How to check the battery capacity of an electric screwdriver by a multimeter
There are a huge number of batteries production technologies, but the most common and popular among them are the following:
- Lead-acid batteries are most popular for the automotive sphere of production due to simplicity of manufacture and low cost. But further, for use in power tools, they did not show themselves much, since they have small power with large dimensions and large weights.
- Nickel-cadmium batteries have significantly surpassed lead-acid elements. After all, with small weight and compact dimensions, they give out greater power. But, of course, there are its negative aspects, in particular, the toxicity of the battery. Since the production of such battery elements is harming the environment. For example, in the countries of the European Union, this type of battery is considered prohibited.
- Nickel-metallhydrid elements are considered a more advanced option from the previous type of batteries. After all, they are completely safe for the surrounding world. But there is a shortcoming in the form of high current self.discharge indicators.
- Lithium-ion batteries, although they have almost perfect parameters, since they have a high capacity, small size and small weight, are not very popular. All because such a progressive element has a high cost, and therefore does not afford every layman.
Varieties of batteries
To date, the most common nickel-cadmium type of battery. Its undoubted dignity is considered:
The maximum voltage of an individual element reaches 1.38 volts.
Nickel-metallogid type is actually a competitor to the aforementioned type of battery. True, its parameters are much worse, but the elements are completely safe from an environmental point of view.
The named batteries must be sent for storage in a charged state, otherwise after a month they will fail.
Relatively not so long ago, the battery began to produce for screwdrivers:
They are distinguished by a small size and a large container. There are two disadvantages:
How to check
To check the power supply unit for operation, you just need to remove the current and voltage indicators at the time of charging. over, it is necessary to repeat the procedure several times to get the most accurate values.
Such observations indicate that the battery is completely serviceable and functional. In most cases, further analysis is not required.
At the same time, the working battery will also steadily increase the current strength of the current. If in an hour the indicator reached the value of 1 A, then this indicates the serviceability of the device.
There is also a method of accelerated testing of the battery, which consists in measuring the voltage at idle (without load). This voltage should reach the required value that is directly related to the operating voltage of the battery elements (cans). If the indicator is lower, then the probability of failure of one or more elements is high.
A separate type of check of the battery capacity by a multimeter from an electric screwdriver can be considered under load testing. Here, additional equipment is used, which needs to be fucked. Ideal for this incandescent lamps are suitable. The power of such a lamp must correspond to the battery power. Otherwise, the results of the audit may not be accurate enough. In most cases, the power is equal to half the current, which the battery is given, multiplied by the voltage. For standard batteries from screwdrivers in the check, use lamps 12 in.
The battery is connected to the load through the multimeter, which then the readings are removed. After a few minutes, the voltage should be measured. It should be higher than 12.4th century. If such an indicator has not been achieved, then there is clearly any malfunction. Additionally, it is recommended to pay attention to the brightness of the light bulb. It should be sufficiently stable.
The malfunction can lie not only in the battery, but also in the charger itself. Therefore, you must first check the charger for an electric screwdriver by a multimeter.
It includes a direct current measurement mode and using probes is connected to a charger. The value of the current force on the meter should be as close as possible to what is indicated on the case. If this is not the case, then the device is best replaced with a new.
The voltage of the battles of the battery
After the first stage of the audit, it will become clear whether the device is properly or not. If the testing indicated the inconsistency of the parameters, then it is logical to start repairing, accompanied by the replacement of faulty cans.
You need to open the battery housing and identify the malfunction. For this, a multimeter is also used, which is connected to each element separately. The voltage of each can should be at least 1.2 century. All inconsistencies indicate an element breakdown. Faulty banks must be removed from the common circuit and replaced with new.
If such a check shows does not reveal a breakdown, then you need to resort to testing under load again. And here the level of resistance is already of fundamental importance, which is directly related to the voltage and power of the current. Each element is tested separately, and the resistance is also calculated. In the event of a malfunction, this indicator will clearly deviate from the norm and quickly reveal a broken element.
