How To Solder Batteries For Ni Cd Screwdriver

Choosing a battery How to choose the right cordless tool? What to look for when buying cordless tools? Pros and cons of different types of batteries: NiCd, Ni-MH or Li-ion?

Table of Contents:

2. Nickel Metal Hydride (Ni-MH)

They appeared a little later than the first model and immediately made things easier for people. However, the pluses of the past battery became the minuses of this type. The alloys used, the compositions of the anodes and electrodes play a very important role in the quality and durability of Ni-MH batteries. Therefore, each manufacturer uses a different production technology, depending on the tasks. As a result, it was possible to achieve more capacity with a smaller size and reduce the memory effect.

One of the important achievements was the elimination of the use of toxic cadmium Cd. But the main disadvantages of steel are: heating of the elements, a high degree of discharge during storage, a rather narrow range of operating temperatures, irreversible loss of capacity when discharged to zero, etc.

  • Relative environmental friendliness of Ni-Cd compared to Ni-MH;
  • Reduced the threshold of the memory effect;
  • Increased capacity while reducing weight and volume;
  • Good performance when observing temperature values.
  • Expensive compared to Ni-Cd batteries;
  • Self-discharge is 1.5 times higher than that of nickel-cadmium batteries;
  • Decrease in working capacity after 200-300 charges and discharges;
  • Increased heat generation during charging, therefore additional parts (fuses and temperature switches) are added that do not contribute to reliability;
  • Practical uselessness and inoperability at temperatures below 10C and above 40C;
  • Due to the technological features of Nickel-Metal Hydride batteries, when discharged to zero, an irreversible loss of power of the negative electrode manifests itself.

The conclusion is almost the same as that of nickel-cadmium elements: the need to constantly follow the recommendations for the use and storage of these elements. Agree that you can simply forget to do this.

1. Nickel-cadmium (Ni-Cd)

A model that emerged in the twentieth century and has advantages and disadvantages. They are classified as alkaline batteries. These batteries (accumulators) are in demand today. They found their main application where a constant level of high current output is required: trams, trolleybuses, electric cars, air transport, etc. This is because the Ni-Cd battery delivers stable power and does not overheat. They are also used in various tools: screwdrivers, drills, etc.

A significant limitation in the use of this type of battery is the extreme toxicity of cadmium (it is a heavy metal with increased toxicity). In addition, nickel-cadmium batteries have a pronounced memory effect. That is, when charging an incompletely depleted battery, a new discharge cycle will only be up to the level from which it was charged. Therefore, it is worth charging this type only after a complete discharge. However, storage of Ni-Cd is desirable not in a deep discharge, otherwise it will cause irreversible destruction processes in the battery.

Among the advantages is stable operation even at negative temperatures, fast charge without heat generation, low internal resistance and low specific gravity.

  • Cost. Affordable price of such Ni-Cd batteries;
  • Fast battery charging and stable high power output;
  • Capacity and operating parameters are maintained at temperatures up to 20C;
  • Average sum of charge and discharge cycles. With strict adherence to the rules, possibly up to 1000 cycles;
  • The shelf life is practically unlimited (subject to strict adherence to the rules).
  • High self-discharge level Ni-Cd loses about 8-10% of its capacity in the first day after full charge;
  • Monthly loss of up to 10% of the charge level during storage;
  • It is necessary to apply the recovery technology after long-term storage (at least 5-7 discharge-charge cycles);
  • High toxicity of cadmium;
  • There is a ban in some countries on the use of such batteries and special equipment is required for their disposal.

As we can see, despite the rather impressive advantages, there is one significant drawback: the need for careful monitoring of the battery condition and strict compliance with storage conditions. Otherwise, you simply cannot avoid buying a new one.

Nickel cadmium, nickel metal hydride, lithium ion. Terms that apply to cordless tools. What should you choose?

Technology has stepped forward, creating something new every year, without which a person cannot imagine life. So, many builders and creative people cannot imagine their work without tools that work on a battery, thanks to which the work goes faster and better.

All of these tools are designed on the principle of storing energy from electricity or from a battery, and then releasing energy to make the device work. First of all, the duration of the work will depend on the battery, and secondly on the materials from which the tool manufacturers were made.

There are the following main types of batteries:

Choosing a battery Lithium-ion batteries (Li-Ion)

This is the latest developed battery, which is used, including in the tools of Greenworks and other companies. Having collected all the disadvantages of the previous models, the manufacturers tried to turn them into advantages and they did it. These are no longer alkaline elements and they are actively replacing Ni-Cd and Ni-MH.

