How to convert a 12v screwdriver to lithium batteries

Table of Contents:

The meaning and procedure for converting screwdrivers to lithium batteries

Why do nickel-cadmium batteries fail quickly? In a garland of series-connected cans, each one is special. The chemical process is individual, the charge in closed systems is different. In the event of a malfunction in one bank, the design does not provide the required voltage. The control system and charge balancing in individual components is not provided.

  • Each Ni-Cd bank provides 1.2V and Li-ion 18650 3.6V.
  • Lithium battery capacity is 2 times that of nickel-cadmium battery, similar size.
  • An overheated li-ion battery threatens an explosion and fire, therefore, the installation of monitoring the uniformity of the charge in the banks is mandatory. BMS is not installed in nickel-cadmium batteries. the manufacturer is not interested.
  • Lithium cells have no memory effect, unlike Ni-Cd, they can be charged at any time and within an hour.
  • The screwdriver becomes much easier after converting the battery to li-ion, using 18650 cells.

There are only two obstacles to converting a screwdriver for lithium batteries. it is impossible to work with it at minus. The capacity of cans decreases, starting from a decrease already from 10 0 C. Lithium batteries are expensive.

Knowing what input voltage is required for the screwdriver, the charger is reworked, taking into account the placement of the lithium battery cans and control elements in the factory container. You can also do with a flashlight by upgrading the socket for a block of 18650 cells.

convert, screwdriver, lithium, batteries

Let’s say you need to rework a 12 V screwdriver using Ni-Cd cans on li-ion. If you use 3 cans, the output voltage is not enough: 3.6 x 3 = 10.8 V. With 4 components, the power of the apparatus will be higher: 3.6 x 4 = 14.4 V. This will make the instrument 182 g lighter. its power will increase slightly, capacity. solid pluses. But when dismantling, it is necessary to leave the terminals and the native thermal sensor.

Conversion of the 12 V Hitachi screwdriver to 18640 lithium batteries

Features of the conversion of the 12 V Hitachi screwdriver for lithium batteries. The very compact battery compartment is designed for finger cells. Therefore, you should prepare a place for 18650 cells. It is necessary to cut one side of the partition in order to tightly place 1 element.

You need to get a gumboil, a flat metal connecting tape, hot glue. It is necessary to install lithium batteries in a screwdriver during alteration through a protective controller. It should service 3 18650 cells, 3.7V and rated for 20-30 amps.

Remove the old battery from the socket, carefully disconnect the contacts in the assembly with the temperature sensor and the power indicator. Clean up and sign contacts. They should be brought out to one side, connected with solder to the leads from thick wires and filled with hot melt glue on the assembly.

Assemble a power source with one of the 3 cell controllers. Build a serial circuit of 3 Li-ion cells. Connect the controller. The conversion of the 12-volt lithium battery is completed when the structure is installed in the unit, secured, and the charging indicator lights up. After fully charging, the measurements show 12.17 volts in the external network. But this is enough for trouble-free long-term operation of the device.

Accumulators and batteries

Energy storage information website

Conversion of a screwdriver to lithium batteries 18650 14 V

When converting screwdrivers of different power and flashlights from Ni-Cd to Li-ion, batteries of the form factor 18650 are more often used. They easily fit into a container or a nest, since instead of two or three relatives, one lithium is installed. Alteration of the screwdriver battery should be carried out taking into account the characteristics of lithium 18650 batteries.

This type of energy source does not tolerate deep discharge and excessive charge. Hence, it is necessary to use voltage control boards. Since each battery has its own character, their charge is corrected by a balancer. The point of reworking a screwdriver with a voltage of 14.4 V lies in creating a device using lithium batteries to facilitate a hand tool and increase its performance. Lithium 18650 batteries are most suitable for these purposes.

When selecting components, it should be taken into account that the starting current of the screwdriver is high, you must select the appropriate BMS for the required number of cans and at least 30 A.

  • Lithium-ion cans in the amount of 4 pcs.
  • 4 cell li-ion battery controller, CF-4S30A-A works well. It has a built-in balancer that controls the charge of each element.
  • Hot melt glue, flux for soldering TAGS, solder.
  • Heat-resistant tape;
  • Connecting jumpers or thick insulated wire with a cross section of at least 0.75 squares, cut for bridges.

The procedure for converting a screwdriver for 18650:

  • Disassemble the case and remove a bundle of 12 Ni-Cd cells from the container.
  • Remove the garland, leaving the connector with the “” and “-” pins. Instead of a temperature sensor, a thermocouple from the controller will be installed.
  • Solder the assembly, considering that you cannot use acid, only neutral flux and pure solder. During the connection period, do not warm up the covers. Work pointwise.
  • Connect the balancing points to the controller according to the diagram. The board has connectors.
  • Connect assembly with plus and minus pins.
  • Check the functionality of the circuit. If everything works, assembled the battery, place the controller in the socket, secure with a sealant.

