How to disassemble the battery of a 12 volt Hitachi electric screwdriver
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.
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.
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. 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.
- an electric screwdriver becomes much easier after converting the battery to li-ion, using 18650 cells.
There are only two obstacles to converting an electric 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 an electric 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 convert a 12 V electric screwdriver using Ni-Cd cans to 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 slightly increase, capacity. solid pluses. But when dismantling, it is necessary to leave the terminals and the native thermal sensor.
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.
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 goes 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 battery upgrade cost about 1000 rubles. Makitov’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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The inevitable has come. the batteries in my old Hitachi DS 12DVF3 are completely dead. They have become disgusting to hold a charge for a very long time, but the available capacity was enough for small household needs, so I never thought about solving this problem. Until the moment when I needed to drill a hole in a stainless steel kitchen sink, which took me forty minutes! One hole! One battery could not be swung at all, while the other did not work, twists for twenty seconds, charges for about ten minutes. It was then that I realized that it was time to give a new life to my favorite instrument. It is clear that first it was necessary to familiarize myself with the theory a little in order to understand what in general I have to do. Of course, this topic is not at all new and everyone who is not lazy is engaged in the translation of screwdrivers into lithium. But each does it in his own way, depending on his education, the amount of laziness and the concept of beauty. I needed everything to be done absolutely correctly from the technical point of view, so that it did not look scary from the outside and that the batteries could be conveniently used. After re-reading and reviewing a huge amount of material, I took a project from AlexGyver as a basis.
Here you need to carefully break off the upper contact pad, it will be needed later. You will also need nickel jumpers to solder the second unit to the batteries, so I move this stuff aside for now. Next, I try on new components in order to understand the front of the upcoming work.
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 desired 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 an electric screwdriver to lithium batteries, mainly to the 18650 form factor, is justified.
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.
I have two chargers, DC9710 and DC1414 T. And they work differently now, so I’ll tell you exactly how.
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.
Battery 12V Rebuild Step by Step | EB12B Battery for Hitachi Impact Driver WH12DH
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.
Repair: 12v cordless drill battery replacement
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.
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.
How to disassemble the battery of the Hitachi electric screwdriver
When the batteries of the screwdriver have worked out their service life, the user is faced with the question of how to disassemble the battery from the Hitachi electric screwdriver so that later it can be carefully assembled. The battery case is disassembled not only in order to replace the spent cans with serviceable ones, but also to transfer the battery from nickel-cadmium to lithium-ion batteries.
First, the type of attachment of the battery case is determined. The module can be mounted on:
A combined mounting option is also common, when the battery for the Hitachi electric screwdriver is simultaneously attached, for example, to glue and screws.
A clip-on housing can have one latch in the center, or two latches on the sides. Paired latches open after pressing them at the same time.
The screws are unscrewed with a suitable screwdriver. They remember from which particular hole each product was unscrewed, so that during assembly the screws were in their places. This is important as the length of the screws varies. A long screw threaded into a short hole will pierce the plastic of the sheathing and could pierce the battery. The leaked electrolyte can irreversibly damage nearby batteries, an electronic board, and under unfavorable circumstances, their explosion may occur.
How to disassemble the battery of a 12 volt Hitachi electric screwdriver, bonded with glue
The adhesive layer is destroyed mechanically using a pointed object such as a flat screwdriver. In this case, the movements must be very careful not to damage the device. This method of parsing is quite risky, since a sharpened tool can split the body and become completely unusable.
The case, fixed with glue, is very convenient to disassemble using a building hair dryer. With a hot stream from a safe distance, they warm up the adhesive layer for several seconds along the entire perimeter of the casing. Then, when it heats up, it is carefully separated into two parts. Gloves are recommended to avoid scalding.
If it is not possible to use a construction hair dryer, you can use the alternative option of neatly separating the glued body. The glue seam around the entire perimeter is tapped with a hammer with a rubber striker (or similar soft material). Movements should not be strong and fast, the process should last at least half an hour. From tapping, the adhesive layer softens and the halves of the case are easily separated from each other.
