Battery disconnect switch - confused

[Rainier]

Forgive me, I am confused. I have a TT with two 12V batteries hooked up in parallel. I store my TT at a storage facility and want to help protect my new batteries. I purchased a battery disconnect switch and am confused on how to hook it up. I'll mount the switch to one of the battery boxes and the switch has two posts. Specifically how do I connect it. Do I need another jumper cable from the ground of the second battery to the switch? What goes on the second post on the switch? The trailer ground? Sorry not good at this kind of stuff. Thanks for you help.

[Burnt_Marshmall]

downtheroad wrote:
Wire it on the negative line between the second battery and the trailer.

That's what I do. Current comes off the negative side on a DC battery.

[352]

Put in a ( Perko ) switch. Look it up

[Lwiddis]

"IMO the switch is more convenient than pulling the fuse"

Me too, Hedge.

[samsontdog]

coolbreeze01 wrote:
Trailers usually come with a battery disconnect switch.

Very few that I have bought came with one.

[Bobbo]

hedge wrote:

Bobbo wrote:

hedge wrote:
What difference would it make (+ or -)? it would disconnect the breakaway either way as far as I can surmise.

In either way the breakaway could be wired to bypass it.

I've only owned two trailers but both of them only had a single point battery connections so a disconnect on either side would have disabled the breakaway.

The breakaway switch should be wired prior to the disconnect. That way the breakaway switch ALWAYS has power. It has NO drain on the battery as long as the pin isn't pulled, so there is no reason it should be after the disconnect.

I guess I've just never seen a trailer wired that way.. but I haven't owned a trailer in a few years.

It's still just convention, a bypass could be wired on the negative side as well.

While the negative could be bypassed, it would be difficult since the brakes are grounded through the frame.

[hedge]

Bobbo wrote:

hedge wrote:
What difference would it make (+ or -)? it would disconnect the breakaway either way as far as I can surmise.

In either way the breakaway could be wired to bypass it.

I've only owned two trailers but both of them only had a single point battery connections so a disconnect on either side would have disabled the breakaway.

The breakaway switch should be wired prior to the disconnect. That way the breakaway switch ALWAYS has power. It has NO drain on the battery as long as the pin isn't pulled, so there is no reason it should be after the disconnect.

I guess I've just never seen a trailer wired that way.. but I haven't owned a trailer in a few years.

It's still just convention, a bypass could be wired on the negative side as well.

[enblethen]

The switch has two posts.
One goes to the batteries. It can go to the negative or positive. Many feel negative is better. You would run from batteries, one wire each to one post.
Other post goes to the rig's power distribution panel.
There should be a fuse or circuit breaker at the battery to protect the wiring between batteries and the power distribution panel. It can be either side of the switch.
The break away switch must stay active even when switch is in the off position.

[Bobbo]

hedge wrote:
What difference would it make (+ or -)? it would disconnect the breakaway either way as far as I can surmise.

In either way the breakaway could be wired to bypass it.

I've only owned two trailers but both of them only had a single point battery connections so a disconnect on either side would have disabled the breakaway.

The breakaway switch should be wired prior to the disconnect. That way the breakaway switch ALWAYS has power. It has NO drain on the battery as long as the pin isn't pulled, so there is no reason it should be after the disconnect.

[coolbreeze01]

Trailers usually come with a battery disconnect switch.

[hedge]

What difference would it make (+ or -)? it would disconnect the breakaway either way as far as I can surmise.

In either way the breakaway could be wired to bypass it.

I've only owned two trailers but both of them only had a single point battery connections so a disconnect on either side would have disabled the breakaway.

[beemerphile1]

Bobbo wrote:

downtheroad wrote:
Wire it on the negative line between the second battery and the trailer.

hedge wrote:
also the switch should be on the negative side not positive like the fuse would be.

Don't do this. It will disable the breakaway brake on the trailer. Connect it to the positive wire. That way the breakaway trailer brake will still be functional even if you forget to turn the battery back on before towing.

Preach it! I'm with you 100 percent. With a MH, put it wherever you want. With a trailer, it goes in the positive with the breakaway feed connected prior to the switch.

[Bobbo]

downtheroad wrote:
Wire it on the negative line between the second battery and the trailer.

hedge wrote:
also the switch should be on the negative side not positive like the fuse would be.

Don't do this. It will disable the breakaway brake on the trailer. Connect it to the positive wire. That way the breakaway trailer brake will still be functional even if you forget to turn the battery back on before towing.

[hedge]

1. you will have a + and a - cable between the batteries to parallel them.

2. wire the Trailer + to battery 1 +

3. wire the Trailer - to one side of the switch

4. You need a new wire to connect the other side of the switch to battery 2 -

IMO the switch is more convenient than pulling the fuse, also the switch should be on the negative side not positive like the fuse would be.

[downtheroad]

Wire it on the negative line between the second battery and the trailer.