When a battery is used intermittently or only in case of a power outage, it is charged using a floating charge method. This method is commonly applied to charge fixed batteries that are used for specific purposes. One of the significant advantages of the floating charge method is that it can minimize the gas evolution rate of the battery and avoid overcharging. Furthermore, as the battery is connected to the DC power supply in parallel, it can instantly release a large current to stabilize the voltage of the power supply and ensure normal electricity consumption when electric equipment operates at high power. However, one disadvantage of the floating charge method is that some batteries may be unevenly charged or undercharged, which requires regular equalization charging to balance all the batteries.