The halves are carefully disconnected, making sure that the connections of the wires, protection and balancing boards are not broken (if the battery is a lithium-ion type). These connections are carefully unsoldered, worn out batteries are removed, and new ones installed and soldered. In this case, the soldering tool must have a power of no more than 65 watts, because otherwise, the batteries become very hot, their electrolyte boils, which can provoke an explosion.
How to disassemble a battery using a regular mallet
In order to disassemble the battery from a Bosch electric screwdriver, “Metabo” or any other tool of 12 volts or more, you need to make some effort. If you just pick out the adjacent edges of the battery pack with a screwdriver, it will turn out to be sloppy. In addition, there is a greater risk that the fragile plastic structure will simply break.
Therefore, it is recommended to take a mallet and begin to slowly tap on the edge of the seam until characteristic sounds appear, meaning that the seam itself begins to weaken on the sly. It will take a long time to knock, and it will take time and patience. But it is in this way that you can ensure that the disassembly of the battery from the Makita electric screwdriver will be crowned with success, without unnecessary breakdowns and losses.
After a while, you will hear a crack of a breaking seam. The batteries themselves inside from such manipulations will not be damaged. Only the seam holding the block will break, and the “cans” and the two halves of the plastic case will remain unharmed.
When we disassemble the block, knock on the body with a mallet lightly, without making any special efforts, so that it bounces slightly off the surface. From time to time, between tapping, you can try to slowly pull back the bottom cover of the block, thereby checking how much the seam has loosened. In such cases, the mallet itself will be slightly damaged, but there is nothing wrong with that.
When the clicks when tapping become regular, you should check the block with some thin knife, carefully inserting it between the halves of the case. When the two parts of the case begin to open, it will be visible. it means that we have almost achieved our goal.
It is worth warning right away that the battery packs of the 12-volt Makita electric screwdriver are often extremely sturdy and difficult to disassemble. But if you slowly work with a mallet, the seam on the glue will gradually crumble. This may take ten minutes or more in time. But for a person with experience, the whole process takes no more than six minutes.
This is how, gradually and accurately, you can disassemble the battery of the electric screwdriver, which the manufacturer deliberately made “non-removable”. in order not to change the batteries in it, but immediately run after a new one, which is expensive. Of course, this will require some skill and accuracy. But it will also save money, and at the same time learn how to disassemble the battery from the Makita electric screwdriver with your own hands.
Soldering should be done by spot welding using a regular aspirin tablet. It is impossible to solder one element directly to another: any heating causes the evaporation of the electrolyte and a rise in temperature, which can be critical for the battery.
When disassembling the bundle and soldering, it is important not to lose metal particles, which may be indispensable when soldering the elements together. To be on the safe side, you can take care in advance of how to make blanks of spare plates from bending metal. It is important to remember the following: the better I solder, the better the battery will work.
Aspirin gives off a lot of corrosive fumes, so work in a well-ventilated area. A soft fusible composition with flowing properties is taken as a solder. The solder is sprinkled with aspirin powder, so it flows between the plates and connects them securely, and aspirin helps to fix the composition in the right place.
The assembled battery is installed in the case, and the operation of the electric screwdriver is checked. If the tool is running, the newly assembled battery is charged as usual and its functionality is checked again. If there is no drop in revolutions of the instrument, this means that the experiment was successful. Since nickel-cadmium batteries work for a long time with proper operation, there is a chance that a new bundle assembled with your own hands will not fail, and a battery for an electric screwdriver, made by yourself, will work properly.
Charging the batteries
Before disassembling the blocks, be sure to charge them well. With subsequent voltage measurements, this is what will make it possible to understand which batteries are “live” and which are not. Before charging the batteries, it is recommended to clean the internal contacts of the charger with emery paper, because any contact resistance can “give out” an incorrect charging process.
When you charge both batteries alternately, pay attention to how fast they charge. If the battery is charged quickly, and the charge indicator signals the end of the process after just a few minutes, this means that there are definitely faulty cells in the battery. And of course, when the battery charges too slowly, or does not take current at all, it should definitely be disassembled and “tested” all the batteries that are inside. Read more about the charging time of the electric screwdriver battery →
After you charge and disassemble your battery pack, you will see that there are several elements inside it. cans. The number may vary depending on the voltage level of your instrument. The banks are connected in a certain series. Inside there is a thermal sensor brought out to the contact plates.
