Constant current mode: When the voltage of the battery is lower than the value set by the charger, the charger will work under the constant current mode and supply the constant current for the battery.
Constant voltage mode: Using the pulse width modulation(PWM) tech to control the charging current and output voltage of the charger which ensures the battery is fully charged and avoids over charging.
Floating charge mode: When the voltage of the battery is approaching the value of the constant voltage mode, and the current will cut down to the given current gradually, that means the battery power is full, then the pilot lamp will turn green and the fan will stop working. The charger will turn the mode into floating charge mode automatically. At this moment, the battery can be stopped charging or keep on floating charge for half an hour.