Features of charging one type or another
The initial charging of the electric screwdriver is considered a very significant factor, since it depends on it whether the full capacity of the charge becomes active or not. Any type of battery has its own characteristic features of primary recharging. The process of recharging a nickel-cadmium battery is somewhat complicated. Initially, it needs to be recharged three times in a row, and so that the charge capacity remains full.
It is recommended that the nickel-metal hydride species be completely discharged the first time, and also fully charged. The circle of full charging / discharging is repeated 4-5 times, then you can safely charge and discharge the battery regardless of the capacity of the capacity.
There are no special rules for lithium-ion, the capacity remains unchanged for a long time.
How to revive dead NiCd battery from cordless power tools
Advice! The power supply must not be allowed to overheat over fifty degrees.
How to store nickel cadmium screwdriver batteries
Diary entry created by Andrey-АА, 11/07/14 Views: 62.613, Комментарии и мнения владельцев: 21
I bought a new electric screwdriver and decided to take a deeper look at how to properly operate its nickel-cadmium batteries. The goal is to actively work with an electric screwdriver with a battery change (accumulator) without the risk of damaging the batteries ahead of time. Reference: This electric screwdriver has:. Battery. 12V Number of cells. 10 Battery capacity. 1.2 Ah EMF of charged battery. 13.6V. Features:. It is believed that the maximum EMF of a fully discharged battery is 10V All Ni Cd batteries have a “memory” effect, i.e. if they are not fully discharged, they will lose their capacity Ni Cd batteries have high self-discharge The number of charge-discharge cycles for any battery is limited It is believed that the only criterion for the full charge of Ni Cd batteries (at currents greater than 0.1C) is their temperature, equal to about 40C. What I did: 1. First, I studied the mat. part (file attached). 2. Secondly, I took a series of measurements. 3. Thirdly, I worked and made a charger-discharge device for ultra-fast charging and automatic shutdown at a nominal discharge. So, point by point:
Well, the charge there is directly from any of the two chargers described above, and the discharge is through a powerful resistor (24 Ohm) with a circuit on the relay. Relay. automatically turns off the discharge when the voltage reaches 9-10 Volts. Why a forced discharge? It is needed so that the battery capacity does not decrease, that is, to eliminate the “memory” effect (see the “theory” in the file). That is, when the user thinks that the battery needs to be changed, he inserts a semi-discharged battery into the closed switchgear into the discharge mode and, doing his job, waits for the LED to go out. After that, it switches the toggle switch to the charge position and, if this battery has a thermoelement that turns off the charge when the temperature rises to 40-45C, it “forgets” about it. over, he can use a rechargeable battery after 15 minutes (with a fast charge). If there is no thermoelement, then a daily electromechanical timer can be used for shutdown.
Note 1. In principle, you can discharge the battery with the electric screwdriver itself, but I did not like it. The control of the nominal discharge level is approximately the following: if the cartridge, which is already barely rotating without load, is stopped by hand and after that it does not start to rotate itself, then the discharge is close to the nominal. Note 2. At any real charge current, the termination of the charge of Ni Cd batteries can and should be judged by the temperature of the battery. preferably about 40C (at room ambient temperature!). Note 3. Based on the above, recommendations for storage of batteries can be made. The purpose of the recommendations is the maximum battery life. I would single out two different modes of operation of an electric screwdriver:. Rarely. Let one battery lie in the state that was left after the last work, and keep the other discharged. At the beginning of work, use the first (re-discharge in the process of work), and the second can be charged at this time Often. Store one in a charged state, and the other in whatever is left after the last work. Well, if. very often (every day), then you can store both in a charged state. I understand that not everyone has a charger for a fast charge, as well as for a slow one (standard ones usually give an average current between them). However, all the same, they are not difficult to make / find. In any case, I hope that what is written here will help someone to understand a little with such “peculiar” Ni Cd batteries.
If you set out to purchase a cordless screwdriver for household needs and assume that you will rarely use it, study the range of screwdrivers. And above all, pay attention to the use, maintenance and storage of the batteries used in them.
The service life of a storage battery (accumulator battery) depends on its type, capacity and voltage, on the number of charge-discharge cycles, on operating conditions and storage conditions, and of course from the manufacturer.
