Convert The Screwdriver Battery To 18v Lithium

How to assemble one battery from two

It so happens that the best way out of the situation when both batteries are “hooked” is a way to assemble one full battery of two. Using any of the proposed methods, you can disassemble both blocks in order to understand which elements are suitable for further use, and which should be discarded.

For this you will need:

  • Two batteries,
  • Charger,
  • Any thin and flat screwdriver,
  • Scalpel,
  • A piece of sandpaper,
  • Two wires,
  • Load resistance (two are possible),
  • Voltmeter for voltage measurements.

We disassemble the battery with a spatula or a stationery knife

For those who are not used to working as a mallet and want to make the battery disassembly process look quieter and more gentle, you can suggest using a small metal spatula or a utility knife. The main thing is that they do not have sharp edges, like a large screwdriver, which can easily damage plastic.

First, you should completely walk with a knife around the perimeter of the entire block to loosen the seam, and only after that you can begin to “pick” the flexible plastic with a small screwdriver. The method is no less painstaking than the first, and if the person is not experienced enough, damage may remain on the plastic case. However, if you work as carefully as possible, it is possible to do without “losses” in this case.

Charging the batteries

Before disassembling the blocks, be sure to charge them well. With subsequent voltage measurements, this is exactly what will make it possible to understand which batteries are “live” and which are not. Before charging the batteries, it is recommended to clean the internal contacts of the charger with emery paper, because any contact resistance can “give out” an incorrect charging process.

Convert The Screwdriver Battery To 18v Lithium

When you charge both batteries alternately, pay attention to how fast they charge. If the battery is charged quickly, and the charge indicator signals the end of the process after just a few minutes, this means that there are definitely faulty cells in the battery. And of course, when the battery charges too slowly, or does not take any current at all, it should definitely be disassembled and “tested” all the batteries that are inside. Read more about the charging time of the screwdriver battery →

After you charge and disassemble your battery pack, you will see that there are several elements inside it. cans. The number may vary, depending on the voltage level of your instrument. Banks are connected in a certain series. Inside there is a thermal sensor brought out to the contact plates.

How to disassemble and remake a battery from a screwdriver with your own hands

Everyone knows that the battery of a screwdriver sooner or later begins to lose its former performance and needs to be replaced. Usually only a couple of elements in a common bundle “sit down”, but this negatively affects the entire battery. Therefore, it becomes necessary to either replace several elements with new ones, or still change the battery pack completely. Since the complete set of any screwdriver. “Hitachi”, “Makita” and other models. includes two batteries, if you wish, you can try to assemble a whole homemade battery from two. The owners of power tools who use them constantly, sooner or later begin to wonder how to convert the battery of a screwdriver to lithium. As for the newcomers who were first puzzled by this goal, they first of all have a question about how to disassemble the battery from the Makita screwdriver or any other, so as not to damage the fragile plastic box.

Experienced electronics enthusiasts assemble different types of batteries, including power supplies for an uninterruptible power supply (UPS). This is much more difficult than disassembling an electric drill battery. Any drill is often produced with so-called “non-separable” battery packs, which are either firmly sealed with tape around the perimeter, or their two parts fit so tightly to each other that, at first glance, it is impossible to disconnect them without causing forced external damage. However, among folk craftsmen you can also find people who have already thoroughly “got their hands on” with such batteries and can happily share secrets with everyone.

We solder banks

Soldering should be done by spot welding using a regular aspirin tablet. It is impossible to solder one element directly to another: any heating causes evaporation of the electrolyte and a rise in temperature, which can be critical for the battery.

When disassembling the bundle and soldering, it is important not to lose metal particles, which may be indispensable when soldering the elements together. To be on the safe side, you can take care of how to make blanks of spare plates from bending metal in advance. It is important to remember the following: the better I solder, the better the battery will work.

