How to judge the battery capacity of the car

To measure the capacity of the battery, first connect the battery with the appropriate load, 1, measure the current, 2, voltage, 3, time, and finally, when the voltage drops quickly, calculate the capacity of the battery. Please refer to it.

Lead-acid batteries are widely used in automobiles, and their main function is to start the engine. When the car battery in use is unable to start the engine, it indicates that the storage capacity of the battery is insufficient, and it is necessary to charge and check whether the capacity of the battery is normal. If the capacity is lower than the available limit, the battery needs to be repaired or replaced.

1, Using the voltmeter plus load to detect the battery storage capacity

Detecting the battery storage capacity, it is difficult to be accurate only by using the voltmeter or the multimeter's voltage block without load to check whether the battery is fully charged. When measuring voltage alone, the current consumption is extremely small, so there is no large voltage drop inside the battery, so the display voltage is not low, but if a considerable load is added, such as turning on the headlight (load current 10 to 15A), press The horn (load current 6 ~ 12A), the battery will make the light dim, the horn is hoarse, thus showing insufficient power storage.

The correct and reliable detection method is to turn on the starter to detect the battery voltage in the car. The steps are as follows:

a. Connect a voltmeter to the positive and negative poles of the battery at the normal temperature of the engine, and pull out the fuel injector wires to prevent the engine from starting;

b. Start the engine for 5 to 10 seconds continuously, and observe the degree of the voltmeter;

c. When the starter and the line are well connected, the battery voltage of 12V is 9.6V or higher than 9.6V, indicating that the battery technology is in good condition; if the voltage is lower than the above value, the battery is in a deficient state and the power is stored insufficient.

2. Detect the battery storage capacity with a hydrometer

It is also a common method to use the hydrometer to detect the storage capacity of the battery. Generally, the standard specific gravity of the electrolyte at 20 ° C is 1.25 ~ 1.29 kg / L; if the battery is at 20 ° C, the specific gravity of the electrolyte is less than the above value If it is greater than 1.06kg/L, the battery storage capacity is insufficient and needs to be charged. If the battery has a specific gravity of 1.06kg/L or less at 20 °C, the battery is completely discharged or damaged. According to this principle, the specific gravity of the battery electrolyte can be measured by a hydrometer to know the storage capacity of the battery, and the condition of the battery can be further determined.

3, use the battery detector to detect the battery storage capacity

In the daily maintenance and repair, it is really necessary to quickly and accurately detect the amount of battery storage, or use a battery tester.

When using the battery detector to the battery for 10 to 15 seconds, the voltage is maintained at 10.5 ~ 11.6V, indicating that the capacity is sufficient, the battery is not faulty;

The voltage is maintained at 9.6V to 10.5V, indicating that the capacity is insufficient and the battery is not faulty;

The voltage drops below 9.6V, indicating that the capacity is seriously insufficient or the battery is faulty.

The above is just a simple battery tester, which can only measure the battery voltage under the condition of large current discharge, and roughly judge the storage capacity of the battery. In addition to the start-up discharge, the more advanced battery tester can accurately measure the cold start current (CCA), such as the boschbat131 battery tester.

The BoschBAT131 battery conductance and electrical system analyzer can test 6V and 12V wet batteries, flat AGM, spiral AGM and gel batteries, as well as test 12V and 24V start and charge systems for passenger cars and light trucks. It displays the test results in seconds and provides the print results.

The nominal capacity of the battery is ampere (AH), where the (A) discharge current and the time (H) is the discharge time. Therefore, accurate measurement of battery capacity is the product of discharge current and discharge time.

The required materials are: battery, ammeter, voltmeter, high-power discharge resistor (loading appliance), switch, stop watch.

First fully charge the battery to be measured to ensure that the capacity is optimal.

Pass the battery through the switch series ammeter, high power discharge resistor, and connect the voltmeter across the resistor. The regulation resistor is used to control the discharge current. (Note that no discharge resistor can be replaced by a loader).

Make a record at the beginning of the measurement. Close the switch and press the stopwatch at the same time. Record the reading of the voltmeter and ammeter. Observe the reading of the voltmeter and the ammeter. When the readings of the two meters start to decrease, stop the stopwatch and record the time.

The current value for calculating the battery capacity is ampere, the time is hour, and the recorded current multiplied by the time is the capacity of the battery.

The battery capacity is measured with a discharge fork. The discharge fork is a 3V voltmeter and a fixed value load resistor installed in parallel with a discharge meter with a shank. It can only check one cell (2V) of the battery. During the test, the two pins are fastened to a single positive and negative electric pile, and the indicated discharge value is quickly read out within 3 to 5 seconds of the stable position of the pointer. The indication is above 1.75V, indicating that the grid is in full compliance with the standard; the indication should be charged in time between 1.75 and 1.5V; the indication is below 1.5V, indicating that the battery is faulty should be excluded.

First, use the voltmeter plus load to detect the battery storage capacity

Detecting the battery storage capacity, it is difficult to be accurate only by using the voltmeter or the multimeter's voltage block without load to check whether the battery is fully charged. When measuring voltage alone, the current consumption is extremely small, so there is no large voltage drop inside the battery, so the display voltage is not low, but if a considerable load is added, such as turning on the headlight (load current 10 to 15A), press The horn (load current 6 ~ 12A), the battery will make the light dim, the horn is hoarse, thus showing insufficient power storage.

The correct and reliable detection method is to turn on the starter to detect the battery voltage in the car. The steps are as follows: at the normal temperature of the engine, connect a voltmeter to the positive and negative poles of the battery, and pull out the injector wire to make the engine unable to launch. Start the engine for 5 to 10 seconds continuously, and observe the degree of the voltmeter. When the starter and the line are well connected, the battery voltage of 12V is 9.6V or higher than 9.6V, indicating that the battery technology is in good condition; if the voltage is low At the above values, the battery is in a deficient state and the amount of stored electricity is insufficient.

Second, use the hydrometer to detect the battery storage capacity

It is also a common method to use a hydrometer to detect the storage capacity of a battery. Generally, the standard weight of the electrolyte at 20 ° C is 1.25 ~ 1.29 kg / l; if the battery at 20 ° C when the specific gravity of the electrolyte is less than the above value, greater than 1.06 kg / l battery storage capacity is insufficient, need to be charged; When the battery has a specific gravity of 1.06 kg/l or less at 20 ° C, the battery has been completely discharged or damaged. According to this principle, the specific gravity of the battery electrolyte can be measured by a hydrometer to know the storage capacity of the battery, and the condition of the battery can be further determined.

Third, use the battery tester to detect the battery storage capacity

In the daily maintenance and repair, it is really necessary to quickly and accurately detect the amount of battery storage, or use a battery tester. When using the battery detector to the battery for 10 to 15 seconds, the voltage is maintained at 10.5 ~ 11.6V, indicating that the capacity is sufficient, the battery is not faulty; the voltage is maintained at 9.6V ~ 10.5V, indicating that the capacity is insufficient, the battery is not faulty; the voltage drops to Below 9.6V, it indicates that the capacity is seriously insufficient or the battery is faulty. The above is just a simple battery tester, which can only measure the battery voltage under the condition of large current discharge, and roughly judge the storage capacity of the battery. In addition to the start-up discharge, the more advanced battery tester can accurately measure the cold start current (CCA).

Fourth, the conclusion

In summary, the capacity detection methods of the automobile battery include: a voltage gauge or a multi-meter's voltage block plus load detection, a hydrometer detection capacity method, and a dedicated battery detector detection capacity method.

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