C
I finished hooking up my dual battery setup a while back and it seems to be working but I really need someone to explain what is happening when the blue light comes on .I assume it is letting power from the charging system to the second battery. Is it charging both batteries when the blue light comes on? I also noticed that when I was trickle charging my main battery the blue light came on and when I was trickle charging my second battery the blue light came on also.Is this normal?