If the charger is not universal, additional alteration will be required. Screwdrivers for 12 V with a universal charger are assembled in the same way, but a protective connection circuit 3×18650 3.7 V for lithium batteries is used. In the same way, a screwdriver is reworked using a set of 18650 batteries in the amount of 2 elements.

Conversion of the Makita screwdriver to a lithium battery

There is a “Makita” screwdriver with a 1.3 A / h battery and a voltage of 9.6 V. To change the power source to a lithium-ion one, you will need 3 18650 components. The alteration will provide the old tool with new possibilities: it will increase the operating time on one charge. will add power as the operating voltage rises to 10.8V.

The design will require the use of a BMS, a control controller that maintains the lithium cell operating mode within operating limits. With this breaker, each cell will be charged evenly without exceeding 4.2V, the lower voltage is 2.7V. The built-in balancer is used here.

The parameters of the controller should accompany the operation of the instrument when the operating current rises to 10-20 A. The Sony VTC4 30 A board, designed for a capacity of 2100 A / h, can ensure operation without shutdown. Of the 20 amperes, the Sanyo UR18650NSX accepting 2600A / h energies is suitable. The board is needed for 3 elements, which is marked in the 3S classification. In this case, the board must have 2 contacts, plus and minus. If the conclusions are designated with the letters “P-“, “P”, “C-“, they are intended for later models of screwdrivers.

Step-by-step instructions for converting a Makit screwdriver to lithium batteries looks like this.

  • You can disassemble the battery with glue if you tap the junction with a soft-headed hammer while weighing. Direction of impact downward, butt-joint along the lower part of the body.
  • Take only the contact plates from the old assembly, carefully disconnecting them from the battery. The sensor and the breaker must be left.
  • Solder 3 elements in series using TAGS flux and insulated jumpers. The wire cross-section must be greater than 0.75 mm2.
  • Assemble the circuit with the controller, and connect the power supply to the contact connectors with 1.5 square wires.
  • Check the functionality of the circuit and reassemble the case by placing it on the glue again.

In a screwdriver with an old DC9710 charger, after charging the 18650 lithium battery, the red LED on the panel will turn off. The built-in controller monitors the charge level.

Makita DC1414 T charger is used to charge 7.2-14.4 V power sources. While charging is in progress, the red light is on. But when charging a lithium battery, its voltage does not fit into the standards of salt products, and after 12 V, the charger will flash red and green. But the necessary charging is already there. The screwdriver is ready to work.

Converting a screwdriver to lithium batteries 18650

Every craftsman is faced with the problem of reduced tool performance, or complete failure due to the battery. Manufacturers use nickel-cadmium batteries in 12, 14, 18 volt screwdrivers. The sequential assembly of several elements creates the required voltage. Replacing nickel-cadmium batteries with lithium batteries extends battery life by making construction easier. Mandatory BMS board installation adds reliability. Therefore, the conversion of a screwdriver to lithium batteries, mainly to the 18650 form factor, is justified.

Alteration of the Interskol screwdriver for lithium batteries 18650

Sooner or later, the nickel-cadmium assembly of 15 cans fails. One or two elements are lazy, and it is no longer possible to get the output voltage. Modern DSh “Interskol” on lithium batteries serve much better. Alteration of a screwdriver for 18 volt lithium batteries mastered by craftsmen.

It is necessary to purchase a protection board for 5S, 3.7 V and 40-50 A. You will need a balancing board and the energy sources themselves. 5 lithium 18650 batteries, you can leave them with factory thermistors by extending the wires. During installation, create a contact pad, insert the assembly, check the functionality, secure. The assembly features of the wizard’s advice are given in detail in the video. See here for full details on reworking an 18-volt lithium screwdriver

How to convert a cordless screwdriver to a network: 5 options for solving the issue

Why do you need to remodel a mains-powered screwdriver

In order for you to be able to use a screwdriver even in the most inaccessible places without unnecessary wires, at any time, the mobile screwdriver is converted to a network.

To carry out such a procedure is not so difficult as it seems at first glance. With the appropriate skills and all the necessary components, this process will take a little time.

Methods for converting a cordless screwdriver into a network vary in complexity. One of them. powering the charging from a laptop practically does not require knowledge and skills. To mount a computer power supply, you need to know how to handle a soldering iron, and to repurpose a Chinese adapter, you need to know how to handle a measuring device. In addition, there are several other methods for converting a cordless screwdriver directly into a network.


