Batter switch install, ground or posv side? [PIC] - The Hull Truth

heeerefishyfishy · 03-13-2010, 12:31 AM

Should I install the battery switch on the ground side (grounds going to the switch) or the power side?

I'm thinking the ground side might be better ... since there might be a tiny voltage drop across the batt switch, I figure best to put it after the load at the end of the circuit.

Though I really don't think it matters. Thoughts on this?

KeyPineSavage · 03-13-2010, 01:16 AM

Positive side to the switch...always. Too many reasons to go into here too late at night. Main one is that all your negatives from all the batteries in a given bank should be tied together and to ground. If you tried to switch only the negative side, you'd have to connect the positives of the multiple batteries together and then what happens to ground? All of our contemporary systems, electronics, etc. are set up for negative ground. And lots of other issues as well. So just don't do it.

Positives to the switch.

By the way, with DC, if there is voltage drop when wired the one way there would be the same voltage drop wired in reverse (by "reverse," I mean with negatives to the switch.) I think I know what you mean when you say "after the load," but DC circuits really don't work that way. There are not really "before" and "after" spots in regard to loads in the circuit. Anyway, don't do it.

Positives to the switch.

peterbo3 · 03-13-2010, 01:38 AM

Fishy,
As KPS said, positive. There should be a wiring diagram with that Blue Seas switch. If there isn't, go here.
http://bluesea.com/category/1/productdocs/6007
Install instructions are to the right of the switch photo.

heeerefishyfishy · 03-13-2010, 01:43 AM

Got it, thanks for the link.

rwidman · 03-13-2010, 06:06 AM

Quote:

Originally Posted by heeerefishyfishy

Should I install the battery switch on the ground side (grounds going to the switch) or the power side?

I'm thinking the ground side might be better ... since there might be a tiny voltage drop across the batt switch, I figure best to put it after the load at the end of the circuit.

Though I really don't think it matters. Thoughts on this?

It matters. The switch goes on the positive side.

Before you do anything more, buy a good book on boat wiring and study it. If there's something you don't understand, buy another book and study it.

BTW: A "tiny voltage drop" anywhere in the circuit is the same. It doesn't matter if it's in the positive or negative portion of the circuit.