Battery disconnect switch
Printed From: R-pod Owners Forum
Category: R-pod Discussion Forums
Forum Name: Podmods, Maintenance, Tips and Tricks
Forum Discription: Ask maintenance questions, share your podmods (modifications) and helpful tips
URL: http://www.rpod-owners.com/forum_posts.asp?TID=14666
Printed Date: 20 Jun 2025 at 10:10am
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Topic: Battery disconnect switch
Posted By: mountainman
Subject: Battery disconnect switch
Date Posted: 25 May 2021 at 7:11pm
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I recently added a 2nd 12 volt battery to my unit, in parallel. I want to add a battery disconnect switch, using the negative cable. The unit I bought did not come with instructions.
Which cable goes where and to which post on the switch, on or off side? Any help will be appreciated.
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Replies:
Posted By: campman
Date Posted: 25 May 2021 at 7:28pm
Here is a basic video from RV DIY..
https://www.youtube.com/watch?v=XxddcFI5QQI
And another video to watch, for good measure.
https://www.youtube.com/watch?v=j5hIxEtZDDo
Hope this helps,
Andy
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Andy and Laurie
'16 F150 5.0 4X4 w/factory tow pkg
'21 RP192
"If the women don't find you handsome...at least let them find you handy!"
Red-Green
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Posted By: offgrid
Date Posted: 25 May 2021 at 7:42pm
You should put the disconnect in the positive (ungrounded) cable not the negative (grounded) conductor. Code is to always disconnect the hot line never the grounded one. That leaves all you appliances properly groundcreferenced.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold
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Posted By: campman
Date Posted: 25 May 2021 at 7:54pm
OG, I thought it went on the positive side as well, but Mountainman asked for instruction on how to put it on the negative side so that is what I found and posted.
Sounds like an active discussion may ensue, different views will be shared and I will learn a bit more if it does. ;-)
Andy
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Andy and Laurie
'16 F150 5.0 4X4 w/factory tow pkg
'21 RP192
"If the women don't find you handsome...at least let them find you handy!"
Red-Green
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Posted By: campman
Date Posted: 25 May 2021 at 8:04pm
Mountainman, I have tried to hold back and not bother you about it but can't hold back anymore as it might help you down the road...you added a new battery. Is it an exact match for your original battery...same age, manufacturer, size, rating, and a dedicated deep cycle battery?
If the original battery is well used, it is a different size etc, then you may inadvertently shorten the life of your new battery as it will try to do all the work. You want them to charge and discharge as evenly as possible, which is why it is best to change them as a pair. This is true for 12 volt as well as 6 volt batteries.
Andy
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Andy and Laurie
'16 F150 5.0 4X4 w/factory tow pkg
'21 RP192
"If the women don't find you handsome...at least let them find you handy!"
Red-Green
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Posted By: mountainman
Date Posted: 25 May 2021 at 8:08pm
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Sorry, yes I did replace both with Interstate batteries.
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Posted By: offgrid
Date Posted: 26 May 2021 at 6:19am
The reasoning for placing the switch in the positive/hot/ungrounded conductor is the same as for any other fuse, switch, or circuit breaker in your trailer, house, and any other building. If you leave the negative/neutral/ungrounded conductors intact then you know you have everything safely tied to chassis ground and to your house/campground ground when you are on shore power. The electric code requires this (with very few exceptions) and contrary to a common misunderstanding the code applies to low voltage DC systems.
I think the confusion probably comes from the recommendation to disconnect the battery negative first while doing maintenance. That is done so you don't inadvertently short a tool to the chassis which could happen if you disconnect the positive first. But temporary maintenance and repair activity is not the same as a permanent switch. So disconnect your negative first, then your positive, install the switch in the positive conductor, and reconnect the negative. Or better yet, use tools with insulated handles around batteries. You can tape up a couple of wrenches for that purpose.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold
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Posted By: LAPod
Date Posted: 29 Jul 2021 at 3:10pm
Originally posted by offgrid
The reasoning for placing the switch in the positive/hot/ungrounded conductor is the same as for any other fuse, switch, or circuit breaker in your trailer, house, and any other building. If you leave the negative/neutral/ungrounded conductors intact then you know you have everything safely tied to chassis ground and to your house/campground ground when you are on shore power. The electric code requires this (with very few exceptions) and contrary to a common misunderstanding the code applies to low voltage DC systems.
I think the confusion probably comes from the recommendation to disconnect the battery negative first while doing maintenance. That is done so you don't inadvertently short a tool to the chassis which could happen if you disconnect the positive first. But temporary maintenance and repair activity is not the same as a permanent switch. So disconnect your negative first, then your positive, install the switch in the positive conductor, and reconnect the negative. Or better yet, use tools with insulated handles around batteries. You can tape up a couple of wrenches for that purpose.
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I could be mistaken, but if you're putting the switch on the negative at the battery, I believe the whole system will still be grounded, albeit disconnected from the battery. I think the grounding would stay in place elsewhere.
At the end of this article from Car & Driver, it mentions that disconnect switches should be on negative cables... https://www.caranddriver.com/features/a26873586/car-battery-disconnecting/. And here's a second article explaining why they suggest on negative: https://www.motortrend.com/how-to/kill-switch-positive-or-negative/
Most references I've seen have said negative, but I am not sure, which is how I came to this thread.
Also, on the Rpod, there are two sets of wires connecting to the battery posts. A larger and smaller gauge set. I'm guessing the switch should be on the larger gauge only? Is the smaller gauge for the recharge from the converter? TIA!
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2015 Rpod 176T
2008 Toyota Highlander Hybrid
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Posted By: StephenH
Date Posted: 29 Jul 2021 at 6:40pm
No. The smaller is for connecting a solar panel into the system. The heavier battery cables connect to the converter and are used both for powering items when there is no shore power or for recharging the battery.
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StephenH
Happy is the man that findeth wisdom,...
http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS
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Posted By: offgrid
Date Posted: 29 Jul 2021 at 8:56pm
Nope, the whole system is not grounded if you put the switch in the negative, because you are breaking the grounded conductor. So if you left a load on and disconnected the negative the whole negative side of the system would be hot. The article you read is totally wrong, it is an electric code violation to break the neural/grou ded conductor. And the Code does apply to RVs.
Put the switch in the positive conductor which is where every other switch and fuse in the trailer is located as well.
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1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold
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