  • Using a power supply device from a personal computer instead of a battery;
  • Giving new life to the car battery;
  • Using, as source, a power supply from halogen lamps;
  • By connecting the Chinese 24V power supply board.
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For brainy craftsmen, such manipulations are not difficult. If you are not confident in your abilities, then it is better not to risk it and seek the help of a knowledgeable specialist.

Converting a screwdriver to a network using laptop charging

In the event of a battery failure, a household screwdriver can be switched to mains power by making some changes to its design. This does not require a lot of expenditure of finance, time and effort. The positive nuances of such a transformation are obvious: you do not need to constantly charge the battery, and at the same time, the forced downtime will go away. After all, the shortest duration for charging the device is more than 3 hours.

However, when deciding to perform such a transformation with your screwdriver, you should understand that from now on you will need an alternating current to work with it. You will no longer be able to use it away from communications.

If you need to connect the screwdriver to the network, you can use the charger from an old laptop. It has similar characteristics to a screwdriver, and it can be easily found in every home or workshop. But, nevertheless, check what output voltage is shown for your charging. In this case, chargers for 12-19V are suitable.

Scheme of your actions:

  • We take out unusable batteries from a failed battery pack.
  • We take charge from the laptop.
  • Cut off the connector and strip the wires from insulation.
  • We solder the bare wires or wrap them with electrical tape.
  • We make an outlet for the wire in the case.
  • Assembling the structure.

This manipulation will allow you to use the screwdriver at any moment, and without stopping for charging.

How to convert a battery device to a screwdriver from a 220 volt network

Today the screwdriver belongs to the devices that we very often use in everyday life. It is also irreplaceable in production. This device is suitable for a variety of electrical and construction work. With its help, furniture and other items are assembled, the design of which requires threaded connections.

The cordless screwdriver is compact and portable. But not everyone is happy with these advantages, because the device quickly runs out of battery, and you have to interrupt work halfway. Therefore, many owners of this tool are interested in the question of how you can remake a screwdriver with a battery on a network.

The reason for this decision is also the fact that when the device is not used for a long time, the battery is discharged independently, which leads to a breakdown of the screwdriver due to the destruction of some elements. It is impossible to repair a failed battery, and it is not always possible to purchase a new one. Often, component parts can only be purchased from the official representatives of the manufacturer. Accordingly, the cost of a new battery will be almost equal to the cost of a new screwdriver. Therefore, some craftsmen come to the decision to turn the screwdriver into a network.

Materials and tools required for this:

  • Charger from this screwdriver;
  • His native battery;
  • Soft stranded electrical cable;
  • Soldering iron and solder;
  • Insulating tape;
  • Acid.

First, you need to solder the loose ends of the cable to the terminals of the charger. You need to know that copper wires of a cable with brass contacts can be soldered only after they have been treated with acid. Experts recommend using special solder, but sometimes the simplest methods are used in the form of acid treatment.

Convenient screwdriver from the network: features of use

The cordless cordless screwdriver is a great helper in your home. Almost everyone who he has never let down can agree with this. Those who stopped working halfway have a completely different opinion. This tool will help you always and everywhere, but exactly until the time the battery is discharged. over, the quantity in it is limited. In moments of idleness, the battery can also deteriorate. Batteries usually last no more than three years. When this time expires, it has to be changed or sent to the museum of obsolete things. The situation is possible if you convert the screwdriver into a network one. There are enough ways to do this.

The power supply unit of the device provides the function of changing the alternating current with a voltage of 220V. Standard screwdrivers consume a constant current, with a nominal value in the range of 9-18V. In this regard, connection to the network is carried out subject to the use of an electronic transformer. For these purposes, products of the Toshibra and Feron brands are most suitable.

Mains transformers of these brands are of high quality and reliable in operation. In addition, they are quite compact, lightweight, and do not complicate the work with the tool. Their load characteristics are close to those required for a standard screwdriver. In their design there are 2 input and output wires, which allows you to supply power to halogen lamps and other types of electricity consumers with a voltage of 12V. However, to use the converted device, you need to adhere to some rules.

Here they are:

  • Let the appliance rest for 5 minutes every 20;
  • Fix the cable at the elbow with your hand so that it does not interfere with the work;
  • Clean the power supply from dust;
  • Do not use too many extension cords;
  • Do not use the device without grounding;
  • It is forbidden to use a converted device for work at height.

Before each start of work with the converted device, make sure it is working properly.

How to make a screwdriver from the network

When the batteries stop working due to the fact that they have simply outlived their life, many begin to wonder how they can fix the situation and remake their old cordless screwdriver into the network with their own hands. After all, it is no longer possible to repair a battery with a destroyed element, and the cost of a new one is almost equal to the purchase of a new screwdriver. But zealous and skillful owners came up with a way out. to power the screwdriver from the mains. Some were even able to invent a device that works simultaneously from the mains and from the battery. But it’s better not to do it.

