My interior lights dim about every 15 minutes or so for a split second. I don't lose power. Any ideas what could be wrong? It seems to becoming more often. Could it be my surge protector? Thanks for any feedback

It could be a loose connection somewhere. Does it flicker during shore power? Try unplugging shore power to see if it still flickers. Try tapping lightly along the power lines and switches of the faulty lights. Are the battery connections clean and tight? Pull the fuse for the faulty lights and check the fuse then re-install it. Does it flicker when an appliance comes on? That would indicate an insufficient cable somewhere such as running an extension cord to the power pole.