There must be a certain degree of strength and weakness. Under the condition of ensuring normal battery operation, most batteries currently used have constant voltage and reduced current. For example, common types of silicon batteries.
But when the light is so dim that the battery cannot work properly, the voltage will drop sharply.
The above is obtained from the volt-ampere characteristic curve of the photovoltaic cell.
Different batteries have different curves. Generally, the point with stable voltage and maximum current is selected as the point for battery efficiency calculation. The actual battery situation is more complicated.
1. Connect the solar panel to the ammeter and voltmeter. An ammeter is placed at the circuit break to measure current, and a voltmeter is connected between the positive and negative poles of the panelsolar to measure voltage.
2. Place the light source at a certain distance and adjust the position and intensity of the light source to achieve the required light intensity.
3. Change the load in the circuit by adjusting the resistance of the variable resistor (load), thereby changing the load current and battery panel voltage.