Aspirin gives off many corrosive fumes, so work in a well-ventilated area. A soft fusible composition with flowing properties is taken as a solder. The solder is sprinkled with aspirin powder, so it flows between the plates and connects them securely, and aspirin helps fix the composition in the right place.

The assembled battery is installed in the case, and the operation of the screwdriver is checked. If the tool is running, the newly assembled battery is charged as usual and its functionality is checked again. If there is no drop in revolutions of the instrument, this means that the experiment was successful. Since nickel-cadmium batteries work for a long time with proper operation, there is a chance that a new bundle assembled with your own hands will not let you down, and a self-made screwdriver battery will work properly.

What is the load for?

Let’s work with the load resistance. As already mentioned, you can take two, each with a nominal value of 1 ohm. If we put both of them in parallel, then the total resistance we get 0.5 Ohm. It is not necessary to adhere to these ratings, but the lower the resistance, the better.

What is the role of load resistors in qualitatively replacing the battery pack? If we take any electrical appliance and measure the voltage in its battery, we get a certain value. However, this value does not show how well a particular battery can give its energy. If we measure the voltage under load, we will have what is called “voltage drop”. It is just from it that you can judge how good or bad the battery is.

The load resistance in the form of two small metal blanks and wires, connected in parallel to each other, is carefully connected to a voltmeter. This loading method is acceptable only if the output voltage of your battery is 12 volts or less (safe voltage level).

The wires are neatly fixed in the “sockets” of the voltmeter with probes, and the DC voltage threshold of 20 volts is set on the voltmeter. This indicator is quite enough to measure U for the entire bunch of elements as a whole and for each element separately, which is especially important.

How to disassemble a battery using a regular mallet

In order to disassemble the battery from a Bosch screwdriver, Metabo or any other tool of 12 volts or more, you need to make some effort. If you just rip open the adjacent edges of the battery pack with a screwdriver, it will be messy. In addition, there is a greater risk that the fragile plastic structure will simply break.

Therefore, it is recommended to take a mallet and begin to slowly tap on the edge of the seam until characteristic sounds appear, meaning that the seam itself begins to weaken on the sly. It will take a long time to knock, and it will take time and patience. But it is in this way that you can ensure that the disassembly of the battery from the Makita screwdriver will be crowned with success, without unnecessary breakdowns and losses.

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After a while, you will hear a crack of a breaking seam. The batteries themselves inside from such manipulations will not be damaged. Only the seam holding the block will break, and the “cans” and the two halves of the plastic case will remain unharmed.

When we disassemble the unit, knock the body with a mallet lightly, without applying any special efforts, so that it bounces slightly off the surface. From time to time, between tapping, you can try to slowly pull back the bottom cover of the block, thereby checking how much the seam has loosened. In such cases, the mallet itself will be slightly damaged, but there is nothing wrong with that.

It should be warned right away that the battery packs of the 12-volt Makita screwdriver are often extremely sturdy and difficult to disassemble. But if you slowly work with a mallet, the seam on the glue will gradually crumble. This may take ten minutes or more in time. But for a person with experience, the whole process takes no more than six minutes.

This is how, gradually and accurately, you can disassemble the screwdriver battery, which the manufacturer intentionally made “non-removable”. with the aim not to change the batteries in it, but immediately run after a new one, which is expensive. Of course, this will require a certain skill and accuracy. But it will also save money, and at the same time learn how to disassemble the battery from the Makita screwdriver with your own hands.

We measure the voltage

Before measuring the cell voltage, prepare a simple pencil with which you will write down the U value given by each battery in a bundle. Since in most cases “running” screwdrivers are equipped with nickel-cadmium batteries packed in dense cardboard layers, it is important to ensure that the batteries are accessible from both sides.

Now it remains to turn on the voltmeter (or multimeter) and start measuring. When measuring, we make each battery an exposure for five seconds and see if the voltage drops (usually it is normally about 1.2 volts for each battery separately). We fix the indicators with a pencil. It is impossible to keep the probes on batteries for a long time, because the resistance increases, and they can simply burn out.