First of all, we managed to achieve stable operation in wide temperature ranges, from 20C to 60C, and managed to achieve the most acceptable storage results. Self-discharge per year is only about 10.20% of the total capacity. The safety against internal short circuits has been significantly improved, the charge-discharge characteristics have been improved, etc. Of course, this type of battery also has its drawbacks. Let’s start with them.

  • Of course, this is the cost of Li-Ion. Unfortunately, while it is higher than that of alkaline;
  • Reduced operating time at low temperatures;
  • Storage conditions are not lower than 0C, and ideal conditions are about 40C with half the battery charge level;
  • Limited service life, approximately 2 to 6 years;
  • Special chargers are required, designed for a specific battery, due to the technical features of charging Li-Ion batteries with different currents.
  • Undoubtedly, this is the practical absence of the memory effect. You can recharge your device as needed.
  • Large capacity with low battery weight.
  • Low self-discharge;
  • The ability to quickly charge Li-Ion Li-ion batteries without consequences, provided that special chargers are used that comply with the rules for combined charging with different currents.
  • The weak resistance of lithium-ion batteries to overcharging is solved simply by using a special relay in the chargers, which turns off the battery power when fully charged.
  • High fire safety: a special protection system keeps charge and discharge processes under control.
  • High energy capacity, unlike all other types of batteries.

Lithium-ion batteries are by far the most suitable for continuous and intensive use of cordless tools. Of course, price is the deciding factor in some cases. But in this case, you can apply the proverb Miser pays twice.

How To Solder Batteries For Ni Cd Screwdriver

Summing up, let’s say that before buying a cordless tool, read the information about its capacity, i.E. How long the device will work without recharging, and also pay attention to the voltage with which the tool can work. So, for example, screwdrivers have a range from 3 to 36 V. When purchasing drills, saws, jigsaws, hammer drills or screwdrivers, pay attention to our Greenworks tool, a manufacturer that really creates high-quality tools with a long service life. And in confirmation of this, an extended warranty of 2 years for equipment.

Now in the 21st century, there is a trend towards the development of smart batteries. Greenworks specialists are actively working on this. Already now, Greenworks batteries are embodied: smart charging is a special chip that controls the level and uniformity of the charge of all battery cells, a shutdown circuit when fully charged, a special relay that protects against battery overheating, it is fire and explosion safety, battery cells only from leading manufacturers SAMSUNG or LG , etc.

You ask, what’s next?

We think that personal identification of batteries, condition monitoring and optimization of all processes are not far off, all on the screen of your smartphone!

Another way to measure

It practically repeats the previous one, only in order to discharge the instrument, you will use a 40 W lamp. The advantage of this method is that you do not have to assemble and disassemble the battery several times.

If everything is in order inside, then the problem may lie in the charger, which should already be dealt with.

Also, several methods are proposed for restoring entire blocks:

  • Add the boiled down electrolyte;
  • Eliminate the so-called memory effect.

Adding boiled away electrolyte

The following procedure algorithm will help to cope with this problem, which requires accuracy.

  • Unusable jars, which you have identified with a lamp or multimeter, must be removed by cutting off the connecting plates;
  • Taking a punch (d = 1 mm), make a hole in the body from the side of the “-” sign;
  • Pump out air in a volume that matches the volume of distilled water (0.5-1 cubic cm), which must be poured through the hole;
  • Cover the hole with epoxy and return the element back to the circuit.

After the procedure, before use, it is worth recharging (it will be enough five times) your electric tool.

How to properly disassemble a screwdriver battery

An ordinary battery consists of a case, inside which there is a chain of connected elements, and sometimes also a thermal sensor installed by manufacturers to help you work in critical modes.

Each person who has used this device in his life will not have difficulty working with a screwdriver and opening the case, and then all that remains is to examine the circuit as a whole.

See also  How To Replace The Battery For A 12 Volt Screwdriver

About the features in the repair of nickel-cadmium batteries

Strong overheating is unlikely to have a positive effect on the state of the elements, it is worth watching this. After reflashing old elements, study the rules for distilling a new battery. This action should be carried out once every six months. This can provide maximum battery capacity. Recharging must be done with a preliminary discharge.

