How to replace the battery for a 12 volt screwdriver
The process of designing a battery pack for a screwdriver
Having picked up a new device and all the parts necessary for the design, you can get to work. Assembling a 12V power supply for a do-it-yourself screwdriver consists of the following steps:
- Having chosen the optimal power supply, check it for similarities with the declared characteristics, which will depend on which screwdriver. Better to use a computer block as a base for a new battery.
- Disassemble the screwdriver and remove the old drive. If the body is glued, gently tap along the seam with a hammer or notch with a thin knife blade. This will open the box with the least damage.
- Unsolder the cord and leads from the plug and separate them from the rest of the structure.
- In the place where the battery power supply for the screwdriver was previously located, place other contents removed from the case.
- Route the power cord through the opening in the housing. Connect it to the PSU by soldering in place.
- Solder the PC power supply output to the battery terminals. Remember to observe polarity.
- Connect the designed battery to the instrument and test it.
- If the dimensions of the new charger exceed the parameters of the old battery, it can be built into the handle of the screwdriver.
- To limit the supply of voltage from the mains to the battery with a parallel supply output, install a diode with the required power from inside the cable break “” between the battery socket, including the output, but with the pole “-” towards the engine.
Car battery as a power source
A car battery is a great option for remotely connecting a screwdriver to the mains. To realize the idea, simply disconnect the clamps from the work tool and power up to a power source.
Important! The use of such source for long-term operation of the screwdriver is highly discouraged.
VOTO 12 Volt Lithium-ion Battery Cordless Screwdriver. Battery Replacement
What you need to know when starting to design
Examine the markings or design features indicated on the body of the working tool, and, based on these indicators, determine the voltage required for the power supply. In our case, it will be enough to assemble a 12V power supply for a screwdriver with your own hands. If the required readings are different from 12V, keep looking for an interchangeable option. Having chosen an analogue, calculate the current consumption of the screwdriver, since the manufacturer does not indicate such a parameter. To find out, you need to know the power of the device.
If you do not have time to select a device, and the calculations take too much time, take any power supply you come across. When buying it, in addition to the current, ask about the battery capacity. To design a 12V power supply for a screwdriver with your own hands, a device with a capacity of 1.2A and a charge of 2.5 will be enough. Remember, before looking for a recharge, determine the following necessary parameters:
- Block dimensions.
- Minimum current.
- Required voltage level.
Battery or power supply from computer equipment
A device that supports a PC or laptop charge will do just fine for the purpose. The process of introducing a power supply into a screwdriver is as follows:
- The screwdriver body is completely disassembled.
- They remove the old power source, and the wires are unsoldered.
- The wiring of the new unit is connected to the wiring of the old one that powers the previous battery. When carrying out such an operation, it is important to observe the polarity!
- Include a screwdriver and check for operability. If all the wires are connected correctly, then the machine will work.
- There is a hole in the body of the device where the plug with a connector for recharging can be easily placed. By upgrading the screwdriver in this way, you get an improved device, which now in the process of work is also recharged like a laptop from a 220V network.
- The new power supply is mounted inside a screwdriver, securing it with glue.
- The rest of the body elements are returned to their place and the product is twisted, giving it its original appearance.
That’s all! Now you know how to make a network out of a cordless screwdriver.
Materials and tools for modernizing a screwdriver
Alteration of a computer power supply for a screwdriver is not difficult, moreover, such an activity is informative, especially for beginners in the field of radio mechanics. Having the necessary skills and all the components, in a short time you will have a transformed network screwdriver. To carry out the work, you will need:
- charger from a screwdriver;
- old factory battery;
- soft stranded electrical cable;
- soldering iron and solder;
- insulating tape;
- power supply from a computer (or other).
Using a welding inverter to power a screwdriver
To remodel the old structure, prepare a power supply circuit for a 12V screwdriver. The old design is improved to some extent by adding a secondary coil.
When compared to a computer battery, the advantage of an inverter is immediately noticeable. Thanks to the design features, it is immediately possible to determine the required voltage level and output current. This is the ideal method for those who live in radio engineering.
Various power supply options can be used to create a compact battery for trouble-free screwdriver operation.
The question often arises whether it is possible to connect a screwdriver to a car battery. Indeed, you can use a battery that has worked out its resource, the capacity of which is already small for a car, but sufficient for a hand tool. The standard voltage of car batteries is 12 volts.