Practice shows that if only one element of the entire bundle fails, this negatively affects the operation of all batteries. If the voltage indicator on any “bank” is 1 volt or less, it has already exhausted its resource. In order to finally make sure of this, you should check the self-discharge level of each battery in the bundle.

After the unusable elements are “calculated”, we disconnect them from the rest with a scalpel, and in their place we put usable batteries from a spare battery. So we redo the whole block, collecting one full-fledged from two.

A little about how to convert a battery from cadmium to lithium and who needs it

Let’s talk about how to convert the battery yourself from one type of battery to another. There are many on the Internet on this topic, where a lot is said about what advantages there are if it is lithium in the screwdriver. However, if you do not use the tool intensively and constantly, there is absolutely no point in a lithium battery. Lithium-ion batteries tend to “age” more quickly than cadmium, and simply do not have time to develop their resource under conditions if the tool is used from time to time.

Alteration of a screwdriver battery using lithium batteries may be necessary for professional craftsmen who use the tool on a daily basis and need powerful power sources. Of course, with a strong desire, you can re-solder the battery to lithium, but whether it is advisable is up to you. Read more about which batteries are best for a screwdriver →

Thus, you can not only disassemble the battery of any screwdriver, but also solder one of two bundles, which will last as long as possible, and you do not have to buy a new battery in the near future.

The work of a converted battery, provided that the cells are correctly soldered, will be no worse. The main thing is to treat the process with patience and maximum care, so that at the first experience, you will finish the job with minimal losses and solder everything correctly. If you manage to collect everything, this will become an additional incentive to continue your experiments in the field of electronics. Assemble the battery yourself once. and you can save money on buying new batteries for the screwdriver in the future.

How to remake and assemble?

Often, the master already has an old cordless screwdriver that suits him completely. But the device is equipped with outdated nickel-cadmium batteries. Since the battery will still have to be changed, there is a desire to replace the old battery with something newer. This will not only provide more comfortable work, but also eliminate the need to look for batteries of an outdated model on the market.

The simplest thing that comes to mind is to assemble a power supply from an electronic transformer in an old battery case. Now you can use the screwdriver by connecting it to the household power supply.

14.4 volt models can be connected to car batteries. Having assembled an extension adapter with terminals or a cigarette lighter plug from the body of an old battery, you get an indispensable device for a garage or work “in the field”.

If we convert an old battery to lithium, we can take into account that 18650 lithium cells are extremely widespread in the market. Thus, we can make screwdriver batteries based on readily available parts. over, the prevalence of the 18650 standard allows you to choose batteries from any manufacturer.

It will not be difficult to open the case of an old battery and remove the old filling from it. It is important not to forget to mark the contact on the case to which the “plus” of the old battery assembly was previously connected.

Depending on the voltage for which the old battery was designed, it is necessary to select the number of lithium cells connected in series. The standard voltage of a lithium cell is exactly three times that of a nickel cell (3.6 V instead of 1.2 V). Thus, each “lithium” replaces three series-connected “nickels”.

By providing for the design of the battery, in which three lithium cells are connected one after another, it is possible to obtain a battery with a voltage of 10.8 volts. Among nickel batteries, these are found, but not often. When four lithium cells are connected to a garland, we already get 14.4 volts. This will replace both 12 volt and 14.4 volt nickel batteries. these are very common standards for nickel cadmium and nickel metal hydride batteries. It all depends on the specific model of the screwdriver.

After it was possible to determine the number of successive stages, it will probably become clear that there is still free space in the old building. This will allow two cells to be connected in parallel in each stage, which will double the battery capacity. To connect lithium batteries to each other in production, a nickel strip is used. Segments of tape are connected to each other and to lithium elements by resistance welding. But in everyday life, soldering is quite acceptable.

Soldering lithium cells should be done with great care. The joint must be thoroughly cleaned beforehand and a good flux must be applied. Tinning is done very quickly, with a well-heated soldering iron of sufficiently high power.

