Question on Dual Battery Setup

[dbruesehoff]

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.

[Wylietunes]

An arc usually indicates a poor connection. This can lead to a fire or exploded battery. Grounding between the new battery and old battery is typically ok as long as the cable gauge is proper. Since you had two batteries already, but now separated by a dual bank switch, I dont see the addition of the switch changing anything on the ground side, if it was correct before.

[dbruesehoff]

An arc usually indicates a poor connection. This can lead to a fire or exploded battery. Grounding between the new battery and old battery is typically ok as long as the cable gauge is proper. Since you had two batteries already, but now separated by a dual bank switch, I dont see the addition of the switch changing anything on the ground side, if it was correct before.

Thanks for the comment. I am going to grab a new ground cable and clean up the connections and see if that helps. It was hooked up + to + and - to - prior to adding the switch. I am guessing when I isolate to the secondary battery it is bringing the poor connection to the surface. I'll see if the new cable helps and report back.