In view of the mass of 14 kilograms, it is advisable to use such source at a stationary workplace, scaffolding or mobile platforms. The length of the wire is 2-3 meters. Charging will have to be done by a third-party device due to the high charging current.
The main parameter that needs to be taken into account is the supply voltage indicated in the passport or on the case. The motors used in screwdrivers also operate at reduced voltage, losing somewhat in speed and torque. The most affordable of the batteries will be acid for cars, motorcycles, as well as for uninterruptible power supplies.
How to replace the battery for a screwdriver
It should be noted right away that the handicraft modifications will reduce the screwdriver‘s mobility due to the additional wire from the new power source and its weight. On the other hand, the operating time on a single charge will increase to 12–20 hours, versus 2–3 with a native battery. This will be very useful in remote sites without power supply.
For convenience and safety, double-insulated flexible wire such as PVA and ShVVP should be used. Section 0.75 mm 2 and more. You can connect it in two places:
- to the screwdriver handle;
- to the body of the old battery.
The cast body is cracked with a sharp blow to the screwdriver, or it is separated by a hacksaw blade at the soldering point. Then the old lead battery is removed, and power from a new source is connected to the free wires, observing the polarity.
How to power a screwdriver from a third-party battery
The service life of a screwdriver is 5–7 years, and its battery life is at best 2 years. This means that by replacing the power source, it will be possible to extend the life of the beloved instrument by at least 2 years. Of course, it is best to find an original battery, but the problem is its availability and cost.
Gel (batteries for UPS)
Their advantage is a sealed body and a paste-like electrolyte, which allow the instrument to be used in any spatial position. It is possible to use a charger from a screwdriver. Here you can not be afraid of acid burns or spoiled clothes. You can attach the battery directly to a screwdriver or carry it in a bag or s.
They differ in mass in the range of 2-4 kilograms. Voltage 6 and 12 volts.
It should be borne in mind that connecting a new power supply is an interference with the factory design. This means that it is important to pay attention to personal and fire safety. Remember that you need to:
- observe polarity;
- securely insulate wire connections;
- use chargers rated for the capacity of this battery.
A minimal knowledge of electrical engineering is sufficient to replace the battery. Locksmith skills will also come in handy. It is necessary to provide increased mechanical strength of the wire connection points.
Reverse or reverse
This option allows you to unscrew a screw or drill bit stuck in the material. The change in the direction of rotation occurs when the polarity of the power supply is changed, which is carried out through a special button. It is usually installed close to the trigger.
Examples of the location of the backstop button in a screwdriver
Most often, the button for switching the direction of travel has three positions: on average, the tool is locked. This increases safety: if you accidentally touch the lever, the screwdriver will simply stop, rather than immediately start to rotate in the opposite direction.
After you have decided on the type of screwdriver and power supply, you need to focus on the technical specifications. They determine which screws and in which material you can screw.
An example of the technical characteristics of a screwdriver
The main parameters of the battery and the tool itself
The main parameter that characterizes the operation of a screwdriver is the voltage of the battery, which, in turn, determines the power of the electric motor and the torque. For household models, the difference in voltage between screwdrivers is small. on average, it is in the range of 10.8-14.4 V. productive options designed for permanent use can be equipped with batteries of 24-36 volts.
The battery voltage of the screwdriver depends on the type of battery. you can answer what the difference is, knowing what metals were used to make it. For nickel-cadmium batteries, larger in size with a similar capacity, the value of the indicator is a multiple of 1.2 V (this is exactly the voltage for one cell of which the battery pack is composed), for lithium-ion batteries. 3.6 V.
Among other, equally important characteristics, one can note:
- the power of the screwdriver, by which you can also determine the speed of tightening screws and self-tapping screws. To carry out repairs on our own, models with a capacity of 500-700 W are quite enough. A professional repairman will need more powerful equipment. 800–850 W;
- the number of revolutions of the rotating part of the device per unit of time. This parameter determines whether the screwdriver will be able to perform the task assigned to it. for example, tighten the required type of fastener. So, for a bolt, self-tapping screw and a screw, 500 rpm is enough, for drilling it will take 1200 rpm;
- torque, the value of which can become one of the main answers to the question of what the voltage of the screwdriver’s battery affects. According to this characteristic, it is possible to determine both the diameter and the length of the screw to be screwed or self-tapping screw. Large fasteners, as well as drilling deep and wide holes and hard materials, require a serious torque value. The maximum value of the indicator is 10-60 Nm.