The soldering itself is done by quickly and confidently heating the place where the wire is connected to the lithium cell. To avoid dangerous overheating of the element, the soldering time should not exceed three to five seconds.

It is good that now there are ready-made electronic control and balancing modules on sale at fairly low prices. It is enough to choose the solution that suits your particular case. Basically, these controllers differ in the number of series-connected “steps”, the voltage between which is subject to equalization (balancing). In addition, they differ in their permissible load current and temperature control method.

In any case, it is no longer possible to charge a homemade lithium battery with an old nickel battery charger. They have fundamentally different charging algorithms and control voltages. You will need a dedicated charger.

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Difference from nickel cadmium batteries

Historically, the first truly mass-produced rechargeable batteries for handheld power tools were nickel-cadmium batteries. At a low price, they are quite capable of relatively large loads and have a satisfactory electrical capacity with reasonable dimensions and weight. Batteries of this type are still widespread today, especially in the inexpensive sector of handheld power tools.

The main difference between lithium batteries and nickel-cadmium batteries is low weight with high electrical capacity and very good load capacity.

In addition, a very important difference between lithium batteries is the significantly shorter charging time. This battery can be charged in a couple of hours. But the full charge cycle of nickel-cadmium batteries takes at least twelve hours.

There is another peculiarity associated with this: while lithium batteries can easily tolerate both storage and operation in an incompletely charged state, nickel-cadmium batteries have an extremely unpleasant “memory effect”. In practice, this means that in order to extend the service life, as well as to prevent a rapid loss of capacity, it is advisable to use nickel-cadmium batteries until they are completely discharged. After that, be sure to charge to full capacity, which takes a considerable time.

Lithium batteries do not have this disadvantage.

How to charge properly?

Lithium batteries are quite finicky about charger specifications. Such batteries can be charged quite quickly with significant current, but excessive charging current leads to severe heating and fire hazard.

It should also be borne in mind that when cells are connected in series in a battery, lithium sources are very prone to uneven charging of individual cells. This leads to the fact that it is not possible to charge the battery to full capacity, and the element, which regularly works in the undercharged mode, simply wears out faster. Therefore, chargers are usually built according to the “charge balancer” scheme.

Fortunately, all modern factory-made lithium batteries (except for outright fakes) have built-in protection and balancing circuits. However, the charger for such batteries must be specialized.


The device of a lithium rechargeable battery is not too different from the design of batteries based on other chemistry. But the fundamental feature is the use of anhydrous electrolyte, which prevents the release of free hydrogen during operation. This was a significant disadvantage of the batteries of the previous designs and led to a high probability of fire.

The anode is made of a film of cobalt oxide deposited on an aluminum base-current collector. The cathode is the electrolyte itself, containing lithium salts in liquid form. The electrolyte impregnates a porous mass of electrically conductive chemically neutral material. Loose graphite or coke is suitable for it. Current collection is carried out from a copper plate superimposed on the back of the cathode.

For normal battery operation, the porous cathode must be pressed tightly enough to the anode. Therefore, in the design of lithium batteries, there is always a spring that compresses the “sandwich” from the anode, cathode and negative current collector. The ingress of ambient air can upset the carefully balanced chemical balance. And the ingress of moisture and does threaten the danger of fire and even explosion. Therefore, the finished battery cell must be carefully sealed.

A flat battery is simpler in design. All other things being equal, a flat lithium battery will be lighter, much more compact, and will provide significant current (that is, more power). But it is necessary to design a device with flat-shaped lithium batteries, which means that the battery will have a narrow, specialized application. Such batteries are more expensive than their counterparts.

To make the sales market wider, manufacturers produce battery cells with universal shapes and standard sizes.

