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 depleted 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).