# Battery Cut Off



## usmc03 (Jun 6, 2006)

So how hard is it to install a battery cut off? I have been thinking about doing this for a while but am not very mechanically inclined. I still haven't installed the drawer mod for the tip out.

I would like to save the batterys from draining all the time and am too lazy to just unhook them.

Thanks
Lance


----------



## Dreamtimers (Mar 7, 2005)

Easy, check a boating supply for switch. Also get an extra cable to connect the output of the switch to the place the battery cable was connected. Connect the non battery end of the battery cable to the input of the switch. It is possible to connect either positive or negative leads, but most people seem to think the neg. terminal is preferred. Good luck
Dave


----------



## Airboss (Jul 14, 2007)

Yup, pretty easy. Just take a bit of advice and don't cheap-out on the switch. I'm now in the process of installing my 3rd switch because I got dupped twice on Harbor Freight crap.


----------



## Scoutr2 (Aug 21, 2006)

If you go with a simple knife-blade type of battery disconnect, then by all means, install it on the NEG terminal. There will not be any sparks to ignite propane or battery vapors when you open and close the switch.

But if you have a sealed switch (one that prevents vapors from getting to the actual switch, where sparks could occur), then you can hook that into the POS side of the battery. I have a sealed switch from a piece of heavy equipment installed on the positive side of the battery. But there is a reason for that. I wanted to make sure that when the battery is disconnected, the electric tongue jack cannot be operated by someone, while my trailer is in storage. The jack has its own grounding system (thru the mounting bolts into the trailer frame), so if the NEG side of the battery were disconnected, the jack would still operate. The only way to disable the jack is to cut the electric power from the positive side.

But be sure that the switch is truly sealed - and designed for use in the elements. Otherwise, there are two propane tanks and a battery in close proximity that can provide vapors for combustion. That would not be a good combination.

Mike


----------



## hautevue (Mar 8, 2009)

I think that when you disconnect the NEG of the battery, the powered jack cannot work. While the jack has its own hot wire, and a ground directly to the case (and thus to the TT frame), the battery itself is floating above ground--there is no wire connected to the frame or any other wire, to complete the circuit through the power jack back to the NEG terminal of the battery. Am I missing something?


----------



## Nathan (Jan 2, 2007)

Scoutr2 said:


> If you go with a simple knife-blade type of battery disconnect, then by all means, install it on the NEG terminal. There will not be any sparks to ignite propane or battery vapors when you open and close the switch.
> 
> But if you have a sealed switch (one that prevents vapors from getting to the actual switch, where sparks could occur), then you can hook that into the POS side of the battery. I have a sealed switch from a piece of heavy equipment installed on the positive side of the battery. But there is a reason for that. I wanted to make sure that when the battery is disconnected, the electric tongue jack cannot be operated by someone, while my trailer is in storage. The jack has its own grounding system (thru the mounting bolts into the trailer frame), so if the NEG side of the battery were disconnected, the jack would still operate. The only way to disable the jack is to cut the electric power from the positive side.
> 
> ...


HUH? When I connected my new batts last week, I put on the negative last. It sparked just like the positive would have.


----------



## CamperAndy (Aug 26, 2004)

hautevue said:


> I think that when you disconnect the NEG of the battery, the powered jack cannot work. While the jack has its own hot wire, and a ground directly to the case (and thus to the TT frame), the battery itself is floating above ground--there is no wire connected to the frame or any other wire, to complete the circuit through the power jack back to the NEG terminal of the battery. Am I missing something?


100% correct, not missing anything.


----------



## SoCalOutback (Dec 18, 2005)

I'm planning on installing a remote battery cutoff like this one: Battery Cut Off

I'm lazy and don't like lifting the cover off the propane tanks when I put my trailer back in storage.

It's as simple as installing it on the positive side of the between the battery post and the cable going into the trailer. Then connecting the control wire to the remote panel.


----------



## CamperAndy (Aug 26, 2004)

Nathan said:


> HUH? When I connected my new batts last week, I put on the negative last. It sparked just like the positive would have.


Also 100% correct. The old rule of thumb (which still holds true) is to always connect the Negative last and disconnect it first. Not to prevent a load arc (which will happen no matter if you disconnect the positive or negative of the load) but to prevent the tool that is being used to disconnect the battery from being able to make a circuit and carry current. If you disconnect the ground first it does not matter if your tool touches ground, there will be no arc but if you disconnect your positive first and touch the wrench to ground then you have a massive arc that can do very bad things.


----------



## CamperAndy (Aug 26, 2004)

SoCalOutback said:


> I'm planning on installing a remote battery cutoff like this one: Battery Cut Off
> 
> I'm lazy and don't like lifting the cover off the propane tanks when I put my trailer back in storage.
> 
> It's as simple as installing it on the positive side of the between the battery post and the cable going into the trailer. Then connecting the control wire to the remote panel.


Usable but not recommended since the control draws current and is just another load on the battery system.