Among lithium batteries, the 18650 version actually dominates today. Such batteries have a look similar to the cylindrical finger-type batteries familiar in everyday life. But the 18650 standard specifically provides for somewhat larger dimensions. This avoids confusion and prevents such a power supply unit from being mistakenly replaced in place of a conventional saline battery. But this would be very dangerous, since the lithium battery has two and a half times the standard voltage (3.6 volts versus 1.5 volts for a salt battery).

For an electric screwdriver, lithium cells are sequentially collected into a battery. This allows the voltage to the motor to be increased to provide the power and torque required by the tool.

The rechargeable battery necessarily contains in its design temperature sensors and a specialized electronic device. a controller.

This circuit:

  • Monitors the uniformity of the charge of individual elements;
  • Controls the charge current;
  • Prevents over-discharge of cells;
  • Prevents battery overheating.

Batteries of the described type are called ionic. There are also lithium-polymer cells, this is a modification of lithium-ion. Their design is fundamentally different only in the material and design of the electrolyte.

How to choose?

When it comes to choosing a battery for a screwdriver, the task comes down to the selection of the electrical device itself, which will include a battery of a specific model.

The rating of inexpensive cordless screwdrivers this season looks like this:

  • Makita HP331DZ, 10.8 volts, 1.5 Ah, lithium;
  • Bosch PSR 1080 LI, 10.8 volts, 1.5 Ah, lithium;
  • Bort BAB-12-P, 12 volt, 1.3 Ah, nickel;
  • Interskol DA-12ER-01, 12 volts 1.3 Ah, nickel;
  • Kolner KCD 12M, 12 volt, 1.3 Ah, nickel.

The best professional models are:

  • Makita DHP481RTE, 18 volts, 5 Ah, lithium;
  • Hitachi DS14DSAL, 14.4 volts, 1.5 Ah, lithium;
  • Metabo BS 18 LTX Impuls 201, 18 volt, 4 Ah, lithium;
  • Bosch GSR 18 V-EC 2016, 18 volts, 4 Ah, lithium;
  • Dewalt DCD780M2, 18 Volt 1.5 Ah, lithium.

The best reliable cordless screwdrivers:

  • Bosch GSR 1440, 14.4 volts, 1.5 Ah, lithium;
  • Hitachi DS18DFL, 18 Volt, 1.5 Ah, Lithium
  • Dewalt DCD790D2, 18 Volt, 2 Ah, Lithium.

This voltage is considered the industry professional standard for lithium batteries. Since a professional tool is designed for long-term active work, and also implies an additional level of comfort, a significant part of the produced 18-volt screwdriver batteries are fully compatible with each other, and sometimes even interchangeable between tools from different manufacturers.

In addition, 10.8 volt and 14.4 volt standards are widely used. The first option is found only among the most inexpensive models. The second is traditionally “middle peasant” and can be found both among professional models of screwdrivers and in models of the middle (intermediate) class.

But the designations of 220 volts in the characteristics of the best models cannot be seen, since this suggests that the screwdriver is connected with a wire to a household power outlet.

Advantages and disadvantages

  • The main advantage of lithium batteries is their high electrical capacity. This allows you to create a lightweight and compact hand tool. On the other hand, if the user is ready to work with a heavier device, he will receive a very powerful battery that allows you to work with a screwdriver for a long time.
  • Another advantage is the ability to fill lithium batteries with energy relatively quickly. A typical full charge time is approximately two hours, and some batteries can be charged in half an hour with a special charger! This advantage can be an exceptional reason for equipping a screwdriver with a lithium battery.

Lithium batteries have some specific disadvantages.

  • The most noticeable is the significant drop in practical capacity when operating in cold weather. At subzero temperatures, tools equipped with lithium batteries have to be warmed up from time to time, while the electrical capacity is fully restored.
  • The second noticeable drawback is not too long service life. Despite the assurances of the manufacturers, the best samples, with the most careful use, withstand no more than three to five years. Within a year after the purchase, a lithium battery of any common brand, with the most careful use, can lose up to a third of its capacity. After two years, hardly half of the original capacity will remain. Average life of normal operation is two to three years.
  • And another notable drawback: the price of lithium batteries is much higher than the cost of nickel-cadmium batteries that are still widely used in handheld power tools.

