Conversion of an 18 volt electric screwdriver to lithium

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.

Conversion of the Makita electric screwdriver to a lithium battery

There is a “Makita” electric 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. charge, will add power as the operating voltage rises to 10.8 V.

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 4.2 V, the lower voltage is 2.7 V. 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.

DeWalt 18V XRP Conversion to 20V Lithium ION

Step-by-step instructions for converting a Makita electric 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 downwards, butt-joint along the lower part of the body.
Take only the contact plates from the old assembly, carefully disconnecting them from the battery. Leave the sensor and breaker.
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 an electric screwdriver with an old DC9710 charger, once the 18650 lithium battery has finished charging, 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. electric screwdriver ready to work.

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 separated. In this case, the case is not damaged in any way, I have already disassembled 4 pieces this way.

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.

Conversion of the “Hitachi” 12 V electric screwdriver to 18640 lithium batteries

Features of alteration of the 12 V Hitachi electric 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 an electric screwdriver during rework 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-on 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.

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 cells, 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 is 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 permissible 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 30-amp 18650 cells (2100 mAh capacity) and 20-amp Sanyo UR18650NSX (2600 mAh capacity). They work fine in my electric 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 collect 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, the 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 done 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.

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.

Conversion of an electric 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 battery of an electric screwdriver should be carried out taking into account the characteristics of lithium batteries for 18650.

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 an electric screwdriver with a voltage of 14.4 V lies in the creation of 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 electric screwdriver is high, you must select the appropriate BMS for the required number of cans and at least 30 A. jumpers.

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 an electric 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 Interskol electric screwdriver to 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 DS “Interskol” with lithium batteries serve much better. Alteration of an electric 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 electric screwdriver

If you have (or have been lying around with friends) an old Ni-Cd screwdriver and all the batteries have sat down, and even the charger has broken down (burned out), order an MT3608 board on Ali for 40r, look for an old charger from a cell phone (all in bulk) and old laptop batteries (of which we need Li-Ion 18650 batteries).

Today we will be converting an old screwdriver from nickel-cadmium batteries to lithium-ion batteries, and, accordingly, its charger.

Everything is easily redone. Let’s start with batteries.

If the screwdriver was at 12V, we will need 4 18650 batteries (16.8V maximum), if at 14.4V. 5 pcs (21V maximum), if at 18V. then 6 pcs (25.2V maximum). The safety margin of the electric motor and other mechanisms in the screwdriver is large, and we will not be in the way of increasing the power.

First, 18650 Li-Ion batteries are tested, if there is anything to choose from, they are selected with the same capacity. Expensively and accurately, this can be done using a BT-C3100 V2.2 device or similar. The approximate capacity of 18650 batteries from laptops is 1800-2200 mAh, sometimes you need to divide by 2 the capacity written on the battery case. And so it is enough to charge Li-Ion 18650 batteries up to 4.2V in any charging suitable for them with a voltage limitation, give the same load and after the same time measure the voltage on them. If it fell to the same values, then it is normal. For example, we load a fully charged 18650 onto a 12V lamp from a car, and after a minute we measure how much is left of 4.2V. If about the same, the batteries are suitable.

We throw out the old dead / closed Ni-Cd batteries from the body of the replaceable battery, and instead of them we solder Li-Ion to the voltage we need. For the Li-Ion batteries themselves, it is better to leave flat connectors from the laptop, but if you still solder wires to Li-Ion, cool the soldering place with a blower, solder quickly with flux or acid to reduce the heating time of the battery surfaces, in order to avoid damage Take wires for soldering from an old computer PSU, or thicker.

We check how the screwdriver turns, usually this is an increase in power by 20-40% and a decrease in the weight of a replaceable battery.

Now we move on to reworking the charging, especially if it burned out or not. They are different for different companies, Bosch, Shturm, Hitachi, everything is different. From the charging case, you can get all the stuffing, except for the terminal block. By and large, we only need a terminal block to connect a removable battery. Of course, everything will be better in the case. I had too much current from a heavy transformer, and it was heavy, so I found a better use for it (in a laboratory PSU).

We solder the output of the charger for the cell to the MT3608 board on the VIn contacts, plus, minus. We turn on, tighten the resistor to the output voltage we need, this is 16.8, 21 or 25.2V, respectively, what kind of Li-Ion battery you have.

MT3608 is a Step Up (boost) voltage converter with pulse width modulation, on ordinary boards, the output capacitor must be soldered to the large contact of the VOut output and, accordingly, cleaned the ground next to it to solder the capacitor. This is a deficiency of the Chinese, the board works worse from the factory.

We limit the charge current, for this we need a 5-15 Ohm resistor and the simplest and smallest diode. Solder the VOut plus wire directly to the battery plus terminal block. And VOut- through a resistor in the negative wire. From the measuring point of the resistor, we solder the diode (anode) (cathode with a strip) to the FB signal of the microcircuit, this is the 3rd contact of MT3608, fine, but it rings out on the potentiometer on the other side of the board, which is much easier to solder.

We connect the battery for charging and check the charge current, it will be from 50 mA (15 ohms) to 200 mA (5 ohms). Accordingly, the current from the cellular charging will be, for example, 50mA (21V / 5V / efficiency) = 300mA, and for 200mA (21V / 5V / efficiency) = 1200mA (it may be too large, not every cellular charging will pull it). We check the charging, if it heats up or the voltage from it sags from 5V to 2.5V, then the current should be reduced to avoid overheating.