If the signal from the temperature sensor to the charger is incorrect, then the battery will receive either an undercharge or an overcharge. Both are highly undesirable for the battery and adversely affect its performance. This is why it is strongly recommended to clean the contacts before charging both batteries.
How to disassemble and remake a battery from an electric screwdriver with your own hands
Everyone knows that the battery of an electric screwdriver sooner or later begins to lose its former performance and needs to be replaced. Usually only a couple of elements in a common bundle “sit down”, but this negatively affects the entire battery. Therefore, it becomes necessary to either replace several elements with new ones, or still change the battery pack completely. Since the complete set of any electric screwdriver. “Hitachi“, “Makita” and other models. includes two batteries, if you wish, you can try to assemble a whole homemade battery from two. The owners of power tools, who use them all the time, sooner or later begin to wonder how to convert the battery of an electric screwdriver to lithium. As for the newcomers, who were puzzled by this goal for the first time, they first of all have a question about how to disassemble the battery from the Makita electric screwdriver or any other, so as not to damage the fragile plastic box.
Experienced electronics enthusiasts assemble different types of batteries, including power supplies for an uninterruptible power supply (UPS). This is much more difficult than disassembling the battery of an electric drill. Any drill is often produced with so-called “non-separable” battery packs, which are either firmly sealed with tape around the perimeter, or their two parts fit so tightly to each other that, at first glance, it is impossible to disconnect them without causing forced external damage. However, among the craftsmen you can find people who have already thoroughly “got their hands on” such batteries and can happily share their secrets with everyone.
We measure the voltage
Before measuring the voltage of the cells, prepare a simple pencil with which you will write down the value of U issued by each battery in the bundle. Since in most cases “walking” screwdrivers are equipped with nickel-cadmium batteries packed in dense cardboard layers, it is important to ensure that the batteries are accessible from both sides.
Now it remains to turn on the voltmeter (or multimeter) and start measuring. When measuring, we make each battery an exposure for five seconds and see if the voltage drops (usually it is normally about 1.2 volts for each battery separately). We fix the indicators with a pencil. It is impossible to keep the probes on batteries for a long time, because the resistance increases, and they can simply burn out.
Practice shows that one has only to fail one element from the entire bundle, this negatively affects the operation of all batteries. If the voltage indicator on any “bank” is 1 volt or less, it has already exhausted its resource. In order to finally make sure of this, you should check the self-discharge level of each battery in the bundle.
Repeated measurements are taken after 15 minutes. When measuring, be sure to check the primary U values with repeated ones. If it turns out that there are batteries, the voltage of which after the initial measurements dropped sharply during the second measurement, it means that they have a high self-discharge, and it is these elements that have already completely become unusable.
After the unusable elements are “calculated”, we disconnect them from the rest with a scalpel, and in their place we put usable batteries from a spare battery. So we redo the entire block, collecting one full-fledged from two.
What is the load for?
Let’s work with the load resistance. As already mentioned, you can take two, each with a nominal value of 1 ohm. If we put both of them in parallel, then the total resistance we get 0.5 Ohm. It is not necessary to adhere to these ratings, but the lower the resistance, the better.
What is the role of load resistors in qualitatively replacing the battery pack? If we take any electrical appliance and measure the voltage indicator in its battery, we will get a certain value. However, this value does not show how well a particular battery can give its energy. If we measure the voltage under load, we will have what is called “voltage drop”. It is just from it that you can judge how good or bad the battery is.
The load resistance in the form of two small metal blanks and wires connected in parallel to each other is carefully connected to a voltmeter. This loading method is acceptable only if the output voltage of your battery is 12 volts or less (safe voltage level).
The wires are neatly fixed in the “sockets” of the voltmeter with probes, and a constant voltage threshold of 20 volts is set on the voltmeter. This indicator is quite enough to measure U for the entire bunch of elements as a whole and for each element separately, which is especially important.
We disassemble the battery with a spatula or a clerical knife
For those who are not used to working with a mallet and want to make the battery disassembly process look quieter and more gentle, you can suggest using a small metal spatula or a utility knife. The main thing is that they do not have sharp edges, like a large screwdriver, which can easily damage plastic.