How to convert a screwdriver to lithium batteries

Most older models of cordless screwdrivers were equipped with NiCd batteries. As everyone knows, these batteries do not have a lot of power, moreover, they have a “memory” effect, due to which the volume of capacity is significantly reduced. Therefore, many owners of such equipment undertake the conversion of screwdrivers to 12V 18650 lithium batteries. The process is laborious, but if you follow the steps, the result will be crowned with success.

Preparatory moments

The first step is to determine the maximum voltage value. For this purpose, you need to calculate the number of elements. For three parts, the most acceptable value is 12 volts, for 4 parts. 16 volts.

Take as a basis a battery for a screwdriver with a maximum voltage of 14.4 V. In this case, it is recommended to use 4 cells. Thus, not only will the difference in volts be equalized, but the capacity indicator will also increase. It turns out that screwdrivers on a lithium battery can work much longer.

As for the type of batteries, experts recommend giving preference to the 18650 series, it is the most optimal option. Next, you need to deal with the capacity and discharge current. With the normalized operation of the device, the consumed current level varies within 5-10 Am. But if an unexpected sharp descent occurs, then the value rises to 25 Am. In order not to harm the battery during such a drop, it is recommended to select cells with an increased value of the discharge current, for example, up to 30 Am.

High discharge current 18650 batteries

Instead of four lithium ion cans, eight can be used. But for this it is necessary to fasten 2 elements in parallel. Further, the connecting pairs must be connected in series. It is important to consider here that not all battery cases are capable of accommodating 8 parts at the same time.

The controller must be selected according to the indicator of the rated voltage, as well as taking into account the discharge current. These values ​​must match. precisely, the voltage will completely coincide for both the battery and the controller, but only the operating discharge current should be 2 times less than the limit.

For example, it looks like this. the controlling device for charging-discharging is calculated for 13-14 Am, while the protective function will turn on when the current rises sharply to 30 Am.

Even when converting a screwdriver to lithium, it is necessary to take into account the dimensions of the protective board, since it must completely fit into the equipment case. Otherwise, it is necessary to use imagination to increase the body part. Leaving this part open is strongly discouraged.

Pros and cons of modernization

Before converting a screwdriver to 18650 lithium batteries, you need to figure out what the master will get as a result. The advantages of these manipulations are as follows:

  • multiple increase in the operating time of the screwdriver;
  • increase the battery charge rate. for a full set of energy for lithium batteries, approximately 1 hour is required;
  • an increase in the power of the charge current to an indicator of 1-2 C;
  • reduction of costs for the regular purchase of new NiCd batteries due to their insufficient operating life;
  • complete absence of memory effect in lithium batteries.

Also, before remaking a battery with your own hands for a more modern technology, you should be aware of the negative consequences:

  • a mandatory connection of the controller is required to determine the charge level, since the device cannot be charged more than 4.2 V and discharged less than 2.7 V;
  • lithium-ion batteries for the Li-lon series screwdrivers lose their capabilities when used in low temperature conditions;
  • when converting a screwdriver to a lithium battery, it may be difficult to adapt the charger from NiCd, here you will have to use a universal device.

Step-by-step instruction

After all the constituent elements and tools for replacing the batteries in the screwdriver are prepared, you can start collecting. As an example, the conversion of 12 volt equipment to a Li-lon battery was disassembled, inside of which there were 12 NiCd rechargeable batteries 1.2 V each.

  • First of all, you need to dismantle the case and get the built-in battery out of it. This requires wire cutters, since the connector itself must remain in place.
  • Take the controller and thermocouple. These elements must be installed in the area where the temperature sensor was. By the way, if this part has not yet been removed, it should be removed. You also need to remember that you need to select all the parts in such a way that they can fit into the tool body.

Since the batteries are not current, to facilitate their work, it was decided to put 2 batteries in parallel

  • After that, in strict sequence, solder all the prepared parts. Solder the controller to the board according to the chosen scheme. The main thing here is not to forget to connect the balancing points. For this, the diagram has a special connector and wiring.
  • The final stage is considered to connect the output to the pole and minus.
  • The main part of the work is done, now it remains to carefully assemble everything into the case without damaging anything.

If the kit had a standard charger, then there will be no problems with them. Such devices are quite suitable for lithium battery packs. All the charge will still flow through the controller, which completely eliminates the possibility of battery overheating from power surges.

If initially a 12 volt screwdriver, it is better to assemble according to this scheme

Cordless Drill Lithium Battery Conversion using 18650 Cells

Many people are wondering if it is possible to make a charge that will charge two types of batteries? Circuits for such devices exist, and they are working, but using such a charger is not recommended due to the voltage difference between the battery blocks.

