Most screwdriver models use batteries to charge the battery so that the tool can be used anywhere without connecting to electricity.
To provide long term battery life, at least for the period specified in the data sheet, several important conditions must be taken into account:
- Charge the battery properly;
- Properly store the battery during periods when the device is not in use;
- provide correct work tool.
Accumulator charging
- Charge the battery before using the tool for the first time.
- To achieve maximum battery capacity, charge the battery to the lowest power (not zero) and charge the battery at least 3 times (this is not necessary for lithium-ion batteries).
- The battery charging time must comply with the instructions in the included manual.
- Once the battery is charged, disconnect Charger from the charger.
- Don't forget that lithium ion batteries do not allow complete discharge.
- Use only certified chargers of the appropriate type.
How to repair a cordless screwdriver and its malfunction
They have two types - pulse and regular. Pulse devices allow you to quickly charge batteries (one hour), usually charge the battery within 5-7 hours.
Battery storage
- When the screwdriver is not in use, remove the battery.
- Nickel-cadmium and lithium-ion batteries last for half an hour, and nickel-metal hydride batteries are fully charged.
- After storing a NiCd battery, perform 3 complete drain cycles and charge NiMH batteries within 24 hours.
Tool operation
- It is important to consider the operating temperature.
Overheating negatively affects the long-term operation of all types of batteries. Lithium-ion batteries are not well tolerated low temperatures. Typically the operating range of all batteries is 10-40°C.
- Follow the instructions for use in the user manual.
Battery capacity is one of the main criteria for choosing such a tool.
Therefore, before purchasing a screwdriver, pay attention to the choice of battery and study the operating conditions of the device. This way, you can compare the performance of the tool with your requirements and you will not be disappointed in the future.
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Part two.
In the first part of the article, we found an unusable element in the assembly of a nickel-cadmium battery. What to do next with a broken battery? Is it possible to restore this item?
We devote the second part of our article to the options for repair, repacking and restoration.
There are essentially two repair options - the first is an attempt to rock and restore the damaged element, the second is to replace it with the same one with the same capacity.
The option of repairing an element is associated with difficulties of the following nature - as a rule, the element dries out - that is, loses its tightness - the electrolyte boils away from it (during loads due to poor contact) if the electrolyte has not completely boiled away, then it is possible to restore the operation of the element by compression or by shock therapy - with In it, the element is flashed with a strong voltage of higher voltage and current - which starts the processes inside the battery.
It should be noted that you should not confuse the methods of restoring lead-acid batteries from cars and nickel-cadmium batteries from portable tools. The difference is that lead acid batteries lose capacity mainly due to sulfation of the plates, while nickel cadmium batteries most often fail due to shock loads- they overheat and the electrolyte simply boils away from them.
Nickel-cadmium batteries by their nature are very patient and this fact makes them most suitable for harsh operating conditions; they have a relatively weak self-discharge current - 10% on the first day, and then no more than 2-3% per month. However, in practice, this property sometimes turns against them - strong starting currents passing through the battery heat up not only the motor of the same screwdriver, but also the battery itself, and therefore endanger it.
Also, nickel-cadmium batteries have a so-called memory - if they are insufficiently discharged and then recharged, the battery loses its effective capacity.
This problem is quite easy to deal with - we will return to this issue a little later.
So, we have a bank that does not accept a charge - and we will change it. The question arises where we will get the replacement element - everything is simply from exactly the same battery of the same screwdriver - we have two more batteries - and out of three non-working batteries we will make two absolutely working ones and there will still be a supply of living batteries left.
Don’t let the age of the batteries scare you - six years is not too old for a nickel-cadmium battery; batteries that are 10-15 years old exist and are still in use. However, it should be noted that the capacity of such batteries drops over time by 20-30% of the nominal value - therefore, we recommend immediately buying screwdrivers with capacitive batteries - they are less susceptible to the aging effect.
So we repeat the experiment with the search for bad elements in the two remaining batteries - in the first case, one element was found in the second out of two. We will make the assembly in which there are two bad elements a donor.
Resoldering the elements.
For soldering we use low-corrosive flux - as well as tin as solder. This is necessary so that the jumpers do not act as resistance to the circuit between the battery cells.
