Can I Connect Negative Battery Terminals On 2 Batteries Operating Independently on Switch

Question:

I want to keep two batteries separate to power the same system and switch between the batteries through a switch, battery 1, battery 2 and disconnect/ no battery when storing the boat. Is it ok to connect both of the negative terminal together?

asked by: Doug

Expert Reply:

No. The best way to isolate things electrically would be to keep the batteries completely separate; you'll want to use independent grounds for each battery in your system. You can still charge the batteries independently with a battery charger like the NOCO Genius Smart Battery Charger - AC to DC - 6V/12V - 5 Amp # 329-GENIUS5.

expert reply by: Erik B