When my solar panels are sitting in the sun all day but the battery is full, where does the extra power go?

Question

Edit: I should mention it’s a boat system so it’s not grid tied

In: 510

Answer 1

Assuming your system is not tied to the grid, no extra power is generated. Once the battery is charged the controller will not be allowing any power into the battery. This results in an open circuit on the panels, as if they weren’t connected to anything at all. The voltage across the panel will increase until the incoming sunlight balances the voltage, and the incoming sunlight power will turn into heat just like if you sat a black object in the sun.