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New battery packs on the market are sold on average about 2000-3000 rubles. And the cost of upgrading nickel-cadmium to lithium-ion does not exceed 1000 rubles. Therefore, the rework is fully justified.

How to transfer a screwdriver to lithium batteries (welding batteries into a battery)

Lithium-ion batteries (li-ion)

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

  • Work at temperatures from 18 ° С to 50 ° С

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

DIY: Ni-Cd To Lithium Battery Conversion By Using 18650 Cells

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

  • Lithium battery with overheating and overload protection

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: clip

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

Battery type: Li-Ion

Battery device: slider

Voltage: 18V

Battery type: Li-Ion

Battery device: clip

Voltage: 10.8 / 12V

Lithium-ion batteries (Li-ion) serve as a self-contained power source for all sorts of tools and equipment. from scissors to saws, from flashlights to radios and even vacuum cleaners.

Lithium batteries: features

  • Higher energy density. Li-ion batteries are 2. 3 times lighter than similar Ni-Cd batteries.
  • Low self-discharge. Lithium-ion batteries are stored without loss of capacity, while Ni-Cd batteries lose up to 10% of their capacity in a month. Li-ion battery is ready for use even after long periods of inactivity.
  • No memory effect or maintenance. The Li-ion battery can be charged at any time without risk of capacity degradation. Ni-Cd or Ni-MH batteries must be fully discharged to last longer.

The only thing to remember when buying a Li-ion battery is that it is not recommended to charge it at temperatures below 0 ° C. This can significantly reduce the service life.

How to translate a hitachi screwdriver to lithium batteries: a description of the process

If the cans were sold without nickel electrodes, they are soldered. It is important to do this with great care, as overheating can irreversibly damage the battery, or even provoke an explosion. Before starting the process, it is useful to clean the soldered surfaces so that the likelihood of overheating decreases and the connection is strong.

The batteries are connected in series, the board is connected. The power wire is soldered to the microcircuit and the contact pad. Then, using a multimeter, the voltage readings are checked: for each battery, this figure should be about 1.3 V.

Upon completion of the test, all connections are carefully insulated. The assembled cassette is carefully placed in the case, the wire is laid without kinks and creases. The halves of the case are held together.

Conversion of the Hitachi screwdriver to lithium batteries

Nickel-cadmium batteries are inconvenient because of their “memory effect”, so switching to lithium-ion batteries is expedient and profitable.

Preparation: selection of the necessary devices, elements

A battery pack that has lost its working qualities must be disassembled. The halves of the case can be fastened with glue and / or screws, clamps. To disconnect the glued seam, it is carefully tapped with a rubber hammer so that the halves of the plastic case separate from each other, but do not crack. The elements collected in a “cassette” are removed from the opened case. The contact pad is carefully separated, it will need to be fixed on new lithium batteries.

The new Li-Ion battery for the Hitachi screwdriver requires the purchase of additional accessories, while the following circumstances must be taken into account:

  • New batteries must be similar in size and voltage to the old ones.
  • It is more advisable to choose batteries already equipped with nickel plates so as not to waste time on soldering.
  • The lithium-ion battery needs a BMS board (Battery Management System). It evenly distributes energy between the banks, protects the device from sudden power outages, turns it off if the charging time is exceeded, or the batteries are discharged to almost zero. To protect against overheating, a thermal detector is connected to the board.
  • To connect the cassette to the contact pad, you need a power insulated wire of suitable thickness.

First activation after the transition, terms of use

The assembled lithium-ion battery pack must be put into working order. This is to ensure that new batteries do not wear out prematurely. The unit is fully charged and begins to be used intensively until the charge is depleted to zero and the device turns off. After that, it is recharged to 100% again, and work until it is completely discharged. This cycle can be repeated a third time. After this preparation, the battery module can be used normally.

Converting a DeWalt 12V Cordless Drill from NiCad to Lithium LiFePO4

You need to start charging the battery with lithium-ion banks when it is discharged to 20%, charging should always be done to 100%. Do not overexpose the device on recharging. as soon as the batteries are full, the charger must be disconnected.

Putting together a lithium-ion battery

Here are the new elements of Sanyo UR18650NSX (according to this article they can be found on Aliexpress) with a capacity of 2600 mAh. For comparison, the old battery had a capacity of only 1300 mAh, half the size.

It is necessary to solder the wires to the elements. The wires must be taken with a cross section of at least 0.75 sq. Mm, because we will have considerable currents. A wire with such a cross section normally works with currents of more than 20 A at a voltage of 12 V. You can solder lithium-ion cans, short-term overheating will not harm them in any way, this has been verified. But you need a good fast-acting flux. I use TAGS glycerin flux. Half a second. and you’re done.