Electric screwdriver without a battery
Do not exclude the breakdown of the electrical screwdriver itself. The use of a deliberately serviceable battery or connecting equipment to the network directly will help to identify this fact. The second approach will also be an excellent option in case of urgent need to use the tool. Mobility will certainly be lost, but the functionality can be used.
Electric screwdriver can be used with an external power supply stuck in a socket. Then you just need to choose a rectifier with the necessary parameters. Movements will be limited only by the length of the low.voltage cable connected directly to the tool.
You can also create your own prototype of ordinary network electric screwdriver. Then the power supply will be placed in the battery housing and will allow you to use the tool quite conveniently. In this case, the main question will be the selection of the necessary power supply of small sizes with suitable characteristics. The process can be complicated by the need to search for a powerful but compact transformer.
It is advisable to carry out a check of the battery of an electric screwdriver regularly to prevent various breakdowns at the most inopportune time. Of course, this applies only to preliminary testing, without disassembling the case. The batteries are sufficiently short.lived components that have to be replaced periodically. But proper operation in compliance with the standards for recharging will help to save the devices with efficient.
How to check the battery of an electric screwdriver by a multimeter
For the very first diagnosis, you need to determine the voltage and power of the battery during charging an electric screwdriver. Normally, the device should show 13V 30 minutes after connecting to the network. After 1 hour, the value will change by 0.5V.
The maximum voltage indicator of an electric screwdriver should reach 17V.
The current strength when connecting to the network in a well.working device should reach more than 1 ampere in 1 hour.
The multimeter itself is transferred to the DC mode. to check the battery voltage. At the same time, the switch of modes must be put on the value of 20V. This means that the voltage value on an electric screwdriver does not exceed the value of 20 volts.
When measuring the voltage of an already fully charged electric screwdriver, the value should be equal to the number of “cans” multiplied by the voltage of each battery.
Typically, the amount of battery in the device is 10-12 pieces. With the tension of nickel-cadmium batteries in 1.2V, the required value will reach a maximum of 14.4V.
Testing batteries of the battery
To identify which of the “battles” of the battery is faulty, you need to fall out each and measure the voltage at the poles.
To connect to the device, the probes are used, one of which (red) is connected to a positive, and the second (black). to the negative pole of the drive. A value in volts will be displayed on the multimeter display.
The screws of the Makita brand with Li-Lon should show a voltage of 3.6-3.8V. This corresponds to the characteristics of lithium-ion batteries. In simple Chinese Budget Chinese models, the Russian Interskol with Ni-CD should be-1.4V, the minimum value is 1.2V.
It happens that the check in this way does not show any malfunctions, although the battery quickly sits down. Then check each battery with a light bulb (25 watts and 12V). The resistor is also used to measure the resistance level, for example, by 10 Ohms.
When they are connected to each other for a couple of minutes, the brightness should not change. If it goes out or flickers, then the drive has an insufficient capacity.
Also compare the resistance values in all battery, having previously disconnected them from a thermal attewer.
The resistance level in the battery is calculated by the formula:
where n is the voltage, a is the current strength, s is the resistance of the resistor.
Suppose the value of the first battery turned out to be 0.60 Ohms, and the second. 5 ohms. This means that the second battery is unsuitable for operation.
Nickel-cadmium battery can be restored if you try to make up for a lack of electrolyte. To do this, in the battery body from the minus, you need to make a hole with an awl. Pour 1 cube of distilled water with a syringe with a syringe. Clock the hole with epoxy glue and collect the battery.
All other types of “cans” (Li-lon, ni-mh) are not subject to restoration. In this case, you will need to buy a similar battery and replace.
The battery check helps to identify the cause of the inoperability of the battery and eliminate it. At the same time, funds are saved to buy a new device.
This method involves the use of several bulbs or small electric motors that are connected to each supply element in the battery system of an electric screwdriver.
