Battery on/off -- Pos or Neg side?

[BackInAction]

When I add an on/off to my battery box, which side (positive or negative) should I install the switch?

It seems like a silly question to me, but I've seen significant debate in another forum without any real conclusion.

[Len & Cheri]

You are correct, no one will agree. I say always break the positive side and the switch instructions I have confirm that.

[KyDan]

The same goes here. There are folks who are very passionate about which side of
the battery to put the switch. More seem to think it should go in the positive side
but some think it absolutely should go in the negative side.

I'm a positive side kind of guy
I'm an ex-electrician and it just seems right that way to me.
Fuses are generally in the positive side of the circuit and they are
a form of switch, even tho they are a one time switch!

It will work perfectly fine either way. Just be sure the switch is ahead of
all connections. Some slides and maybe front jacks are tapped off the
battery wire pretty close to the front end. If you want the disconnect
to be total then it's gotta be the first thing in the line.

[Herk7769]

Originally Posted by LFugate

You are correct, no one will agree. I say always break the positive side and the switch instructions I have confirm that.

My two cents has the positive side switched as well.

[BigDTx]

Pos

[BackInAction]

Lou;

That's a fancy switch. How is that wired? I was expecting 2 leads from the switch, not 4.

[Len & Cheri]

Originally Posted by BackInAction

Lou;

That's a fancy switch. How is that wired? I was expecting 2 leads from the switch, not 4.

Thats the switch I have as well. You can select all OFF, or switch 1 on, or switch 2 on, or switch 1 and 2 on. It's a very nice switch and I believe it's designed for boats which I why I picked that one. I'm hoping it holds up to the weather longer than the other cheaper one I had.

[Triguy]

Mine is wired off of the positive.

I have a Blue Sea disconnect switch and Blue Sea instructions are to install off of the positive terminal per American Boat and Yacht Council standards.

[Iggy]

Originally Posted by BackInAction

When I add an on/off to my battery box, which side (positive or negative) should I install the switch?

It seems like a silly question to me, but I've seen significant debate in another forum without any real conclusion.

Switch the Positive side. The reason why is if you jus switch the negitive you can still make a direct short inside the trailer from a positive line to the frame which is ground.

If you switch the positive at the battery you will never have the posibility of a short inside your trailer.

My 2 cents

[budlemon]

bayyery disconnect swiches in cars such as my classic truck are put on the neg. cable direct current (batteries) flows from neg. to pos. look it up . your alternator on your truck goes to pos. post pos. in neg. out we have to run asmall bypass wire to radios etc. to maintain pushbutton stations gas safety sensors.

[Herk7769]

Originally Posted by BackInAction

Lou;

That's a fancy switch. How is that wired? I was expecting 2 leads from the switch, not 4.

The one going down goes to Bat #1; The one going left goes to battery #2. The remaining two wires are connected to the "common" One exits the top going to my Inverter (via a 150 Amp fuse) and one exits to the right going to the coach converter.

[Herk7769]

Originally Posted by budlemon

bayyery disconnect swiches in cars such as my classic truck are put on the neg. cable direct current (batteries) flows from neg. to pos. look it up . your alternator on your truck goes to pos. post pos. in neg. out we have to run asmall bypass wire to radios etc. to maintain pushbutton stations gas safety sensors.

You are correct that electrons depart the negative terminal and travel via the circuitry to the Positive terminal. That is why the negative terminal is "negative"... It is loaded with negatively charged electrons that were stripped from the positively (now) charged plates. Without the negatively charged electrons the atoms of the plate become positively charged due to the Protons in the nucleus.

I still break the positive with my switch. In the "big scheme of things" it really does not matter what you switch as long as you do not complete the circuit. Most folks follow the convention of breaking the red wire used in negatively grounded vehicles like our campers.

[Herk7769]

Originally Posted by Iggy

Switch the Positive side. The reason why is if you jus switch the negitive you can still make a direct short inside the trailer from a positive line to the frame which is ground.

If you switch the positive at the battery you will never have the posibility of a short inside your trailer.

My 2 cents

Iggy, this is not the case. The electron content of the battery will not change if you get a wire and go from the positive terminal to the dirt (or frame). There is no way to get more electrons into the battery than there are protons in the battery. Electrons have to leave before new ones can come in. Thus no way to short the battery without a connection to the negative terminal.

[Iggy]

Originally Posted by budlemon

bayyery disconnect swiches in cars such as my classic truck are put on the neg. cable direct current (batteries) flows from neg. to pos. look it up . your alternator on your truck goes to pos. post pos. in neg. out we have to run asmall bypass wire to radios etc. to maintain pushbutton stations gas safety sensors.

Their is many reasons to switch the negitive wire in a circuit but I'm not going to get into that.
Can you answer this question.

Why do builders place a fuse on the positive wire closest to the power source?

The answer will tell you why you need to switch the Positive wire and not the Negitive.

[Malco]

Where do you get this switch and do you install it outside on the frame next to the battery or does it have to be inside somewhere under cover?

[Iggy]

Originally Posted by Malco

Where do you get this switch and do you install it outside on the frame next to the battery or does it have to be inside somewhere under cover?

Usually put in the compartment near the battery. This makes it easy to disconnect the battery after you have disconnected and parked for storage.

[KyDan]

I put mine in the toe kick area right next to my power center.
Since my battery positive lead ran uninterrupted from the tongue to
the power center this made adding a cut off switch easy and I didn't even
need any extra wire. I just cut the positive lead and connected both ends
to either side of the switch. I'm just using a single battery switch.

Go to amazon.com and look for battery switch or harborfreight.com
or go into an Autozone and ask for a battery disconnect switch.

Many of us use this one. It's a little pricey but probably the best.
http://www.amazon.com/Blue-Sea-Syste...474859&sr=8-11

[BackInAction]

I see this one used often as well, mounted right on the top, or side, of the battery box...

Amazon.com: Pico 5575pt Master Batt Isolator Switch: Automotive

[Malco]

Originally Posted by BackInAction

I see this one used often as well, mounted right on the top, or side, of the battery box...

Amazon.com: Pico 5575pt Master Batt Isolator Switch: Automotive

That one looks like an easy one to install.Thanks

[jimh]

Originally Posted by budlemon

bayyery disconnect swiches in cars such as my classic truck are put on the neg. cable direct current (batteries) flows from neg. to pos. look it up . your alternator on your truck goes to pos. post pos. in neg. out we have to run asmall bypass wire to radios etc. to maintain pushbutton stations gas safety sensors.

there was a time some vehicles were pos ground. i rigged an automotive gen to my Harley 165 and had to change the system to pos ground because the gen i bought was pos ground.