How To Replace The Battery In A Screwdriver Battery

Restoration of battery performance for screwdrivers

Kegs that showed low voltage can not be replaced with new elements, but try to reanimate them. They do it like this:

  • They are armed with a syringe, distilled water, a screwdriver with a drill ø 0.8-1 mm.
  • A hole is drilled in the upper part of the battery case.
  • Distilled water is drawn into the syringe and, using a needle, it is slowly introduced into the hole on the body.

Important! If electrolyte flows towards the battery when water is introduced into the battery case, the battery is discarded. This recovery method is only suitable for dry batteries.

  • If after 30 minutes the multimeter shows an increase in the voltage value, then the battery will be able to serve for quite a long time.
  • The hole is sealed with epoxy.
  • The battery is inserted into the socket of the charger and the voltage is brought to the nominal value.

Replacing batteries in a screwdriver

There comes a time when the owner of a cordless screwdriver begins to notice that his tool has begun to work worse. The whole reason is that the battery is out of order. Typically, a power tool is sold with two power boxes. If one unit starts to junk, it is possible that the second battery leaves much to be desired. Replacing two batteries in a screwdriver is a rather expensive operation.


Failure of power units occurs when screwdrivers are often used as a drill. Active overload can cause the electrolyte to boil inside the batteries. This is fraught with swelling of their bodies and leakage of electrolyte.

In order not to recklessly spend on purchasing new batteries, you need to diagnose old batteries. Everything can be done only by repairing the charging elements. The battery is checked in this order:

  • The battery is connected to the charger.
  • After half an hour, the voltage is measured. The voltage is usually 13 volts. After 2 hours, the voltage at the battery terminals will be 14V. Finally the battery will show 17v.
  • If after 60 minutes after the start of the charging process, the current strength is 1 A or more, then the battery is fully functional.
  • Next, check the battery under load. Usually they connect a 40-watt lamp or take a 12-volt light bulb for a 35-watt car headlight.
  • If after three minutes the voltage at the box terminals is less than 12.4 V, then one of the cans or several pieces at once requires replacement.

Renovation work

In the case of low battery values ​​for screwdrivers, they need to be repaired. Proceed as follows:

  • The body of the power block is separated into two parts, making the banks accessible. To do this, it is enough to remove the housing screws with a screwdriver;

Attention! Brand manufacturers make battery boxes non-separable. Home craftsmen disassemble them using a knife and screwdriver.

  • A block of nickel-cadmium cans, interconnected by nickel strips by means of spot welding, is found under the housing cover;
  • The purpose of the repair is to identify inoperative battery circuit elements. To do this, the cans are freed from the nickel tape using wire cutters and pliers;
  • Each “keg” is checked by a tester. The voltage should be between 1.2-1.4V;
  • With a low index, elements are set aside for further resuscitation;
  • Rejected kegs are checked for swelling, body integrity and absence of electrolyte drips;
  • Bloated, cracked items dispose of.
  • The rest of the banks can be tried to “bring back to life”.

Re-flashing the capacity of battery cells

Nickel-cadmium batteries “suffer” from one drawback called the memory effect. During the operation of the tool, the batteries can “remember” the moments of undercharging. Therefore, no matter how much such batteries are charged, they will still remain undercharged.

To remove this phenomenon, the batteries of the screwdrivers are reflashed, restoring their nominal capacity. The essence of the method is that a current is supplied to the battery poles with a voltage three times higher than the nominal value of 1.2v.

The capacity is restored in the following order:

  • The battery is disassembled into separate elements. Spot-welded nickel tape is torn off the battery poles with pliers.
  • Each element “suspected” of having a memory effect is exposed to a powerful charger. You can use the device to charge car batteries.
  • The charger is set to impulse with a voltage of 3.6 V.
  • The terminals of the wires of the charger are pressed to the same poles of the battery for 3-5 seconds.
  • After that, the elements are tested with a multimeter. If the voltage is 1.4 V, then this means that the battery has restored its capacity and got rid of the harmful memory effect.
  • The rest of the banks that did not meet the required requirements (less than 1.4 volts) are disposed of.