----------



## SoCalOutback (Dec 18, 2005)

CamperAndy said:


> I'm planning on installing a remote battery cutoff like this one: Battery Cut Off
> 
> I'm lazy and don't like lifting the cover off the propane tanks when I put my trailer back in storage.
> 
> It's as simple as installing it on the positive side of the between the battery post and the cable going into the trailer. Then connecting the control wire to the remote panel.


Usable but not recommended since the control draws current and is just another load on the battery system.
[/quote]

It does not draw current when off or on, it uses a latching relay. It will only draw current when moving the relay. It's specifically designed for this application.


----------



## CamperAndy (Aug 26, 2004)

SoCalOutback said:


> I'm planning on installing a remote battery cutoff like this one: Battery Cut Off
> 
> I'm lazy and don't like lifting the cover off the propane tanks when I put my trailer back in storage.
> 
> It's as simple as installing it on the positive side of the between the battery post and the cable going into the trailer. Then connecting the control wire to the remote panel.


Usable but not recommended since the control draws current and is just another load on the battery system.
[/quote]

It does not draw current when off or on, it uses a latching relay. It will only draw current when moving the relay. It's specifically designed for this application.
[/quote]

I was going from the picture (looks like a starter type relay) and should have read the PDF file attached. Interesting way to do isolate the batteries. Give us a report on how it works when you get it installed.


----------



## usmc03 (Jun 6, 2006)

Thanks for all the replies. Is it possible to get a picture of one that is already installed? I am not much for reading instructions and tend to go off of pictures. It is the Marine Grunt in me.


----------



## Scoutr2 (Aug 21, 2006)

CamperAndy said:


> . . . but if you disconnect your positive first and touch the wrench to ground then you have a massive arc that can do very bad things.


Isn't this why the jack would still work with the NEG battery post disconnected? Power from the POS is flowing to and through the jack thru its ground to the frame. I haven't tried it, but this is the reasoning I used.

Mike


----------



## Scoutr2 (Aug 21, 2006)

usmc03 said:


> Thanks for all the replies. Is it possible to get a picture of one that is already installed? I am not much for reading instructions and tend to go off of pictures. It is the Marine Grunt in me.


Here's what I did.










Just a piece of sheet metal, bent and painted, then bolted to the battery tray strut. A couple labels from a Labelmaker and the switch, of course (mounted from behind).

Mike


----------



## Oregon_Camper (Sep 13, 2004)

Here is the cut off switch I had on my 28RSS


----------



## CamperAndy (Aug 26, 2004)

Scoutr2 said:


> . . . but if you disconnect your positive first and touch the wrench to ground then you have a massive arc that can do very bad things.


Isn't this why the jack would still work with the NEG battery post disconnected? Power from the POS is flowing to and through the jack thru its ground to the frame. I haven't tried it, but this is the reasoning I used.

Mike
[/quote]

You have to have the circuit complete by getting back to the battery. If the negative pole is disconnected you can touch the positive to ground and nothing with happen since the current can not get back to the battery. Disconnect the negative on the battery and the power jack will not work as there is no complete loop.


----------



## Scoutr2 (Aug 21, 2006)

CamperAndy said:


> . . . but if you disconnect your positive first and touch the wrench to ground then you have a massive arc that can do very bad things.


Isn't this why the jack would still work with the NEG battery post disconnected? Power from the POS is flowing to and through the jack thru its ground to the frame. I haven't tried it, but this is the reasoning I used.

Mike
[/quote]

You have to have the circuit complete by getting back to the battery. If the negative pole is disconnected you can touch the positive to ground and nothing with happen since the current can not get back to the battery. Disconnect the negative on the battery and the power jack will not work as there is no complete loop.
[/quote]

I'll have to try that . . . just to satisfy my curiosity. But you seem to be more knowledgeable than I about that.

Mike


----------



## Fanatical1 (Jan 9, 2006)

Here's what I did. I mounted the switch in a piece of treated lumber using a couple of small steel angles to attach it to the angle iron frame
below the propane housing. This keeps it out of the rain but still reachable without removing the propane cover. The switch I used was
a cheap Chinese knock off that quit working after two weeks. Don't make that mistake.


----------



## Airboss (Jul 14, 2007)

Here's how I mounted my switch, but again I caution anyone about using this particular switch. I've had two fail. (That's right, it took two before I learned my lesson.)


----------



## Fanatical1 (Jan 9, 2006)

I was tempted to go and get another at Harbor Freight, but your experience has changed my mind. I ordered this one mainly because it is waterproof 
and I know this company makes good products. A little more than I wanted to spend at $31.00 plus shipping, but I try to do things correctly the first
(or at least second....... OK...., sometimes third) time.









Battery Disconnect Switch


----------



## usmc03 (Jun 6, 2006)

Oregon_Camper said:


> Here is the cut off switch I had on my 28RSS


I like that, where did you get it? It also looks easy enough for me to install.

