The negative side is removed only when disconnecting a battery..
This is because a wrench applied to the hot side of a battery can inadvertently come in contact with ground (the frame of vehicle).
Sometimes a mechanic will be wearing a ring which is on a finger grasping the wrench. . when the ring bumps the metal frame a bad burn results.
Disconnecting the battery negative side prevents that from ever happening.
That said, you would install the battery cut off in the positive side of the battery.
That is because you want ALL downstream circuit dead.
The confusion is because many people are taught to disconnect the negative side of a battery first. . .and that is correct. But it is NOT correct when removing power from downstream circuits.
RichieC wrote: The negative side is removed only when disconnecting a battery..
This is because a wrench applied to the hot side of a battery can inadvertently come in contact with ground (the frame of vehicle).
Sometimes a mechanic will be wearing a ring which is on a finger grasping the wrench. . when the ring bumps the metal frame a bad burn results.
Disconnecting the battery negative side prevents that from ever happening.
That said, you would install the battery cut off in the positive side of the battery.
That is because you want ALL downstream circuit dead.
The confusion is because many people are taught to disconnect the negative side of a battery first. . .and that is correct. But it is NOT correct when removing power from downstream circuits.
Is there really any power to the downstream circuits if the ground is disconnected? In other words, if I remove the negative cables from the negative posts of your batteries, what will have power?
05 Dodge 3500 4x4 DRW Long Bed 4dr
07 Lance 992
III so far.
If we are talking about supplying battery power from the truck battery to the camper, then all metallic connections from the camper frame to the truck frame or body should be considered as "ground" back to the truck battery. Examples would be the hold downs, or possibly a metal part of the camper touching a metal part of the truck bed. A switch in the positive lead on the power from the truck battery will eliminate ALL truck battery power to camper, but a switch on the ground leg leaves the possibilities of other grounds still being intact.
WX2G wrote: If we are talking about supplying battery power from the truck battery to the camper, then all metallic connections from the camper frame to the truck frame or body should be considered as "ground" back to the truck battery. Examples would be the hold downs, or possibly a metal part of the camper touching a metal part of the truck bed. A switch in the positive lead on the power from the truck battery will eliminate ALL truck battery power to camper, but a switch on the ground leg leaves the possibilities of other grounds still being intact.
You put the cut off switch in the negative lead of the battery, and only the battery lead. The purpose of the switch is to isolate the battery. Open it, and the battery is out of the circuit. Yes, the truck can still power the camper. If you want the camper dead, open the switch and unplug the truck. It is a "battery cut off" not a "camper cut off."
Again, IF WE ARE TALKING ABOUT SUPPLYING BATTERY POWER FROM THE TRUCK (chassis power) to the camper and providing a means to disconnect that power from the camper, the disconnect switch should be in the positive, "hot" line, not the ground line.
Two Winnebago motorhomes,and a Holiday Rambler motorhome I have owned, and my current Lance camper are all wired this way. In addition, a fuse at the supply battery, essentially an "overload switch", is correctly and logically located in the Positive, not the ground lead.
If we are talking about isolating a particular battery or battery set from another set, disconnecting the ground will certainly isolate that battery.
Two Winnebago motorhomes,and a Holiday Rambler motorhome I have owned, and my current Lance camper are all wired this way. In addition, a fuse at the supply battery, essentially an "overload switch", is correctly and logically located in the Positive, not the ground lead.
You can add the Eagle Cap Campers - the factory install battery disconnect switch is that way too.
Quote: =mrblaine
Is there really any power to the downstream circuits if the ground is disconnected? In other words, if I remove the negative cables from the negative posts of your batteries, what will have power?
You have a point there.
But the circuitry will still have potential.
With the positive side disconnected, it won't even have potential.
A minor technical point, to be sure.
And in the case where the camper circuitry is getting power from the truck connected battery power, the camper's battery disconnected negative won't matter.
The camper circuitry can be hot!
Would it make sense to have a battery disconnect switch that leaves the camper circuit hot when the truck is connected?
It probably depends on what one wants.
So why would you want a disconnect that removes power from the camper when it's on the truck and the truck is running?
The purpose of the disconnect is so you can kill power to:
a) place the camper in storage and not drain the battery
b) work on the camper wiring safely
c) kill power if something fails
Placing the disconnect between the camper loads and the truck / battery connection doesn't do all of the above. Opening a switch placed there leaves the wiring to the truck still hot. You'll still have power with the switch open unless the battery is disconnected.
Placing the switch in the battery lead does all of the above unless you're into storing your camper or doing wiring with the truck running.
OK, I have been working the past couple of days and just got a chance to read all the post and get my TC battery cut off switch installed. Lets clear up what I was trying to do. I can unplug my camper plug to disconect from the truck power but I had to take the cable off the battery in the TC battery box (got sparks some time)wrong line and got tired of doing that and wanted the cut off switch that didn't come installed on my TC. I was thinking that my TC battery might go dead from sitting for a week or two between use if something was left on or if the two safety sensors might drain it. I drive another work rig during the week. I asked about pos. or neg. because in my mind I planned on getting one and putting it in the pos. line untill I read the instructions and it said install in the neg. line. I went with the neg. line its done.
Gary,Shelley and Morgan (Mini Dachshund)
2003 Dodge Ram 2500 4x4 5.7 4.10 QC SB
2004 Lance 815
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