As for the types of batteries included in the package of cordless screwdrivers, three types of batteries are currently used:
- Ni-Cd. nickel. cadmium;
- Ni-MH. nickel. metal hydride;
- Li-Ion. lithium ion;
The advantages of nickel-cadmium (Ni-Cd) batteries include 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 and heavy and, with frequent undercharging, 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%.
Nickel-cadmium batteries can be stored discharged.
The advantages of nickel-metal hydride (Ni-MH) batteries include 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, long charge. it is recommended to charge for 3 hours, with frequent undercharging they lose some 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%.
Store NiMH batteries fully charged.
The advantages of lithium-ion (Li-Ion) batteries include small dimensions and weight, up to 3,000 charge-discharge cycles, high energy consumption and no memory effect, low self-discharge. up to 7% per month and the possibility of fast charging.
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, the inability to work at negative temperatures, high price.
Lithium-ion batteries can be stored both discharged and charged.
Now, when you have familiarized yourself with the type of rechargeable batteries, their advantages and disadvantages, you can decide on the choice of a model for purchase.
We can recommend you an electric screwdriver from the household line with a nickel-cadmium battery. With proper care, even with rare use, it will serve you for five years for sure.
the electric screwdriver is the most demanded tool used by professional non-amateurs. Use is rarely convenient, especially if you are away from two hundred twenty V. With a cordless tool, this problem is solved, with its help, of course, move freely without dragging the cord along.
One of the elements of any cordless tool is a battery that provides autonomous operation. However, what is the correct way to charge the battery in order for it to last as long as possible? Further in detail in the text of the article.
electric screwdriver. How to extend battery life.
How to increase battery life. How to properly discharge and charge the battery. What will happen to.
As you can see, each rechargeable battery is endowed with characteristic features, taking into account which, it will be possible to properly charge the electric screwdriver.
What is the optimal amount of time for charging?
The recharging period is usually indicated in the device manual. In most cases, the device has a special indicator that helps you understand how long it takes to charge. After charging is complete, disconnect it to avoid damaging the batteries. The average charge for an electric screwdriver is thirty minutes to seven hours. Longest period for 1.2 V Ni-Cd, two mA feed approximately seven hours.
Should I charge before long-term storage??
Don’t use an electric screwdriver battery for a long time? Experts give the following recommendations.
- Nickel-cadmium batteries, before being stored, must be discharged to the point where the electric screwdriver ceases to function at full capacity. For long-term storage, it is necessary to carry out 3-5 full circles of charging / discharging.
- Nickel-metal hydride ones are provided with a higher self-discharge value, in contrast to the previous elements. Experts advise keeping them charged, and after a long break, put them on charge for a day. The capacity decreases after 200-300 charge-discharge cycles. Partial discharge allowed for this type.
- Lithium-ion devices are distinguished by the complete absence of the “memory effect”. The battery can be charged whenever you want. It is not recommended to completely discharge them, as a result, you can disable the protective circuit. Equipped with special controllers that shut off the element at high temperatures to prevent overload. You can keep the cell charged only 50%.
In order for the battery to last a long time “like a clock”, you must first join the instructions supplied with the device. It should be noted that screwdrivers differ not so much in price, power, manufacturer, but are divided into professional not semi-professional. Accordingly, the batteries will also have different prices, the quality is not the capacity of the charge. Professional types are equipped with more capacious power supplies, which will cost one level more, while at the same time they will work longer than conventional ones. Manufacturers of the discharge version are allowed to recharge as long as necessary. The high cost is not intolerance to low temperatures discourages some people from buying, so they are in little demand. Charge batteries at temperatures between ten and 40 ° C. If the battery heats up in charge, it must be cooled to avoid further damage.
Nickel-cadmium battery is endowed with compact dimensions and not large capacity. Following the attached instructions, they will of course be fed more than one thousand times. There is a memory effect, if you charge it for 30 years, than a full discharge occurs, this can reduce the energy consumption. Before the first use, it is necessary to charge more than two or three times without discharging the battery. Then it is also recommended to completely discharge the device not to charge the device, this allows you to bring the capacity to the required operating state. The same rule applies when the tool is stored.
Nickel Metal Hydride Ni-MH
They belong to the newest generation of batteries, therefore, they are somewhat weaker than the previous version, which is an undoubted advantage. The disadvantage of the NMGB is the highest self-discharge current. In order for the battery to function for a long time, it must be kept charged. If the passage of a prolonged non-use of the electric screwdriver (about a month), it must be completely recharged.
