How to restore the battery of a screwdriver
Topping up with distilled water in Ni-Cd battery
This is done when disassembling the case and if the internal resistance has increased (significantly more than 0.3. 0.6 Ohm). A small drill (0.5 mm) is carefully drilled into the body of the element and a few milliliters of pure distilled water is injected into it with a syringe. Then the hole is sealed with a soldering iron. These manipulations require skill and a beginner may not succumb.
After a while, about 12-24 hours, the electrolyte will return to its normal state and the cell will recover for a more or less long period.
To complete the work you will need:
- Mini drill drill 0.3-0.5 mm (as a last resort, a strong awl);
- 1 ml syringe with a needle and distilled water;
- Soldering iron 40-60 W, POS-61 solder and flux.
Where to make a hole:
The sequence of actions is as follows:
- Cut the paper cover from the element along the axis and remove it;
- Drill a hole as shown in the picture above. The drill should go 3-4 mm, no more;
- Introduce 10-15 ml of distilled water into the hole made;
- Wait 12-24 hours until the entire volume is soaked;
- Charge the cell to the rated voltage;
- Solder the hole with a well-heated soldering iron;
- Put on a paper cover and seal it with tape.
Recovered cells can be collected into a battery.
An example of how to do it yourself on
This method is similar to the previous one and is perhaps simpler. No need to disassemble the charger, or use a laboratory power supply. You only need:
- Car bulbs;
- Pieces of wire;
- Soldering iron with solder and flux.
Test scheme: For such a test, you must first put the battery on charge and charge in the usual way. Then the rated load is applied. It is not difficult to find out the current, for this divide the power consumption by the rated voltage. For example, if a screwdriver consumes a power of 50 W (typical case), at a voltage of 18 V, then the current should be 50/18 = 2.77 A. To achieve such a current, or close to it, you can dial in parallel car bulbs from turns.
If the battery delivers the rated current for several minutes, the voltmeter shows a voltage slightly lower than the rated voltage, and the bulbs do not fade, then the battery is in good order. However, it may happen that for Ni-Cd the current will soon begin to weaken. This is a manifestation of “memory”. In this case, you need to carry out restoration. Lithium-ion batteries do not have a memory effect, although in theory it exists, in practice it is believed that it simply does not exist.
The multimeter can be used in two modes: voltage measurement and current measurement. If there are two devices, then this is even better, you do not need to make unnecessary switches.
The measurement setup is shown below: One multimeter switches to voltage measuring mode (voltmeter), the other to current measuring mode (ammeter). If there is only one device, then instead of an ammeter, you will have to use just a wire. The wires from the battery to the voltmeter can be thin, and the wires from the power source to the battery are thicker, but do not get too carried away, in the end, wires of 0.5 mm.kv are suitable for the entire circuit.
If the voltage on the battery is normal, but the charge current is small, much less than one ampere, then for a Ni-Cd battery this may mean a malfunction of one of the battery cells. The restoration of the screwdriver battery is canceled here, repair is needed. For Li-ion, this means that either it is normal, or also a malfunction of one of the elements.
Let the Ni-Cd battery have a nominal voltage of 18 volts. Then it is easy to find out how many elements are inside without opening the case. Knowing the nominal voltage of Ni-Cd 1.2 V, divide: 18 / 1.2 = 15. This means that there are 15 elements in the case. If the voltmeter shows an open voltage of 16.8 V, then this may mean a short circuit in one of the cells, and simply a discharge of a normal battery. Such a battery in a discharged state gives 15 V. If a charged one shows 16.8 V or so, then one of the cells is short-circuited. It will not work either, you will have to replace it.
If the battery, when charging, passes a current of more than one ampere, and the voltage gradually increases, increasing by 0.1 V every 5-10 minutes, and at the end of the charge the voltage is slightly higher than the nominal, then the battery is in order, no recovery is required.
Eliminating the memory effect
This recovery method is applicable to nickel cadmium batteries. It is very simple to execute. First, the battery is discharged completely with a screwdriver or other load, such as lamps or resistance. Then it is fully charged. And this must be done several times. If the battery does not have any other defects, then it will fully recover. It makes no sense to restore lithium-ion batteries in this way.
