1. The voltage of the solar panel is usually stable from morning to night (when it is exposed to sunlight), that is, basically about 30V, but the output power always changes in the morning, evening, small and noon. If the quality is good, the output of solar energy can reach 240W at noon.

        2. Your system is a 12V system, but the battery voltage is too high, so it is not suitable for use with 30V / 240W solar panels. Generally, the charging voltage is 1.5 times the battery voltage. In other words, for a 12V battery pack, the 18V solar panel is correct.

        3. When charging a 12V battery, the power is actually much less. In the case of a normal controller, the voltage equivalent to 18V is charged. This is about 18 x (240 / 30.2) = 143w solar panel.

        4. If the controller is an MPPT controller, the above issue is not a problem. The MPPT controller has a wider input voltage range, and at the same time, it can convert more voltage into current for charging, which also enhances battery protection.