There are also two types of battery chargers: ordinary and impulse. Standard charging is completed with non-professional tools, the charge lasts about 3-7 hours. The impulse device is designed for professional models and is able to power the battery for a maximum of one hour.
Tip: the Interskol electric screwdriver is distinguished by its versatility, besides the main function, it can also be used as a drill.
Nickel Cadmium Batteries. Help for engineer | Schemes, principle of operation, formulas and calculation
Nickel-cadmium batteries (Ni-Cd) have a significantly smaller area of application compared to lead-acid batteries, due to the tightening of requirements regarding the environmental side of the use of these batteries and their recycling.
The main area of application, which was briefly mentioned in the general information about batteries, is the use in the form of a standard galvanic cell, the use of large nickel-cadmium batteries in electric cars (used as traction), as on-board batteries in airplanes and helicopters, in trams and trolleybuses. Of course, we must not forget to mention the use of these batteries to power autonomous tools for construction, for example, screwdrivers, drills, etc.
As mentioned earlier, nickel-cadmium batteries are being actively replaced by other types, for example, nickel-metal hydride batteries have 2 times more specific characteristics compared to nickel-cadmium, which led to the fact that equipment using this type of batteries has improved its consumer properties. However, nickel-cadmium batteries together with nickel-metal hydride batteries have an oxide-nickel positive electrode, which determines the similar properties of these batteries.
Nickel-cadmium batteries need a full discharge, if they are used and not completely discharged, crystals form on the inner plates of the elements, which to a large extent irreversibly reduce the capacity of the battery, this effect is called the “memory effect”.
The other side of their gradual fading into the background is the relatively expensive disposal cost compared to other species. Disposal of batteries such as Ni-Cd batteries occurs in furnaces at very high temperatures, in which cadmium becomes excessively volatile, and if the furnace is not equipped with a special filter that must trap toxic substances evaporated during melting, then these melting products will poison the environment.
The nominal voltage of a fully charged battery is 1.2V (in some 1.36), discharged 1V, these are the threshold voltage values at which the battery is used. Charging nickel-cadmium batteries can be said to be standard for all types of batteries. with a current equal to 10% of the battery capacity for about 16 hours. The nominal discharge mode of the battery takes place at a current equal to 20% of the capacity. Ni-Cd batteries have a fairly wide operating temperature range of 50 to 40 ° C. Self-discharge is approximately 10% and increases with use (operating time). For example, lithium-ion batteries and their brothers lithium-polymer batteries have much less self-discharge.
Storing Nickel Cadmium Batteries
It is recommended to store batteries in a discharged state so that during storage they do not lose their capacity due to self-discharge, after charging they will restore their properties completely. If you store batteries at a low temperature, this significantly reduces the self-discharge current, which, for example, when stored in an environment with a temperature of 0 ° C, will be exactly 2 times less than when stored at a temperature of 20 ° C.
It is highly recommended, after long-term storage, to charge-discharge the battery with a current equal to the capacity.
Benefits of Nickel Cadmium Batteries:
1) the ability to store in a discharged state;
2) a large number of working cycles with correct operation;
4) adaptability to work in harsh operating conditions;
Disadvantages of nickel-cadmium batteries:
1) the main disadvantage of these batteries is the memory effect;
Redox reactions in the battery
Next, I want to write the general reactions in the battery, cathode, and anode (reading from left to right. charge, from right to left. discharge):
The general reaction in a nickel-cadmium battery is:
The process that takes place on the positive nickel oxide electrode:
The process that takes place on the negative cadmium electrode:
Li-Ion technology is advanced today. Lithium cells are much more compact and lighter than the previous ones with the same electrical capacity and, which is very convenient, can be charged with an increased current. At the same time, the time to fully charge lithium-ion batteries can be reduced to 1-2 hours.
A big advantage of this type of battery is the almost complete absence of memory effect. the instrument can be recharged at any time and to any level. Self-discharge of a Li-Ion battery is relatively low and amounts to approximately 2-3% of its capacity per month.
As for the shortcomings, until relatively recently these were high degrees of fire and explosion hazard. If used improperly, the battery could catch fire or even explode. over, the burning element is almost impossible to extinguish with water. this only intensifies the combustion.
