youtubeMany coaches have battery disconnect switches installed in them. However, these switches sometimes go unused or unnoticed by owners. In fact, when I was working as an RV Technician a few years ago, I was passed a phone call from a service customer. They had recently purchased a trailer and were unable to get any of the electrical systems in the trailer working after pulling into a campground. The lady mentioned she had checked the battery connections, the fuses, and everything else she could think of. I asked if she had a battery disconnect. She asked what that was, so I explained it to her. She put me on hold for a few minutes, came back to the phone, and told me that’s what the problem was. Battery disconnect switches are a great way to conserve your batteries while your RV is in storage, even for a short time.


12V-48V Battery Isolator Power Cut Off Master Switch - Amazon.com

When I park my RV at the storage lot, I usually disconnect my batteries at the switch, even if I’m going to be back at the RV in a week or so. In addition to preventing parasitic loads from slowly draining your battery, it also prevents battery drain from loads that might inadvertently be left on, such as lights or fans. Even though my RV has solar panels that keep the batteries fresh (as long as there is some solar energy), I regularly make use of my battery disconnect switch, which is conveniently located with my other coach controls.


Battery Disconnect Switch with Keys - Amazon.com

Battery disconnects come in many different styles, from blade switches right at the battery terminal to relay-controlled remote switches like mine. A very common style for trailers is the marine-style rotary contact switch. Whatever form you have, it is a good idea to make use of the battery disconnect switch whenever you are going to be away from your RV, unless of course your coach is plugged in while it is in storage. Note that there are some loads that are NOT wired through the disconnect switch, most notably the LP detector. This is a commonly overlooked parasitic load. I usually recommend pulling the fuse for the LP detector, unless you have a separate power switch, as many large coaches do.


Top Post Knife Blade Master Switch - Amazon.com

If your RV doesn’t have a disconnect switch, you might consider having one installed. Simple switches are quite inexpensive and don’t take long to install. It is quite a simple DIY project if you are relatively handy and have the tools required. As with any project, be sure to plan it out first, including where you would like your switch to be located. The basic tools required will be a wire cutter and crimper large enough to handle the gauge wire you are working with, as well as extra battery wire and the hardware necessary to mount your switch. Simply splice the switch into the positive lead from the battery at a convenient mounting location (as close to the battery as possible ideally). If you are not handy with basic electrical work, have somebody do the job for you. Typical locations are beside the battery on the trailer A-frame (applicable to NEMA-rated marine battery switches that are weather-proof), or inside a front storage compartment on a trailer. For aftermarket installation on a motorhome, it would typically be installed in the electrical bay.


Marine Battery Cut Off Switch - Amazon.com

In our Northwest climate, where the coldest it gets is around freezing, you can leave your batteries in your RV over the winter (if you are not using your coach) and simply disconnect your batteries at the switch. You don’t have to remove your batteries for winter storage, as long as they remain cool and dry in the RV. Just make sure they are fully charged and topped up with electrolyte (unless they are maintenance-free). With the batteries disconnected, you don’t have to worry about loads draining the battery, and in the spring, you can just flip the switch and you’re ready to go. Note that the battery may self-discharge over the winter to some extent, but if it does so to a large extent, it is a good idea to have the batteries tested, as they may be worn out.


High Current Battery Disconnect Switch - Amazon.com

So, make good use of your battery disconnect switch. It is there for a good reason, and it provides good peace of mind while your RV is in short- or long-term storage. If you visit your stored RV frequently, like I do, you can be sure your lights will work when you need to grab that item you left in your coach. Also, you don’t have to lie awake at night wondering if you left the fridge on in your RV.

Steve Froese
Author: Steve FroeseEmail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Steve Froese is a Licensed Professional Engineer in British Columbia, as well as an Interprovincial Red Seal RV Technician, which is equivalent to a Master Certified RV Technician in the USA. Steve was a personal friend and colleague of the late Gary Bunzer (“the RV Doctor”), and works closely with FMCA as the monthly “Tech Talk” columnist, as well as being a member of the Technical Advisory and Education Committees. Steve and his family are lifelong and avid RVers, mostly in the Pacific Northwest.

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