Conversion of the hitachi 12v screwdriver to lithium

High-current accumulators 21700

conversion, hitachi, screwdriver, lithium

The most profitable and up-to-date battery format. With slightly larger dimensions, they have higher energy consumption and stable quality. If space permits in the battery case, I recommend them. I myself make a 21V battery for a pseudo-Makitovsky instrument from these jars, and of course from the originals of Samsung 40T.

Nicd to Lithium Battery Makita Cordless Drill 8.4V 2200mAh

High current 18650 batteries

Actually, the most important element in the rework. Good cans with a current output of at least 15A are needed; for a tool with a brushless motor, batteries with a current output of at least honest long 20A are desirable. LG HE4 2500mah, Samsung 25R 2500mah, Samsung 30Q 3000mah and LG HG4 3000mah (“chocolates”) are ideal in terms of price / quality ratio. The quality of the repackaging has dropped a lot lately, but Liitokala is still more or less normal, especially with welded contacts.

BMS protection boards

A necessary element when converting a battery to lithium power. It is necessary to protect batteries from overdischarge, overcharge, excessive current and short circuit (short circuit). For 12V shura we purchase 3S BMS, for 14V. 4S BMS, for 18V. 5S BMS. For collector shura, it is advisable to find out (determine) the maximum current (almost at the cartridge stopper) and select a board for a slightly lower current, so that with excessive efforts not to burn the engine (1 link). For brushless. for the maximum possible current, because the motor protection is available in the controller (2 link).

Connecting wires and tapes

To connect all the elements, use nickel tape (ref. 1) or large stranded wires (ref. 2). The former are used for spot welding, the latter for soldering. There is no difference, just resistance welding is faster and more technologically advanced in production, i.e. it can stamp many more batteries at a lower cost. For home, you can not bother and just solder, but just do not overheat the positive contact, i.e. do not hold the soldering iron tip for more than 20 seconds on it.

Everything for converting a screwdriver to lithium on AliExpress sale. Basic components

Everything for converting a screwdriver to lithium on AliExpress sale. Basic components (part 1). The topic provides a quick guide and links to the basic components that are needed to convert a screwdriver to lithium power and more. It is very simple!

About a year ago I already made a small selection of screwdrivers alteration, but it turned out a little messy, and many links stopped working. Therefore, I decided to make an updated version in several parts. In this (first) part, the necessary elements will be listed, without which it is impossible to normally remake the battery. The second part will list elements that improve battery safety and durability, and improve overall usability. In the third part. tools and accessories for alteration, both for amateurs and specialists.


Charging the assembled battery from a native charger will not work, well, only partially. A specialized device is required. I recommend purchasing chargers from the first link. they have good circuitry and stock, choose the one for the required voltage. The second link is for simpler options. Worse, but work.

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 operability, 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

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 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.

Conversion of the Makita screwdriver to the 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 give the old tool new possibilities: it will increase the operating time on a single 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 Makita screwdriver to lithium batteries looks like this.

  • It is possible to disassemble the battery with glue if you tap the junction with a soft-headed hammer on the weight. 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.
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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.

The Makita DC1414 T charger is used to charge 7.2-14.4 V power sources. While charging, 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.

How to convert batteries on a screwdriver to lithium

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 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 LED.

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.

In total, the upgrade of the oBosch battery 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.

Note: This article and the images in it are subject to copyright. Partial or complete reproduction on other resources without consent is prohibited.

Energy storage information website

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 the design lighter. Mandatory BMS board installation adds reliability. Therefore, the conversion of a screwdriver to lithium batteries, mainly to the 18650 form factor, is justified.

Pros and cons of modernization

Before converting a screwdriver to lithium 18650 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;
  • increasing the battery charge rate. for a full set of energy for lithium batteries, approximately 1 hour is needed;
  • 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.

Alteration of the “Hitachi” 12 V screwdriver for lithium batteries 18640

Features of reworking 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 rework through a protective controller. It should serve 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.