There are two types of screwdriver torque. starting (larger in magnitude and required to start the device in operation) and constant, that is, working. The parameter value for modern equipment models can be adjusted. to find out how many modes can be selected for a particular device, you can find out in the documentation available for it. over, tools with a pulsed mode of operation (turning on the rotating part by jerks) have more screwing capabilities. allowing you to periodically increase the torque, they can screw in a larger screw.
The given value of torque from electric motors is not constant and depends, first of all, on the speed of the motor, the higher the speed, the lower the torque on the shaft.
In addition to the voltage of the screwdriver and its power, the capacity of the battery should also be evaluated. The characteristic is measured in ampere-hours or milliampere-hours. The higher the indicator, the longer the screwdriver can work without recharging.
The average battery capacity of the household model is 1300 mAh, which is enough for 2-3 hours of operation. Professional equipment requires more time to complete the work. and a master who uses a screwdriver for a whole working day should purchase a model with 1.5-2.0 Ah batteries.
- Capacity. Reflects the amount of energy that can be stored. It is clear that the larger this parameter, the better (but also more expensive).
- Voltage. There is a rechargeable battery for a screwdriver for 10 V, 12 V, 14.4 V. Household models usually go with such parameters. A more serious tool works with 18 V and 24 V.
What characteristics to choose a screwdriver?
To choose a screwdriver for home or professional use and not regret, you must view these parameters. If you have picked up several models, compare them according to these characteristics, because it depends on them how long the interval between the charges of the screwdriver batteries will be.
|Bosch GSR 1800-LI 1.5Ah x2 Case||hammerless drill||quick-clamping 0.8-10 mm||1300 rpm||34 Nm||2||29 mm / 10 mm||Li-ion||1.5 Ah / 18 V||reverse, spindle lock, electronic speed control||power button lock||1.4 Kg||case, two batteries, charger||RUB 6.7. RUB 7.5.|
|Bosch GSR 18-2-LI Plus 2.0Ah x2 Case||hammerless drill||quick-clamping 1.5-13 mm||1900 rpm||63 Nm||2||38 mm / 13 mm||Li-ion||2 Ah / 18 V||reverse, spindle lock, electronic overload protection, electronic speed control||bit socket, spot light, power button lock||1.49 kg||case, two batteries, charger||11 thousand rubles. 13.5 thousand rubles.|
|Makita 6347DWDE||hammerless drill||quick-release / 1.5. 13 mm||1300 rpm||80 Nm||2||38 mm / 13 mm||Ni-Cd||2.3 Ah / 18 V||reverse, electronic speed control||bit socket, power button lock||1.5KG||two batteries, charger, bit, case||13 tr.|
|Makita 6347DWAE||hammerless drill||quick-release / 1.5. 13 mm||1300 rpm||80 Nm||2||38 mm / 13 mm||Ni-Cd||2 Ah / 18 V||reverse, electronic reverse, electronic speed control||bit socket, power button lock||1.5KG||two batteries, charger, bit, case||11.3 tr. 12 tr.|
|Hitachi DS18DVF3||hammerless drill||quick-release / 13 mm||1200 rpm||45 Nm||2||21 mm / 12 mm||Ni-Cd||1.4 Ah / 18 V||reverse, electronic speed control||bit socket, additional handle||2 Kg||case, flashlight, set of attachments||7.6 tr. 9.5 tr|
|Hitachi DS18DSFL||hammerless drill||quick-release 2mm / 13mm||1250 rpm||41 Nm||2||38 mm / 13 mm||Li-ion||1.5 Ah / 18 V||reverse, electronic speed control||power button lock||1.7 kg||two batteries, charger, case||RUB 8.7. 11.6 tr|
|Metabo BS 18 10mm 1.3Ah x2 Case||hammerless drill||quick-release / 1-10 mm||1600 rpm||48 Nm||2||20 mm / 10 mm||Li-ion||1.3 Ah / 18 V||reverse, spindle lock, electronic speed control||bit socket, spot light, power button lock||1.3KG||two batteries, charger, case||7.7 tr. 8.1 tr.|
|Metabo BS 18 Li 2012 13mm 2.0Ah x2 Case||hammerless drill||quick-release / 1.5-13 mm||1600 rpm||48 Nm||2||20 mm / 10 mm||Li-ion||2 Ah / 18 V||reverse, spindle lock, electronic speed control||bit socket, spot light, power button lock||1.5KG||two batteries, charger, case||RUB 10.3. 10.9 tr.|
|RYOBI RCD18021L||hammerless drill||quick-release / 1.5-13 mm||1600 rpm||45 Nm||2||38mm / 13mm||Li-Ion||1.4 Ah / 18 V||reverse, spindle lock, electronic speed control||socket for fastening bits, magnetic holder on the body, spotlight, power button lock||1.2KG||one battery, charger, bit, bag||7.1 tr. 7.8t.r.|
|RYOBI R18DDP-0||hammerless drill||quick-release / 13 mm||1600 rpm||45 Nm||2||32 mm / 13 mm||18 in||reverse, electronic reverse, spindle lock, electronic speed control||socket for fastening bits, magnetic holder on the case, locking of the power button||1.81 kg||bit (without battery and charger)||2.7 tr. 2.9 tr.|
It is worth saying a few more words about the number of work speeds. Not to be confused with the number of rotation speeds. These are two modes of operation that are used when working with different sizes of screws or drills. When working with small screws / drills, you can select a higher speed, when screwing in large screws or drilling large holes, a lower speed.