You may ask why such a small charging current, because it will take a long time to charge. The first moment, at high charge currents, close to 1.0C (C-capacity of the Li-Ion battery), the charge time is about an hour, the battery will definitely die after 1-2 years of such atrocities. Second, even old Li-Ion batteries tend to recover at low charging currents (unless, of course, chemistry leaks and swells), and charging with a low current will definitely prolong the life of the battery.

Cons: Long full charge time (10-20 hours). It is extremely undesirable to plant Li-Ion batteries below 3V per cell, that is, to do a full discharge (when the screwdriver turns much weaker), Li-Ion batteries lose their capacity much earlier in the cold, already at 0 degrees the screwdriver will work little (You can wear a glove or a scarf or a scarf only for the battery of a screwdriver for short-term work in the cold, or only warm up the battery in a room on a heating battery).

Somehow I came across a very weak Chinese cell phone charger. Written 5V, 450mA. Even at 21V 50mA, MT3608 overloaded charging and the output voltage dropped to 2V, charging boiled. What had to be redone:

First, I made a voltage limitation for the beginning of the conversion Uin for the MT3608 (so that the converter does not transfer the charger power supply to the 2V 2A state, when everything starts to get very hot and burn). In a diagram of simple parts, the resistor R2 can be replaced with a 1-10-100kΩ trimmer (10k is optimal and R1 is 10k then). This made it possible to start the StepUp converter only from an increased input voltage, the maximum current for Chinese charging was at a voltage of 4.3 V, if you slightly increase the trimmer, the converter stopped and the voltage jumped to 5V.

I also wanted to raise the charging current, 21V 80 mA was not enough.

The higher the voltage on the secondary winding of the high-frequency transformer of the charging power supply converter, the more power can be removed at the same current (and the maximum current depends on the wire cross-section), but you can reach oversaturation or overheating of the transformer, and the power supply circuit can go into protection or burn out.

At the output of the charging power supply, there is a feedback optocoupler and a 3-4 Volt zener diode or resistors to stabilize 5.2V. I was lucky and came across a charger, including a 7.5V protective zener diode, which I soldered instead of a measuring zener diode, and got 9V at the charger output. Above 10V, it is better not to overclock a charger for a cell phone, usually at 11-12 volts stabilization breaks down.

As a result, I tightened the limitation of input voltage consumption by 8.2 volts, received 21V 140mA at the output of the converter, as a result, 13 hours of charge for my 1800mAh 18650 batteries is normal.

Tags: from scrap parts, can be found everywhere, readily available, easy to alter, simplicity, easier when there is nothing.

Leave Комментарии и мнения владельцев, share your experience, advise who got what, how best to redo it. If you shoot a video of the rework, post a link here.

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).

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 sq. Mm on the battery contacts. because the space allows. Before soldering them to the mating contacts, I put a piece of heat-shrinkable tube 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.

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

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

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

Convert Dewalt 18v battery to 20v LITHIUM. 25 DIY UPGRADE!!

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

What you need to estimate before starting work?

It is necessary to determine the number of cells in the battery, which ultimately decides the voltage value. 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.

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.

Stages of preparatory work

First of all, you need to find out the highest voltage value for the charge, this is done by calculating the number of cells. In the case of using three capacitors, the most effective voltage will be 12v, and for four. 16v.

Consider the option with an electric screwdriver designed for a voltage of 14.4v. In this case, it is necessary to use four containers, therefore, the difference in volts is equalized and the volume of the container increases. As a result, the tool with a Li-Ion battery can work significantly longer.

With regard to the type of cells, the conversion of the device to lithium batteries is considered more reliable using 18650 batteries. At this stage, it is necessary to determine the volume of capacity and the discharge current. Under the condition of standard operation of the device, the current consumption is in the range from 5A to 10A. However, in the event of an unexpected sharp decrease, its value can reach 25A. In order to protect batteries from damage when such surges appear, cells with a discharge current of 30A should be used.

Conversion of an electric screwdriver to lithium batteries

Converting a Ni-Cd battery of an electric screwdriver to Li-ion. Colossal capacity 4400mAh!

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, 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.

Conversion of an electric screwdriver to lithium batteries. Ni-Cd to Li-ion

Conversion of an electric screwdriver to lithium batteries. almost all models of old-style screwdrivers worked on nickel-cadmium batteries. This type of battery belongs to inexpensive products, but does not have enough power for a screwdriver, moreover, it has a memory effect.

It is this property of the battery that contributes to a gradual decrease in the value of its capacity. For this reason, most owners of such a tool benefit from converting it to 18650 lithium batteries with a voltage of 12v. Of course, the work with the rework is not fast and requires some costs, but if everything is done correctly, then the end result is worth it.

Makita DC9710 charger and lithium-ion battery

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.

Replacing batteries in a screwdriver with lithium

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 cans are used in the role of 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.

Putting together a lithium-ion battery

Cordless Drill Lithium Battery Conversion using 18650 Cells

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

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

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

Sources:

http://schemy.ru/info/peredelka-shurupoverta-na-litievye-akkumuljatory/

Articles conversion, electric, screwdriver, volt