There are ways to “restore” asymmetric current, when the charging current pulse is larger, and the following discharge gap is smaller, so that the difference is positive. This method is incorrect, it does not take into account the fact that chemical processes are much slower. Even more wild is the method of recovery with high current pulses. You shouldn’t use them.
To restore a Ni-Cd battery, you will need:
- Several car bulbs;
- Copper wire 0.5. 0.75 mm.kv;
It is better, of course, to have an uncomplicated special stand for restoration, but this is more suitable for professional repairmen than for ordinary users of screwdrivers. But be that as it may, working with two multimeters is much more convenient than with one.
The recovery steps are as follows:
- Determine the minimum, nominal and maximum battery voltage.
- Determine the rated load current.
- Turn on the switch S1 to position P (discharge). If the current is low, you can slightly increase the load by adding a few bulbs.
- Wait until the voltmeter shows the minimum voltage.
- Turn switch S1 to position З (charge). Monitor the current during charging.
- Wait until the voltmeter shows the maximum voltage.
- Switch S1 to position 0.
- Wait 20-30 minutes.
- Switch S1 to discharge position.
- Go to step 4.
- Repeat steps 4-10 until the discharge current is less than the rated load current during the normal operating time of the screwdriver.
In practice, do 3-4 to 7-8 cycles. If condition 11 in the recovery algorithm cannot be reached, then the battery must be repaired.
This method requires disassembling the battery case. It is applied when the battery or its cell stops delivering good current and recovery attempts fail. One bad link is enough here, since they are connected in series. But to find such an element, you need to check the internal resistance of each of them.
Of course, you need to start with a general inspection of all the cans: are there any cracks, leaks, etc. A defective element will immediately give itself out in appearance.
The current return test is performed using Ohm’s law for the complete circuit (aka the first Kirchhoff’s law). To do this, you need to take a resistance with a nominal value of 10 ohms, designed for 25 W, and an ammeter. The element under test is short-circuited to a resistance connected in series with the ammeter.
For example, suppose a current of 100 mA is obtained for a 1.2 V Ni-Cd battery. Let’s write it down and re-measure, but not the current, but the voltage across the element. First, we will measure the open voltage, without connecting a resistor, and then connect the resistor and see how much the voltage has dropped. Let the first time it was 1.2 V, and after connecting the resistor it became 1.05 V. Then the internal resistance of this element: This is not too little, if all the elements are like that, then the battery can provide the screwdriver with only half the power. The lower the internal resistance, the better the element, but with an indispensable condition: it must give a nominal, or close to this voltage. If the voltage is too low, or very close to zero, then the element is short-circuited, it is not suitable and cannot be restored. If the internal resistance is more than 3 ohms, then you can try to restore (see below) or replace.
Diagnostics of malfunctions of the battery
It is not necessary to suspect a screwdriver battery malfunction or to restore it immediately, but first try to replace it with the second one from the kit, before charging it properly. If the screwdriver does not rotate well, then this may be caused by breakdowns in its mechanics (motor or gearbox). If in doubt, replace the power supply, if possible. If everything points to the battery, then you can start diagnosing and restoring it.
First of all, you need to find out the type of battery. This is written on its body and the possibility of recovery depends on it. The rated voltage should also be indicated. It usually lies in the range of 14. 19 V. Then, without disassembling the case of the battery block, they check it. Two methods can be used for this:
- Checking with a multimeter;
- Load test.
Gas release from Li-ion batteries
As a result of improper use of Li-ion cells (overdischarge abuse), swelling is possible. As a result of decomposition of salts, oxygen is released and creates a high pressure in the body of the sealed element. These gases are vented with special valves, but small elements may not have them.
ATTENTION! Forcibly releasing gas from swollen Li-ion batteries, by destroying their case, is strictly prohibited by any instructions for their operation, this is a gross violation of fire safety!
The consequences of such an autopsy can be seen on this
Types of batteries and their differences
A power source for a hand tool should provide it with energy for at least half an hour of operation at moderate load or 10 minutes at full load. And at the same time, it is enough to quickly restore your charge. If these conditions are not met, the instrument loses all commercial meaning, it will simply not be bought. Typically, the power of the screwdriver varies between 80-160 W.
