In the practical work, the overcharge phenomenon of storage batteries is often found in regional automatic weather stations, which shortens the service life of the battery. To solve this problem, a self made solar charge/discharge controller can be used to stop charging when the battery terminal voltage reaches the upper limit value. As the protector uses only the electric energy of the solar battery rather than that of the storage battery, it will stop working when there is no sunlight. In this way the controller extends, to the greatest extent, the working hours of the collector. In addition, the controller can work anytime as it is plugged without altering any of its wiring, so to ensure the long term stable operation of the regional weather station.