First, you should completely walk around the perimeter of the entire block with a knife to loosen the seam, and only after that you can begin to “pick” the flexible plastic with a small screwdriver. The method is no less painstaking than the first, and if a person is not experienced enough, damage may remain on the plastic case. However, if you work as carefully as possible, it is possible to do without “losses” and in this case.
If, when disassembling the battery pack, you still have cracks or other damage, you should not be upset, because this type of plastic lends itself well to gluing with dichloroethane.
This method involves the use of several bulbs or small electric motors that are connected to each power supply in the battery system of an electric screwdriver.
First, the entire battery is fully charged. Then, one 3-4 V light bulb or a low-power “motor” is connected to each “bank”. The method makes it possible, without measuring devices, to identify inoperative elements in the system, which will lose their charge before all under load. Blocks that have lost their capacity will certainly reveal themselves.
Restoration of the battery of an electric screwdriver 18 volts
18 V is a common power, which corresponds to the presence of 15 units. As a donor, you need to choose an electrical appliance with a voltage of 14.5 V, that is, a 12 V car battery will not work.
The “memory effect” and what to do with it?
If we are talking about ni cd batteries, then for them there is such a thing as “memory effect”. This “painful symptom” is defined quite simply. When the battery, after going through a full charge cycle, quickly discharges, and after a short pause continues to function again, then this is a correct diagnosis, which, with proper skill, can be cured.
What needs to be done to heal the “memory effect”?
First, the battery is fully charged (preferably at low currents). Then a small load is applied to it in order to achieve a complete discharge. This simple trick allows the inner plates of the battery to be fully activated. As an example of a successful load, you can use a conventional 220 V incandescent lamp with a power of 60W. The slow charging and discharging process should be repeated at least 4-5 times. The result of these measures will be the return of the original battery capacity by 80%.
By the way, if you carry out work on a disassembled battery, where “weakened” batteries are already known, then a shock effect with a large current can return them to operation. If the electrolyte is present in the battery, then you can always restore the battery using this method.
Battery repair for Hitachi electric screwdriver 12v
Almost every battery in a power tool is the most expensive part. an electric screwdriver is no exception, because a replaceable battery can make up 30% of the total cost of the tool. After the device is discharged, it is necessary to purchase a new electric screwdriver, but to save finances, there is another option. restoration, which will extend its service life.
How to repair an electric screwdriver battery at home
Can all types of batteries be reanimated? Nickel-cadmium blocks, which are found in almost all modern screwdrivers, lend themselves better to repair.
For the recovery process, you need to understand the basics of electricity. That is, to have school knowledge about the operation of batteries.
To work you will need tools and materials:
- soldering iron;
- tin (with low corrosive flux).
A donor will be required to resuscitate the battery. In the complete set of an electric screwdriver, it may be available, or you need to find it yourself, for example, by removing it from another old device.
To start the operation, you need to fully charge (about 6 hours) both batteries, swing it. Then remove the plastic cover from the part to be restored using a screwdriver. This procedure must be done carefully so as not to damage the clips. Otherwise, for subsequent assembly, you will need glue, like “Moment”.
Partial replacement of worn-out cells
It will be more economical to replace each cell separately if you have free time. Here you will need the skill of spot welding. soldering the cells with an ordinary soldering iron can change their characteristics and spoil!
Determine the malfunction of the screwdriver battery
Charge the battery to a full level, remove from charge and disassemble to access the cells. 2. Using a multimeter, measure the voltage (in DCV mode) of each cell (battery). 3. In good condition, Ni-Cd and Ni-MH give out 1.2-1.4 V, and Li-Ion. 3.6-3.8 V. 4. Assemble the battery and discharge it until the screwdriver rotation is clearly slowed down. 5. Disassemble and measure again. a voltage drop to the level of 0.4-0.8 V indicates the wear of such a cell.
Elimination of the “memory effect”
If, after a full charge, the screwdriver quickly consumes battery power and after a while continues to work a little, then you are faced with the “memory effect” of Ni-Cd or Ni-MH.
To eliminate the “memory effect” in a screwdriver, its calibration (training) will help: charge up to 100% (as low as possible with a current); completely discharge the tool with a low power rotation feed for a long time; repeat this procedure 3-5 times, and the battery will come back to life.