C 27 12 Volt power problem

[Buzzlovelace]

Hello.
Thank you for your consideration.
Here's whats happening and what I have done.
When perko switch is on #1 battery, the cabin lights are much dimmer than when I switch to #2(the starting battery.) My first thought was that battery #1 was not charging as well as battery # 2. So I took out both batteries and had them tested, both were fully charged. So then I figured it must be corroded battery terminal. So I cleaned them and reinstalled. I Still have the same problem. Any insight is appreciated. Now at least I know I wont get caught at sea with a dead battery

Thank You, Buzz

 

[philwsailz]

If you have voltage in both batteries, and the lights dim with battery switching, it points to the ground side of the circuit. The two battery legs share a common ground circuit. I would check to make sure that the ground cables are firmly connected to both batteries. Then I would check to make sure the white ground wire for the interior lights is firmly connected to a common ground bus, properly tied to both batteries.

 

[Buzzlovelace]

Thanks Phil ,
Thats the next thing I will look at. I have been following you post on your 27'