Battery switch insatll question.

[sjk984]

Ok after they wanted $390 to install a second battery on my small boat I decided the directions looked simple enough. I have installed the second battery and wired everything but the motor to the deep cycle. I have the positive leads hooked to each side of the switch and the motor positive ti the main as show in the diagram. My question is

Do I run a neg lead from the second batt. to the starting batt or how else would I ground the second battery?

Now I am by no means an expert but the diagram with the switch shows the starting and 2nd battery connected to gether and run to the engine.

Thanks Steve

[silver one]

sounds right. I ran bolth my + leads from each batterie to the switch. then 1 + from the switch to the 50 amp main breaker on the engine. then I ran bolth - leads to - on the engine. wich is were they run them from the factorie. So I guess to answer your question is that I would just run the - from the deep cycle to the exsisting - on the engine. that way if you loose one - you still have a second incase it wont roll over on 1 batterie. if you tie it to the other batterie and that connection for whatever reason goes bad then you will be dead in the water. There is more then one way to do it. this is just the way I did it.

[Nailer]

Yes the grounds tie together.