(4) Detection of no-load loss

The no-load loss of the controller is also called the static operating current, the test method is shown in Figure 1. Disconnect the input of the solar cell module and the connected load, and connect the DC stabilized power supply to the battery input end of the controller. When the LED is not working, use an ammeter to measure the input current of the controller, and its value should not exceed 1% of its rated charging current.

(5) Test of voltage drop of charging and discharging circuit

①Adjust the current of the charging circuit of the controller to the rated value, and measure the voltage drop of the charging circuit of the controller with a voltmeter. The value should not exceed 5% of the rated voltage of the system.

②Adjust the current of the discharge circuit of the controller to the rated value, and measure the voltage drop of the discharge circuit of the controller with a voltmeter. The value should not exceed 5% of the rated voltage of the system.

(6) Detection of various protection functions

① Load short-circuit protection: check whether the output circuit of the controller has a short-circuit protection circuit. The controller should be able to withstand any load short circuit protection.

②Internal short-circuit protection: check whether the input circuit of the controller has a short-circuit protection circuit. The controller should be able to withstand the circuit protection of internal short circuits.

③Reverse discharge protection: The controller should be able to prevent the battery from discharging backward to the solar cell assembly. The test circuit is shown in Figure 2. Add an ammeter between the positive and negative input terminals of the solar battery of the controller (equivalent to short-circuit the positive and negative ends), adjust the output voltage of the DC stabilized power supply connected to the input end of the battery, and check whether there is current passing through the ammeter. If there is no current through, the controller reverse discharge protection function is normal.

④Reverse polarity protection: Connect the positive and negative poles of the solar cell and battery input terminals of the controller to the output terminals of the DC stabilized power supply adjusted to the rated voltage, and check whether the controller is damaged and whether the DC stabilized power supply is short-circuit protected. If there is no damage, the reverse polarity protection is normal.

⑤Lightning protection: Disassemble the controller casing and visually check whether the type and rating of the lightning arrester used can ensure the absorption of the expected impact energy. The controller shall have a circuit protection function that can damage the circuit or components caused by lightning strikes in a multi-thunder zone.

(7) Detection of resistance to overvoltage and overcurrent impact

①Impact resistance voltage detection: add the output voltage of the DC stabilized power supply to the solar battery input terminal of the controller, apply 1.25 times of the nominal open circuit voltage and keep it for 1h, check that the controller should not be damaged after power on.

②Inrush current resistance detection:

Add the output voltage of the DC stabilized power supply to the input terminal of the solar cell of the controller, connect the variable resistor to the battery terminal, adjust the variable resistor to make the charging loop current reach 1.25 times the nominal short-circuit current and keep it for 1h, then check that the controller should not be damaged after power on. The switching components of the switching controller must be able to switch this current without damaging itself.

(8) Environmental temperature and humidity test detection

① Low-temperature storage test: The test method is carried out in accordance with the “Test A” method in GB/T2423.1-2008. Unpack the controller, no electricity, no battery, put it in a low temperature environment with a temperature of -25℃±3℃ for 16h, and then return to normal room temperature for 2h, power-on detection, the controller should be able to work normally .

②Low-temperature working test: The test method is carried out in accordance with the method of “Test A” in GB/T2423.1-2008. Unpack the controller, power on and add rated load, put it in a low temperature environment with a temperature of -5°C ± 3°C for 2 hours, and then restore it at normal room temperature for 2 hours. The controller should be able to work normally all the time.

③High temperature storage test: The test method is carried out in accordance with the “Test B” method in GB/T2423.2-2008. Unpack the controller and place it in a high-temperature environment with a temperature of 70℃±2C for 2 hours, without power and no battery, and then restore it at normal room temperature for 2 hours. After power-on detection, the controller should be able to work normally.

④High temperature work test: The test method is carried out in accordance with the method of “Test B” in GB/T2423.2-2008. Unpack the controller, power on and add rated load, put it in an environment with a temperature of 40℃±2℃ for 2h, and then restore it at normal room temperature for 2h, the controller should be able to work normally all the time.

⑤ Constant damp heat test: The test method is carried out in accordance with the “Test Cab” method in GB/T2423.3-2006. Unpack the controller, no electricity, no battery, and put it in a hot and humid environment with a temperature of 40℃±2℃ and a relative humidity of 93%±3% for 48h. After the test, the controller should be able to work normally after power-on detection and the controller should be able to work normally after recovering under normal environment for 2h.

(9) Vibration resistance test

Place the controller on the electromagnetic vibrating table. After vibrating with a frequency of 10~55Hz and a vibration amplitude of 0.35mm, after 30 minutes of vibration in each of the three axes, the controller should be energized and checked, and the controller should be able to work normally.