Hi all - I have had dual batteries on the boat since day one, but recently decided to install a battery switch by blue seas so I can switch over to one battery and run the radio when parked. I am wondering how you guys are grounding the second battery? Right now I have it inline with the primary battery with a 18" ground cable. When I run them together and start the boat everything operates as it should when I switch over to the secondary batter and try to start the boat the ground cable throws a small spark and a little puff of smoke. Wondering if I either need a larger gauge wire or if I should be grounding directly to the engine block.
Anyone have any thoughts or suggestions? Oh in case anyone asks when I start the boat with the primary battery only there is no spark or smoke.
Thanks for the help.