I want to switch between batteries for my electronics using an on/off/on rocker switch?

I have equipment that runs off a 12v deep cycle battery, but only one at a time, in parallel it causes noise in the system.  We have to switch batteries halfway through the day because the electronics don't work at certain voltages.  We currently have to hop in the back of our rtv, unscrew the wing nuts and switch the power cable (positive and negative ring terminals) to a new battery.  Id rather make this easier for my crew and found an on/off/on rocker switch that seconds as a volt gauge for whatever battery it is toggled too.  Could someone help me out with the wiring configuration using this rocker switch? 

Picture of I want to switch between batteries for my electronics using an on/off/on rocker switch?
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iceng3 months ago

If we answered your question you could select the Best Answer individual with a simple mouse click...

Jack A Lopez3 months ago

That switch looks OK to me.

I am imagining the wiring is like the picture Iceng drew for you, in a previous reply.

Although I think would have drawn the switch slightly differently, in a way to sort of make clear its three positions (throws?), namely {battery 1, off, battery2}

I mean, I am imagining it as a single pole, triple throw, switch, with its middle position connecting the switch's single pole to air, to nothing.

Actually, if you want, I can draw for you, upon request, a diagram the way I see it.

In words: The switch has this single pole. The left switch position connects the pole to the positive terminal of battery 1. The middle switch position connects the pole to nothing. The right switch position connects the pole to the positive terminal of battery 2.

Also in words: That little voltmeter thing and your load are connected in parallel.

Also in words: The negative terminals (black wires) of a bunch of things, { battery 1, battery 2, voltmeter, load}, are all connected together.

The Wikipedia article for "Switch", I think does an OK job of explaining this jargon of "poles" and "throws" for describing different kinds of switches.


RyanS428 (author) 3 months ago

there are no motors. Imagine a big computer right off a deep cycle battery. The power is just to ring terminals connecting to the positive and negative terminals on the battery.

iceng RyanS4283 months ago

I think if the computer draws over an amp then that rocker is too small, there are also fan motors and cd drive motors..

Also because the power switch makes before it brakes a connection you do not interrupt the power to the computer in switching to the other battery.

RyanS428 (author)  iceng3 months ago

The consoles (yellow boxes at the top) don't have internal fans. See the setup. They draw about 1 amp each. They are EM61MK2s. Anyway, Say it could support this rocker. How would the wiring be setup?

iceng RyanS4283 months ago

Black wires go to common ground = minus of both batteries.. The red wires go to the individual positive on each battery.. Then your Computer load goes in parallel with the digital meter.

iceng3 months ago

Sorry that is only for a few lights and to read battery voltages .. If you are running motors that switch is much too light and may weld shut in one position !

This (pictured) is the battery switch you need


It has ALL_OFF, BAT_1, BAT_2 and ALL_ON (batteries in parallel)... It can switch 250 Amperes and carry stater current up to 360 amps temporarily..


That is a really nice option indeed!
But I was more thinking about the normal way of doing this switching in a controlled way.
Dual battery systems usually incorporate an automatic battery isolator that charges the primary battery first (like the starter battery in a 4WD) then the second battery once the first is full.
The noise described can be from the electronics in this isolator checking the charge levels.
But a similar system can be added to switch and seperate the batteries.
Think of these battery guards that disengage a relay to cut all consumers off and make sure the battery is going below minimum voltage.
Would not be too hard to modify them so switching between the batteries is fully automated.