We solder the other ends of the wires to the board according to the diagram.

I always put even thicker wires of 1.5 mm2 on the battery contacts. because the space allows. Before soldering them to the mating contacts, I put a piece of heat-shrink tubing on the board. It is necessary for additional isolation of the board from battery cells. Otherwise, the sharp edges of the solder can easily rub or puncture the thin film of the lithium-ion cell and cause a short. It is possible not to use heat shrinkage, but at least something insulating to be laid between the board and the elements is absolutely necessary.

Now everything is insulated as it should.

The contact part can be fixed in the battery case with a couple of droplets of super glue.

Battery ready for assembly.

It’s good when the case is on the screws, but this is not my case, so I just glue the halves again “Moment”.

The battery is charged with a standard charger. True, the algorithm of work is changing.

I have two chargers: DC9710 and DC1414 T. And they work differently now, so I’ll tell you exactly how.

How to disassemble a screwdriver battery

How to disassemble an old battery? There are batteries where the halves of the case are fastened with screws, but there are also glue ones. My batteries are one of the last ones, and I generally believed for a long time that they could not be disassembled. It turned out that it is possible if you have a hammer.

In general, with the help of intense blows to the perimeter of the edge of the lower part of the case (a hammer with a nylon head, the battery must be held in the hand by weight), the gluing site is successfully disconnected. In this case, the case is not damaged in any way, I have already disassembled 4 pieces this way.

The part of interest to us.

From the old circuit, only contact plates are needed. They are permanently spot welded to the upper two elements. You can pick out the welding with a screwdriver or pliers, but you need to pick it as carefully as possible so as not to break the plastic.

Everything is almost ready for further work. By the way, I left the standard thermal sensor and disconnector, although they are no longer particularly relevant.

But it is very likely that the presence of these elements is necessary for the normal operation of a standard charger. Therefore, I highly recommend saving them.

What board is needed and what elements are needed to convert a screwdriver to lithium-ion

So, here is my 9.6 V 1.3 Ah battery. At the maximum charge level, it has a voltage of 10.8 volts. Lithium-ion cells have a nominal voltage of 3.6 volts, with a maximum voltage of 4.2. Therefore, to replace the old nickel-cadmium cells with lithium-ion ones, I need 3 cells, their operating voltage will be 10.8 volts, the maximum is 12.6 volts. Exceeding the rated voltage will not damage the motor in any way, it will not burn out, and with a larger difference, there is no need to worry.

Lithium-ion cells, as everyone has known for a long time, categorically do not like overcharging (voltage above 4.2 V) and excessive discharge (below 2.5 V). When the operating range is exceeded, the element degrades very quickly. Therefore, lithium-ion cells always work in tandem with an electronic board (BMS. Battery Management System), which controls the cell and monitors both the upper and lower voltage limits. This is a protection board that simply disconnects the can from the electrical circuit when the voltage goes out of the operating range. Therefore, in addition to the elements themselves, such a BMS board will be required.

Now there are two important points that I experimented with unsuccessfully several times until I came to the right choice. This is the maximum allowable operating current of the Li-Ion cells themselves and the maximum operating current of the BMS board.

In a screwdriver, operating currents at high load reach 10-20 A. Therefore, you need to buy elements that are capable of delivering high currents. Personally, I have successfully used Sony VTC4 30Amp 18650 cells (2100mAh capacity) and 20A Sanyo UR18650NSX (2600mAh capacity). They work fine in my screwdrivers. But, for example, Chinese TrustFire 2500 mAh and Japanese light green Panasonic NCR18650B 3400 mAh are not suitable, they are not designed for such currents. Therefore, there is no need to chase the capacity of the elements. even 2100 mAh is more than enough; the main thing when choosing is not to miscalculate with the maximum permissible discharge current.

Likewise, the BMS board must be rated for high operating currents. I saw on Youtube how people assemble batteries on 5 or 10-ampere boards. I don’t know, personally, when I turned on the screwdriver, such boards immediately went into defense. In my opinion, this is a waste of money. I will say that the Makita company itself puts 30-ampere boards in its batteries. Therefore, I use 25 amp BMS bought from Aliexpress. They cost about 6-7 and are searched for “BMS 25A”. Since you need a board for an assembly of 3 elements, you need to look for such a board, in the name of which there will be “3S”.

Another important point: some boards have different contacts for charging (designation “C”) and load (designation “P”). For example, a board can have three pins: “P-“, “P” and “C-“, as on the native Makitov lithium-ion board. Such a fee will not work for us. Charging and discharging (charge / discharge) must be carried out through one contact! That is, there should be 2 working contacts on the board: just “plus” and just “minus”. Because our old charger also only has two pins.