After resoldering the elements, it’s time to check. And training the battery with subsequent erasing of the memory effect. We take two rebuilt battery assemblies and assemble them into housings. It is clear that elements from different assemblies have different charges - and equalization is required - for this we will train the battery.
As in the case of identifying bad elements in the assembly, so with training, we will first charge and then discharge the batteries.
We install the batteries in the charger, preferably overnight, since in addition to the main charging currents, there are supporting currents that make it possible to recharge.
After charging the batteries, let them cool for a day.
We measure the battery voltage - 16.1 V and 15.9 V - excellent voltage of a charged battery, approximately 1.33-1.35 V for each cell.
Then we begin intensive training. For training, we chose a 35 black self-tapping screw - we will screw it into the stump of a freshly cut maple. Maple is essentially a very hard wood and the work of a screwdriver will be very intense...
The first battery started working - the first impression is very good, the first hundred tightened and unscrewed screws have passed - the fatigue of the screwdriver is not felt, and the heating of the tool and battery is already felt. We change the battery and repeat a hundred cycles of twisting and unscrewing (see.
photo below)
We consistently change batteries during operation. Let the screwdriver cool down after 300 cycles.
So the result is the first battery - 316 cycles, the second - 324.
Conclusion: the battery has acquired a powerful charge that will allow it to be used in operating mode a long period time.
Why are three cycles enough - firstly, it takes time, secondly, we don’t need to use ultra-deep discharges followed by a shock charge, it won’t be critical for us to tighten a screwdriver with 30-40 more or less screws, because we have two batteries and we alternate them at work.
In the future, it is advisable to repeat such training cycles no more than once a quarter, and you should try to completely discharge the tool and charge it. And then it will serve you for many years.
See continuation in part.
How to extend the life of a screwdriver battery?
For questions about battery repair, as well as purchasing cells (cans), please contact our specialists:
Most household screwdrivers are equipped with Ni-Cd or Ni-MH batteries. Unfortunately, their service life turns out to be short, and the cost of a new battery is comparable to the price of the screwdriver itself. You can increase the life of your battery by following two basic rules: fully discharge it before charging and do not exceed the charging time. IN professional models screwdrivers, these functions are performed by the charger, and in simple models it, in best case scenario, maintains the charging current at permissible limits, but does not control the charging time in any way and does not pre-discharge the battery.Pre-discharging the battery is especially important, since usually working with a screwdriver when the charge drops to 20-30% becomes inconvenient due to a decrease in torque, and it is put on charge. In this case, the so-called “memory effect” reduces the capacity and after several charge cycles the battery becomes unusable.
To completely discharge the battery, it is convenient to use the flashlight included in some screwdriver kits. If it is not there, then you can discharge using a suitable 12...26 V light bulb or even a regular resistor with a resistance of 100...200 Ohms. True, in the latter case you will not be able to control the process by the glow of the light bulb, but if you leave the resistor connected for several hours, the battery will definitely be discharged. The option for the laziest is shown in Fig. 1:
Fig.1. Forced discharge of the screwdriver battery
Another, more nice option, requires a little time and minimal radio amateur skills, but will undoubtedly bring satisfaction from the results of your work. It consists of modifying the charger, to which a discharge resistor, a “Charge/Discharge” switch and an LED indicator are added - Fig. 2.
Fig.2. The second option for discharging the screwdriver battery
The second condition for a long and fruitful battery life is maintaining the charge time, not allowing it to be exceeded. It is also not required here special effort and you can successfully use any suitable devices, for example, an alarm clock or a timer on your phone. If you are a supporter of full automation, then a conventional electronic time relay, for example, shown in Fig. 3, - perfect solution Problems. The charging time is usually indicated in the screwdriver data sheet and is 5-8 hours.
Fig.3. Time relay for charging the screwdriver battery
Using the described simple methods, you will significantly extend the life of the battery and will be able to drill more holes and screw in screws to the delight of your household.
info - radio-nn.ru
If you set out to purchase cordless screwdriver for household needs and assume that you will rarely use it, study the lineup screwdrivers. And first of all, pay attention to the use, maintenance and storage of the batteries used in them.
After that, make your choice.
Battery life depends on its type, capacity and voltage, on the number of charge-discharge cycles, on operating conditions and storage conditions, and of course on the manufacturer.