We are looking for the weak point of your battery

To determine which part is out of order and can no longer function in the same mode, you will need a multimeter. It is needed to measure voltage. Since this parameter differs slightly on different types of batteries, first find out which one you have. So,

Nickel cadmium and nickel metal hydride batteries have a voltage of 1.2 V, while lithium ion batteries are already 3.6 V.

Next, follow these steps in the sequence below.

  • First. Fully charge your screwdriver battery;
  • Second. Measure the voltage of all cans in turn;
  • Third. Note which of them the voltage is below the norm (in accordance with the fact that the error is allowed only 0.2 V);
  • Fourth, put the battery back in place, turn on and work with the device to discharge it until the power decreases;
  • In the last step, you disassemble the instrument again and measure the voltage with a multimeter. If the deviation is 0.7-0.5. You can safely consider this a malfunction.

Features and rules for charging the battery of screwdrivers

The batteries are made from different materials. This affects the size, weight, the ability to drill at subzero temperatures, voltage, capacity, susceptibility to the memory effect. The latter especially affects the principle of charging a screwdriver.

Charge the battery before storage?

As with the previous point, it depends on the type, whether it makes sense to charge the battery before storage.

For storage, the lithium-ion battery must be removed with a charge of 50%, periodically (1 time / 1-2 months) removed and recharged.

Store discharged.

Maintain charge level at all times, replenish periodically.

Checking the battery condition with a multimeter

It will be helpful to determine the reason why the battery is not charging. The procedure will reveal the health of the batteries. Here are some easy-to-implement methods that you can use at home. Prepare the equipment: in addition to the multimeter, you will need tools for disassembling the battery (pliers, soldering iron, screwdriver, knife.

  1. Check the battery on charging by taking readings at 30 minute intervals. The voltage should rise steadily until fully charged.
  2. A quick method to check the condition of the battery. We measure U with no load. We compare the result with the real voltage and the number of elements. Indicators differ. The battery has non-working parts that need to be replaced.

Storing the screwdriver battery

Free from memory effect: can be recharged at any stage. Do not allow a full discharge to turn off the protective controllers that prevent overloads. As a result, the device may not withstand intensive use and fail.

Before storage, the battery is discharged almost completely (to the state of an inoperative tool). To put the device away for long-term storage (more than 6 months), perform 3 to 5 full charge-discharge courses.

Than other types are subject to rapid self-discharge. After a long storage period, you need to put the battery on the charger for at least a day to replenish the energy reserves. A decrease in capacity is noted after 300 charge-discharge cycles.

How to properly charge the battery for a screwdriver?

The cordless tool is convenient in nature, in places where there is no stable permanent access to power supply. The absence of a cable allows you to avoid the inconvenience with extension cords, fear of overloading the network, entanglement with wires, inability to crawl to hard-to-reach areas.

The operation of the cordless tool has its own characteristics. How to properly charge the battery without damaging it? What are they made of, how do they differ? Answers in the article.

How long does it take to charge the screwdriver battery?

Before charging a cordless drill or screwdriver, you need to determine how long this procedure will take. The period is prescribed in the instructions attached to the instrument. Some models have a light indication that will show when the device is fully charged. After charging is complete, immediately disconnect the battery from the charger.

Typical charging times range from half an hour to 7 hours, depending on the type of battery and charger. Nickel-cadmium are fed with energy for the longest time, 3-7 hours.

How to solder batteries for the ni cd screwdriver

To begin with, there is a lot on the Internet for recovering batteries from screwdrivers, and they are all the same as a mirror, a brief description of the recovery process that these people offer is that we take the battery, push it with a power supply unit or another battery, then charge and use , and it’s strange that someone doesn’t look, but what kind of stress will he have when he’s lying down for a week or two. I offer a completely different way to restore

Which does not just charge and use until the battery dies again. And one that you did and use as a new battery until the need arises. This method was filmed in draft about a month ago, but I never dared to post it on the site, I just didn’t want to reshoot it for a more correct explanation. And frankly speaking, I have very little free time lately.

But now the time has passed which has shown that the recovery option that many people on the network offer to use are not destined to live for more than a certain period of time. And my version, even after 2-1 month of inactivity, as if nothing had happened quietly works and charges, I still tried to shoot a new video, where in the brink I will try to tell everything.

In fact, everything turned out to be very simple, and the NI-CAD 1.2V battery I disassembled helped me in this, which showed me that even with all the zeros on the outside of the device, inside the patient is rather alive than dead and feels very good.