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In general, as you might have guessed, with my experiments I threw out a lot of money both on the wrong elements and on the wrong boards, having made all the mistakes that could be made. But I got invaluable experience.

Converting the battery of the screwdriver to Li-Ion

I won’t say anything new in this article, but I just want to share my experience of upgrading the batteries of my old Makita screwdriver. Initially, this tool was designed for nickel-cadmium batteries (which have long since died, just as those bought for replacement have died). The disadvantages of Ni-Cd are well known: low capacity, short lifespan, high price. Therefore, cordless tool manufacturers have long since switched to lithium-ion batteries.

Well, what about those who have an old instrument? Yes, everything is very simple: throw away the Ni-Cd cans and replace them with Li-Ion of the popular 18650 format (marking indicates a diameter of 18 mm and a length of 65 mm).

Makita DC9710 charger and lithium-ion battery

Previously, the battery was controlled by the device itself. When the full level was reached, it stopped the process and signaled the completion of charging with a green indicator. But now the BMS circuit we have installed is engaged in level control and power off. Therefore, when charging is complete, the red LED on the charger will simply turn off.

If you have such an old device, you are in luck. Because everything is simple with him. The diode is on. charging is in progress. Off. charging completed, battery fully charged.

Makita DC1414 T charger and lithium-ion battery

There is a small nuance here that you need to know. This charger is newer and is designed to charge a wider range of batteries from 7.2 to 14.4 V. The charging process on it proceeds as usual, the red LED is on:

But when the battery (which in the case of NiMH cells is supposed to have a maximum voltage of 10.8 V) reaches 12 volts (we have Li-Ion cells with a maximum total voltage of 12.6 V), the charger will blow the roof. Because he will not understand what kind of battery he is charging: either 9.6-volt, or 14.4-volt. And at this moment Makita DC1414 will enter error mode, alternately blinking red and green LEDs.

This is normal! Your new battery will still charge. though not completely. The voltage will be approximately 12 volts.

That is, you will miss some part of the capacity with this charger, but it seems to me that you can survive.

Total battery upgrade cost about 1000 rubles. Makitovsky’s new Makita PA09 costs twice as much. over, we ended up with twice the capacity, and further repairs (in the event of a slight failure) will consist only in replacing lithium-ion cells.

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Converting the battery of a screwdriver to lithium cells

Many screwdriver owners want to convert their batteries to lithium battery cells. Many articles have been written on this topic and in this material I would like to summarize information on this issue. First of all, we will consider the arguments in favor of converting a screwdriver to lithium batteries and against it. And also consider some moments of the process of replacing batteries.


Let’s start with the benefits:

  • The energy density of lithium-ion cells is much higher than that of nickel-cadmium, which are used by default in screwdrivers. That is, the battery on lithium cans will have less weight than on cadmium with the same capacity and output voltage;
  • Lithium battery cells are charged significantly faster than Ni-Cd. It will take about an hour to charge them safely;
  • Lithium Ion batteries have no memory effect. This means that they do not need to be fully discharged before charging.

Now about the disadvantages and complexities of lithium batteries.

What you need to estimate before starting work?

It is necessary to determine the number of cells in the battery, which ultimately decides the magnitude of the voltage. For three elements, the ceiling will be 12.6, and for four. 16.8 volts. We are talking about reworking widespread batteries with a nominal value of 14.4 volts. It is better to choose 4 elements, since during operation the voltage will drop pretty quickly to 14.8. A difference of several volts will not affect the operation of the screwdriver.

In addition, more lithium cells will give more capacity. This means longer operating time of the screwdriver.

Lithium battery cells 18650

The nominal voltage of lithium cells is 3.6-3.7 volts, and the capacity in most cases is 2000-3000 mAh. If the battery case allows, you can take not 4, but 8 cells. Connect them two by two into 4 parallel assemblies, and then connect them in series. As a result, you will be able to increase the capacity of the battery. But not every case will be able to pack 8 cans of 18650.

And the last preparatory step is choosing a controller. According to its characteristics, it must correspond to the rated voltage and discharge current. That is, if you decide to assemble a 14.4 volt battery, then choose a controller with this voltage. The working discharge current is usually chosen half of the maximum permissible current.

Charge-Discharge Controller Board

Above, we established that the maximum permissible short-term discharge current for lithium cells is 25-30 amperes. This means that the charge-discharge controller must be rated for 12-15 amperes. Then the protection will be triggered when the current increases to 25-30 amperes. Do not forget also about the dimensions of the protection board. It, together with the elements, will need to fit into the battery case of the screwdriver.