Regarding types batteries included in the package cordless screwdrivers, then three types of batteries are currently used:
- Ni-Cd – nickel – cadmium;
- Ni-MH – nickel – metal hydride;
- Li-Ion – lithium – ion;
To the advantages nickel-cadmium (Ni-Cd) batteries It can be attributed to the fact that they are not expensive, reliable and energy-intensive, on average they can withstand up to 2,000 charge-discharge cycles. The service life reaches up to five years.
The disadvantages are that nickel-cadmium batteries are large in size and weight, and if they are frequently undercharged, they lose some of their capacity, and this process is called the memory effect. When stored for more than a month, the self-discharge of a charged battery reaches about 20%.
Keep nickel-cadmium batteries can be discharged.
To the advantages nickel metal hydride (Ni-MH) batteries can be attributed to a reduction in weight and an increase in energy intensity by 30% compared to nickel-cadmium batteries.
The disadvantages are that nickel-metal hydride batteries can withstand up to 1,000 charge-discharge cycles, a long charge - it is recommended to charge for 3 hours, with frequent undercharging they lose part of their capacity (memory effect) and the inability to work at low temperatures. When stored for more than a month, the self-discharge of a charged battery reaches about 30%.
Keep nickel metal hydride batteries must be fully charged.
To the advantages lithium-ion (Li-Ion) batteries We include small dimensions and weight, up to 3,000 charge-discharge cycles, high energy intensity and no memory effect, low self-discharge - up to 7% per month and the ability to quickly charge.
The disadvantages are a low service life of up to 2 years, when the battery is completely discharged it fails and cannot be restored, there is a possibility of an explosion when charging, it is afraid of shocks and overheating, it is impossible to work at negative temperatures, high price.
Keep lithium-ion batteries Can be both discharged and charged.
Now that you have become familiar with the type of batteries, their advantages and disadvantages, you can decide on the choice of model to purchase.
I wish you success! May the skill be with you!
Posted at 09/01/2012, 18:14 h
Lithium-ion batteries are currently the most advanced (and expensive) type of battery for high-volume, mass-produced power tools. Structurally, a lithium-ion battery is no different from the batteries discussed above. The difference is in the chemical process. The battery anode is made of lithium oxide with cobalt or manganese, the cathode is made of graphite. Used as an electrolyte organic solvent. During the charging process of the battery, lithium ions move and bind to the negative carbon electrode material, and the reverse process occurs during operation.
Invented back in 1912, lithium-ion batteries for a long time didn't find practical application due to technological problems. One of the main ones was the problem of dendrites - crystalline formations, similar to a tree, developing on the surface of the positive electrode. The dendrite grew after each charge-discharge cycle, eventually reaching the surface of the negative electrode, after which it immediately followed short circuit and battery explosion. This, as well as some other problems, were eliminated in 1991 by Sony, which equipped the battery with a control electronics unit that is supplied Li-Ion batteries and to this day.
In most respects, lithium-ion batteries are significantly superior to nickel-cadmium and nickel-metal hydride batteries. For example, the nominal voltage of one cell is 3.6 V, the energy density can reach 200 Wh/kg, self-discharge is lower than other types of batteries (does not exceed 5% per month), fast (and even ultra-fast) charging is possible and There is absolutely no memory effect.
The “fly in the ointment” is the rather short service life of the lithium-ion battery (it used to be about three years, now it’s from seven to ten), and it doesn’t matter whether it worked or not. However, the topic of a short term is also a kind of myth - someone claims that Li-Ion batteries they last no more than three years, practice shows that it’s definitely five to seven, and the Mitsubishi company says about its i-MiEV electric car that its batteries will lose no more than 10% of their capacity in ten years. Also theoretically, the number of possible charge-discharge cycles is less than with other types of batteries. The disadvantages can also be added to the limitation of the operating temperature range and, of course, high cost.
It is also worth noting the electronics mentioned above, which mandatory is built into any Li-Ion battery to prevent all sorts of emergencies (otherwise it simply will not pass certification). Essentially, this is a simple chip that controls temperature and voltage, but it constantly consumes energy - as you might guess, it gets it from the battery itself. Although this consumption is negligible, a completely discharged Li-Ion battery left on a shelf for a year will most likely become unusable: the chip will eat up the remaining energy, and the charger will no longer be able to revive it due to chemical features batteries. So it is better not to completely discharge Li-Ion batteries, but be sure to charge them when sending them for storage.
