# Battery Disconnect Switch



## tomstacey616

Hey all, I have recently moved from CT to VA and now I have to store my 2004 21RS at a "storage facility" due to restrictions in our community... and I do not want my battery to die while it sits idol until we can camp again. Does anyone have a parts list and how to install a disconnect switch? What do most of y'all do in VA when it comes to the "winter months" regarding the battery and winterizing.... this is my FIRST season with it and refuse to stop camping while we have "non-freezing" weather.....


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## KTMRacer

I don't have a parts list, but go to any marine supply store and get a perko or equiv. battery disconnect switch. it will have instructions for installation and is a quality unit that can handle the current. In my case I installed it inside the front pass through, but they can be installed on the tongue as well.


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## riggsp

Welcome to Virginia...I'm originally from Va. but now in N.C...I don't have part numbers, or pictures (sorry, for some reason I haven't been able to post pictures of mods I've done)but I got a battery disconnect switch (it ha s removable key) and a long battery cable from Advance Auto Parts, and black plastic electrical handy box and cover from Lowes...cut out the cover to fit the switch and attached it with a couple of screws, mounted the box on the inside of a panel convenient to the battery, disconnected the battery ground, ran it into the box and to one side of the switch, ran the new cable from the other side of the switch back to the battery ground...costs about $25.00 to complete, and works great...when I winterize (at the last possible minute)I remove the battery, store it in my garage (off the floor) so it doesn't freeze, and put it on a "float" charger until spring.


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## Wolfpackers

What the above post says except I got my switch at Harbor Freight. Installed it 4 yrs ago and have had no problems. I used the round(ish) handy box and painted it black as all Lowes had were blue. Also recommend to put the switch on the negative cable, not the positive.

The removable key (removes when battery is disconnected) looks exactly like what I see on the instrument panels on Nascar cars. I'm sure theirs didn't come from HF, but could be the same manufacturer.


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## cdnbayside

1 - BEP Marine battery switch
4 - stainless steel machine screws #6 x 1-1/2 + nuts
1 - 4 gauge 12" battery cable

Drill 4 holes in side of battery box to match holes in battery switch.
Attach trailer negative wire to switch.
Attach 12" battery cable to switch and other end to negative terminal on battery.
Mount battery switch with screws and nuts to battery box.
Test switch operation.
Complete
Estimated time 10 minutes


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## tomstacey616

cdnbayside said:


> 1 - BEP Marine battery switch
> 4 - stainless steel machine screws #6 x 1-1/2 + nuts
> 1 - 4 gauge 12" battery cable
> 
> Drill 4 holes in side of battery box to match holes in battery switch.
> Attach trailer negative wire to switch.
> Attach 12" battery cable to switch and other end to negative terminal on battery.
> Mount battery switch with screws and nuts to battery box.
> Test switch operation.
> Complete
> Estimated time 10 minutes


*Exactly what I was looking for, Thank you!!*


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## Oregon_Camper

Here is my solution. I wanted to have the ability to add a second battery bank, so this swith allows me to switch from 2x6v to 2x12x (external) or both at the same time.


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## Bob Landry

Speaking from the marine industry, ABYC specifies that battery disconnect switches be installed on the positive side. The reason being that AC ground and DC ground are usually tied together so it's possible to draw an arc from the positive side even with the negative lead disconnected. Every OEM battery switch that I have seen has been installed on the positive side of the battery system. That's good enough for me and that's how I install them for customers. With the two grounds connected it is also possible for a high load device to draw current through wiring that is not rated to handle it.


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## CamperAndy

Bob Landry said:


> Speaking from the marine industry, ABYC specifies that battery disconnect switches be installed on the positive side. The reason being that AC ground and DC ground are usually tied together so it's possible to draw an arc from the positive side even with the negative lead disconnected. Every OEM battery switch that I have seen has been installed on the positive side of the battery system. That's good enough for me and that's how I install them for customers. With the two grounds connected it is also possible for a high load device to draw current through wiring that is not rated to handle it.


Bob please find a link to those instructions.

Electrical theory 101 states that once you break the circuit no current can flow. So once the ground wire from the battery(ies) to the system ground (frame) is opened, no matter what other systems are connected to that ground system, no current can or will flow through or from the battery(ies). The use of either negative or positive switch will accomplish this but disconnecting the negative for this application has a long history in the battery maintenance world. To safely disconnect a battery you should always disconnect the negative wire first, the issue has to do with touching tools from the battery to ground. If that happens while disconnecting the negative wire nothing happens, do that when disconnecting the positive wire and you can arc weld the wrench between the positive wire and the ground. The same applies here. So if you put the switch on the positive leg and turn it off and you want to do maintenance on the switch it has the very real possibility that when disconnecting the wire from the switch you could short the battery to ground.

I will always install system isolation switches on the negative leg.

On edit -

Drinking my coffee this morning and doing a little googling and I see that the Blue Sea switch instruction are all listed for positive side for load switching, not just system isolation as we are using the switch for on our trailers. In the case of being able to control multiple outputs putting the control switch on the positive side makes some sense. All device controls are typically wired this way, think of your typical light switch. For complete system isolation opening the ground is better.


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