1. Protect the battery from overcharging and overdischarging, and prolong the service life of the battery.

2. Prevent the solar cell array and battery polarity from being reversed.

3. Prevent internal short circuit of load and controller and other equipment.

4. Photovoltaic system working status display: battery state of charge display and battery terminal voltage display.

5. Load status display: charging voltage, charging current, charging capacity, etc.

6. Auxiliary power supply working status display: solar radiation, temperature, wind speed, etc.

7. Photovoltaic system information storage: system power generation, power loss, power loss records, fault records, etc.

8. Optimized system energy management: photovoltaic square matrix best working point tracking (MPPT) temperature compensation, optimal compensation, etc.
9. Photovoltaic system fault alarm, system telemetry, remote control, remote signaling functions, etc.

The most basic function of the solar charge and discharge controller is to control the battery voltage and turn on the circuit, and when the battery voltage rises to a certain level, stop the battery charging. The older version of the controller mechanically completed the opening or closing of the control circuit, stopping or starting the power delivered to the battery.