Almost every battery in a power tool is the most expensive part. A screwdriver is no exception, because a replaceable battery can account for 30% of the total cost of the tool. After the device is discharged, you need to purchase a new screwdriver, but to save money there is another option - restoration, which will extend its service life.
The battery on the screwdriver runs out quickly
The problem with rapid self-discharge of the battery is quite common. It consists of fast charging, which occurs in about 20 minutes and the same short operation.
This situation may result from malfunction of the temperature sensor located in the removable battery. This temperature sensor may not be installed this way initially. It must be returned to the place of purchase.
If the battery begins to discharge quickly after prolonged uninterrupted use, which could happen after a fall, you need to get it repaired.
Battery won't charge
A screwdriver sometimes fails after prolonged use. Its working element may stop charging, which will lead to the impossibility of fulfilling the functional capabilities of the tool; the tool, roughly speaking, will “die”.
In order to extend the life of the instrument so that you do not have to remove it from visibility, you can try three methods in turn. Each subsequent one is considered more complex and costly. They are:
- restoration and increase in capacity after its reversible loss (memory effect);
- adding distilled water to the electrolyte;
- replacing some or all of the battery packs.
Battery life for screwdriver
The battery can last about three to four years if used and stored correctly. In practice, this period is sometimes reduced to two years. It is very expensive to constantly change a tool, so it is better to choose right away best option for one purpose or another.
There are 3 different types batteries:
- Nickel-cadmium. The most affordable, but short-lived, especially if used frequently in cold weather conditions.
- Nickel metal hydride. A small device that does not have a long service life.
- Lithium-ion. The most popular ones are capable of not being discharged for a long time, but have a higher cost than the above options.
Regardless of the type of battery, their lifespan depends on the number of charges used and storage methods. That is, the more the tool works, the faster it discharges. At the same time, “downtime” in use negatively affects the service life, especially if you store the tool in a condition where it is worn out.
How to restore a screwdriver battery at home
Is it possible to reanimate all types of batteries? Better to repair Nickel-cadmium blocks lend themselves, which are found in almost all modern screwdrivers.
The restoration process requires an understanding of the basics of electricity. That is, have school knowledge about the operation of rechargeable batteries.
To work you will need tools and materials:
- screwdriver;
- tester;
- soldering iron;
- tin (with low-corrosive flux).
To resuscitate the battery, a donor will be required. It may be included with the screwdriver, or you may need to find it yourself, for example, by removing it from another old device.
To begin the operation, it is necessary to fully charge (about 6 hours) both batteries and swing it. After this, remove the plastic cover from the restored part using a screwdriver. This procedure must be performed carefully so as not to damage the fasteners. Otherwise, subsequent assembly will require glue, like Moment.
Refurbishment of nickel-cadmium batteries for screwdrivers
The ni cd battery device is manufactured using the same technology, so any battery can be made a donor of this type.
Such devices are separate components - blocks, with a nominal voltage of 1.2 V and an energy capacity of 1200–1500 MA/h. They are found in screwdrivers from Interskol. Each block affects the power, that is, if its value is 12 V, the number of blocks is 10, 14.4 V - 12, etc. After changing the battery, the power may drop for the first time of operation, but then everything will be restored.
Restoring an 18 volt screwdriver battery
18 V is a common power, which corresponds to the presence of 15 blocks. As a donor, you need to choose an electrical device with a voltage of 14.5 V, that is, a 12 V car battery will not work.
How to restore and start a lithium-ion battery
For these types of batteries, you will need to remember where the positive, negative and charging contacts are located. The voltage control board located on the batteries most often fails, or rather, their stabilizers and protective diodes.
The voltage at the battery output is checked, if the value is significantly less than normal, resuscitation is performed.
Second life of batteries in Bosch, Hitachi, Makita screwdrivers
The brands shown come with a lithium-ion battery. To revive them, you will need a soldering iron and sleight of hand, because if you do everything slowly, the service life may decrease, or the battery will completely explode.
All broken or frayed wiring inside the battery must be insulated, for example, with electrical tape or replaced in advance with new ones.
To restore, the torn parts are soldered metal elements- tapes that can be taken from old blocks.
To assemble, you need to return the cardboard spacer between the blocks and the board to its place. This will be required to prevent a short circuit. Then the contacts are isolated.