Dual Battery Switch

Starcraftobsession

Seaman Apprentice
Joined
Jul 9, 2013
Messages
41
I am wiring my boat and I have a battery switch that controls my two batteries. One is my starting battery (battery 1)and the other (battery 2) is for electronics. I wired in a fuse block. The ground from the fuse block goes to ground of batt. 2 and the positive goes to back side of battery switch and on side for battery 2. My problem is I can have the switch on battery 1 and I can turn my electronics on. I should not have any power to them since I think I have them wired to battery 2. What am I doing wrong? Thanks
 

sam am I

Commander
Joined
Jun 26, 2013
Messages
2,169
Not doing anything wrong, it's just that the battery switch is lining up the engine/alternator up to a particular battery....1, 2 or both (and off).

Your fuse box/electronics just happen to be hard wired to probably a more convenient spot then at battery 2's post. The batt switch's #2 terminal lug is the same connection, electrically that is, it's just down stream of batt 2's post but still on its main power cable perhaps just several additional feet is all. Could hook it up to either place, same diff. Mine is wired like this.......pretty standard.

Also......Even if this main wire goes to a fuse panel, you should have a main inline fuse right after it comes off the switch, just an FYI.
 
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sam am I

Commander
Joined
Jun 26, 2013
Messages
2,169
I should also add that if you care/want too as some others here have, you certainly can move that electronics feed wire over to the engine side of the batt switch.

This way you can line up all the electronics on that feed along with the motor to which ever battery you'd like, 1, 2 or both. Plus, the switch will kill everything now when "off".

This can be more desirable in some aspects, allows a FULL electrical shut down but, just be advised with the engine off, your electronics then can draw down which ever battery their lined up to including the start battery or "both" if that happens to be where you've left the switch.
 
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