Of all the types of batteries that the industry produces, only three types are suitable for these criteria:
- Ni-Cd. nickel-cadmium;
- Ni-MH. nickel metal hydride;
- Li-ion. lithium-ion.
Nickel-cadmium appeared earlier than all others and showed good performance properties. Such a battery has a voltage of 1.35 V… 1.0 V. Here and below we denote the first rated voltage, and the last. the voltage at the end of the discharge cycle. Ni-Cd have a number of charge / discharge cycles in the range of 100. 900, it depends on the quality of the materials and the mode of operation. Ni-Cd is also characterized by a very low internal resistance, they almost do not heat up during charging, they are stored for a long time.
- “Memory effect” interfering with operation.
- Cadmium toxicity, it is a strong carcinogen.
Another type: nickel-metal hydride battery. These batteries have been proposed as a replacement for Ni-Cd. The rationale was the shortcomings of traditional cadmium batteries. In theory, Ni-MH is good: it has a high energy capacity (up to 300 Wh / kg), and is not subject to the memory effect. Voltage 1.25 V. 1.1 V, the number of charge cycles 300-800. Old Ni-MHs are completely self-discharging after a year of storage. It is recommended to store them at a low temperature, from 0 to 20 degrees Celsius. Batteries of a new type LSD Ni-MH (Low Self-Discharge), as their name indicates, have a low self-discharge and heat up less when charging.
Disadvantages: Ni-MH batteries are 10% discharged during the first day, and significant heat generation during charging.
Li-ion batteries have a voltage of 3.7 V. 2.5 V, but in reality it is a little more complicated with it, it all depends on the mode of use of the battery. The number of charge cycles is approximately 600, but this is provided that no more than 20% of the capacity is taken from the battery. Lithium-ion batteries do not like deep discharge. From this they quickly fail. The internal resistance of Li-ion is very small, 5. 15 milliohms. Self-discharge about 1.6% per month with full charge and no load.
Disadvantages: high cost, limited shelf life, not dependent on use. Risk of explosion and fire if improperly handled.
How to restore a battery to a Makita screwdriver
If the battery has ceased to hold a charge, and it is difficult to quickly acquire a new one in the near future, the situation can be corrected if you know how to restore the battery to a Makita screwdriver on your own.
How to restore a 12 volt Makita screwdriver battery by applying high currents
A pulse current is supplied to the problem battery using the popular Imax B6 charger, or similar. Before starting work, you must:
- check the electrolyte balance in batteries;
- set the “nickel-cadmium” mode on the charger.
If the amount of electrolyte remaining in the banks is not large, it is impossible to start recovery, because this will ruin the battery. The missing electrolyte volume is replaced with distilled water, and only then the reconstruction begins.
How to revive a dead rechargeable power tool battery easily
To fill in the water, a hole is made with a thin drill on the side of the battery, as close as possible to the upper edge. Water is poured using a syringe with a needle until the can is completely filled. The procedure is repeated for all batteries, the filled elements are left for settling for a day.
After that, a bundle (“cassette”) of batteries is connected to Imax B6 for charging with the following parameters: 12 volts in short-term pulses, the resistance value is 40 ohms. When the batteries are charged to 100%, they are left again for a day. A multimeter is used to check the voltage at each element, finding out if it has dropped. If an undercharged battery is found, water is added again, charged and the voltage is checked again.
When each can holds a charge stably, the drilled holes are sealed with silicone glue.
The battery housing of the screwdriver contains power elements (batteries, banks). They can be made from different components, which is reflected in their name:
- nickel metal hydride;
Batteries containing nickel and cadmium are widespread and highly recoverable due to their “memory effect”. This effect is a reversible loss of capacity that occurs if the battery charging mode is disrupted. For example, the battery for a Makita screwdriver was not completely discharged, but only up to 40%, but it was set to recharge. The battery remembers the 40% mark and will continue to work only until the discharge of this value is reached. This inconvenience can be corrected in several ways.
Replacing a few worn-out cans
Of the total number of cans in a cassette, only a few can exhaust their resource. They can be removed from the solder by replacing them with serviceable ones. First, they look for damaged elements: they measure the voltage of each with a multimeter, recording the results. The sum of the voltages of all batteries must be within 14 volts. Then the battery is connected to a screwdriver, they work intensively for some time, and measurements are taken again. If the difference between the first and second digits for an individual can is 0.5-0.7 volts, it must be replaced.