Another serious drawback of cells of this type is that they do not tolerate deep discharge and overcharge. In the first case, the battery immediately fails, in the second, it can catch fire. But this problem was also easily solved with the same controller, which disconnects the battery from the load during a critical discharge and from the charger if the battery is charged.
Typical Li-Ion battery life is 600 charge / discharge cycles, but it is also highly dependent on “age”. A lithium-ion battery can be stored for no more than 2-3 years, regardless of whether it works or just lies on the table.
When choosing a tool with such batteries, it should be borne in mind that they will behave badly in the cold (a strong decrease in capacity, which, however, will recover in warmth). In addition, they will not be able to deliver a large current at any temperature, which means they will not provide the large torque required for working with dense materials. And the cost of Li-Ion cells is much higher than that of nickel counterparts.
1997 NiCd Cordless Screwdriver Teardown (It still works after 20 years!)
Restoration with water, step by step
Distilled water recovery is considered more efficient and durable.
- Before recovering the battery, it is necessary to detect the cells with zero voltage.
- Then, in their case, using an electric screwdriver with a thin drill, we make a small hole in the battery with zero voltage. Pour 1 cm3 of distilled water into this hole.
- Leaving the batteries for a while.
- We measure the voltage.
- Charging the batteries.
- If the recovery was successful, we seal the batteries or seal them with a sealant.
- We carry out a full battery charge.
- If the voltage has not increased, we carry out the procedure until the voltage recovers.
There are a number of rules that extend the life of any battery when it is forced to send it for long-term storage:
- When using a power source with a long break, it is necessary to carry out a complete discharge-charge cycle of the cell several times;
- The ambient temperature in the warehouse should not fall below 10 degrees Celsius;
- Periodic charging and complete discharge of the power source, at least once every six months, helps to extend the service life of the battery at rest;
- If the power tool is not going to be used in the near future, the battery must be disconnected from it and cleaned of all visible contamination.
Best way to store batteries. charged or discharged?
If the battery is nickel-cadmium or nickel-metal hydride, then it must be left fully charged if you intend to store less than 30 days, and with a charge of 30-50% of the maximum capacity if the storage period is more than 30 days.
Lithium-ion batteries, according to DeWALT, should be left fully charged. Although this is a strange rule, since from everything that I had to learn about this type of battery, I know that lithium-ion batteries are very slow to self-discharge (they lose about 4% per year). Apparently DeWALT in this case simply decided to play it safe, since the user can leave a fully planted battery for storage. Many people probably know that lithium-ion batteries have electronics that stop supplying current when the charge level reaches a certain minimum level. For the user, this will be zero, but in fact, there is still a charge there. And if such a battery is left to be stored without preliminary charging, then it can simply reach real zero even with its low discharge rates. And for lithium-ion batteries, this is death. they cannot be completely discharged, which is why the electronics are worth it. Here in DeWALT and reinsured. Well i think so.
Leaving an electric screwdriver with a lithium-ion battery and not even using it for a period of time, you will not be faced with the goal of discharging it. Here you can use a fairly common principle, which is that there is an option to charge the equipment, do not store it, but, if desired, take it again so that you can start using it immediately.
Without a loss of charge, such an electric screwdriver can not lie for six months is not easy. But it should be borne in mind that such car batteries should not be stored at negative temperatures.
Storing lithium-ion batteries
Lithium-ion (Li-ion) power sources are sensitive to temperature conditions and residual charge when sent for long-term storage. The available charge level at the beginning of use directly depends on this.
For lithium batteries of an electric screwdriver, the following rules are followed:
- Eliminate the possibility of freezing. when using the refrigerator as a storage space, they are placed in the main compartment, and not in the freezer;
- The optimal temperature regime varies from 1 to 25 degrees Celsius;
- Before being sent for storage, the discharged element is recharged to a level of 40%, this will completely restore the charge if it is necessary to use an electric screwdriver.
The mobility of an electric screwdriver on batteries has one drawback. they are discharged. Compliance with the recommendations for storing batteries increases their service life without losing functionality. In this case, the type of battery used in the electric screwdriver must be taken into account. Nickel-cadmium cells require a complete discharge, and such a procedure will only damage lithium-ion batteries.
