Battery charging technical requirements

Date:Jul 16, 2019

The technical specifications for the service life of lead-acid batteries provided by the factory are given at an ambient temperature of 25 °C. Since the voltage of the single-acid lead-acid battery has a characteristic of a temperature drop of about 4 mV per 1 ° C rise, a 12 V battery consisting of 6 single cells connected in series has a float voltage of 13.5 V at 25 ° C;

When the ambient temperature drops to 0 °C, the float voltage should be 14.1V; when the ambient temperature rises to 40 °C, the float voltage should be 13.14V. At the same time, the lead-acid battery has a characteristic. When the ambient temperature is constant, the charging voltage is 100mV higher than the required voltage, and the charging current will increase several times. Therefore, the battery will be out of control and overcharged.

When the charging voltage is 100mV lower than the required voltage, the battery will be undercharged and the battery will be damaged. In addition, the capacity of the lead-acid battery is also related to the temperature. The capacity will decrease by 1% for every 1 °C decrease in temperature. Therefore, the manufacturer requires that the user of the lead-acid battery emits 25% of the rated capacity after the battery is released in the summer. It should be charged in time.

Obviously, the lead-acid battery in daily use cannot be in the environment of 25 °C for a long time. There are still early, middle and late temperature differences in the day, not to mention the four seasons of spring, summer, autumn and winter. Temperature difference, therefore, various thyristor rectification types, transformer step-down rectification types, and general switching regulator power supply type lead-acid battery chargers commonly used in the market, charging the battery in a constant voltage or constant current manner, It is impossible to meet the stringent technical requirements that need to be met for the supplementary charging of lead-acid batteries.

Looking at the methods used to charge lead-acid batteries in the past, and the lead-acid battery chargers developed according to these methods, it is not difficult to see that the technology is not perfect, and charging these batteries with lead-acid batteries is bound to have a direct impact. The service life of lead-acid batteries, at the same time, these chargers also have problems of narrow operating range, large volume, low efficiency, and poor safety factor.

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