An attempt to regenerate the bus relative to the collector plate was made using distilled water, and the process was quite successful, as a result of which I came up with the easiest way to restore them even without disassembling the batteries!

It is enough to drill a hole in the battery in the place behind the rollers, and pour 20.40 ml of distilled water there. After a couple of cycles, the hole is slightly covered with silicone.

Before repeating, I recommend looking at where I tried to describe the process in more detail.

If you are not sure or afraid of ruining a damaged battery, for example, you can do this with one battery.

If your batteries have voltage and are in the operating range, then you may have a problem with the following:

Defective charger

The thermal protection of the battery pack has tripped

There is one battery in the battery pack that has been drained to 0 volts.

Also, if you notice that the drill began to work somehow sluggishly and at the same time it works as long in time after charging, then you probably have a problem with one or more batteries that are at zero!

A very interesting effect on the battery capacity, it was equal to or slightly more than the indicated battery capacity after restoration by this method.

  1. Screwdriver battery: design and types
  2. Fault definition
  3. Is it possible to reanimate the elements and how?
  4. Repair and replacement of screwdriver battery cells


The cost of a new screwdriver is approximately 70% of the cost of the battery for it. Therefore, it is not surprising when, faced with a battery failure, we ask ourselves what next? To buy a new battery or screwdriver, or maybe it is possible to repair the screwdriver battery with your own hands and continue working with an already familiar tool?

In this article, which we will conventionally 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).

Is it possible to reanimate the elements and how?

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 helped, we find a replacement and change;
  • 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 good, the problem is in other elements, or in the control circuit.

Screwdriver battery refurbishment is available primarily for Ni-Cd batteries, but these are generally the most common in household screwdrivers.

So how do you reanimate a screwdriver battery? There are two types of resuscitation for these types of batteries:

  1. Compaction or compression method (it will work in cases where the electrolyte is still present, but the volume is lost);
  2. Firmware with voltage and current greater than nominal. This method allows you to eliminate the memory effect, and although not completely, but to restore the lost capacity.

This method is shown below on.

This method, if its result is positive, will not solve the problem of element failure. Rather, it will only delay the replacement of those that have become unusable and in the future you will still need to repair the battery of the Makita screwdriver or any other.

Screwdriver battery: design and types

It should be noted that regardless of the brand of the screwdriver and the country of manufacture, 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.

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 (pictured below).

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

  • Nickel cadmium (Ni Cd) batteries, with a nominal voltage of 1.2V on the banks;
  • 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 maintaining 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 they do not last long with intensive use.
  • Environmentally friendly production, it is possible to purchase a high-quality branded battery;
  • Low memory effect;
  • Low self-discharge;
  • High capacity compared to Ni Cd;
  • Charge / discharge cycles.
  • Price;
  • Loses some of its characteristics during long-term storage in a discharged state;
  • Does not live long 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, fewer 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 battery pack. Disassembling the unit, for example, to repair the battery of a Hitachi screwdriver (shown below), is very simple, we unscrew the screws around the perimeter and disconnect the case.

The housing has four contacts:

  • Two power, 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 charging current when a certain temperature of the cells is exceeded (usually in the range of 50-60C). 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 how to parse a block.

Fault definition

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. We note right away that all the elements cannot fail at once, and since our circuit is sequential, when one element fails, the whole circuit does not work. So, our task is to determine where we have the weakest link in the chain.

To do 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:

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 an easier method. We disassemble a fully charged battery to the contacts and. We connect a 12 volt lamp. 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. In view of the rarity, we will not focus on the battery elements.

We figured out the problematic elements, they need to be repaired. How to repair a screwdriver battery? In general, there are 2 methods available for repair, so to speak. This is the restoration and replacement of elements that have become unusable.

Repair and replacement of screwdriver battery cells

A more effective way to repair batteries for a screwdriver is to replace elements that we have identified as faulty.

We also need a soldering iron, a low-corrosion flux (preferably an alcohol flux for rosin) and tin. We do not talk about spot welding, since for a one-time battery repair there is hardly a need to purchase or assemble it

There is nothing complicated in the replacement itself, especially if at least some. Then there is experience in soldering. On the graphs, everything is shown in sufficient detail, we cut off the faulty element, instead of it we solder a new one.