Replacing batteries in a screwdriver with lithium

All pros and cons of converting a screwdriver battery to lithium cells

First, you should think about whether I need this alteration? After all, it will be a frank “self-propeller” and in some cases can lead to failure of both the battery and the screwdriver itself. Therefore, let’s consider all the pros and cons of this procedure. It is possible that after that, some of you will decide to abandon the conversion of the Ni─Cd battery for a screwdriver to lithium cells.

Battery replacement

Well, then the assembly process itself follows. Disassemble the battery case first. If this is a 14.4 volt model, then there will be 12 nickel cadmium batteries with a nominal value of 1.2 volts inside.

Assembling Nickel Cadmium Batteries

After that, you need to solder the purchased items into an assembly with a serial connection. Next, the controller is soldered to it in accordance with its circuit. In this case, balancing points are connected. The board has a special connector for them, and often wires with a connector are supplied in the kit.

Screwdriver battery housing

After assembling the battery, the terminals for plus and minus are soldered, and the whole structure is placed in the case. In principle, this is the end of the process. Problems can only arise with the charger. But in most cases, standard screwdriver chargers charge lithium cells without problems. In this case, the charge of the cans goes through the controller, so nothing terrible will happen to the elements themselves.

The cons

  • Lithium battery cells cannot be charged above 4.2 volts and discharged below 2.7 volts. In real conditions, this interval is even narrower. If you go beyond these limits, the battery can be damaged. Therefore, in addition to the lithium cans themselves, you will need to connect and install a charge-discharge controller in the screwdriver;
  • The voltage of one Li─Ion cell is 3.6─3.7 volts, and for Ni─Cd and Ni─MH this value is 1.2 volts. That is, there are problems with assembling a battery for screwdrivers with a voltage rating of 12 volts. From three lithium cans connected in series, you can assemble a battery with a nominal value of 11.1 volts. Out of four ─ 14.8, out of five ─ 18.5 volts, and so on. Naturally, the voltage limits during charge-discharge will also be different. That is, there may be problems with the compatibility of the converted battery with a screwdriver;
  • In most cases, 18650 standard cans are used as lithium cells for alteration. They differ in size from Ni─Cd and Ni─MH cans. In addition, you will need space for the charge-discharge controller and wires. All this will need to fit in a standard battery case of a screwdriver. Otherwise, it will be extremely inconvenient for them to work;
  • A cadmium battery charger may not be suitable for recharging a battery after a redesign. You may need to revise the charger or use universal chargers;
  • Lithium batteries lose their performance at low temperatures. This is critical for those who use a screwdriver outdoors;
  • The price of lithium batteries is higher than cadmium.

Conversion of a screwdriver to lithium batteries

Battery preparation and assembly

There are often cases when a high-quality screwdriver ceases to perform its functions due to a weak battery. It is a pity to throw out such a tool, it is better to rework the screwdriver battery. Nickel batteries are usually found in cheap equipment because of their poor performance.

Advantages of injection molded batteries:

  • Good current efficiency;
  • The power of the screwdriver does not decrease when the battery is discharged;
  • The product is slowly discharging;
  • Charging time is 1-1.5 hours;
  • The battery can be recharged without sacrificing volume.

Injection batteries have a convenient “can” shape with a diameter of 18 mm and a length of 65 mm. To convert the screwdriver to a high-quality battery, you should purchase high-current cans.

To alter a screwdriver battery, you need to connect the molded batteries. A special battery compartment is prepared for this. You can also try soldering the devices, but this will require a weak soldering iron, since such products do not tolerate overheating. Experienced craftsmen use precision welding to connect injection-molded batteries with their own hands.

It is important that all banks have the same capacity, otherwise the battery with lower rates will fail faster. To secure the system, it is recommended to include board protection in the molded battery circuit.

Alteration sequence

To transfer the screwdriver to a rechargeable battery, you need to disassemble the battery. It is recommended to leave the terminals from nickel devices. Any excess plastic inside the case should be removed. If there is not enough space, then you will have to abandon the special compartment, and connect the injection battery circuit with soldering. The board is glued to the top of the batteries using double-sided tape.

A thick power cable can be used as the power wire to connect the terminal block. Then a hole is made in the case to install a charging socket. The terminal block is connected in parallel to the molding battery with your own hands with the output from the protection module. The wires are soldered vertically to the protection board.

It is important to fix the block with the terminals to prevent it from slipping (you can insert a regular bamboo skewer). Then the structure is assembled, the bolts are screwed in.

It remains to check the correctness of the conversion of the screwdriver for injection-molded batteries in practice. To do this, the battery is connected to the tool and several screws are screwed.

Then the battery is fixed to the screwdriver. If there is only one battery, then it can be safely bolted. When it is possible to change the device, then you can use ordinary chamber rubber bands.