Illumination of the working area
A very convenient option that does not really affect the price of a screwdriver is the illumination of the work place. In good light it is much easier to control the instrument.
Work area lighting is a useful additional feature of the screwdriver
An LED is built into the handle or the body of the tool near the chuck, which lights up when the start button is pressed. If you want to choose a screwdriver that is comfortable to work with, see that there is a highlight of the work place.
The screwdriver chuck is of two types: key and keyless. The quick-release (usually has three petals) allows you to change the nozzles in a matter of seconds. the cartridge is turned a little by hand, the nozzle is changed, after which it is turned a little in the opposite direction again. In addition, there is one more positive point: in such a holder it is fashionable to install a nozzle of any thickness. The main thing is that the shank fits into the holder.
Types of chuck for screwdriver
The same operation with a key chuck requires a special key. It is inserted into a special socket, rotated until the nozzle is free. After replacement, the key turns in the opposite direction. The disadvantage is obvious: you must have this key at hand.
By structure, keyless chucks can have one or two couplings. If there are two couplings, one of them fixes the chuck, the second. the shaft. If there is only one coupling, then there is a shaft locking button on the body.
It is not difficult to choose a screwdriver according to this parameter. usually everyone converges on quick-clamping ones. They allow you to fix nozzles of large sizes, although they are a little more expensive, other things being equal.
Rechargeable or mains
Having decided on the class, you will need to decide whether you need a network screwdriver or a cordless one. The disadvantages and advantages of both are obvious: the battery pack has higher mobility and the cord does not interfere with work, but it weighs more. The network does not depend on the availability of battery power, but not all construction sites have power supply. In general, the choice is not easy. The decisive moment can be that a cordless screwdriver with a good battery costs decently more than a similar model powered by a network. The difference is due to the presence of the battery. good options are not cheap.
With a power screwdriver, the length of the cord is important
If you decide to choose a cordless screwdriver, pay attention to the cable length. The longer it is, the more convenient it will be to work. you don’t have to carry a carrier.
To choose the right battery-powered screwdriver, you need to pay attention to the type of battery. The duration of work on one charge depends on this, as well as the order of storage.
- Lithium-ion (Li-lon). Holds a charge for a long time, quickly charges, has a large number of recharges, almost never discharges during storage. In general, a good option, but expensive. Therefore, it is probably more common on professional models, where the duration of work on one charge is important. The disadvantages include the fear of the cold, which is important in our country.
Lithium-ion batteries are long-lasting, not self-discharge, but expensive
Nickel-metal hydride batteries are not a bad option, but they do not have a very long life.
The cheapest type of batteries is nickel-cadmium, but they have a “charge memory”
So, if you choose a cordless screwdriver for periodic work, a nickel-cadmium battery will also work. If used carefully, it lasts a long time. If you start large-scale work, it is better to use other batteries. there will be less downtime, work will move faster.
The cost of a new screwdriver is about 70% of the cost of the battery for it. Therefore, it is not surprising when, faced with a battery failure, we ask ourselves the question. what’s next? Buy a new battery or screwdriver, or maybe there is an opportunity to repair the screwdriver battery with your own hands and continue working with an already familiar tool?
In this article, which we will conditionally divide into three parts, we will consider: the types of batteries that are used in screwdrivers (part 1), their possible causes of failure (part 2) and available repair methods (part 3).