Several nuances should be noted:

  • When soldering with a soldering iron, try to solder quickly, so that the battery does not heat up, because risk ruining it;
  • If possible, implement the connection using native plates, or use the same copper plates, this is important because the charging currents are large and if the section of the connecting wires is incorrect, they will heat up, respectively, the thermistor protection will work;
  • In no case do not confuse the plus of the battery with the minus of the serial connection, which means that the minus of the previous can goes to the plus of the new can, and the minus of the new one. Plus the next one.

After the new elements have been soldered, it is necessary to equalize the potentials on the banks, since they are different. We carry out a charge / discharge cycle: we set it to charge overnight, give it a day to cool and measure the voltage on the elements. If we did everything correctly, the picture will be something like this: on all elements the same indicator of the multimeter, within 1.3V.

Next, we proceed to discharge the battery, insert the battery into the screwdriver and load it in full. The main thing is to spare the screwdriver itself, otherwise you will have to repair it too. We bring it to full discharge. We repeat this procedure two more times, i.E. Charge and discharge completely.

It should be noted that the procedure for erasing the memory effect should be carried out every three months. It is carried out by analogy with the above-described training.

Such a not very tricky procedure will prolong the work of your screwdriver, at least until you have to replace it with a new one.

Converting a screwdriver battery from Ni-Cd to Li-ion using a BMS protection board

Price: 3.50

Hello everyone, today I want to tell you about my next alteration of a home tool, without which any repair cannot do. This time I decided to remake my old, well-working Chinese Tandem screwdriver. It all started when the native Ni-Cd batteries stopped not only holding a charge, but also being charged. It is not profitable to buy a new battery, it costs as much as a new inexpensive screwdriver with two Ni-Cd batteries. After reading a little information on the Internet, it was decided to convert it to li-ion 18650 batteries, which have proven themselves well.

Having disassembled the Ni-Cd battery and throwing out the old batteries, leaving only a block with contacts for connecting to the screwdriver itself, I placed the batteries in the case. For ease of installation and ease of use, AB decided to install it in special slots. They can be easily inserted and also easily removed for charging in another charger if the family will not charge them. Also, these batteries can be used in another device.

After finishing the assembly, I started the screwdriver, worked with it a little and even tried to charge the AB with my own charger, in which there is no charge level control. After that, I had a question, how to control the state of the AB? To do this, I installed a small voltmeter and a shutdown button, which were also bought at Aliexpress. On a voltmeter, it was possible to see the battery voltage and, at the right time, set or remove from charging. And if you are not too lazy to unscrew the screws, then you can calibrate the capacity on the charger.

But, as I said above, the current consumption under heavy load is very large, and the contacts and wires in the slots are very thin and flimsy, the Chinese do not provide soldering, everything is done on crimping. They were the first to not stand it and began to retreat and break off, the constant pulling out of the elements was not very convenient and not practical. Attempts to replace wires and strengthen contacts were in vain. After much torment, I decided to solder the battery with wires and discard the slots.

Also, to monitor the state of each element separately (charge and discharge voltages), I bought a BMS board for 5 AB on Ali with a voltage of 21V and a current of 100A. You will not be able to do without it if you go to get a high-quality battery, and the price of the issue is not too high for such a rework. It can charge and discharge the cells separately and monitor the voltage and current. The dimensions of this board are such that they can be placed almost anywhere. The boards are available for a different number of elements. Having soldered everything together and packed the batteries into the case with hot melt glue, everything worked out for me. The weight and charging time of the battery have decreased significantly, while the operating time has increased.

The board practically does not heat up. A couple of days later, one more revision had to be made, since the button could not withstand the working current of the screwdriver and burned out. It was replaced with a new one and a 12V, 40A automotive relay was added. The relay allowed to unload the power button, but added temperature. As it turned out, it heats up quite a lot with a long operating time.

In the end, I want to say that the most important part of my rework is the BMS board. You cannot do without it, since it is impossible to control the charge and discharge of li-ion batteries in another way. And overcharging and overheating of the battery is very dangerous and can lead to a fire.

