Use a battery detector. Connect the positive and negative terminals of the battery detector to the positive and negative terminals of the battery, and automatically enter the system to select the model of the battery, such as 34B19, 55B24, 55D26, etc. (marked on the battery) to measure the charging status and health status of the battery. Charging status is the battery power, measured as a percentage of the value, when less than 100%, charging can be. The health state is the storage capacity of the battery, when the measured value is 0%, it indicates that the battery life has been exhausted, try to replace the new battery, otherwise even if it can be used temporarily, it may not be started on the halfway one day. In addition: to determine the battery power can also be by listening to the engine starting when the sound of the starter is strong, if it sounds no power, the engine rotation is weak, it proves that the battery is insufficient (except for the starter failure). 1, how to judge the car battery is insufficient Answer: in general. To judge the battery's power, first listen to whether the sound of the starter is strong when starting. If it sounds like there is no power, there are two situations, one is that the battery is insufficient, the other is the maintenance of the starter, the battery on the dashboard is mainly to see after the car starts up, whether the generator is used for power generation, when the light shows that the generator does not generate power, the need to maintain the generator, generally can not see the battery power.