At first the whole battery is completely recharged. Then, each “bank” is connected to one 3-4 V light bulb or low-power “motor”. The method allows you to identify unemployed elements in the system without measuring instruments, which will lose their charge earlier than everyone else. The blocks that have lost the capacity will certainly reveal themselves.
How to check the battery capacity of an electric screwdriver by a multimeter
The main property of the battery is the capacity. This value shows accumulated energy, that is, current strength in 1 hour. Measured in a/h.
How to check the battery capacity by multimeter?
- Disconnect the battery from an electric screwdriver.
- Charge the battery 100%.
- Using a multimeter, resistor and light bulbs, measure the time for which the lamp will go out, the voltage at the output of the battery.
- Calculate the capacity of the device according to the formula/
- Compare the results obtained with the electrical screwdriver specified in the operation instructions.
Suppose the voltage of the battery reaches 18V. With a power of incandescent lamp in 10, the battery discharge time should reach a mark of at least 2.3 hours.
If the connected bulb goes out after 30 minutes, then the calculated battery container will be:
This value is significantly lower than the values for example, the nickel-cadmium battery of an electric screwdriver in 1.3 ah.
Check the indicators under load
This means that we will check, during what period of time the battery of the electrical screwdriver will be completely discharged, provided that the additional load is connected to it. for example, an electric light bulb.
The load level must be selected, focusing on the power of the battery. If it is not indicated in the operating instructions, it should be calculated independently. It will be equal to half the current of the current given by the battery during work multiplied by the current of the current source. Typically, this indicator is from 35 to 40 watts, which means that the headlight from the car from 35 watts, or a 12-volt bulb can serve as a load.
To remove the battery readings, you need to connect to the lamp through the ammeter, and the indications themselves are removed with a voltmeter. Connection time is two to three minutes, after which we measure U. If it is less than 12.4 volts, some “bank” certainly failed. A significant decrease in the brightness of the light bulb may also indicate a malfunction of the battery. If it quickly goes out in two to three minutes, the battery is clearly out of order, and its capacity is very small.
What additional methods of restoration of batteries for screwdrivers exist?
It is worth noting right away that not all batteries are subject to the possibility of restoration of performance. In particular, with the best success you can reanimate “banks” with a typical difference of the difference between NI CD. Such batteries are now equipped most typical screwdrivers models. Of course, in the tools of the tools you can find screws of the Makita or Hitachi or Bosch brand, the nutrition element of which is built on a lithium basis, but there are not so many of these models yet.
In general, if we talk about the serviceability of the battery block and the methods of its restoration, in any case, you need to pay attention not only to the batteries themselves inside the case, but also to make sure that the charger is good for the charge. It is likely that the functionality of the power supply has lost the ability to provide the required current when charging.
Many masters, faced in practice with the repair of nickel cadmium nutrients, restore them by adding an electrolyte. The battery in the process begins to lose the electrolyte, since it evaporates.
The physical impact on the battery “bank” helps to fix the situation with a drill. In the body of the battery, you need to make a small hole (diameter 0.8-1 mm). Armed with a medical syringe with a needle, a couple of drops of distilled water should be injected inside the battery. Then the hole is reliably poured with epoxy resin. This cycle of measures will extend the operation of the supply element for several more charge/discharge operations.
Of course, the most simple and obvious way of resuscitation of the battery unit for an electric screwdriver is the physical replacement of the faulty block with a working. Here, even the help of a specialist may be inappropriate, since the operation can easily do even the person who at least once used a soldering iron and held a screwdriver in his hands. Here the main thing is to show a little dexterity in order to prevent the overheating of the cans at the time of their soldering/dropping.
Powertools Beginner Guide!
Of course, there are quite a few ways of resuscitation of batteries, but not each of them is available to a simple user. If you extend the life of your screwdriver with a full.time battery, you are not able to independently, then seek help from qualified specialists. They will make unmistakable diagnostics and “come up with” how to restore the tool battery with minimal labor costs.
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