Hi Guys,

So this may be hard to explain without a diagram but after some advice to whether or not this will work.

So I have a battery in my boat. It powers everything. I've just fitted a second battery with a selector switch. So now the positive cables that came off the first battery are connected to the COMMON port on the switch and positive from both batteries goes to BATT 1 and BATT 2. So that's fine but what I want to know is that the original battery is grounded inside the outboard and is all nicely sealed. I don't want to try and run my second battery ground cable to the same point on the engine so is it ok to ground the second battery to the first batteries ground? Keeping in mind the first battery is already grounded?

Thanks