# Installing A Battery Cut-off Switch



## California Jim (Dec 11, 2003)

OK I made a brief attempt to find this on the 12v side of life and even did a search here. I'm out of patience now and perhaps some of the new folks could benefit from seeing this again.

Installing a battery cut-off switch. Which wire and WHY.

Thanks!


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## tdvffjohn (Mar 10, 2005)

Negative side, no spark when turning on and off. Same reason when hooking up jumper cables, neg last.

John


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## hurricaneplumber (Apr 12, 2004)

Jim,

I put mine on the negative side, to the right of the propane tanks (drivers side), up under the frame, it is easy to reach and doesn't get all crudded up with road dirt. Plus when it is off the red handle is exposed so you know if it is off or not.

Good luck

kevin


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## PDX_Doug (Nov 16, 2004)

As John says.

Also, you have mutiple leads coming off the positive side of the battery, all of which would have to be 'cut' to truly shut off the system.

On the Negative side, it is just one wire.

Happy Trails,
Doug


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## CamperAndy (Aug 26, 2004)

4 votes negative.

Grounding the wrench is not a concern when working on the negative wire.


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## campntn (Feb 20, 2005)

Put mine on the negative side. knife type. LOVE it. Yea, you can just unscrew the wingnut, but this is really easier and quick when your hooking/unhooking.
mb


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## kjp1969 (Apr 25, 2004)

I did the negative wire also, but ran the wires into the front pass-through storage compartment and put the marine switch there. I figure if one of my wires chafed and grounded, there would not be a short, the switch would just be bypassed.

Kevin P.


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## JimWilson (Feb 24, 2004)

Negative gets my vote too.

Looks like it's unanimous...


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## Oregon_Camper (Sep 13, 2004)

I have 2 6 volts, but you'll get the idea with this picture.


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## Y-Guy (Jan 30, 2004)

Yep negative side, no sparks.


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## California Jim (Dec 11, 2003)

Okie Doke. Negative it is. I was just wondering about some stray voltage finding it's way to the batts via the hot lead. Guess that's still not possible without a ground.

To hijack my own thread, do you all think the batts will charge properly with the ground disconnected and hooked up to my 3 stage deep cycle charger as the hot side is still connected to the converter? Will the converter's voltage be present and confuse the charger? The charger does have and will supply it's own ground so I am wondering about this









I really dont want to shut the converter down as I leave my fridge on all the time and would then run on propane or not at all due to the possible lack of a 12 volt source.


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## CamperAndy (Aug 26, 2004)

California Jim said:


> Okie Doke. Negative it is. I was just wondering about some stray voltage finding it's way to the batts via the hot lead. Guess that's still not possible without a ground.
> 
> To hijack my own thread, do you all think the batts will charge properly with the ground disconnected and hooked up to my 3 stage deep cycle charger as the hot side is still connected to the converter? Will the converter's voltage be present and confuse the charger? The charger does have and will supply it's own ground so I am wondering about this
> 
> ...


With the ground disconnected the converter will not affect the batteries. So connect the external charger if you want and charge away.


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## Y-Guy (Jan 30, 2004)

Jim I always disconnect the batteries with the switch when I charge them with the external charger, no problems on my end of things.


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## California Jim (Dec 11, 2003)

Thanks Guys!







I kind of figured I was over ANALizing this one







Just want to be sure.


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## Thor (Apr 7, 2004)

I connnected mine on the negative side as well. Actually installed two, so I can isolate my batteries.

Thor


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## cookie9933 (Feb 26, 2005)

Concerning sparks, I beg to differ. You get just as many sparks on the negative side as positive. The reason you connect a jumper cable to the negative side last is that you are supposed to be connecting it to a good ground (but not the negative battery post) on the vehicle getting jumped. This keeps any sparks that may result away from the battery itself, which could theoretically explode due to hydrogen gas that may be present in an explosive concentration.

If there isn't any load (draw) from the battery when you throw the switch, there won't be any sparks. If there is a load, the bigger the load the bigger the spark. But electrically speaking, a disconnect switch could be on either - or +.

Bill


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## nascarcamper (Jan 27, 2005)

I did the negative as well as I did mine like kjp1969 did with the cutoff in the pass through. No worries about knicked wire grounding out on the chassis. Most boats I've owned were wired that way as well so it was automatic for me.


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## California Jim (Dec 11, 2003)

So how did y'all run that wire through the wall of the camper into the storage area? How did you seal it up? I like this idea too but am hesitant to do any drilling that wasn't up to the highest standard of quality when finished.


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## kjp1969 (Apr 25, 2004)

California Jim said:


> So how did y'all run that wire through the wall of the camper into the storage area? How did you seal it up? I like this idea too but am hesitant to do any drilling that wasn't up to the highest standard of quality when finished.
> [snapback]60658[/snapback]​


I just drilled a hole up throught the floor about 1" wide (used a hole saw) and ran the wires through inside a plastic wire loom. It's about 8" up behind the front fiberglass, so I didn't worry about water splashing up there. Plus, the 3 wires (2 to the switch, one return) take up almost all of the hole.
Kevin P.


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## nascarcamper (Jan 27, 2005)

Right through the floor for me two. Drivers side next to the chassis. I didn't run but two wires and put them in different holes so they were tight. Recently checked the plastic and everything is fine and it's been almost a year. Not sure what the 3rd wire would be for???


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## kjp1969 (Apr 25, 2004)

nascarcamper said:


> Right through the floor for me two. Drivers side next to the chassis. I didn't run but two wires and put them in different holes so they were tight. Recently checked the plastic and everything is fine and it's been almost a year. Not sure what the 3rd wire would be for???
> [snapback]60912[/snapback]​


I have 2 6v in series, and a 12v as a reserve. So I have two battery negatives going to a selector switch, and a single ground going out. We usually run off the 6v bank until it dies, and then switch to the 12v if necessary. Why so complicated? Well, I had the batteries, and figured it would be better to hook them all up than just store them in the garage. Plus, we do a lot of dry camping.
Kevin P.


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## nascarcamper (Jan 27, 2005)

kjp1969 said:


> nascarcamper said:
> 
> 
> > Right through the floor for me two. Drivers side next to the chassis. I didn't run but two wires and put them in different holes so they were tight. Recently checked the plastic and everything is fine and it's been almost a year. Not sure what the 3rd wire would be for???
> ...


 Slick rig. I usually have power but I'll keep that in mind.


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## Martybeech (Mar 13, 2004)

As others have said, on the negative side. I have posted pics of a marine cutoff switch in the gallery. Since we leave it plugged in to AC at our home base campground I can turn off the switch to prevent overcharging. The converter seems to charge the dual 6volts to near the max (verified with a tester). I have finished my 3rd summer with the setup and it works fine.


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