We figured out the purpose of the battery structure elements, now we will consider how to determine the malfunction, this is part 2 of the screwdriver battery repair. We note right away that all the elements cannot fail at once, and since our circuit is sequential, when one element fails, the whole circuit does not work. So, our task is to determine where we have the weakest link in the chain.
For this, we will need a multimeter, and for the second method of troubleshooting a 12V lamp, if your battery for a screwdriver is also 12 volt. The procedure is as follows:
Note. The difference between the cells in the battery of 0.5. 0.7V is considered significant, this means that the cell becomes unusable.
Thus, we have found candidates for “resuscitation” or “amputation” and replacement with new elements.
If your screwdriver operates on a voltage of 12 or 13V, you can search with a simpler method. We disassemble the fully charged battery and connect a 12 volt lamp to the contacts “” and “-“. The lamp will be a load and will drain the battery. Next, we take measurements on the battery cells, where the voltage drop is strongest, there is also a weak link.
There are other ways, instead of a lamp, you can choose a resistance, but for this you already need the basics of electrical engineering, and it is doubtful that a resistor with the necessary resistance would be at hand.
Other faults are very rare. For example, loss of contact at the soldering points of the batteries or the power contacts of the unit, failure of the thermistor. This problem is more inherent in fakes. Due to the rarity, we will not focus on the battery elements.
With the “problem” elements sorted out, it is necessary to repair. How to repair a screwdriver battery? In general, there are 2 ways available for repair, so to speak. This is the restoration and replacement of elements that have become unusable.
Is it possible to “reanimate” the elements and how?
Let’s proceed to part 3 of repairing a screwdriver battery and immediately make a reservation that the concept of “resuscitation” for lithium. ion batteries is not applicable. There is no memory effect in them, most likely, lithium decomposition has occurred, and nothing can be done about it. In such batteries, it is necessary to find out what the cause of the malfunction is: the element itself or the control circuit. There are two options here:
- we change the control scheme from another, but similar to ours, battery, if it helps, we find a replacement and change it;
- apply 4V to a cell with a current of about 200mA, this requires an adjustable charger. If the voltage on the element rises to 3.6V. the element is working properly, the problem is in other elements, or in the control circuit.
Screwdriver battery refurbishment is available mainly for Ni-Cd batteries, but they are usually the most common in household screwdrivers.
So how to reanimate a screwdriver battery? There are two types of “resuscitation” for these types of batteries:
- The method of compaction or compression (it will work in cases where the electrolyte is still present, but the volume is lost);
- “Firmware” voltage and current greater than the nominal. This method allows you to eliminate the memory effect, and although not completely, but restore the lost capacity.
This method is shown below in the video.
Note. As a rule, in a nickel. cadmium battery, the main reason for the loss of capacity is the boiling off of the electrolyte, and if it is critically small, no “firmware” will help.
This method, if its result is positive, will not solve the problem of failure of elements. Rather, it will only postpone the replacement of those that have become unusable and in the future you will still need to repair the battery of a Makita screwdriver or any other.
- Screwdriver battery: design and types
- Fault definition
- Is it possible to “reanimate” the elements and how?
- Repair and replacement of screwdriver battery cells
Screwdriver battery: design and types
It should be noted that regardless of the brand of the screwdriver and the country of the manufacturer, the batteries have an identical structure. The assembled battery pack looks like this.
If we disassemble it, we will see that it is assembled from small elements that are assembled sequentially. And from the school physics course, we know that elements that have a serial connection harmonize their potentials.
Note. The sum of each battery gives us the total voltage at the contacts of the battery.
Typesetting parts or “cans”, as a rule, have a standard size and voltage, they differ only in capacity. Battery capacity is measured in Ah and is indicated on the cell (pictured below).
For the arrangement of screwdriver batteries, the following types of elements are used:
- nickel. cadmium (Ni. Cd) batteries, with a nominal voltage on the “banks” of 1.2V;
- Nickel-metal hydride (Ni-MH), cell voltage. 1.2V;
- lithium-ion (Li-Ion), with voltage. 3.6V.
Let’s consider in more detail the advantages and disadvantages of each type.
- The most common type due to its low cost;
- Low temperatures, such as Li-Ion batteries, are not scary;
- Stored in a discharged state, while retaining its characteristics.
- Produced only in third world countries, due to toxicity during production;
- Memory effect;
- Small capacity;
- A small number of charge / discharge cycles, which means that they do not “live” for a long time with intensive use.
