The use of screwdrivers has become a part of the construction business. Cordless drills allow you to perform tasks in places where there is no external power source or it is difficult to feed the extension cord. But over time, the batteries are out of order. Some found it possible and easy to repair the screwdriver battery with their own hands. What is needed and is it possible to restore existing elements? To answer this question, you need to understand the types of existing batteries.
Varieties of batteries
Manufacturers of screwdrivers use batteries in their models that are incompatible with competitors' products. But this concerns the external structure, the internal components are the same and can be of several different types. Among them are:
- nickel-metal hydride.
Each of these options has its advantages and disadvantages. Most often on the battery case you can find the inscription Ni-Cd. It says that inside there are elements that have a nickel-cadmium composition. Previously, such batteries have been used in mobile phones. This is due to the low cost of the elements for such batteries. According to their service life, they are inferior to the other two groups. This is due to a small number of discharge / charge cycles. Usually the voltage on one bank is 1.2 volts. To achieve a voltage of 12 volts, you will need to use 12 cans for one battery.
This negatively affects the weight and dimensions of the battery. For a battery of 18 volts, you need 18 elements. Positive properties are endurance to deep discharge. Also, they can be stored uncharged, which does not affect their impact. If you leave the battery for a long time, then after a while it will lose its charge. The production of such elements is not environmentally friendly, therefore it is not allowed in every country.
Nickel-metal hydride batteries were designed as a replacement for the previous species. They have become more widely used in the domestic sphere. Conventional finger-type batteries are made on the principle of nickel-metal hydride batteries. Such products have almost no memory effect. This means that you can charge them until they are completely discharged. But there are some limitations, which lie in the period of stay in a partially discharged state. If the battery has been in it for more than a month, then it must be completely discharged before charging. Their production does not cause such harm to the environment, as nickel-cadmium.
Products can hold a charge longer, but their cost is two or more times higher than that of the first option. Batteries that contain nickel metal hydride cells can withstand up to 300 charge / discharge cycles. In addition, this type of battery self-discharge rate is also several times higher. Not so long ago, elements were developed that are subject to less self-discharge. The voltage of one element is also 1.2 volts. Manufacturers advise charging the standard elements with a small current for a long time.
Recently, lithium-ion batteries have become very popular. They are used not only in screwdrivers, but also in most engineering and electronics, which is powered by a portable source. Such elements are identified by the inscription on the package or the case of Li-Ion. One such element has a voltage three times greater than one of the banks of the previous two, it is 3.6 volts. Elements can be of a very different capacity. At the same time, their dimensions remain small, which reduces weight and makes the screwdriver more compact. The number of cycles has been increased to 500. The element is devoid of the memory effect, so it can be charged at any time when it is required. The production of such batteries is more expensive, so the equipment with them also has a large price tag.
What exactly is faulty
For the correct detection of a malfunction, it is necessary to understand that the energy source consists of individual cans, which are connected in series. For nickel-cadmium and nickel metal hydride, the charge controller is installed in the charger, and in lithium-ion it is most often found in the batteries themselves. If the battery is not charging from the charger, you need to check what voltage the device is giving out. To do this, a voltmeter is connected to it and measurements are taken. If everything is in order, then the reason lies in the elements themselves. Usually the components do not fail together. One or several cans have lost their capacity.
To check this, you will also need a multimeter, which is put into the voltmeter mode for DC measurement. It is also necessary to disassemble the battery to gain access to individual banks. But before that, you need to insert the discharged product into the charger and wait until the end of the cycle. When it is signaled to reach full charge, then you can proceed to disassembly. Most often, the body is not folded. This means that you will have to use imagination and observation to open it without damaging the internal components. Often, the halves can be glued together, so you can use gasoline "Kalosha" and a syringe with a needle. It is necessary to apply a small portion to the joint and wait until the degreaser dissolves the glue.
Now with the help of a multimeter it is necessary to make voltage measurements on each element. It is important not to confuse the probes in places, since the testimony may be incorrect. In a charged state, lithium-ion batteries can have a voltage of up to 4.2 volts, if it is below 3.5, then we can assume that the element has problems. In the other two kinds of elements, the voltage of the charged can is between 1.2 and higher. After taking measurements on good banks, you can put a "+" sign, and those who lost capacity - "-". You can choose any convenient designation. After the check, you can collect the source. Bonding the halves of the body is not worth it. You can rewind them with electrical tape, because you need another disassembly.
The battery must be put into operation until it becomes clear that it has lost capacity or discharged. After that, the source housing can be dismantled and measured on separate elements, which were labeled as failed. If the voltage on them sagged by 0.5 volts from the nominal lower threshold, then the elements were detected correctly and their further maintenance or replacement will be required. After disassembling the battery, you must carefully inspect all the connection and soldering points. If any of the elements have bad contact, then it can be all the fault, and the bank will be in order.
Is it possible to restore cans?
Recovering items that have lost capacity is not an easy task, which does not always bring results. In most cases, the procedure may extend the life of the cans a little, but later a replacement will be required. Lithium-ion batteries can not be restored, so do not try. Most often, when they fail, they swell, deforming the internal components, and with this there is nothing to be done. The first method that can be applied is the selection of another control system. You can move banks from a non-working battery to a worker and see if anything changes. If this helped, then the issue is resolved. But the donor battery should be a similar model. For nickel-cadmium cans, you can try restoring several charge and discharge cycles. If after this occurs a normal set of capacity, then you can use some time.
To repair the screwdriver battery will require the presence of similar or the same cans, as in its own battery. A soldering iron, flux, which does not have a corrosive effect on the material, tin and wash, which will remove the flux residues, is necessary.
The soldering iron for the work must be of sufficient power to warm the plates well. Damaged items are deleted and discarded. It is better to take them to the disposal points, so as not to damage the environment. Under the existing scheme new banks are substituted and connected by native plates. It's worth working quickly, so that the battery cells can not overheat too much, which can damage them. It is important to carefully look at the marking of the elements, so as not to confuse the polarity. The first is applied to the flux, followed by tin. After the battery is assembled, it is necessary to give the new banks the required capacity. For these purposes, it is necessary to perform several cycles of full discharge and battery charge. For more information on repairing the battery, see the video.
Repairing the battery for a screwdriver is a simple task if you know about the nuances that were described in the article. The main problem can be the selection of suitable cans, which would correspond to the current parameters and in size would fit a specific battery.
How to choose a Hilti screwdriver
How to choose a shock drill
Vice manual metal