Features, advantages and disadvantages of lithium batteries for screwdriver

  • Features:
  • Advantages and disadvantages
  • Difference from nickel cadmium batteries
  • How to choose?
  • How to remake and assemble?
  • How to charge properly?
  • How to store?

If a hand-held power tool powered by a household power supply is tied to an outlet with a wire, limiting the movements of a person holding the device in his hands, then battery-operated counterparts of the units “on a leash” provide much more freedom of action in work. A battery is essential when it comes to using screwdrivers.

Depending on the type of battery used, they can be conditionally divided into two groups. with nickel and lithium batteries, and the features of the latter make this power tool the most interesting for the user.

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How to store?

What’s great about lithium batteries is that they are not too demanding on storage conditions. They can be stored, whether charged or discharged, at almost any reasonable temperature. If only it was not too cold. Temperatures below 25 degrees Celsius are fatal for most types of lithium batteries. Well, and above 65 degrees of heat, it is also better not to overheat.

However, when storing lithium batteries, be sure to take into account the very high probability of fire.

Proper storage conditions are when the battery has at least 50% charge and the room temperature is between 0 and 40 degrees. At the same time, it is advisable to save the batteries from moisture, including in the form of drip (dew).

Which battery is better for a screwdriver, you will find out in the following.

Selection of tools and materials

Soldering technology is distinguished by its specificity. The temperature of the soldering iron tip is constantly high. If the battery is held for a long time under such thermal exposure, it will quickly deteriorate. Therefore, the heating of the soldering iron should be minimal.

Soldering work requires a lot of experience. For example, a 40-watt soldering iron will take a long time to heat up, you can simply “overdo it”. To start remodeling ion batteries, you need to purchase the following parts:

  • 18650 battery.
  • BMS board CF-4S30A-A /
  • Wires with a cross section of 2.5 sq. Mm.
  • Soldering iron.
  • Old battery case.

Finding the right battery

The connection of the batteries is made in series, therefore, the voltage rating of each cell is summed up with the subsequent one. That is, to get 14.4 volts, you need four 3.3 V cells.

To convert a cordless screwdriver, you only need to buy miniature batteries from a well-known manufacturer. For example, LiFePO4 batteries manufactured by Sistem A123. The cell capacity reaches 2,300 mAh. This value is sufficient for the efficient operation of the electric tool. Cheap batteries made in China won’t do much. They will fail quickly.

When choosing a battery for rework, copper strips need to be located on the terminals. Soldering such elements is much easier.

The nuances of the soldering process

First, the contact part of the battery is thoroughly degreased. Then, tinning is carried out by heating the applied solder. POS-40 solder is most suitable for tinning.

The contact of the soldering iron with the battery contact should not exceed 2 seconds. The process of soldering the battery plus requires special attention. The most suitable jumpers are considered to be copper wires with a cross section of more than 2.5 mm. Sq. All wires are covered with cambric, which plays the role of a good insulator.

The mini-batteries must be connected with special jumpers according to the developed scheme. Metal strips or thin wires can become jumpers.

The final step is to connect the wires to the battery terminals made in the compartment. If the assembly of the prefabricated block is difficult, the stiffeners must be removed. Since they are made of plastic, it is easy to snack on them with ordinary side cutters.

Algorithm for converting a battery to a lithium-ion battery

How to redesign a screwdriver to get the best performance? This requires strict adherence to a certain technological sequence.

DIY li-ion lithium screwdriver conversion

For several decades, screwdrivers have been used for various jobs. These devices are powered by nickel or cadmium batteries. But progress does not stand still, scientists have found a replacement for such outdated batteries. They were replaced by lithium counterparts. To use such a battery, you need to rework the screwdriver. A lithium battery will enhance the performance of your old instrument. over, it is possible to carry out such an alteration independently, without resorting to the services of special firms.

