Principle analysis of generator function and cold start current definition

The role of the generator: 1. Charging to the battery to keep the battery fully charged 2. Supply current to each appliance 3. Only when the generator's power generation is lower than the appliance's current consumption, the battery is supplemented by the power supply. After the car is started, the battery will supply current if the charging system is insufficient. Otherwise, the battery will only be in the state of charging, and there is no pay for the car's electrical appliances (except for filtering). Basically, the current output of the generator is quite sufficient (at least above 80A). After the car is started, the electric appliances of the whole car depend on the output of the generator, which is not directly related to the battery.

If the car is equipped with a lot of redundant electrical equipment, it is necessary to strengthen the generator instead of the battery. After all, the role of the battery is mainly at the time of starting or the power generation of the generator, which is lower than the current consumption of the electric appliance. After the car starts, the normal working voltage is about 14V. If the power generation is lower than the current consumption of the electric appliance, the current will be supplied from the battery and the voltage will gradually decrease until the ignition or injection system does not work normally, but the engine is turned off during this process. The performance is also poor (mainly the electric fire can supply voltage reduction).

CCA (Cold Start Current) is defined as: the new battery is fully charged, at zero degrees Fahrenheit (17.8 degrees Celsius), and the current is continuously supplied to 7.2V for 30 seconds. As can be seen from this definition, this is more like a design specification, and it is more troublesome to measure. It is necessary to use many measurements, each time discharging to 7.2V with different currents. The current value can be up to 30 seconds.

CCA is the main indicator of the ability to shake the engine. Mainly reflects the internal resistance of the battery, although the capacity of the plate design is also relevant, it is not straightforward.