Installing new cans in the battery box

All cells can be replaced with new batteries. But, if unusable “barrels” have been identified, and some of the elements have shown their efficiency, you can replenish the battery with only a few banks. This will allow you to get out of the situation at the lowest cost.

Additional Information. There should be no doubt what to replace the unusable banks with. They can be exchanged for exactly the same elements. Under no circumstances should nickel-cadmium cells be exchanged for lithium-ion batteries or other sized cans.

Typically, a battery prefabricated structure has two levels. The bottom row usually consists of 10-11 elements. The upper level holds two batteries or one bank. You need to form a new pyramid in the same order as the old configuration.

It is necessary to observe the same position of the poles as before. Can restore connections in two ways:

  • Soldering.
  • Spot welding.


For soldering nickel-cadmium batteries, it is better to use an induction soldering station. The soldering iron tip is made of copper coated with a ferromagnetic alloy. Due to the inductive nature of the electrical impulse, the sting of the device does not overheat. This is important because battery banks do not tolerate high temperatures. The electrolyte can boil and the cell can simply explode. The soldering process proceeds as follows:

  • For the convenience of soldering, the batteries will need to be fixed in the desired position. You can put a rubber ring on them or wrap them with threads.
  • The nickel strip is cut into the required lengths. If one is not at hand, the tape can be cut from a simple tin can.
  • Prepare solder, flux and tip cleaner from brass shavings.
  • First, the flux is applied with a sting to the back of the nickel strip and the top pad of the battery. Then both sides tinker.
  • Press the tape to the jar and heat it from above with a soldering iron tip. After setting, the soldering proceeds to the soldering of the next element.
  • It is recommended to press a metal rod (thick hardware or similar material) near the junction during soldering. This will create heat dissipation and prevent the battery from overheating.
  • The repair block made of batteries is again enclosed in the battery casing, fastening its parts with screws.
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Checking under load

Battery test circuit with an ammeter.

The preliminary check does not allow us to estimate the capacity of the battery, i.e. the time during which it will be discharged. To estimate the parameter, it is necessary to test the battery under load. If the power is indicated on the drive, then the load power is selected according to this value. If the capacity of the battery is unknown, the load can be approximately selected on the basis that its capacity is half of the product of the current given by the battery during operation and the voltage of the battery. Usually it is sufficient to use a 35-40 W load. As such a load, you can use a 35 W car headlight lamp or a 12 V spot lamp of the same power.

A circuit is being assembled, where the battery, as source of electricity, is discharged to the load through an ammeter. The voltage is measured with a voltmeter. The battery turns on for 2-3 minutes. If during this time the brightness of the loading lamp has not decreased, then the battery capacity can be preliminary estimated as normal. This conclusion should be supported by measuring the voltage (it must be more than 12.4 V). At voltages between 12 and 12.4 V, look for a possible damaged element. Voltage below 23 V indicates insufficient battery capacity.

If the brightness decreases noticeably, then this indicates the presence of non-working elements. And it’s really bad if the lamp goes out. This means the battery is discharging very quickly and its capacity is very low.

The main types of batteries

The most common type of drive used in screwdrivers is the nickel-cadmium battery. The main advantages of such elements are high capacity with small dimensions and weight, as well as a fairly long service life (up to 3500 cycles). The electromotive force of the element reaches 1.37 V, and the specific electric energy. up to 65 Wh / kg. Limits the use of such elements (especially in imported tools) harmful production.

Nickel-metal hydride batteries for the screwdriver are becoming the main competitor to nickel-cadmium copies. The main advantage of such elements is safety and environmental friendliness. It is recommended to store the cells in a charged state, since if they are not used for a month, they may be discharged to such a state that they cannot be charged.

In the latest models of screwdrivers, modern promising types of batteries are used: lithium-ion and lithium-polymer. They have a very high capacity with small dimensions, but their cost is still quite high.

Checking by resistance value

Multimeter device diagram.

The performance of each battery can is more likely to be assessed by comparing the cans by their internal electrical resistance. This parameter clearly indicates the reliability of the battery. The resistance value is determined by calculation as a result of dividing the operating voltage by the operating current strength minus the load resistance.

The operating voltage is necessarily measured under load, and a resistor with a precisely defined value of its own electrical resistance should be used as the load. It is possible to recommend a resistor with a resistance of 10 ohms and a power of 25 watts to create a load. The check is carried out for each bank separately. The operating voltage and current are measured.

For example, consider the averaged check. For a new battery bank, the internal resistance is 0.1 ohm. In general, the lower the internal resistance of the bank, the better it is. In real conditions, an operating voltage of 1.19 V and a current of 112 mA was obtained for one can and 1.18 V and 70 mA for the second can. The resistance will be 0.63 ohms and 5.71 ohms, respectively.

A significant excess of resistance indicates the unsuitability of such a battery.

Battery Cell Test

After a preliminary check has established the presence of faults in the drive, it is necessary to open the screwdriver and remove the battery, i.e. battery cells connected in series with each other. The battery includes from 10 to 12 cells (cans), each has an operating voltage of 1.2 V. Usually, a battery of 10 such cans is installed in screwdrivers.

Checking the elements begins with a visual inspection of the attachment points. Failure in fastening (soldering, welding) can lead to underestimated parameters. Then the voltage on each bank is measured. The voltage should not be less than 1.2 V. It should be borne in mind that thermal sensors are placed in modern screwdriver designs to monitor battery charging. When measuring, they should be disconnected, and the device should be connected to the main terminals (poles of the jar). Identified banks with an underestimated value of the operating voltage are disconnected from the battery and must be replaced. If a simple voltage measurement did not reveal the presence of inoperative elements, then measurements should be made under load using a method similar to the preliminary check of the drive.

General information about the battery

Battery type table.

In the general case, an electric storage device is source of constant electric current by converting a chemical reaction into electrical energy. During operation, it transfers the accumulated electricity into the electrical circuit. When charging the battery of a screwdriver, the current is passed in the opposite direction and the process of energy storage takes place.

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The main parameter of any battery is the capacity of accumulated energy, which indicates how much current the battery can deliver in one hour. Therefore, battery capacity is usually measured in ampere-hours.

The principle of operation of any battery is based on electrolysis. Consequently, the battery consists of two electrodes. the anode and the cathode, which are in the electrolyte. A chemical reaction creates an electrical charge on the electrodes (poles). The potential difference between the electrodes determines the battery voltage, which is considered one of the most important characteristics of the battery. Serial connection of individual batteries leads to the addition of their electrical voltages.

The main parameters of the storage devices depend on the electrode materials and the electrolyte composition. In nickel-cadmium batteries, the anode is made from a mixture of nickel hydrate with graphite, and the cathode is cadmium hydrate or metallic cadmium. Potassium hydroxide with the addition of lithium hydroxide was used as an electrolyte. The nickel metal hydride battery uses a similar anode, but the cathode is made of a rare earth nickel alloy. In lithium-ion batteries, the cathode is made of carbon and the anode is made of lithium dioxide and cobalt. The electrolyte is a saline solution containing lithium ions. The difference between the lithium-polymer version is only a change in the composition of the electrolyte. it is a gel-like polymer substance.

How to quickly check the battery of a screwdriver?

Recently, the screwdriver has become a fairly popular tool. For convenience, many tend to purchase a screwdriver powered by a charging battery. Over time, of course, the question arises: how can you check the battery of a screwdriver?

Diagram of a nickel-cadmium battery for a screwdriver.

Drive test principles

Battery tester circuit.

Checking the screwdriver battery means determining its real basic parameters. A battery test is usually done to determine the quality of the battery or the cause of the failure. In the first case, it is aimed at clarifying the quality of the new battery, and in the second, it includes measurements of parameters on the battery that do not power the screwdriver in the required volume. The test is carried out only when the battery is fully charged.

When testing batteries for a screwdriver, remember about the influence of the “memory effect”. This phenomenon is based on the fact that frequent charging of an incompletely discharged battery can change the cell’s capacity due to residual charges from the previous charge. Nickel-cadmium specimens are especially susceptible to the “memory effect”. This property causes a full “training cycle” to be performed before testing. It consists in completely discharging the battery and then fully charging it.

The most important parameter of a screwdriver battery is its capacity. To determine it, there is a special device. a battery tester of the “pendant” type, but it is mainly used by professionals, and for most users it is not available. Therefore, this parameter is usually analyzed by evaluating other parameters. The current and voltage at the output of the battery are directly measured.

First stage of verification

Checking the battery only makes sense when it is fully charged. The first stage of the check is carried out at the stage of battery charging. At this stage, voltage and current are measured, as well as their recovery rate. In other words, these parameters are measured periodically after a certain period of time.

Battery voltage test circuit.

Voltage control is performed as follows. After 0.5 hours of charging, the battery voltage is measured. For example, it reached 13 V, which is normal. The increase in voltage gradually decreases and after another 0.5 hours of charging reaches 13.5 V. The last measurement after 2 hours of charging shows a voltage of 14 V, and for the last 0.5 hours its growth is not noted. Charging has reached the maximum possible. The drives in fully working condition have a voltage value of 17 V. The conclusion of such a test is that there are non-working cells in the battery. In the given example, there are most likely two such elements.

The quality of the battery can also be assessed by measuring the current during charging. A normal battery is characterized by a stable increase in the accumulated current in the first hour of charging. If the current reaches a strength above 1 A, then we can talk about the performance of the battery.

If the battery is already installed in the screwdriver in a charged state (for example, a new one), then the first voltage measurement on it is made without disassembling the tool. Using a simple tester or voltmeter, the voltage between the poles is measured. It should be remembered that the measured no-load voltage corresponds to an open-circuit voltage which is slightly higher than the rated operating voltage. For example, with 12 cells at 1.2 V, each operating voltage will be 14.4 V, and the open circuit voltage is set to 17 V. If the measurement shows a voltage value lower than the required one, then this means that there are non-working cells or the battery is not fully charged.

Thus, the first conclusions about the health of the battery can be made already at the first stage of testing, by using a simple tester. Based on the results of such a check, it is established that it is necessary to disassemble the screwdriver and the battery.

Dismantling the battery of the screwdriver

Let’s start repairing the screwdriver battery. We remove the battery from the handle of the screwdriver and unscrew the three self-tapping screws that are located under the sticker below.

After unscrewing the screws, carefully push back the hooks of the latches, as in the photo. And remove the bottom of the plastic battery case.

Inside we see lithium-ion cans of the Chinese company HighStar, model ISR18650-1300 Li-Ion. This means that the batteries have never been changed. Because it is known that Interskol purchases batteries from this company and inserts them into almost all of its cordless tools.

The photo below shows the insides of the screwdriver’s battery in all its glory with cans in the amount of three pieces, which were produced already in 2011. These batteries lasted five years during active use at a construction site. So the result is very decent. Usually they die earlier, probably in cold weather they were not exploited.

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To replace the battery cells, you need to disassemble it even more. I advise you to remember the location of the plus, minus and charging contacts so as not to confuse the wires when reassembling.

Pay attention to the voltage control board on the batteries. stabilizers and protective diodes especially often fail on it. It is imperative to ring suspicious radio elements on this board with a multimeter.

We check the voltage at the output of the battery. it turned out 4.4 volts, but it should be 3.7 x 3 = 11.1 volts in the norm and 10.8 volts with the minimum charging of the batteries. In general, the banks are dead. they need to be changed unambiguously.

We continue to disassemble the battery of the Interskol screwdriver

This can be done in several ways. you can unsolder the wires that go to the board.

You can also simply remove the contacts from the top battery cover. The photo shows the shape of the curved contacts so you can easily remove them yourself.

Under the plastic cover, we see how the batteries are connected to each other. They were spot welded. This solution is used in almost any battery of another tool. This is a safe and gentle battery connection. At the same time, the destructive heating of the lithium batteries themselves is minimal.

Carefully tear off or bite off the metal tape with pliers to disconnect the cans from each other. From the side of the board, they were also connected together with a tape and put on glue on a cardboard gasket. This is done so as not to short-circuit anything on the board. Remember to put it back in place when reassembling the battery.

Due to the absence of a spot welding device, new lithium-ion batteries will be soldered very quickly with a well-heated powerful soldering iron. We remember that heating lithium-ion batteries reduces their service life and is generally explosive.

Pay particular attention to the condition of the wires inside the battery. They can be broken or frayed. They need to be qualitatively isolated or replaced with fresh ones. Since I was repairing a screwdriver battery on the road in the field, I had to apply a brilliant invention of the engineering mind. I took out a blue radio tape.

Duratest Screwdriver Battery Replacement

When disassembling the battery of the Interskol DA-10 / 10.8 ER screwdriver, I was pleasantly surprised. a thermal sensor was installed in the budget screwdriver to control the temperature of the batteries. It turns out that when the lithium cans overheat, the protection circuit turns off the power until the temperature returns to normal. True, the owner never managed to drive him into such a regime. We carefully tear off this thermal sensor so as not to break it. then we will place it in the same place on new cans.

Do-it-yourself screwdriver battery repair with battery replacement

Hey! Today we will repair the battery of the screwdriver. Did you know that the history of the creation of the screwdriver goes back to the deep Middle Ages. already in the 15th century, when the knights put on armor before the battle, and the squires helped them to twist parts of the armor, guess what? Screwdriver!

This went on for a long time, until in 1907 the Canadian inventor Peter Robertson patented the Robertson screw with a standard square hole, into which the tip of the screwdriver was inserted. Since that time, screws began to be produced on an industrial scale and used in households. Later, in 1934, inventor Henry Phillips redesigned the head of the screw and a Phillips screw was introduced into which the corresponding screwdriver was inserted. By that time, the engine had already been invented and the idea of ​​creating a “screw and screw rotator” was in the air. However, there were big problems with the batteries. their weight and dimensions. The problem was solved only in the 1980s, when the first nickel-cadmium Ni-Cd and lithium-ion Li-Ion rechargeable batteries appeared.

The USA and Japan were the first to master the production of household and professional cordless drills and screwdrivers. All this happened thanks to the emergence of new energy-intensive batteries of electricity. We will urgently change them inside the Interskol DA-10 / 10.8 ER cordless drill-screwdriver that fell into my hands. The malfunction was as follows. when the button was pressed, the engine simply did not spin, but the LED lit up, though it shone weakly.

Solder batteries

can be done in different ways, for example with thick wires. I decided to solder a torn-off metal strip taken from old cans. First, I tinned the tapes in the places of future contacts on both sides. Then I tinned the battery contacts with a well-heated soldering iron with a drop of solder. But so that they do not get too hot. let them cool down. Then he pressed the tape to the contacts of the cans and soldered the tape again without severe overheating of the battery cans.

replace, battery, screwdriver

The minus leads are the most difficult to solder, but with a good flux, things go very quickly. True, then it is better to wash the flux afterwards to clean the insides of the battery.

When assembling, do not forget to replace the cardboard gasket between the banks and the board. This is so that fresh soldering does not short-circuit anything on the board.

This completes the repair and restoration of the lithium-ion battery of the Interskol DA-10 / 10.8 ER screwdriver. Almost all batteries of popular screwdriver manufacturers are repaired in approximately the same way: Bosch, Makita, DeWALT, Metabo, Hitachi, Elitech, Skil and my favorite Bison. This concludes my story about repairing a screwdriver battery. Ask questions in the comments. Better yet, in the corresponding thread on our forum or write to the Solder Master personally by mail.

Best regards, Solder Master. Successful repairs!