How to Test Battery Screwdriver Performance
The multimeter is a multifunctional device for measuring various parameters of the electric current, therefore, it can also be used to check the battery charge. To perform this work, you can use various types of multimeters. The cost of the product does not matter, the main thing is that the digital or analog measuring device is in good condition. How to check the battery with a multimeter will be described later.
What parameters can be checked?
Using a multimeter, you can measure voltage with high accuracy. By the magnitude of the electric voltage, it is possible to determine whether the battery is charged or whether the cell must be charged with direct current.
Using a multimeter, you can check the voltage of not only acid batteries, but also the batteries of cell phones. To check the mobile phone for the amount of battery charge, the device is switched to a direct current measurement mode of up to 20 V. In this mode, a digital device allows you to measure voltage, with an accuracy of hundredths of a volt.
The battery of a screwdriver can also be easily checked with a multimeter. The rated voltage of the device, in this case, can be found in the documentation of the power tool, and if the voltage is less than this value, the battery must be charged.
The battery capacity can also be checked with a multimeter. There are several ways to do this.
Check with a multimeter for current leakage. If it is necessary to measure this parameter on the car, then in addition to the leakage of current to the body, the leakage in the on-board network of the car is checked.
Thus, it is possible to prevent a quick discharge of a battery and increase its operational life.
How to measure voltage
If you need to check only the battery voltage, the multimeter is put into DC mode. If you need to check the source of electricity, the voltage of which does not exceed 20 volts, then in this sector the mode switch is set to 20 V.
Then the black probe of the multimeter should be connected to the negative terminal, and the red one to the plus of the battery, at that moment, the DC voltage will be shown on the device’s display.
Usually, a serviceable and fully charged car battery has a voltage of 12.7 V. If the electrolyte density is normal at this voltage, then the source of electricity can be used for its intended purpose.
The voltage of lithium-ion batteries of cell phones, as well as alkaline or gel batteries, which are used to start engines of various motor vehicles, diesel generators and other devices that require a certain charge of electricity, is measured in a similar way.
How to measure capacity
The multimeter can also be used as a tester to measure battery capacity. Battery capacity can be measured using a battery check. To check the capacity, you first need to fully charge the battery. Then you need to make sure that the battery is maximally charged by measuring the voltage and density of the electrolyte.
Video: How to Test Battery Screwdriver Performance
Next, you need to connect a load of known power, for example a 24 W incandescent lamp, and note the exact time the experiment began. When the battery voltage drops to 50% percent of the previously set reading of a fully charged battery, the lamp should be turned off.
The measurement of capacity, which is expressed in a / h, is carried out by multiplying the current strength in the circuit when the load is connected, by the number of hours during which the control discharge of the battery was carried out. If you get a value that is as close as possible to the nominal indicator of a / h, then the battery is in excellent condition.
Check internal resistance
To check the battery for serviceability with a multimeter, you need to measure the internal resistance of the battery. You can check the operability of the power source using a multimeter and a powerful 12 V bulb. Check the battery in the following order:
- The 12 V lamp is connected to the battery.
- After a few seconds, the lamp glows, the voltage at the battery terminals is measured.
- The lamp turns off and the voltage is measured again.
If the measurement difference does not exceed 0.05 V, then the battery is in good condition.
In the event that the value of the voltage drop is greater, the internal resistance of the power source will be higher, which will indirectly indicate a significant deterioration in the technical condition of the battery.
Thus, it is possible to fairly accurately check the source of electricity for serviceability.
How to check leakage current
The battery can be discharged on its own, even if its terminals are not connected to consumers of electricity. The self-discharge value is indicated in the documentation for the battery and is a natural process. Especially noticeable loss of electricity can be observed in acid batteries.
In addition to the natural leakage of electric current, there may be sections in the circuit that are wet or with thinning insulation. In this case, even at the time when all consumers of electricity are in the off state, an additional leakage of current occurs, which can lead to a complete discharge of the battery, and in some cases, to the ignition of a damaged place.
Especially, this phenomenon can be dangerous in the on-board network of a car, in which the entire body and units are negative conductor, on which there may be a sufficient amount of flammable substances to form an open flame even from a small spark or electric arc.
To identify such an “unauthorized” consumption of electricity, it is necessary to turn off the ignition of the car, as well as turn off devices operating in “standby mode”, for example, a radio tape recorder and an alarm system.
To measure the current strength on the battery with a multimeter, it is possible only if the measuring device is switched to the current measuring mode indicated by the “10 A” icon. To do this, the rotary switch is put into the appropriate mode, and the red plug into the socket marked with the sign "10 ADC".
The red probe of the multimeter is connected to the battery “”, and the black one, with the terminal disconnected. At this moment, any indication of the device should be completely absent. If the multimeter shows any value, then the leakage current is significant, and it is necessary to make a detailed diagnosis of the vehicle’s on-board network.
Likewise, leakage is measured in other electronic systems. When conducting diagnostics, care should be taken, and if there is a suspicion of a significant leakage of electric current, which is manifested by arcing when the terminal is disconnected or connected, the leakage meter should not be measured with a multimeter.
If you neglect this rule, then you can "burn" the device, which is not designed to test large currents.
How to check the battery charge with a multimeter and not damage the fragile electronic "stuffing" of the device?
In order for the tester to check the battery is not the last, you must correctly select the diagnostic mode. If you want to check the amperage, it is strictly forbidden to do this without additional load, which should not exceed 120 watts.
When choosing a direct current measurement mode, care should be taken not to mistakenly turn on the multimeter in the resistance measuring mode, which, in most multimeter models, is next to the position of the switch for measuring direct current.