Restoration of cans
Batteries that have not passed the test should not be thrown away in a hurry. The main reason for their failure is the evaporation of water through the sealing gum located between the body and the middle tire. When there is a complete “zero” on it, the battery is briefly charged by impulse supply of 12 V voltage through a resistance of 40-50 Ohm. In this case, it should be monitored so that the case does not overheat. If after that there is still no voltage on it, the can can be thrown away.
When deciding how to restore a screwdriver battery, it is necessary, first of all, to identify faulty banks that spoil its work. If the battery is dead, it must be charged, and then the voltage on all cells must be checked. It should not differ from the nominal by no more than 10%.
Repair is how to restore the battery capacity of the screwdriver as a whole. It is affected by the serviceability of each element. It must have a given capacity, which means the ability to power the load connected to it. Sometimes it is better to replace failed elements that are quickly discharged. They can be detected by corrosion damage or the presence of characteristic traces of electrolyte on the surface.
One or two elements can seriously interfere with the operation of the entire line.
If the battery is used for more than 3 years, then most of the cells may be faulty. In this case, it is better to replace them all. It is important that they are of the correct voltage and size. Separately assembled batteries cost less than assembled new batteries.
The serviceability of each can is checked by the value of the internal resistance, which should be about 0.06 ohms. To do this, a load is connected to it (a 5-10 ohm resistor) and the current and voltage are determined. It is convenient to use low-voltage incandescent lamps. Measurements are made with two different resistances, respectively 30% and 70% of the permissible load. The 2nd is subtracted from the 1st voltage, and the 1st is subtracted from the 2nd current. Then the results of the subtraction are divided and, in accordance with Ohm’s law, we find the internal resistance of the battery.
The battery is often sold with a spare. Of the two, you can collect one and there will still be banks in stock. It is desirable to use them somewhere as power sources, for example, for a flashlight with a car lamp.
After diagnostics, the tested elements are assembled into a line. The selected kit must be soldered in the same order. The body of the can is negative and the middle bus is positive. Then, without assembling the battery, you should connect the charger to it. In this case, it is necessary to control the temperature of the elements. If they are in good order, then there should be no strong overheating. After the charging time has elapsed, as well as after a day, the voltage on each cell should be measured. If any battery “runs out” by more than 10%, it must be replaced with a new one. After the battery passes the test, you can finally assemble its case. The fastening screws are screwed into place according to the size, and acetate-acrylate (“Super-glue”) is used as the glue. With the correct selection of elements, the battery will serve as good as new. After charging, it should be subjected to intense training, applying maximum load to the screwdriver until it is discharged. Such cycles should be repeated 2 more times, and then. 1 time per quarter.
When deciding whether it is possible to restore the battery of a screwdriver, it is necessary, first of all, to figure out how to extract the elements from it. The battery is housed in a plastic case of two halves. First, unscrew the connecting screws. If the connection is made with glue, then you have to tinker with a screwdriver or chisel. Disassemble carefully so that you can then glue the case again.
Elements connected in series are placed inside. Some designs use parallel-serial connection.
Battery recovery in Aeg screwdriver
2 Li-Ion batteries are sold with the screwdriver. If one of them does not charge, this does not mean its malfunction. It is possible that it is too much discharged. To do this, you can try to “train” the battery by applying a pulse voltage to it, and then put it on charge. The easiest way is to connect to a charged battery for a few seconds.
After it was not possible to restore the battery of the Aeg screwdriver using the above method, its case should be disassembled and each jar should be checked.
Battery recovery of the Hitachi screwdriver
How to restore the battery of a Hitachi screwdriver? Both Ni-Cd batteries need to be charged, after which they should be disassembled and the voltage measured at each cell with a load of 1.5 ohms. Elements showing lower voltage can be discarded, and one high-quality battery can be assembled from the whole. Just 1 or 2 cans can spoil the battery experience. How to restore the battery of the “Hitachi” screwdriver, as well as all other models, depends, first of all, on the type of cells installed in them.
Interskol screwdriver battery
The Interskol screwdriver is one of the most popular due to its versatility. In addition to the main function, it can also serve as a drill.
