Tips: when the battery is charged by the solar panel, the voltage of the solar panel should exceed 20%-30% of the working voltage of the battery to ensure normal charging of the battery.

The battery is an important component of the solar power supply system. Its main function is to store the electric energy generated by the solar panel in the battery immediately for use by the electric equipment. The battery has the function of storing electric energy and stabilizing the voltage.

The main technical parameters of the battery are voltage and capacity. The voltage refers to the rated voltage of the battery, that is, the normal working voltage, and generally has 3V, 6V, 12V, 24V, 36V, and the like. Capacity refers to the ability of the battery to store electricity. Generally, 4AH, 6AH, 12AH, 20AH, 40AH, 60AH, 120AH, etc. are commonly used. For example, in the case of a 40AH battery, it means that when the battery is charged with 4A current, it can be fully charged for 10 hours; if it is charged with 1A current, it takes 40 hours to be fully charged. The reverse is also true when discharging. Under normal circumstances, the charge and discharge time of the battery is preferably 10 hours of charge and discharge rate.

When the battery is charged by the solar panel, the voltage of the solar panel should exceed 20%-30% of the working voltage of the battery to ensure normal charging of the battery. 

For example, charging a 6V battery requires an 8-9V solar panel, and charging a 12V battery requires a 15-18V solar panel.

• 4.5V - 5V solar panels for 3.2V DC battery 
• 5.5V – 6V solar panels for 3.7V DC battery 
• 8V / 9V solar panel for 6V DC battery 
• 12V solar panel for 9V DC battery 
• 15V – 18V solar panel for 12V DC battery 

As for the use of solar panels to charge the battery, how to match, mainly depends on your actual needs.