Solar street lights are mainly composed of solar photovoltaic cell components, batteries, charge and discharge controllers, lighting fixtures, etc. The bottleneck of the popularization and promotion of solar street lights is not a technical problem, but a cost problem. In order to improve the stability of the system and maximize its performance on the basis of reducing costs, it is necessary to reasonably match the output power, battery capacity and load power of solar photovoltaic cells. For this, theoretical calculations alone are not enough. Due to the rapid change of sunlight intensity, the charging current and the discharging current are constantly changing, and the theoretical calculation will bring about a large error. Only by using automatic tracking and monitoring of charging and discharging current can the maximum power output of photovoltaic cells in different seasons and directions be accurately determined. This confirms that the battery and load are reliable.

Use the conditioning circuit to sample the output current of the photovoltaic cell, the discharge current of the battery and the working voltage of the battery's charge and discharge at a certain frequency, and send the collected data to the computer through the USB data acquisition module. Real-time display and statistical analysis are performed on the LabVIEW software platform.

The battery output signal is a floating signal. Using differential measurements minimizes effects on the circuit under test and reduces measurement errors. In the conditioning circuit, a differential amplifier made of high-precision, low-drift integrated operational amplifier ICL7650 is used, and the differential signal above the precision small resistor connected in series with the charging and discharging circuit is used as the current detection signal. The small signal obtained by the large resistance voltage divider built in the battery is used as the voltage signal. To eliminate interference, two equivalent resistors are connected between the two input terminals of the differential amplifier and the signal ground. The output signals of the two differential amplifiers are respectively sent to the two input channels of the USB acquisition module to complete signal conditioning and acquisition.