Lithium-ion batteries do not have this disadvantage, but they have a much higher price. During operation, when every minute counts, a little recharging is often required to maintain the required power of the screwdriver. Here, such batteries are indispensable, since their capacity can be quickly restored.
The buyer chooses the battery of the Interskol screwdriver on his own, depending on his preferences, capabilities and the required work. Nickel-cadmium batteries are used in most cases.
How to restore the Interskol screwdriver battery if it has not been used for a long time? During operation, one must try to ensure that there is no voltage drop to zero. For a 1.2 V can, the discharge is produced up to 0.9 V. If it is completely discharged during long-term storage, the charger may not “see” it. It is necessary to “push” the battery with another, more powerful source of current, so that a small voltage appears on it. After that, you can connect it to a standard charger.
Battery maintenance guidelines
- If the battery has not been used, it should be discharged to the permissible load once a month and recharged.
- It is advisable to buy a screwdriver with two batteries included.
- Screwdrivers must be stored and used in conditions that exclude moisture ingress.
How to properly top up distilled water
Distilled water only evaporates from nickel-cadmium batteries when they overheat during operation. Therefore, to eliminate the problem and restore their functions, water must be refilled. This procedure is performed in the following sequence:
- After disassembling the battery, mini-batteries will be found inside. Their number may be different, depending on the brand of the instrument. The defective element is determined by a multimeter. In a working battery, the voltage is 1-1.3 V. If this indicator is lower, then the element is defective and needs to be repaired.
- Further, the faulty parts are carefully removed without destroying the connecting plates. You will need them later for reassembly.
- A hole of no more than 1 mm is drilled in the side part. It is not located in the middle, but closer to the bottom or top of the battery. You only need to drill the wall, without going deep inside the element.
- Distilled water must be drawn into the syringe. The needle is inserted into the hole and through it the battery is completely filled with water. After that, she must stand in this position for at least a day.
- After a day, the battery is charged with a special device, and then left in a charged state for another 7 days.
- After a week, the capacity and voltage are checked again, and if it has not dropped, then the hole in the case is sealed or sealed with silicone.
After all the manipulations, the batteries are assembled into one piece and inserted into the battery case. The connecting plates are soldered or spot welded. Then the performance of the entire battery is checked again, after which it is completely discharged with the help of small loads. The charging and discharging process is performed at least 3 times.
Replacing old batteries
In this way, you can repair the battery of any screwdriver. The repair procedure itself is not particularly difficult and begins with disassembling the battery. With the help of a multimeter, faulty elements are determined, in which the voltage will be below normal. Then they are carefully removed and the exact same mini-batteries are purchased instead.
New parts are installed in their places and connected with existing plates. Soldering or spot welding is used for the connection. In this case, you need to ensure that the battery does not overheat. Therefore, the work must be done accurately and quickly using flux or rosin.
Structural elements of the screwdriver
The screwdriver is rightfully considered an indispensable universal tool. The modern screwdriver market is represented by a large number of models equipped with batteries. Despite the variety of brands and modifications, all batteries have the same structure and only slightly differ from each other.
Each of them includes separate elements connected in series with each other. They are all made to standard sizes and have the same voltage level. Certain types of elements differ only in capacity, measured in A / h and indicated in the marking. There are 4 contacts in the tool body that perform various functions. Including, two are power, designed for charging and discharging. In addition, in the upper part there is a control contact included in the circuit together with a special temperature sensor. It protects the battery, disconnects the charging current and limits it to the set value by changing the temperature.
The fourth contact is separately located, connected together with the resistance. It is necessary when using charging stations of increased complexity, capable of equalizing the charges of all battery cells. Such stations are rarely used in everyday life due to their high cost. A conventional 12-volt screwdriver does not require such stations. One of the reasons for the failure of a screwdriver is a malfunction of the battery, that is, its separate element. In such cases, the daisy chain breaks down the entire circuit. Therefore, it is very important to pinpoint the faulty location. As a rule, this happens after the expiration of the established service life. This problem can be solved in two ways: purchasing a new battery or repairing and restoring an old battery.