Hello everyone! On the Web, they often ask how to store the batteries of an electric screwdriver correctly so that they do not fail prematurely. In this article I will try to give an answer to the question posed.
At one time, I also asked this question and one wonderful thought came to my mind: “Why not look in the operating instructions for any electric screwdriver?” With this “brilliant” thought, I took instructions from Makita and found in it only general words
Well, this is about what you need to store so that the battery contacts cannot be accidentally closed with a paper clip, coin or other metal object, that storage should be in conditions where the air temperature does not exceed 50 degrees, and the like, which is also of course important. but it seems clear
And everyone is interested in about the following questions:
- with what level of charge should the batteries be left for storage?
- they must both be removed from the electric screwdriver or one can be left inserted?
- how long can you store without recharging?
Read also: Designation of zinc in the periodic table
As a result, having reviewed the instructions from different manufacturers, I was able to find some useful information. over, even if you look in the instructions for different screwdrivers of the same manufacturer, but differing in the type of battery, then it will be the same. At the same time, if the manufacturer believes that it is necessary to indicate some special information for certain types of batteries, then it is indicated, but in general for all types the conditions are basically the same.
Or Makita, for all types of batteries, gives a universal advice, to recharge the batteries every six months of storage if they have been idle for so long.
In general, what can you say based on the information provided by the manufacturers? Let’s go in order.
How to properly charge new lithium-ion batteries in a screwdriver?
One of the most popular tools among home craftsmen can rightfully be called an electric screwdriver. And this is no coincidence. with its help you can not only tighten / unscrew screws / screws / self-tapping screws, but also drill small holes, and using special attachments, you can grind and polish surfaces and even sharpen the cutting tool.
Another feature of screwdrivers is their mobility, that is, it is not at all necessary that there is an outlet nearby. It is enough to purchase an electric screwdriver with a battery.
But this is where the lack of cordless screwdrivers comes to light. In order to work successfully with such a tool, you need to have a battery with good characteristics and ease of maintenance.
Until now, nickel-cadmium batteries have proven themselves well, but recently they have been replaced by lithium-ion.
And if users about the first have more or less complete information about the properties and maintenance procedure, then the second type has a lot of questions and one of them is how to properly charge lithium-ion batteries and how to store them when they are not in use.
In everyday life, users have the opinion that before starting to work with the battery, it is necessary to carry out a three-fold “discharge-charge” cycle. This is true for Ni-Cd batteries, but not for Li-Ion.
First of all, it should be noted that lithium-ion batteries, unlike nickel-cadmium batteries, do not have a memory effect, and, therefore, they can be charged at any stage of discharge (including immediately after purchase). It is for this reason that manufacturers send them on sale charged 3/4 of the norm.
But still, to extend the guaranteed service life, some rules must be followed:
1) Li-ion should be charged with a residual charge of 20-50%;
2) attention!. it is unacceptable to discharge lithium-ion batteries below 10-20%. For them, this is a critical value, but it should be borne in mind that the lower the degree of discharge, the more discharge-charge cycles they will withstand:
3) Li-ion should be charged at a temperature of 10-30 degrees, and operated in the range from minus 10 to plus 45 degrees;
4) once every 4 months, you need to carry out a full cycle “discharge-charge”, discharging the battery to almost zero, and then put it on charge for 12 hours. This is necessary to calibrate the charge level sensor in the battery controllers;
5) another feature of lithium-ion batteries is that they cannot be stored fully charged for a long time, otherwise they will permanently lose 20% of their capacity in just three months. Send the battery for long-term storage with a charge of 40-60% of its full capacity, and then it will lose only 1% in the same three months;
6) If you have two batteries in the kit, then charge one of them to the recommended value (40-60%) and send it to the reserve for a month, and after this period, charge up to 100%, use it in work until it is discharged to 40-60% ((or artificially discharge) and send back to storage for another month;
7) Let the second one be your main worker and, if you worked it intensively, put it on charge, even if it is discharged by less than 10%.
If you completely follow the recommendations recommended by the manufacturers, then most likely you will not need to buy a second battery at all, since the service life of an electric screwdriver and a lithium-ion battery is almost the same. Well, unless you are a professional worker, for example, in the assembly of furniture, when one battery cannot handle the entire shift, then a backup battery will be needed.