- Environmentally friendly production, there is an opportunity to purchase a high-quality branded battery;
- Low memory effect;
- Low self-discharge;
- High capacity compared to Ni. Cd;
- charge / discharge cycles.
- Loses some of its characteristics during long-term storage in a discharged state;
- Does not “live” for a long time at low temperatures.
- No memory effect;
- Self-discharge is almost absent;
- High battery capacity;
- The number of charge / discharge cycles is several times greater than that of previous types of batteries;
- To set the required voltage, fewer “cans” are required, which significantly reduces the weight and dimensions of the battery.
- High price, almost 3 times in comparison with nickel. cadmium;
- After three years, there is a significant loss of capacity, because Li decomposes.
We got acquainted with the elements, let’s move on to the rest of the elements of the screwdriver battery pack. Disassembling the unit, for example, for repairing the battery of the Hitachi screwdriver (pictured below), is very simple. unscrew the screws around the perimeter and disconnect the case.
The body has four contacts:
- Two power, “” and “-“. for charge / discharge;
- Upper control, it is switched on through a thermal sensor (thermistor). A thermistor is necessary to protect batteries, it cuts off or limits the charge current when a certain temperature of the cells is exceeded (usually in the range of 50. 600C). Heating occurs due to high currents during forced charging, the so-called “fast” charging;
- The so-called “service” contact, which is connected through a 9K ohm resistance. It is used for complex charging stations that equalize the charge on all battery cells. In everyday life, such stations are useless, due to their high cost.
That’s actually the whole design of the battery. Below is a video on how to disassemble a block.
Repair and replacement of screwdriver battery cells
A more effective way to repair batteries for a screwdriver is to replace elements that we have identified as faulty.
Note. When purchasing a new element, make sure that its capacity and dimensions coincide with the native elements.
We also need a soldering iron, a low-corrosion flux (preferably an alcohol flux for rosin) and tin. We are not talking about spot welding, since there is hardly a need to purchase or assemble it for a one-time battery repair.
In the replacement itself, there is nothing complicated, especially if at least some. then there is experience in soldering. The photographs show everything in sufficient detail, we cut off the faulty element, instead of it we solder a new one.
Several nuances should be noted:
- When soldering with a soldering iron, try to solder quickly, so that the battery does not heat up, because risk spoiling it;
- if possible, implement the connection using native plates, or use the same copper plates, this is important because the charging currents are large and if the cross-section of the connecting wires is incorrect, they will heat up, respectively, the thermistor protection will be triggered;
- in any case, do not confuse the plus of the battery with the minus. the connection is sequential, which means that the minus of the previous can goes to the plus of the new can, and the minus of the new one. plus the next.
After the new elements have been soldered, it is necessary to equalize the potentials on the “banks”, since they are different. We carry out a charge / discharge cycle: we set it to charge overnight, give it a day to cool down and measure the voltage on the elements. If we did everything correctly, the picture will be something like this: on all elements the same indicator of the multimeter, within 1.3V.
Next, we proceed to discharge the battery, insert the battery into the screwdriver and load it “in full”. The main thing is to spare the screwdriver itself, otherwise you will have to repair it too. We bring it to full discharge. We repeat this procedure two more times, i.e. charge and fully discharge.
It should be noted that the procedure for erasing the “memory effect” should be carried out every three months. It is carried out by analogy with the above-described training.
Such a not very tricky procedure will prolong the work of your screwdriver, at least until you have to change it to a new one.
Diagram of the internal structure of the screwdriver.
Of course, before proceeding with the repair, it is necessary to make a high-quality diagnosis of the device. It is not always possible to immediately find a specific malfunction. Almost all batteries of modern screwdriver batteries consist of several cells connected in series. They have a specific voltage rating. Everything here directly depends on what type of battery we are talking about.
So, you need to disassemble the battery. Now each element can be measured with a multimeter. It is necessary to set the nominal battery voltage on it, and then make measurements. This is done quite simply. Each element should have approximately the same reading. Before disassembling the battery, it must be fully charged.
Next, the screwdriver battery should be assembled and worked with it until the power is completely lost. After that, the mechanism is again disassembled and voltage measurements are made on each bank. If any value is half the nominal value, then this bank is out of order. By the way, there may be several of them, so all defective elements must be replaced. Do not postpone this procedure indefinitely.