How to restore a screwdriver battery
The battery life is relatively short, on average 5 years. After a set period, the battery abruptly stops working. In such a situation, it is not always possible to quickly acquire a new power source, so the home craftsman has to solve the problem of how to restore the screwdriver’s battery, at least for a short time. In some cases, after a successful recovery, the batteries work normally for quite a long time.
- Structural elements of the screwdriver
- What batteries are used in screwdrivers
- General repair recommendations
- How to eliminate memory effect
- How to properly top up distilled water
- Replacing old batteries
- Battery gas release
How to eliminate memory effect
When a battery is very often undercharged and then discharged, it has a so-called memory effect. That is, the battery gradually, as it were, memorizes the minimum boundary of charging and discharging, as a result, its capacity is not fully used and gradually decreases more and more.
This problem is typical mainly for nickel-cadmium batteries and to a lesser extent affects nickel-metal hydride batteries. In any case, the battery capacity needs to be restored. The memory effect does not affect lithium-ion batteries at all. In order to solve the problem of whether the element can be repaired, it is recommended to completely discharge and charge the battery using a 12 volt light bulb. The positive and negative wires are soldered to it, which are connected to the battery contacts. This procedure is repeated five times or more.
What batteries are used in screwdrivers
Correct diagnostics requires knowledge of the main types of batteries used in screwdrivers and the design features of each of them. Each battery consists of mini-batteries connected in series in a single chain. Depending on the material of manufacture, they are nickel-cadmium (Ni-Cd), nickel-metal hydride (Ni-MH) and lithium.
The first option, Ni-Cd, is the most widely used. In these batteries, each cell has a voltage of 1.2 volts, for a total of 12 volts with a capacity of 12,000 mAh. They differ from lithium in the possibility of recovery, since they have a well-known memory effect, which is a reversible loss of capacity. Due to the design features of batteries, not all methods are suitable for their recovery. For example, lithium cells cannot be recovered using Imax B6 charging, since lithium gradually decomposes, loses its quality and does not hold 18 volts. The same method is not always suitable for Ni-Cd batteries, since in some cases the electrolyte can completely boil off in them. Nevertheless, there are many options for recovery.
Different types of batteries also differ in their own operating voltage. This difference is due to the materials used to make a particular battery. This factor also affects the capacity, which ensures long-term operation of the tool without additional charging. Therefore, at the initial opening of the case, first of all, the type of elements placed inside is determined. The fact is that it is not allowed to replace lithium mini-batteries with nickel-cadmium ones, since their operating voltages differ significantly. Accordingly, the methods of repair and restoration will differ.
General repair recommendations
To repair the battery, you will need measuring instruments. a 2 A ammeter, a 2 and 15 V voltmeter, a tester, an ohmmeter and a milliammeter. The body is manipulated with a screwdriver, scissors and pliers. A magnifying glass may be needed to detect defects.
While solving the problem, can the battery be repaired, the faulty element is searched for and its further replacement. For verification, a standard scheme is used, and based on the data obtained, the state of individual parts is analyzed. It should be remembered that not only mini-batteries may be faulty, but also the terminals of the screwdriver itself. Determining the causes begins with measuring the voltage with a tester on each individual battery. All non-working elements are marked and separated from non-working ones. If the battery is rapidly discharging, do not immediately disassemble it. First, you can try to restore the battery capacity of the screwdriver. For this purpose, the battery is fully charged and deeply discharged over several cycles. In most cases, the capacity is almost completely recovered.
Often the screwdriver stops working due to the failure of the terminals. During operation, they gradually unbend, as a result, the contact is broken and the battery is not fully charged. To repair the charger, you must first disassemble it, and then carefully bend each terminal. After that, you need to check the quality of charging using measuring instruments.
If the measures taken did not help, you just need to replace the faulty part. If a specific cause of a malfunction is found, it is recommended to use the recovery methods below.
Battery gas release
This repair method applies to lithium-ion battery cells. During the period of operation, they overheat, as a result of which electrolyte evaporates from some batteries. This causes gases to build up inside the battery, causing swelling and bending of the plate. After that, you have to restore the screwdriver battery. The solution to this problem is carried out in the following order:
- Dismantling the battery and finding a faulty battery with a multimeter. Usually, there is no voltage at all in such elements.
