Disconnecting your batteries can be very useful in maintaining battery health, working on the RV electrical system, and safely replacing batteries. That’s where an RV battery disconnect switch comes into play. Let’s learn what these switches do, how to use them, and why you might want one if your rig does not have one.
What Is An RV Battery Disconnect Switch?
They’re devices that interrupt the flow of power from your house batteries to the RV cabin. It’s a valuable piece of equipment when it comes to storing your RV and doing maintenance. The switch typically resides in the battery compartment or a nearby bay.
How RV Battery Disconnect Switches Work
You can disconnect your RV batteries by removing the negative cable that connects the cabin of your rig to the battery bank. Doing so manually is cumbersome and leads to wear and tear on the battery cable and post.
That’s where an RV battery disconnect switch makes life easier. Instead of the cabin’s negative cable connecting directly to the battery bank, it connects to the disconnect switch. A second, usually shorter, negative cable then connects the switch to the battery bank. Engaging the switch stops the flow of power from the batteries to the RV cabin.
Why the Battery Disconnect Switch Is Important
The battery disconnect switch is important in increasing battery health and protecting yourself when doing maintenance and repairs. The ease of using a disconnect switch versus manually disconnecting the batteries makes it an important device to have in any RV.
If you were to ever have an electrical issue or electrical fire quickly switching the battery disconnect could prevent further damage. Because of this knowing where it is located and how to quickly get to it is critical.
Pro Tip: Use this guide on How to Safely Disconnect Your Car or Truck Battery to avoid a shock!
When Should You Use the Battery Disconnect Switch?
There are two primary situations when you should use an RV battery disconnect switch: storage and maintenance.
When you’re storing your RV without shore power, employ your disconnect switch. Even though you may shut off all of the appliances, they might still pull a small charge. Even when fully disconnected, batteries lose charge over time. This is usually negligible. But when batteries are left connected, appliances that are turned off still pull enough of an additional charge to drain and damage the batteries potentially.
What about if you are connected to shore power? Should you still disconnect the batteries. Well when disconnected the batteries will not charge so the answer depends. The answer will depend on what type of battery charger you have and what type of batteries. If you have lead-acid batteries and a multi-stage converter/battery charger with a storage mode, then no, leave it on. If you only have a 3 stage charger, then turning it off and using a battery tender would be better. And if you have lithium-ion batteries, then leave them on.
Using the disconnect switch to stop the flow of power when doing maintenance helps ensure your safety. You should disconnect the power any time you’re doing repairs, whether you have a disconnect switch or not. The switch just makes it simpler.
When replacing batteries its much safer to have a disconnect switch that is off than trying to wrench off the terminals with them on. This is because if your wrench makes contact with the RV frame and the batteries are connected you could cause a short. This could cause a bright spark that could blind, burn or cause a fire.
Does Every RV Come with a Disconnect Switch?
Most RVs now come with an RV battery disconnect switch installed, but not all. Older RV’s in particular did not have battery disconnect switches. If your rig doesn’t have one, they’re fairly easy to install. Even if you don’t want to or don’t feel comfortable installing one yourself, it’s relatively inexpensive to hire a professional.
Where Is It Located?
The disconnect switch is typically located next to the batteries or in a nearby bay. It’s also sometimes found in or engaged from the RV cabin itself. The switch should be located as the first item off the battery wiring before anything else is connected to the batteries, even the ground. This enables it to properly shut down the entire battery system.
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How to Install a Battery Disconnect Switch on an RV
Installation is easy. You simply connect the negative cable from the RV cabin to one side of the switch. You then connect a shorter negative cable from the other side of the switch to your battery bank, where the cabin’s negative cable was formerly attached.
Once you connect the cables, it will cut the power from the batteries to the cabin when the switch is dis-engaged. Most RV battery disconnect switches have mounting holes, making it easy to use screws or bolts to mount the switch next to the batteries or in a nearby bay.
Should a Battery Disconnect Switch Be on the Negative Or Positive Side of the Batteries?
I recommend installing battery disconnect switches on the negative lead.
Many RV’s come with the battery disconnect switches installed on the positive battery lead into the RV. This has been common practice for many years and it does work, however, installing it on the negative side has an additional benefit.
Primarily when replacing or working on the battery wiring, if the negative is not disconnected you can cause a short circuit if you touch the positive lead to the RV frame. This can be avoided by disconnecting the negative first or if the battery disconnect is installed on the negative lead the risk is mitigated.
Increase Safety And Maximize Battery Life
In our opinion, these switches well worth the investment. You should be able to purchase a simple disconnect switch for anywhere between $15 and $30. You could even do the installation yourself to save more money.
Using an RV disconnect switch is a great way to increase your safety, maximize your battery life, and get the most out of your RVing experience. This small investment can save your batteries and protect you when you’re doing maintenance. Do you have one?
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Read More From The Mortons:
Tuesday 16th of May 2023
Ok I'm new to this, so if I'm trying to charge my batteries, do I have the switch on, or off?
Wednesday 1st of June 2022
I do enjoy your articles. Lots of info. Thanks
Tuesday 24th of May 2022
We bought LotFancy to interchange a key style battery to start our caravan. I wish we had used this style the primary time because it is so much easier to use! The switch connects to the hitch and is operated by simply turning the knob. We love it, and it really saves battery life by letting you switch it off rather than leaving a number of the DC devices, just like the clock radio/CD player, running all the time. We recommend this switch.
Monday 24th of January 2022
The Ampper Am-CBS01 is the best battery disconnect switch for RVs on the market. This is an easy solution to keep our travel trailer batteries from getting discharged while in storage. I have never been concerned about its compatibility, either. The device works with 12-volt systems just as it does with 48-volt battery systems. I just drilled 4 holes and mounted it to the top of one of the battery storage boxes and routed the cables through the molded openings.
Tuesday 13th of July 2021
Do you recommend disconnecting Batteries from all solar mppt controllers as well as ALL dc loads such as trailer jacks that usually are connected directly to the battery? The switch in my trailer only shuts off dc to the inside of the trailer but does not completely isolate the battery?
Mortons on the Move
Thursday 3rd of March 2022
Yes having a switch to completely isolate the battery is good for storage replacing batteries and or solar work.