Types of restoration of the performance of previously used battery cells
Diagram of a lithium-ion battery for a screwdriver.
The method of reanimating previously used batteries is very often used, since during the operation of the screwdriver, in other words, during constantly high loads, some elements lose their tightness and become unusable. In this case, it is necessary to make a short-term impact of a strong current on the required battery cell (bank), and, possibly, it will be possible to restore the battery’s performance.
You can also try to gently squeeze or slightly deform the screwdriver’s battery case. Because this can extend the battery life for a short period of time. But in most cases, this method does not guarantee the battery life of the screwdriver and is temporary.
Nickel-cadmium batteries are characterized by significant endurance, since they may not lose charge for a long time or discharge, but very slowly. But in the event that it did not work to restore their performance, it is worthwhile to carry out such a process as replacing the batteries in the screwdriver device.
Battery types for power tools
There are a huge number of battery technologies, but the most common and popular among them are the following:
- Lead acid batteries are most popular in the automotive industry due to their ease of manufacture and low cost. But then, for use in power tools, they did not show themselves much, since they have low power with large dimensions and high weight.
- Nickel-cadmium batteries have significantly outperformed lead-acid cells. After all, they are lightweight and compact in size, delivering great power. But, of course, there are negative aspects, in particular, the toxicity of the battery. Since the production of this kind of battery cells is harmful to the environment. For example, in the countries of the European Union, this type of battery is considered prohibited.
- Nickel-metal hydride cells are considered to be an improvement over the previous battery type. After all, they are completely safe for the world around them. But there is also a drawback in the form of high self-discharge current indicators.
- Lithium-ion batteries, although they have almost ideal parameters, since they have a high capacity, small size and low weight, are not very popular. This is because such a progressive element has a high cost, and therefore is not affordable for every man in the street.
Memory effect of screwdriver batteries
Screwdriver specification table.
Very often, in the process of using a screwdriver, they forget about the rules and recommendations for its operation. This is why batteries lose their charge at the most inopportune times. At this moment, the battery cells instantly catch the memory effect and lose their former performance.
Of course, there are tools that provide the correct charging algorithm. It implies the obligatory discharge of batteries to readings in the calculation of 1 volt for each individual cell. This can happen both after pressing a certain button, and in automatic mode, but it happens that even this does not achieve the elimination of the memory effect.
Although in most cases, the elimination of this effect after such a process as replacing the batteries is carried out by repeatedly discharging and charging the battery cells in a screwdriver. In this case, it is not even necessary to work with the power tool, you can simply use a light bulb. She will slowly but successfully cope with this simple task and completely discharge the battery banks.
So, the work of a screwdriver will sooner or later lead to the fact that its batteries will become unusable. In this case, it is recommended to choose from several options for solving the problem. Indeed, if you wish, you can completely replace the battery assembly, replace the worn-out cans, or try to restore those elements that confuse you.
But in this case, it should be understood that a complete replacement of the screwdriver’s battery is practically equal to the price of a new power tool.
How to calculate a non-working battery cell?
Since the battery is presented in the form of a certain number of cells connected to each other, current flows through it completely. To find a non-working battery cell, you must initially fully charge the entire battery until it is clear that charging is over.
Further, it is recommended to measure the voltage on each individual bank. The voltmeter should not show values below 1.2 Volts. If there are such readings, it means that the battery is not receiving proper power or is not charging.
Important! In order to make sure of your measurements, you need to put a mark on the questionable element and make the assembly back.
So, after several periods of operation of the instrument, it is necessary to reconnect the banks and measure the voltage. Practice shows that the previously mentioned bank will have even less voltage than before, since it begins to lose its performance and “slow down” the screwdriver.
If, when replacing the battery cells, old and new cells were used at the same time, it is necessary to ensure that their charge is equalized. To do this, you need to prepare a charger that will not turn off after a certain period.
Important! The active charging process must be performed for about ten hours.
Charger circuit for a screwdriver.
If the screwdriver operates on a voltage of 12 volts, then an easier method can be used here. It is necessary to disassemble the battery into its component parts. However, they must remain connected to each other. Since the circuit is in series, it is possible to connect a light bulb as a load to opposite ends of the battery. There should be a voltage of 12 volts here. Fortunately, the purchase of such lamps should not cause a problem. Automotive lamps can be used as there is exactly the same nominal voltage. After that, it is necessary to measure the voltage drops on each specific element. The one at which this indicator turns out to be the highest, and failed.