Volt gauge

Do put a fuse in the wire to the meter near the positive lead (from the disconnect switch). This can be about as small of a fuse as you can find. Otherwise, if the meter or the sense wire has a hard short, you can end up with a fairly effective fire starter.

Other than that, it sounds like a decent plan to me.

Manual disconnects are usually at the battery on the negative cable
Disconnect switches inside the RV, are just a control switch that activate a heavy relay in the positive wiring circuit

Isn't the disconnect on the ground side?

Moved from technology

Uh.... Disconnect switch might only be momentary, only hot when pushing the button, the relay is a latching relay
Stays on or off until the next push out the button
So one side of the switch is hot all the time the other side only hot while you push the button, the switch does not hold the relay on, to do what you are thinking
These meters draw so tiny amount of power just wire it direct, if you read really worried about power drain put a switch on the meter

Let me clarify....I may not find a ground source at the disconnect switch, but since the house batteries are located under the steps, about six feet away, I can just run the black wire to the negative battery post. The disconnect switch should have a positive source coming from the BIRD solenoid. I am curious about RoyB's plan...where do you plan to tap into to get power for the gauge? Will it run only with the ignition key turned on?

tenbear wrote:
but I don't think there is a ground there.

This might be a problem.....since you can't really depend on the nearest chassis metal being a good electrical ground.

My RV has 12 V power sockets all over the place so I got a plug-in meter. It can easily be moved to the cab if needed OR used to help out a fellow camper.

Not sure I understand your wiring plan. One of the wires from the meter has to go to ground, the other to the 12v source you want to measure. You can get the 12v from the disconnect switch but I don't think there is a ground there.

I have been wrong before though.

I'm doing the same thing here on my F150 truck. Most of my trucks at least had a menu where you could read your battery voltage but this one doesn't. Ordering from AMAZON...

Have just the spot on the console just under the 12V Socket where they have a little compartment that was for some other option I guess...


Should fit this small meter pretty good. I will use the black sealant to hold it in place...



Roy Ken

Sounds like a good plan