Calling all(or any) wiring guru's?

Question

I am trying to setup a simple switched system for a boat. The object of the circuit is relatively simple but I don't have all I need and am trying to figure out if I can make this work. I have two batteries on this boat one in front one in back the front runs trolling motor and accessories like depth finder and spotlights and such, the rear start the motor and runs rear lights easy right. I am trying to set up a on off on switch that runs a battery meter and connects to both batteries up for battery a and down for b and I have a single pole switch can I make this work without buying a double pole switch. I guess I said all that to ask will this work with like a common ground bus bar setup? I am stumped all the literature is for two load systems and I and trying to do a two source system.

Answer 1

Is the switch you have SPDT (Single Pole Double Throw)? If so, group your 2 negatives together and connect this to the negative on the meter. Take the positive from battery A and connect to one side of the switch, take the positive from battery B and connect to the other side of the switch. Now you should have one terminal left over to connect to, it should be in the center, take this to the positive side of the meter. All you are doing is selecting which battery goes to the meter, simple. Hope this helps, Good luck!

Answer 2

With a single pole single throw (SPST) switch you would need some active circuitry, custom designed for your setup.  Easier to just get a SPDT (double throw) switch and wire it direct to the meter.

Answer 3

It is not clear what you are trying to accomplish.