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.
  • The capacity of a lithium battery is 2 times that of a nickel-cadmium battery, similar in size.
  • An overheated li-ion battery threatens an explosion and fire, therefore, the installation of control of 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.
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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.

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.

Preparatory moments

First of all, you should determine the maximum indicator of the magnitude of the voltage. 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 nominal voltage indicator, 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.

Converting a screwdriver to lithium batteries: instruction

Converting a screwdriver to lithium batteries makes sense. The advantage is that they have a high electrical density. As a result, by installing such a device in a screwdriver body, we can achieve an increase in the duration of the tool many times over. The charging current for high-power lithium batteries, especially for new modifications, it can reach 1-2 C. You can recharge such a device in 1 hour, without overstating the parameters recommended by the manufacturer and without spoiling the quality of the product.

Connecting to a screwdriver

  • A sharp pull on the trigger provokes the activation of the protective current mechanism. But in fact, such a protective mode is unlikely to be needed when using the tool. If you do not specifically provoke protection, then the work of the screwdriver will be stable.
  • The tip should be clamped in a vice. The battery power freely triggers the ratchet, which limits the increase in the number of torsion revolutions.
  • The screwdriver’s lithium battery is discharged electronically. The discharge current should be 5 A.
  • The battery is inserted into the standard charger. The charge current indicator when measured is 3 A, which is acceptable for lithium cells. For the LG INR18650HG2 configuration, the maximum charge current will be 4 A, which is indicated in the technical specification.

Supercharge a Dead Drill Battery (replace Ni-Cd with Li-ion)

Disassembly and assembly

Converting a screwdriver to lithium batteries includes the following steps:

  • Open the old battery by unscrewing five screws.
  • Remove the Ni-Mh battery from the housing. It will be noticeable that the contact pad engaging with the contact group of the screwdriver is welded to the negative contact of one of the Ni-Mh cells. The welding points should be cut using a tool with a DREMEL 4000 cut-off stone installed in it.
  • Wires are soldered to the contacts, the cross-section of which is at least 2 mm 2 for the power leads and 0.2 mm 2 for the thermistor. The contact pad is glued to the battery case with hot melt glue.
  • According to the indicator of internal resistance, four cells are selected on the meter. The value must be the same for all four fixtures.
  • Lithium cells are glued with hot melt glue so that they are compactly located in the housing.
  • Welding of cells is carried out on a resistance welding machine by means of a welding tape made of nickel (its cross-sectional index should be equal to 2X10 mm).

What lithium batteries look like?

Most lithium devices are housed in a prismatic body, but some are cylindrical in shape. These batteries use roll electrodes and separators. The body is made of aluminum or steel. The positive pole goes out to the housing cover.

In prismatic configurations, the electrodes are rectangular plates. To ensure safety, a device is provided in the battery that acts as a regulator of all processes and opens the electrical circuit in critical situations. Increased sealing of the case does not allow electrolyte to leak out and oxygen and moisture penetrate inside.

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How long does it take to replace batteries?

Converting the screwdriver to lithium batteries will take approximately 2 hours. If all parameters are checked, then it will take 4 hours.

Everything can be done on your own, without the help of another person. But contact welding and selection of batteries cannot be carried out without specialized equipment.

What else can you test the state of charge besides the controller?

The screwdriver was converted to lithium batteries. The built-in charger is ideal. But the cost of the controller is quite high. The device will cost 30. which is equivalent to the cost of the battery itself.

To test the charge level of a lithium battery on the go without using a charger, you can use the special RC helicopter lipo battery AKKU portable voltage meter tester alarm 2-6S AOK. The cost of the device is very low. It has a balance and charge connector similar to the iMax6. The device is connected to the battery via an adapter. This voltage level monitor is very convenient. It can measure from two to six lithium cells connected in series, and also give the total indicator or voltage of each element separately with extreme accuracy.

How to Determine the Choice of Lithium Cells?