Thanks


----------



## Airboss (Jul 14, 2007)

Fanatical1 said:


> I was tempted to go and get another at Harbor Freight, but your experience has changed my mind. I ordered this one mainly because it is waterproof
> and I know this company makes good products. A little more than I wanted to spend at $31.00 plus shipping, but I try to do things correctly the first
> (or at least second....... OK...., sometimes third) time.
> 
> ...


Glad to hear I help saved someone another headache. Here's what I ended up with: Guest Battery switch

Let me know how you end up mounting you new switch. I plan on a similar installation as my last one.


----------



## Airboss (Jul 14, 2007)

usmc03 said:


> Here is the cut off switch I had on my 28RSS


I like that, where did you get it? It also looks easy enough for me to install.

Thanks
[/quote]

Although these are neat switches (I had them when I was using 12v batteries) they don't fit on the new trojans. Well, at least they didn't for me. I broke mine trying to make it fit.


----------



## thefulminator (Aug 8, 2007)




----------



## beachbum (Nov 27, 2006)

It doesn't get much simpler than thefulminator or oregon camper's. I got a switch like thefulminator's from Wal-Mart.
david


----------



## Airboss (Jul 14, 2007)

Airboss said:


> Here's how I mounted my switch, but again I caution anyone about using this particular switch. I've had two fail. (That's right, it took two before I learned my lesson.)


And here's the new switch...


----------



## Oregon_Camper (Sep 13, 2004)

Airboss said:


> And here's the new switch...


Is this switch #3? I take it this one is now working for you?


----------



## Airboss (Jul 14, 2007)

Oregon_Camper said:


> Is this switch #3? I take it this one is now working for you?


Yup, this one is working just fine. It was an easier install as well. Wish I didn't try to cheap-out on the switch the first (and second) time.


----------



## Oregon_Camper (Sep 13, 2004)

Airboss said:


> Is this switch #3? I take it this one is now working for you?


Yup, this one is working just fine. It was an easier install as well. Wish I didn't try to cheap-out on the switch the first (and second) time.
[/quote]

Have a link and/or model number?


----------



## Airboss (Jul 14, 2007)

Oregon_Camper said:


> Is this switch #3? I take it this one is now working for you?


Yup, this one is working just fine. It was an easier install as well. Wish I didn't try to cheap-out on the switch the first (and second) time.
[/quote]

Have a link and/or model number?
[/quote]

This is the one I used: GUEST 2111A BATTERY SWITCH UNIV MOUNT WO AFD

Here is another one that would have worked better (made for just one battery), but it cost twice as much: Guest 2112A Universal Mount Marine Battery On/Off Switch

It doesn't bother me much that I have the two battery switch because I can use the #2 terminal in the future if I ever add a power tongue jack and want to isolate it.

_edit: _ Now that I think about it, I'm not sure that I'd be able to hook up the power jack to the switch. Hmmm...


----------



## Oregon_Camper (Sep 13, 2004)

Thanks for the link...









I have 2x6v batteries and I simply want On/Off settings. This one looks like it can control more than I need. Right?


----------



## Fanatical1 (Jan 9, 2006)

Just got mine installed yesterday. I chose this one basically because it's waterproof, made in the USA and I know the company name... I installed it using
the same treated lumber frame that I used with my cheap Chinese made switch that lasted 2 weeks.







I wanted to have mine outside of the propane cover, I have busted too many rubber latches already!


















Disconnect Switch


----------



## Airboss (Jul 14, 2007)

Gentlemen - sorry for the delay...



Oregon_Camper said:


> Just got mine installed yesterday. I chose this one basically because it's waterproof, made in the USA and I know the company name... I installed it using
> the same treated lumber frame that I used with my cheap Chinese made switch that lasted 2 weeks.
> 
> 
> ...


Looks great! Nice install!


----------



## Not Yet (Dec 13, 2004)

I will take pictures of mine in the morning. I installed a marine switch inside the drivers side pass through. Easy to do and always out of the elements.

Jared


----------



## Rookie (Jun 29, 2009)

I might have the answer but when messing with electrical (which I know nothing about) I want to be sure. I bought the following switch:

http://www.campingworld.com/shopping/item/top-mount-safety-switch-with-wing-nut/1311

I have a dual 12V battery setup as the image I attached shows.

So I should mount this switch on the negative post on the battery which grounds to the trailer? I was thinking to mount it to the negative post, then use the wing nut to connect my ground to the trailer and the negative which goes to the other battery. Is that correct? Thanks.


----------



## forceten (Nov 14, 2008)

I added a switch along with my surge protector mod this year.

was thinking of what to do when I just used a 110 regular switch and 2x4 box and wired it in to the battery. Its a remote switch now that is inside the rv. So i can turn the battery on and off from inside no problems. Also added a remote set of cords that i can now plug right into on of my battery tenders if i want the battery nice and topped off before I go someplace.

Both been tested and work just as planned.


----------