Pin wiring diagram

To connect to the charger, you need to select the connectors that correspond to a specific model. Soldering of connecting cables is carried out according to the electrical diagram:

The connectors for connecting to the charger are selected depending on its model. Both connecting cables are soldered according to the diagram.

  • “”. 5 and 9.
  • “-“. 1 and 6.
  • Balancing contacts (ascending). 2, 7, 3, 8 and 4.

Battery replacement

The lithium battery of the screwdriver has a number of advantages that were absent in cadmium counterparts.

The energy density of the Li ion screwdriver battery is much higher. The battery with lithium cells is lightweight, with the voltage of 12 volts, as well as the battery capacity, remains unchanged. Lithium batteries charge faster than ion devices. Safe charging takes about 60 minutes.

Lithium-ion batteries do not have a “memory effect”. In other words, they do not need to be fully discharged to be charged. Among the positive qualities of a lithium battery, there are a number of disadvantages that need to be considered:

  • Lithium batteries should not be charged above 4.2 volts and discharged above 2.7 volts. But this is theoretical data. In real life, the interval gets worse. If the set values ​​are not observed, the battery will simply stop functioning. To avoid such a situation, after converting the screwdriver to lithium, you need to install a special discharge controller in the screwdriver, as well as charge it.
  • One Li ion has a voltage of 3.63.7 V. For a nickel battery, it is no more than 1.2 volts. In other words, converting a screwdriver to li-ion material causes problems associated with the assembly process of a battery, which has a nominal voltage of 12 volts. Three lithium cans connected in series give a voltage of 11.1 volts, four 14.8 volts. The limit values ​​of the charging voltage will change. In other words, altering a battery for a screwdriver is associated with solving the problem of compatibility of a new battery with a tool.
  • To alter the cadmium battery of a screwdriver, craftsmen use 18650 lithium cans. Their dimensions are different from nickel cans. Alteration of the battery for a screwdriver also requires the installation of a controller, which will require additional space.
  • After the rework, the nickel battery charger will have to be modified, or use a universal charger.
  • Subzero temperatures negatively affect the performance of ion batteries. Therefore, such a converted screwdriver cannot always work outdoors.
  • The cost of lithium batteries is much higher than cadmium counterparts.

A few words about the BMS board

It is designed to control the charge or discharge of the battery. CF-4S30A-A is designed for four banks of 18650 rechargeable batteries, giving a discharge current of 30A. The board is equipped with a special “balancer”. It performs the functions of controlling the charge of each element separately. This completely eliminates the possibility of uneven charging. For the board to function properly, the batteries for assembly must have the same capacity. It is desirable that they be taken from the same block.

The industry produces a large number of BMS boards that differ in their technological characteristics. For reworking a screwdriver battery, a board operating on a current value of less than 30A is not very suitable. It will constantly turn on the protection mode.

Some boards require a short supply of charging current to recover. To do this, you will have to remove the battery from the case, reconnect the charger to it. The CF-4S30A-A board has no such drawback. It is enough to release the trigger of the screwdriver, if there is no current causing a short circuit, the board will turn on automatically.

The redesigned battery on this board can be charged with a universal charger. The latest models, the company “Interskol” completes with multifunctional chargers.

Some helpful tips

Of course, installing lithium-ion batteries has a lot of positive qualities:

  • Lack of “memory”.
  • Minimum self-charge.
  • You can operate the tool at subzero temperatures.
  • Long service life (8 years).

However, these batteries are highly sensitive to the charging process. The voltage must always have a minimum value, otherwise the Li-ion battery will quickly become unusable. To fulfill such conditions, you need another memory, the cost of which is an order of magnitude higher. The native charger of the screwdriver will not be able to charge the lithium-ion battery.

It is impossible to say unequivocally which battery for a screwdriver is better. Their service life depends on careful handling, on strict adherence to the instructions supplied by the manufacturer.