- The battery is then pulled out and gas is released from it. In the first case, you will need some kind of flat tool curved at the end. It is brought under the positive contact and the swollen plate is gently pressed down. The gas finds its way on its own, making a hole and going out. In this case, you restore your working capacity only for a short time, because the electrolyte will evaporate completely through the hole and the battery will stop working again.
- In the second case, the positive contact is disconnected using pliers, after which it is slightly bent, but not completely cut off. After that, an awl is inserted under the curved plate and gradually pushed inward. That is, the plate is disconnected from the edge of the battery and the gas is released to the outside. After that, it is inserted into its place, and the hole is closed in the most convenient way. It remains only to solder the contact disconnected at the very beginning.
How to restore the battery of a screwdriver
A real way to restore 100% battery of a screwdriver, according to my method NI-CAD 1.2V
To begin with, there are a lot of videos on the Internet on recovering batteries from screwdrivers, and they are all the same as a mirror, a brief description of the recovery process that these people offer is that we take the battery, push it with a power supply or another battery, then charge and we use it, and it’s strange that someone doesn’t look, but what kind of stress will be on him when he lies down for a week or two. I offer a completely different way to restore
Which does not just charge and use until the battery dies again. And the one that you did and use as a new battery until the need arises. This method was filmed in draft about a month ago, but I never dared to put it on the site, I just didn’t want to reshoot it for a more correct explanation. And frankly speaking, I have very little free time lately.
But now the time has passed which has shown that the recovery option that many people on the network are proposing to use are not destined to live for more than a certain period of time. And my version, even after 2-1 month of inactivity, as if nothing had happened quietly works and charges, I still tried to shoot a new video clip, where in the brink I will try to tell everything.
In fact, everything turned out to be very simple, and in this I was helped by the NI-CAD 1.2V battery I disassembled, which showed me that even with all the zeros on the outside of the device, the patient inside is rather alive than dead and feels very good.
An attempt to regenerate the bus relative to the collector plate was done using distilled water, and the process was quite successful, as a result of which I came up with the easiest way to restore them even without disassembling the batteries!
It is enough to drill a hole in the accumulator in the place behind the rollers. and pour 20.40 ml of distilled water there. after a couple of cycles, cover the hole with a little silicone.
Before repeating, I recommend watching the video, where I tried to describe the process in more detail.
If you are not sure or afraid of ruining a damaged battery, for example, you can do this with one battery.
If your batteries have voltage and are in the operating range, then you may have a problem with the following:
Also, if you notice that the drill began to work somehow sluggishly and at the same time works as long in time after charging, then you probably have a problem in one or more batteries that are at zero!
A very interesting effect on the battery capacity, it was equal to or slightly more than the indicated battery capacity after restoration by this method.
How is the restoration and repair of Ni-Cd batteries performed?
The performance of Ni-Cd batteries (like any other) deteriorates over time and after a while they can come to a state of “zero” discharge. At the same time, charging cannot affect this state in any way. They simply refuse to accept the charge. At the same time, the batteries still have enough resources for further operation. Therefore, over time, there were some ways to restore them. Whether to buy a new nickel-cadmium battery or restore an old one is up to you. We just tried to summarize the data that we managed to find on the Internet about the restoration and repair of Ni─Cd batteries.
A common method for recovering Ni─Cd batteries?
There are many articles and videos on the Internet on the topic of rebuilding Ni─Cd batteries. Most of them concern the recovery of batteries from screwdrivers and other portable tools. This is not surprising, since such batteries are quite expensive and often still need to be looked for. Basically, when restoring nickel-cadmium batteries, one technique is used, which we will now describe.
The image below shows the battery from the screwdriver assembly and its filling.
And the next photo shows one battery of this assembly.
One Ni-Cd battery from rechargeable battery
The recovery method is suitable for nickel-cadmium batteries. Not to be confused with nickel metal hydride. It was tested on roll-type models. In principle, it is suitable for batteries of any age and even leaking ones. Of course, the older the battery is, the less likely it will be to recover.
What you need when carrying out the recovery procedure:
- another working battery with strong current. This can be a battery from an uninterruptible power supply, a car battery, etc.
- crocodiles, pieces of wire. Pieces of wire should have a length of about 10 centimeters and a cross section of at least 1.5 mm 2;
- multimeter for voltage control;
- protective equipment (gloves, glasses).
