-3 times. The battery is disconnected from the charger after final discharge and should not be connected to the screwdriver during storage.
The life of the power supply will be significantly extended thanks to this basic procedure. Such batteries last a very long time in a discharged state without losing their properties. Naturally, you don’t need to count on the possibility of using these batteries forever because the number of complete discharge and charge cycles is limited.
New technologies
The battery for the Interskol screwdriver is also being developed on the basis of elements with a different chemical composition. Hybrid batteries made of metal and nickel can last much longer than the “barrels” described above. The clear advantage of such batteries is the significant large quantity discharge and charge cycles.
There are still disadvantages
Self-discharge and “memory effect” are absent in such high-quality devices. Inability to operate the battery in low conditions temperature regime, as well as high cost represent two significant shortcomings this type of product. Repairing screwdriver batteries with your own hands can be done according to the scheme indicated at the beginning of the article. It will be necessary to completely replace the entire battery contents if it was damaged as a result of exposure to low temperatures.
In many cases, the battery assembly feature prevents its repair. Some models are quite easy to understand. Removing the battery components will be much more convenient thanks to the design of the case, the elements of which are fastened with screws.
Such models are easy to assemble, so they are easy to repair. Glued cases are much more difficult to disassemble. Preheating the battery parts may make the procedure easier.
Conclusion
Faulty screwdriver battery charging or the battery cells themselves can be repaired very easily. The procedure will not seem too abstruse to anyone. Battery components may be removed.
The non-working batteries of the battery pack can be replaced with new ones after opening the case. The charger also needs to be checked. The method of replacing battery components is only advisable if you have spare ones, because their purchase is often comparable in cost to a new battery.
