Battery cutoff switch

A dedicated battery switch is supposed to chop all power to and from a battery save for solar panel charging. The reason panels can be left connected is they should be fused at a substantially lower amperage that could affect the integrity of the panel to control to battery wiring.

The power to the 7 pin connector is turned on/off with the truck ignition switch. Has to be in order to keep from running the truck battery down.

Tennessee_Nomad wrote:
I have a battery cutoff switch on our camper. When the switch is off, does that cut the line from the truck seven pin to the camper battery also? Or should the camper battery charge when the power cord (umbilical) is connected from the camper to the truck, with the switch off.
My thinking is, when the switch is off, that cuts all power to or from the battery.

You are correct. Keep in mind, that you should always engage the switch before attempting to pull the TT. The brake-away switch is only active if the battery cutoff switch is on. This also includes charging the battery from the TV while in transit.

The cutoff switch should remove 12V DC power from the camper distro panel, but leave the 7 pin and emergency brakes actuator wired to the battery. That is how all OEM battery disconnects I have seen are wired, and how it should be wired.

You want your TV to be able to charge the battery for emergency brake use, and the battery has to be able to power the brakes.

I have seen several DIY disconnects installed that don't do it that way, but I don't reccoment it.

Dakota98 wrote:

Tennessee_Nomad wrote:
I have a battery cutoff switch on our camper. When the switch is off, does that cut the line from the truck seven pin to the camper battery also? Or should the camper battery charge when the power cord (umbilical) is connected from the camper to the truck, with the switch off.
My thinking is, when the switch is off, that cuts all power to or from the battery.

You are correct. Keep in mind, that you should always engage the switch before attempting to pull the TT. The brake-away switch is only active if the battery cutoff switch is on. This also includes charging the battery from the TV while in transit.

The breakaway switch should be wired directly to the battery.

Thanks... Yes I always engage the switch when towing. My round about reason for asking the question was... I blew my "trailer battery charge" fuse in the truck and I'm trying to deduce that I have everything back the way it's supposed to be. I replaced a fuse that I believe to be, the correct one.

Shouldn't you also unplug the hookup to your truck when you are dry camping - in order to NOT drain the truck battery?

Yes you should.

Dakota98 wrote:

Tennessee_Nomad wrote:
I have a battery cutoff switch on our camper. When the switch is off, does that cut the line from the truck seven pin to the camper battery also? Or should the camper battery charge when the power cord (umbilical) is connected from the camper to the truck, with the switch off.
My thinking is, when the switch is off, that cuts all power to or from the battery.

You are correct. Keep in mind, that you should always engage the switch before attempting to pull the TT. The brake-away switch is only active if the battery cutoff switch is on. This also includes charging the battery from the TV while in transit.

It depends on the wiring of the camper, of which there are many variations. Often, I understand the breakaway switch and brakes are wired straight to the battery, bypassing the disconnect switch—this may even be a legal requirement in some places, since there's nothing preventing you from driving with the main disconnect switch opened.

Likewise, it's possible the connection from the 7 pin connector is also on the battery side of the disconnect switch, and perhaps the converter/charger, and maybe the propane and CO detectors....

My cutoff switch disconnects any and everything that would normally use it. I always switch it on when traveling, but may disconnect it while plugged in to shore power for long periods.