Attention! Do not neglect protective equipment. Be sure to wear safety glasses and gloves to protect your eyes and hands.
Ideally, the procedure should be carried out on each battery (1.2 volts) separately, and not on the entire assembly at once. In this case, the recovery procedure will be more efficient and the second battery can be used with less power (a standard car battery or a battery from an uninterruptible power supply will be enough).
So, in order, what to do:
- Find a plus and a minus on the battery being restored (or on the entire screwdriver unit, if you are restoring it entirely);
- Then, using a piece of wire and crocodiles, connect the minuses;
- Then a second piece of wire is attached to one of the positive contacts;
- After that, you need to quickly touch the remaining free positive contact with the free end of the wire. Here it is important to make touches quickly and briefly (2-3 touches per second). This procedure takes 3-4 seconds. It is important not to allow welding of the wire at the point of contact.
In general, it is recommended that the wire does not touch the battery terminal itself, but first attach a crocodile or plate to it. And already touch them.
After one cycle of such touches, the voltage is measured on the recovered battery. If it does not appear, then do another cycle. After the voltage appears on the battery, it is put on charge until it reaches its capacity. Most likely, it will be less than the face value. It is also recommended to do a few charge-discharge cycles to train the battery. For details on how to charge Ni-Cd batteries, see the link below.
After searching on the Internet, another, more advanced method of recovering Ni─Cd batteries was found. We also advise you to read the material on how to restore Ni─MH batteries.
What is the problem when using Ni─Cd batteries?
During the operation of Ni-Cd, the voltage and discharge capacity gradually decrease. The following are the main factors driving these processes:
- reduction of the working surface of positive and negative electrodes;
- loss of active mass, as well as its redistribution over the electrodes;
- current leakage due to the formation of metal Cd dendrites;
- processes resulting in irreversible consumption of water and oxygen;
- changes in the composition and volume of electrolyte.
Similar processes occur when Ni-MH batteries are in use. The only difference is in the used electrode materials.
All these changes in the oxide-nickel electrode are caused by constant overcharges, in which oxygen is evolved in the space of the positive electrode. The more batteries go through charge-discharge cycles, the more the crystals of the active mass of the positive electrode grow larger. Therefore, the working surface is reduced, and, therefore, the capacity of the battery.
At the cadmium electrode, the degradation process is mainly determined by the migration of the active mass. As a result, there is some loss of it. In addition, the active mass clogs the pores in the surface layer of the negative electrode. Because of this, the access of the electrolyte to the deep layers is difficult. The migration of the active mass results in the growth of dendritic bridges through the separator to the positive electrode. This leads to numerous short microcircuits and increases self-discharge. On the cadmium electrode, during operation, crystals also grow and the volume of the active mass increases.
In addition to the processes described above, oxidation processes of various additives that are present in the battery take place in Ni-Cd batteries. The cermet of the positive electrode gradually oxidizes with the consumption of water. And another unpleasant process that leads to the loss of performance of the Ni─Cd battery is the selection of electrolyte from the separator. This is due to a change in the porous structure of the electrodes and leads to an increase in the internal resistance of the nickel-cadmium battery.
The electrolyte composition also changes during use. In particular, the volume of carbonates is growing. The electrical conductivity of the electrolyte decreases and all the parameters of the Ni. Cd battery fall during discharge. The picture becomes especially noticeable at low temperatures. What to do in such cases?
Improved battery screwdriver recovery method
What was suggested:
- before carrying out any manipulations with the supply of a pulse current and charging, the author of the method selected elements from the assembly, the voltage at which was zero;
- a hole was made in their body with a micro drill and a thin drill;
- a cubic centimeter of distilled water was pumped into the hole of each element;
- after that the batteries were allowed to stand for some time and their voltage was measured. Elements with zero voltage “cheered up” with impulse current;
- then the cells were charged;
- after that, it is recommended to leave them for a few days, and then check the voltage again;
- if the elements are alive, then the holes are sealed with sealant or sealed. The battery is collected, charged and the screwdriver is ready for use;
- if the voltage is again zero, then another “cube” of distilled water is added, and the process is repeated until successful completion.
Below you can see what the process looked like: