What are the batteries in the screwdriver battery
Destroying a 12 volts dry battery = 8 1.5 volts button cell batteries
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.
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.
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.
4 ways to recover Ni-Cd, Ni-MH, Li-ion screwdriver batteries
Skipping conversations about the benefits of screwdrivers, you can go straight to the topic. The battery or rechargeable battery is the biggest concern for screwdriver owners. It is better to handle them strictly according to the instructions. In the event of a breakdown, there is only one solution. to buy a new battery. However, you can temporarily try to use the problem battery, for which there are some tips here. We emphasize that battery repair is a temporary solution, but first you need to accurately investigate the causes of the malfunction.
- Types of batteries and their differences
- Diagnostics of malfunctions of the battery
- Multimeter method
- Load method
- Item-by-item check
- How to restore the battery?
- Eliminating the memory effect
- Topping up with distilled water in Ni-Cd battery
- Resuscitation by replacement
- Gas release from Li-ion batteries
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 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.
How to restore the battery?
There are several ways to get your battery back on track and reanimate it at home. First, it is the restoration of the normal charge-discharge cycle. You can also, in case of failure, open the battery case as a last resort and examine the individual state of the cells. In some cases, this allows you to completely repair the battery (if there are similar ones for replacement).
Varieties of batteries for screwdrivers
The features of the choice of this product are considered the ability of the engine to implement a change in the number of revolutions of the main shaft, depending on the load. It, in turn, depends on the wood material (while many users also use screwdrivers for screwing in self-tapping screws), and the diameter of the fasteners.
Cans for a screwdriver battery must, therefore, have the following set of consumer characteristics:
- Easily and quickly restore to its original charge level.
- Do not suffer from the notorious “memory effect”, which especially hurts inexperienced users seeking for the future, “just in case” additionally “fill” the bank with ampere hours.
- Allow repair and renewal of their characteristics almost to the original level.
- Approach more models of the vehicle in question.
- Have an optimal price-quality ratio.
- Have minimal self-discharge.
In addition, it is desirable that the screwdriver has an indicator of the remaining battery capacity: this greatly facilitates the convenience of using the tool.
Battery banks differ only in the size of their capacity, and it is determined solely by the type of battery. The following five types are practically used:
- Nickel-cadmium batteries (each bank has a voltage of 1.2 V);
- Nickel metal hydride, which have the same primary voltage level;
- Lithium-ion, characterized by a threefold increased level of their potential (3.6 V);
- Lithium polymer, which do not have a memory effect, are most compact, but, unfortunately, are disposable.
In this case, the number of elements can be different, and depends on the power consumed by the screwdriver, or on the maximum torque developed by the tool. The practical relationship between the main operating parameters (when working on a dry pine bar with steel fasteners with a diameter range of 4. 6 mm) is as follows:
|Rated torque, N ∙ m||ten||16||25||31.5||40||60|
|Power consumption. W||28||thirty||32||42||48||56|
The increase in power is due to the fact that in most professional models of screwdrivers, the drive is carried out not from one, but from several (up to three) batteries connected in series. The screw-in depth of the fastener, its material also matter (aluminum screws have an increased coefficient of friction against wood), as well as the moisture content of the material.
Cans for the battery of the screwdriver. Repair and replacement
Screwdrivers are the most popular type of battery-driven household power tool. The predominant use of this technique far from stationary sources of electricity leads to increased requirements for the quality of battery cans. Their durability, promptness of replacement and recharging often becomes the decisive criterion for choosing a tool model.
Routine routine maintenance of screwdriver battery cans
The loss of battery capacity over time is an inevitable phenomenon, in which case the cans for the screwdriver’s battery should be subjected to simple diagnostics.
The process begins with disassembling the case. a procedure that is very convenient for all models on sale. Upon opening, the following contact sockets are found:
- Power ones to create the required potential difference, they are denoted as standard. “plus” and “minus”;
- A control contact that is supplied with a sensor that limits the limit value of the discharge current. This is necessary in order to prevent an excessive temperature rise on the cans during their forced charging, as well as during prolonged operation of the screwdriver at the maximum operating modes for it (indicated by the manufacturer in the manual);
- Service contact (optional), which is connected to the electrical circuit through an additional resistance and is designed to smooth out the peaks of energy consumption in the case of the tool operating simultaneously with different materials, screw diameters, and their screw-in depths.
In the case when the battery banks do not provide the required output voltage, most often only one of them is “to blame”, since the connection of the elements is always consistent. A tester is suitable for testing, the limits of measuring the electrical parameters of which correspond to the passport value of the voltage on the battery. After full (according to the indicator) charging, the voltage on each bank should be equal to the passport voltage, ± 10% (more often. in “plus”). In this case, the voltage on one of the cans will necessarily be lower by 0.1. 0.2 V.
After that, the body is assembled, and the instrument is included in test or normal operation. It is worth working on a screwdriver until the moment when the power drops noticeably (for example, another screw of the same diameter cannot be screwed into the material for a time that is twice increased against the required time).
When the case is opened, the voltage on the bank that could not be charged to the nominal value will be much less than that of the others. In this case, the final difference in potentials will be much greater than after charging. sometimes up to 0.7. 0.8 V. A defective bank is called “leaking”, and therefore must be replaced first.
To test the cans, it is not necessary to carry out any work on screwing the fasteners. You can connect some external resistance to the battery output, for example, a light bulb of the corresponding operating voltage. The intensity of the voltage drop on one of the cells will determine the battery element that needs to be replaced.
The situation is even simpler when the loss of the capacity of the battery bank is associated with the poor condition of the contacts, or the failure of the thermal sensor. In the first case, this is detected by a sharply increased temperature value at the contact, in the second. by the stability of the service contact. The thermal sensor will have to be replaced. Regarding the equipment that is under warranty service, it is better to do this in a service workshop, otherwise it is possible to install a sensor that does not correspond to the technical characteristics of a particular tool model in terms of its parameters.
Repair of battery cans of screwdrivers
In some cases, screwdriver battery cans can be repaired. This applies exclusively to nickel-cadmium batteries, since neither lithium-ion nor lithium-polymer cells are recoverable. The reason is the chemical instability of lithium compounds, which decompose over time.
It happens in the following way. Over time, the value of the energy required to move electrolyte ions in the environment of lithium oxides increases. This happens because the crystal structure of the cathode changes with an increase in the number of charge / discharge cycles, and so that the ion release energy increases. As a result, the number of free lithium ions decreases with each cycle, and the charge of the can with the same duration of the charging process will be less.
In addition, charging is adversely affected by corrosion, peeling of the graphite plates that make up the anode, etc.
Repair of cans of batteries of a non-warranty tool begins with the replacement of the control circuit. If charging occurs normally with the new circuit, and the banks “sit down” during the operation of the screwdriver as it should be new, then the goal is achieved.
At the same time, replacing the control scheme is a cardinal method, it should be used only when the other, simpler procedures for resuscitation of cans did not lead to the desired result. Therefore, it is worth trying one of the following options:
- Shrink the defective jar in any way. This can be done with pliers, evenly over the entire outer surface, being careful not to snag the places of the contact pins. The electrolyte inside the jar will be condensed, and its storage capacity will be restored, albeit for a shorter period of time;
- Apply an electrical impulse of significantly higher power to the battery, both in current and voltage. In this case, the memory effect gets lost. To do this, a capacitor with a capacity of up to 7000. 7500 mF should be connected to the charged battery as an external load, which must be pre-charged to a potential difference of 18. 20 V. At the same time, make sure that the residual voltage on the bank after discharge is at least 0.6. 0.7 V.
Any of the methods described above allows you to extend the life of nickel-cadmium batteries, but for a fairly short time. The fact is that over time, the electrolyte evaporates from constantly high temperatures inside, and recovery turns out to be impossible.
Replacement of a defective can is performed by soldering a new one using a rosin flux. The process should be carried out quickly, without overheating the jar, after which the battery is immediately put on a control charge / discharge.
Replacing cans in the battery
How to repair a battery for a screwdriver? The easiest way to revive the battery is to replace one of the cans.
It is necessary to find a defective element with a low voltage. To do this, you need to use a tester.
Instructions on how to check the battery of a screwdriver with a multimeter:
- A conventional multimeter has two test leads. a red and a black one. There are two contacts from opposite ends of the can (plus and minus).
- The tester selection lever is set to the “constant voltage” mode. If the multimeter has an automatic selection of values, this is enough. If not, you need to put the lever in position “20”.
- Probes are applied to the contact pads and the voltage is measured. The real voltage is shown on the screen. If there is a “-” sign in front of the numbers, then the probes need to be changed with each other.
- Each bank is checked using this algorithm.
When a broken element has been found, it is simply unsoldered and replaced. You need to use a powerful soldering iron so as not to overheat the jar.
General repair recommendations
How to restore a screwdriver battery? You need to have an elementary understanding of electrical engineering. The battery circuit is idle. Ordinary serial circuit (plus connects to minus).
When repairing Ni-Kd, the following recommendations should be taken into account:
- They have a memory effect. The classic scheme for commissioning such batteries is 3 full charges and 3 discharges to zero. The new element must go through the same buildup.
- A similar item. So that it does not get knocked out of the chain and does not break the battery at all, the new element must fully correspond to the previous rating.
The lithium battery of a screwdriver can be repaired at home if you consider the following:
- They cannot be soldered. Intolerance to high temperatures will lead to a non-repairable condition. To do this, you need to use contact welding (it heats the electrode for a short time without harming the battery). If there is no access to the COP, soldering with a very powerful soldering iron from 100 watts is allowed. Movement must be fast and accurate.
- Identical models. Now there are several main manufacturers of lithium batteries, which are used in popular foreign models of screwdrivers, such as Hitachi, Makita and domestic ones: Interskol, Zubr.
Topping up with distilled water
Restoration of the screwdriver battery with topping up should take place with a completely discharged battery. Ni-Kd batteries are covered with paper. If there was evaporation, then there will be noticeable traces on the surface.
After measuring the voltage, you need to completely discharge all the banks using a 12 volt light bulb. After that, the voltage is measured again. Those elements where it dropped to 0.7 are faulty.
To fill in distilled water, you need to make a hole in the side of the can. A groove is made with a very thin drill (0.5-0.7 mm). You need to make sure that it does not go inside and damage the plates.
A small amount of water is poured with a syringe with a fine needle. After that, the breakdown must be closed with epoxy resin or sealant.
The battery can now be rocked. Each unit must be discharged to zero again by attaching 1.5 volt bulbs to them. When the procedure is over, the battery is collected and it is necessary to carry out 5 charge and discharge cycles.
How to repair a screwdriver battery at home
The cordless screwdriver is a convenient mechanism that allows you to quickly deal with repairs. Instead of a heavy drill on a wire, it is better to take a lightweight screwdriver that can handle the same tasks without being tied to one place.
They have one problem. batteries fail. There are many reasons for this:
- Long downtime. Modern lithium-ion batteries require periodic charging and discharging. They drastically lose capacity if they are idle for a long time.
- Temperature drops. Li-Ion does not tolerate high temperatures. Therefore, there are recommendations for storing these batteries in the refrigerator. But they cannot work in such conditions.
- Overdischarge. The protection system can force the batteries to discharge to zero and a large current must be applied to the input to resurrect them.
The most common cause of failure is the failure of only one element. They are connected in series, which means that even a drop in capacity on one battery will lead to a complete malfunction of the entire battery. In this case, we need:
- Screwdriver. Usually, the body is connected with Phillips screws. Some models have foolproof protection and there may be vandal-resistant sprockets, triangles or even spanners.
- Multimeter. Any model is enough, even the cheapest DT-830. Since measurements are taken in millivolts, Soviet dial voltmeters will not work.
Next, you need to follow the instructions:
- The battery is disconnected from the screwdriver. It must be fully charged.
- The case is disassembled.
- Now you need to remove all the jars. There are more of them in Ni-Kd, since the nominal voltage of one section is less.
- Voltage is measured on each bank. For nickel-cadmium, 1.2 volts is nominal. For lithium. the normal voltage is in the range of 3.6-3.8 volts.