In order to make the selection of lithium-based cells, the limiting factors should be outlined. Currently, lithium devices are produced with a permissible load current of 20-25 A.

Pulse current values ​​(short, up to 1-2 seconds) reach 30-35 A. Battery configuration will not be violated.

There is a way out. reworking the screwdriver in the network

Yes, it loses one of the benefits of a cordless tool. mobility. But for work in rooms with access to a 220 volt network, this is an excellent way out. Especially since you give new life to a broken instrument.

There are two concepts of how to make a network out of a cordless screwdriver:

We build in a ready-made power supply

To do this, you need to purchase a ready-made block with suitable characteristics and dimensions. There is enough such good on the radio markets.

Take the body with you and go to the fitting. When the desired power source is purchased, carefully separate it from the case.

We place the screwdriver in the battery box. All components must be securely fastened.

If necessary, extend the wires connecting the control board and the transformer. If the circuit touches the metal parts of the transformer during operation, a short circuit will occur.

Since the space in the case allows. separate the board and the transformer for better cooling. Whichever quality power supply you choose, the load will be high and overheating is possible.

It will not be superfluous to fix additional radiators on the power control microcircuits. Operate the screwdriver for a long time, disconnect it from the mains and touch the radio parts on the control board.

You yourself will understand which elements need heat dissipation. Holes can be made in the housing for air circulation.

Do-it-yourself rework of the power supply will not take much time, and the cost of the purchased module is incomparable with restoring the battery.

Battery case power supply

Mobility remains, you are limited only by the length of the network cable. The only problem is how to squeeze a sufficiently powerful transformer into a small case.

We recall Ohm’s law again, and we understand that a powerful 220 volt electric motor can be compact.

Using a car battery charger

The principle is the same as using a computer power supply. It is necessary to purchase an old charger for the starter batteries. The modern fashion for compact impulse chargers has left analog linear devices with manual control of voltage and charge current behind board. Therefore, such a device can be purchased on the automotive market for a symbolic cost.


It’s good if the voltage can be adjusted smoothly. in this case, your makeshift power supply will fit any screwdriver.

Converting it to a power tool is reduced to connecting the input of the electric motor to the power terminals of the charger.

Making a homemade power supply

If you are familiar with the principles of building electrical circuits, you can make your own power supply. Scheme giving general concepts. in the illustration.

The transformer can be picked up from an old tube TV, or other household appliances. Power 220 volts 250-350W. The main thing is the power supply. the donor should not be pulsed.

The voltage on the secondary winding is 24-30 volts. The secondary winding is made from a wire of the corresponding section.

However, if the output winding current is at least 15 amperes (see transformer specification), there is nothing to worry about.

After losses on the diode bridge (1-1.5 V on the diode), you will get the required output value.

If you have an electrical engineering education, make the calculation yourself. Or in a practical way: by connecting a 220 volt 100W incandescent lamp as a load, measure the output voltage. E

If it exceeds the needs of the screwdriver, reduce the number of turns of the secondary winding of the transformer.

Conversion of a screwdriver from a battery to a mains supply

  • Battery Disadvantages
  • There is a way out. reworking the screwdriver in the network
  • External power supply
  • Battery case power supply
  • DIY screwdriver alteration
  • Using a power supply from a personal computer
  • Using a car battery charger
  • Making a homemade power supply
  • AC adapter for screwdriver in battery housing
  • We build in a ready-made power supply
  • Homemade power scheme

Those who have used a cordless screwdriver have appreciated its convenience. At any time, without getting tangled in the wires, you can crawl into hard-to-reach niches. Until the battery runs out.

External power supply

The idea is not as absurd as it might seem. Even a large and heavy buck rectifier can just stand near the outlet.

You are equally tied to the power supply, and to the stuck mains plug. And the low-voltage cord can be made to any length.

IMPORTANT! Ohm’s law says. with the same power, decreasing the voltage. we increase the current strength! Accordingly, the 12-19 volt supply cord should have a larger cross section than 220 volts.