The device and repair of Ni─Cd batteries for a screwdriver The main problem of using nickel-cadmium batteries

During the operation of cadmium batteries, the voltage begins to decrease, the discharge capacity decreases significantly. These processes arise due to several factors:

  • The area of ​​the working contact of the electrodes is reduced.
  • The size of the active mass decreases. It begins to redistribute over the surface of the electrodes.
  • Current leakage occurs.
  • A chemical reaction begins causing high oxygen consumption.
  • The volume of the electrolyte changes, changes in its composition occur.
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When using a cadmium battery for a screwdriver, the mechanical strength changes, the volume of the positive electrode decreases. This process worsens the contact of the electrode with the active mass. A drop in conductivity occurs, and the capacity of the nickel-cadmium battery decreases. If this process is not stopped in time, the contact between the working electrodes will disappear. The product will be damaged.

Such changes in lithium ni cd screwdriver batteries occur due to overcharging, which causes a strong release of oxygen. The cadmium electrode begins to deteriorate due to changes in active mass. Its volume is gradually decreasing. It clogs the pores on the surface of the negative electrode. As a result, it becomes more difficult for the electrolyte to get into the deep layers.

In addition, the composition of the electrolyte begins to change. An increase in the volume of carbonates becomes noticeable. As a result, the electrolyte loses its electrical conductivity, all the characteristics of the nickel battery for a screwdriver deteriorate. Especially at sub-zero temperatures. To correct the situation, you should try to restore the cd battery of the screwdriver.

Common way to recover ni cd batteries

The installation of a new battery in the screw gun usually occurs only if attempts to restore its performance have not yielded a positive result. A popular method for recovering cadmium batteries for a screwdriver is to apply high current in small pulses. This happens very quickly, approximately 13 seconds. Over, the current value must be 1020 times higher than the product capacity.

This regenerative technology has been tested on roll-type machines. This cd screwdriver battery recovery technology can be applied to any type of battery, even leaking ones. Of course, the older the battery, the more difficult it is to recover. For work, you need to prepare in advance:

  • Working battery with high current. A car battery will do.
  • Wire, cross section 1.5 sq. Mm.
  • Crocodiles.
  • Voltage monitoring device (multimeter).
  • Protective equipment (glasses, gloves).

The technological process of repairing cadmium batteries takes place in a specific sequence:

  • The poles of the restored product are determined (positive and negative contact).
  • The minuses are connected with a piece of cable. To enhance contact, crocodiles are installed at the junction.
  • A second piece of wire is connected to the positive contact.
  • When all cables are securely fixed, the free end must quickly touch the positive contact. It is very important that the touch is fast and does not take much time (13 seconds).
  • The operation takes approximately 34 seconds. Over, the wire must not be allowed to weld at the point of contact.
  • When one cycle of touches is completed, the voltage is checked. In its absence, the cycle repeats. After the appearance of voltage, the nickel battery is put on full charge to obtain the maximum capacity value.

Improved remanufacturing technology for screwdriver nickel batteries

When analyzing the battery banks, the author of this technique noticed that there was a gap between the positive contact and the negative case. Degradation of the electrolyte became the cause of the break. In other words, during the operation of the battery, an oxidation reaction begins, during which a lot of water is consumed. A decrease in its volume causes changes in the composition of the electrolyte, which leads to a drop in its operating parameters.

After a detailed study of this process, it was proposed to perform several operations to restore the cadmium battery of a screwdriver:

  • Before starting to apply a pulse current and then charge the battery, it is necessary to select all parts with zero voltage.
  • Then, in the body of each part, make a hole with a micro drill with a thin drill.
  • Distilled water (1 cc) is taken and pumped into the hole.
  • The battery should remain at rest after this procedure for about one hour. Then the voltage is measured. Usually, the impulse current raises the zero voltage.
  • After that, all the cells are fully charged.
  • A charged battery does not need to be touched for several days. Then check the voltage.
  • If all elements show signs of life, the holes can be sealed or sealed with sealant.
  • The battery is collected, put on charge.
  • In the case of zero voltage, distilled water is added. The whole process is repeated until a positive result is obtained.


Today, a large number of methods are known for self-repairing a screwdriver battery. To carry out such technological operations, it is necessary to take into account certain nuances associated with the technique, its advantages and disadvantages. The achievement of the desired result depends on this.

Design and types of batteries for screwdrivers

Almost all manufacturers in all countries of the world produce batteries for screwdrivers that are identical in design and principle of operation. Many manufacturers produce batteries for several manufacturers of screwdrivers at once. The rechargeable battery is removable and looks like this.

Battery for Bosch PSR 14.4 V screwdriver

In our case, this is a battery for a Bosch PSR screwdriver of 14.4 V. In it, one self-tapping screw was initially covered with plastic. Opening will void the warranty.

