Equalization/Boost Charge in DC Power Supply System

Equalization charging, also known as boost charging, is a charging method used to ensure that each individual battery in a battery pack can reach a fully charged state. During the use of a battery pack, due to differences in parameters such as internal resistance and self discharge rate among individual cells, these differences will gradually accumulate after multiple charge and discharge cycles, resulting in inconsistent states of charge among the individual cells in the battery pack. The purpose of equalization charging is to eliminate this inconsistency and enable all individual batteries to be fully charged.

During the equalization charging process, the charging device charges the battery pack with a relatively high charging voltage and current. A higher charging voltage can overcome the influence of factors such as internal resistance of the battery, allowing lower battery cells to receive more power replenishment and gradually catch up with higher battery cells. In this way, the voltage and charge of each individual battery in the battery pack tend to be consistent.

Application scenarios

• Communication base stations: Communication base stations typically use a large number of batteries as backup power sources. The performance of the battery pack is crucial as the base station needs to ensure uninterrupted power supply. Regular equalization charging can ensure good performance of each individual battery in the battery pack, improve the overall reliability of the battery pack, and ensure the normal operation of the base station in the event of a power outage.

• Power system: In power facilities such as substations, battery packs are used to provide emergency power for control circuits, protective devices, etc. Uniform charging can ensure that these batteries are always fully charged, providing reliable power support for critical equipment in the event of power system failures.

Equalization charge voltage of lead acid batteries

The average charging voltage may vary depending on the requirements of different battery manufacturers, and should be selected according to the battery user manual. A typical 48V communication power battery pack consists of 24 batteries connected in series. The nominal voltage of a single battery is 2 V, and the average charging voltage of a single battery is generally 2.35 V. The average charging voltage of a battery pack is generally set to 56.4 V (2.35V × 24). For a 24V system, it means 12 batteries with a nominal voltage of 2V are connected in series, and the average charging voltage is 28.2V (2.35x12). For a battery with a nominal voltage of 12V per cell, the average charging voltage per cell is 2.35x12/2=14.1V.