- After measuring, you need to look at which banks the voltage is reduced. For example, if the voltage on two lithium batteries is 3.8, and on one it is 3.5, it means that it is defective.
- The battery is assembled and installed in the instrument. Now she needs to be set to zero.
- The battery is disassembled and the voltage is measured again. If the voltage on the alleged element is much lower than on the others, then it is being replaced or repaired.
Repair and replacement of battery cells
Do-it-yourself screwdriver battery repair can be more extensive. For example, conversion of Ni-Kd to lithium ones. To do this, you need to purchase several Li-Ion batteries and a charging board. The number of batteries must correspond to the original voltage rating.
As practice shows, most screwdrivers can be easily converted from one type of battery to another, without any problems. Thanks to the increased endurance, resistance to constant use and higher capacity, the old screwdriver will last much longer.
What batteries can be used for screwdrivers
Power tool manufacturers always indicate in the characteristics of screwdrivers which batteries are recommended for working with them. The battery type is spelled out in several English letters. To know which battery to choose a screwdriver with, you need to understand the decoding of the abbreviation and know the advantages and disadvantages of each type of battery.
Number of charge and discharge cycles
All batteries have one drawback. sooner or later the energy in them ends and the device must be put on charge. Depending on the type of battery, there is an average statistical limit on the number of charging cycles, after which the battery will no longer be able to store current and will have to be replaced.
For screwdrivers with NiCd batteries, this figure is 1000 cycles, and the tool often continues to work after reaching this figure. This makes it a leader when compared in this characteristic.
A common type of Li-Ion in screwdrivers is capable of being charged and discharged over 600 times. The advanced technology of the last century NiMh is significantly inferior to the previous ones and the battery will withstand only 300-500 cycles.
Nickel Metal Hydride (NiMh)
This type is most often used in AA batteries. They began to be developed in the late 1970s. The main substances for the accumulation of charge and its return are nickel-lanthanum, which serves as the anode, and nickel oxide, which is the counterpart, the cathode. Ion transfer is provided by potassium hydroxide.
Estimated service life
The time that the battery will last on a screwdriver depends on the frequency of use and correct use. To some extent, the number of charge cycles is indicative of how long the battery will “live”. Based on this, you might think that lithium-ion batteries have the shortest lifespan.
In fact, these batteries do not have a number of disadvantages inherent in other types, due to which, in most cases, these batteries serve a longer period.
|Number of charge and discharge cycles||1000||300-500||600|
|The ability to charge quickly||4-8 hours||4-8 hours||30 minutes. 2 hours|
|The cost||cheap||cheap||cost up to 50% of the tool itself|
|Response to tool operation at full power||good performance||good performance||low rates|
|The effect of storing the charge level||there is||there is||not|
|Self-discharge||10% per month||7-10% per month||3-5% per month|
|Working in the cold||can work||can work||poorly tolerate low temperatures|
|Full discharge ratio||tolerate well||tolerate well||must be charged in advance|
What does the battery capacity say?
Battery capacity is written in numbers from 1.0 to 7.0 and is measured in amperes times hours (Ah). The value is deciphered as follows: the specified number of amperes can be delivered by the drive within an hour. But since no screwdriver consumes 1-5 A per hour, its use time stretches from 2 to 8 hours. The higher the capacity, the longer the tool can stay in use.
Working in the cold
Although screwdrivers are more used for indoor repairs and furniture production, sometimes materials have to be fastened outdoors or in unheated buildings where there is a sub-zero temperature. Li-Ion batteries do not tolerate low temperatures.
In cold weather, such a battery can simply fail or discharge three times faster than usual. Nickel powered power supplies are the leaders in this category. They perfectly hold the charge and ensure the functionality of the screwdriver even at 20 degrees of frost.
Response to tool operation at full power
When you need to drill a hole in a dense material or screw a thick and long self-tapping screw, you have to use the tool at full power. In this case, active consumption of charge begins, and the ability to complete the process qualitatively without a drawdown of revolutions depends on the battery’s reaction to this phenomenon.
In view of this, modern Li-Ion batteries are significantly inferior to earlier counterparts. The most powerful in this regard are NiCd and NiMh. When maximum energy output is required, then they are chosen.