Hello, 1. The 5W solar panel produces 18V, charges the 12V battery for 10 hours under enough sunlight, and powers a 10W DC bulb for about 3 hours! It is recommended to choose a charging bottle with higher power, 50-100W power is better. 2. Recommended solar panel brands, Belle/GABREE, Chepinhongzhi, bosin
The rated voltage of the 17.5V solar panel is 17.5 volts. When the 17.5 volt solar panel charges the corresponding battery, the battery can be charged. normally only when the battery rated voltage is lower than the solar panel rated voltage of 17.5V. The battery rated voltage is between 15-16 volts, so the 17.5V solar panel can be charged with a nominal voltage between 15. and 15 volts Batteries between 16 volts.