Battery assembly

The most commonly used Ni-Cd screwdriver batteries, but there are other varieties. Below are the types of elements used in screwdriver batteries:

  • Ni─Cd. Nickel-cadmium batteries. The nominal voltage of one element is 1.2 volts;
  • Ni─MH. Nickel metal hydride. The nominal voltage of one element is 1.2 volts;
  • Li─Ion. Lithium Ion. Rated voltage 3.6 volts.

Device, design and repair of Ni─Cd batteries for screwdriver

Today on sale you can find many models of screwdrivers from both well-known world brands and companies unknown to anyone. There are unpretentious models, as well as functional ones with rich equipment. One thing unites them all they have batteries for autonomous operation. And often the cost of these batteries is more than half the price of the screwdriver itself. Most often, nickel-metal hydride or nickel-cadmium batteries are used as elements of such batteries. In some cases, they can be restored and the screwdriver battery repaired. In this article, we will analyze how this is done.

Varieties of elements for the battery of the screwdriver

Nickel cadmium batteries for screwdrivers are the most common today. They have an affordable price, remain operational at low temperatures, and can be stored in a discharged state without losing their characteristics.

Nickel-metal hydride batteries are less common than nickel-cadmium batteries for screwdrivers. Their advantages include the absence of toxic components, environmentally friendly production, insignificant memory effect and lower self-discharge than nickel-cadmium batteries. In addition, when compared with Ni-Cd rechargeable batteries, nickel-metal hydride batteries have a large capacity and withstand a greater number of charge-discharge cycles. Additionally, we advise you to read about how to charge Ni─MH batteries.

The disadvantages include high cost, sensitivity to negative temperatures. In addition, Ni─MH batteries lose some of their performance when stored in a discharged state.

Battery malfunctions for screwdrivers

As a rule, if the Ni─Cd battery for a screwdriver fails, one or more battery cells fail. Therefore, the primary task when repairing a screwdriver battery is to identify the failed elements.

Total voltage of series assembly

Single cell voltage

  • Fully charge the screwdriver battery;
  • Disassemble the case;
  • Measure the voltages of all elements and mark those with a voltage below the nominal. The rated voltage is printed on the body of each can. They are usually wrapped in a paper wrapper;
  • Then apply a load to the battery (turn on the screwdriver). If you don’t want to assemble again, then connect a load in the form of a 12 volt light bulb to the terminals of the garland;
  • After a while, measure the voltage on the elements again. Those banks in which the voltage differs from the average by 0.5-0.7 volts must be restored or replaced. During visual inspection, special attention should be paid to cans with traces of corrosion and smudges.

Discharging the battery of the screwdriver with a lamp

Then work is underway with elements that are diagnosed as faulty. On this below. And here it is also worth mentioning such malfunctions as a violation of soldering at the junctions of elements, a failure of a temperature sensor, etc. But these types of breakdowns are very rare and do not deserve attention.

Recovery and repair of Ni─MH, Ni─Cd batteries

As far as lithium batteries are concerned, they cannot be restored. During operation, lithium decomposes in them and after 2-3 years there will be nothing to restore. In this case, you just need to replace the failed elements.

But on Ni-MH and Ni-Cd batteries, you can still work. In short, the recovery technique for this type of storage battery is reduced to passing current through them in short pulses. The current must be ten times higher than the capacity of the Ni─Cd cell. This destroys the dendrites and restarts the battery. Further, it is trained in the form of several charge-discharge cycles.

However, the above method often does not help, and after a while the batteries refuse to work again. The problem lies in the fact that during operation in Ni-Cd batteries the volume of electrolyte decreases. Therefore, the method is used by adding distilled water to the inside of the element. Read more in a separate article Ni─Cd batteries recovery and repair.
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Lithium ion batteries are less common in screwdrivers. Among the advantages, it is worth noting the lack of memory effect and self-discharge. The capacity of lithium-ion batteries is higher and the number of charge-discharge cycles is several times greater than that of oxide-nickel batteries. In addition, the cell has a higher rated voltage. Therefore, fewer cells are required, which means that such batteries have less weight and dimensions.

Among the disadvantages should be noted the high cost. When compared with Ni─Cd batteries for a screwdriver, the price of Li─Ion is almost three times higher. It should be noted that after 2-3 years of intensive use of Li─Ion, the battery significantly loses its capacity due to the decomposition of lithium.
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