If you’ve seen or heard of an RV battery disconnect switch before, you might have asked yourself: why would I need one?
RV battery disconnect switches are used to disconnect your batteries from your electrical system and may be useful to have when storing your RV or electrical work. You might also use one if you have an old converter or an external battery charger.
So how do RV battery disconnect switches work? And what are all the reasons to have one? Let’s take a look.
What’s an RV Battery Disconnect Switch?
An RV battery disconnect switch does exactly what it says on the tin: it disconnects your battery.
As you might already know, your RV has two electrical systems: AC and DC. Your AC electrical system is powered by shore power or via battery using an inverter. Your DC system takes power directly from your batteries.
How Does a Battery Disconnect Work?
The battery disconnect on an RV separates your battery from your electrical system. It works like any other electrical switch, such as a light switch.
Usually, wires are attached to two metal lugs on the back of the switch. When the switch is in the off/closed position, electricity flows through it as normal. But when you switch it to on/open, the circuit is broken and electricity stops flowing.
Some RV battery disconnect switches also go directly on the battery terminal. Typically, these work using a metal “blade” that can be lowered and raised. When it’s lowered, it makes contact with another metal part, allowing the current to flow.
Do You Need an RV Battery Disconnect Switch?
So why have an RV battery disconnect switch? There are a few different reasons.
When Your RV Isn’t in Use
The main use of an RV battery disconnect switch is when you’re putting your RV in storage or otherwise not using it for a while.
Even when you aren’t using them, any electronics attached to your batteries will draw a small amount of power. If your electronics stay connected and you don’t charge the batteries, they’ll eventually discharge completely and potentially be damaged.
Using an RV battery disconnect switch prevents your battery from rapidly discharging when not in use. This is especially useful for part-timers and weekend warriors, whose RVs can go weeks or even months without use.
In a similar vein, a battery disconnect on your RV can also help you conserve power while boondocking. Without the extra drain on your battery, you’ll be able to stay out longer without running out of power.
However, it’s important to keep in mind that, even when disconnected, your battery will still discharge. Disconnecting it will greatly slow down this discharge, but not stop it completely.
When Using an External Battery Charger
Another reason is that you want to use an external battery charger, rather than your built-in converter/charger. These smart battery chargers can charge your batteries much quicker than your converter/charger can.
Lastly, you may want to use a disconnect for safety when doing electrical maintenance. An RV battery disconnect switch will keep you safe from shocks and other hazards.
How to Install an RV Battery Disconnect Switch
Installing an RV battery disconnect switch is fairly simple and you won’t need an electrician’s license to figure it out. That said, always read any manuals, instructions, or RV disconnect switch wiring diagrams that may be included. And if you’re still feeling uncertain, it never hurts to enlist the help of a professional.
Before you start installing, there are a few things to get together.
- First, unless your switch goes directly on the battery, you’ll need some extra cables to connect your disconnect switch. As a general rule of thumb, you should try to match the wire gauge to your existing cables.
- You’ll also want a socket wrench or other tool to tighten the lugs on your disconnect switch. Depending on how you mount your switch, you may also need a drill to make holes for mounting hardware.
- One final thing for clarity: when the switch is “on/open”, this refers to the state where no electricity is flowing. When it’s “off/closed”, this is when electricity is flowing. So, if the switch is on, the electricity is off, and vice versa.
With no further ado, let’s look at how to install a battery disconnect switch.
1. Disconnect Your Battery
Before doing anything else, disconnect your battery, otherwise, you put yourself at risk of electric shock.
Always remove the black negative wire from its post first, then the positive wire. The negative side is grounded to your RV’s frame, so there’s no chance of sparks. But if you disconnect the positive side first, you’ll be at risk of sparking.
This is also a good opportunity to clean your battery terminals. If you have a lead-acid battery that requires it, it’s also a good chance to check fluid levels and top off if necessary.
2. Connect Your RV Battery Disconnect Switch to the RV
With the battery disconnected, you can now connect the RV battery switch. When installing the switch, make 100% sure it stays in the on/open position at all times.
Generally, it’s recommended to install the switch on the negative side of the battery. However, using the positive side will still work. For this guide, we’ll install on the negative side, but the process is otherwise the same.
Run your negative (black) wire from the RV side to one of the lugs on your switch. Use your socket wrench to tighten it.
Next, connect the wire for the battery side to the switch the same as the other wire. However, do not connect this wire to the battery just yet.
If your switch mounts directly to the battery post, simply place it on the negative terminal. Again, ensure the switch is open. Then tighten it in place and skip straight to step 4.
3. Mount your RV Battery Disconnect Switch
Before getting everything connected and the energy flowing, you should mount your switch in place. It’s recommended to plan this out before you begin the install process, and if you need to drill, do that beforehand as well.
If your battery has an external box or lid (not the lid where the battery posts are, but one on top of that), this is a popular place to install the disconnect switch. You can also install it on the wall in your RV somewhere, such as in the battery compartment.
Mounting can be done with hardware, and the switch will often include some for you to use. If the mounting surface is smooth, you can also use heavy-duty double-sided tape or command strips.
4. Complete the Circuit and Test it Out
Once everything is in place, you can complete your circuit and test that everything works correctly.
Ensuring the RV battery switch is still in the on/open position, connect the positive wire to the positive post. Then reattach the negative wire to the negative post.
Now, you can switch to off/closed and engage your batteries. If everything is connected properly, your lights and other 12 volt electronics should now work properly.
An RV Battery Disconnect Switch is a Handy Tool to Have
With an RV battery disconnect switch, you have an easy way to disconnect your RV batteries anytime you need to.
Installing an RV battery disconnect switch is easy and just requires attaching a few wires and mounting the switch. Once it’s installed, all you have to do is flick the switch and boom! Your batteries are disconnected.
Do you have a battery disconnect on your RV? Do you need one? Share below in the comments.
Jennifer lives with her husband in a 29′ trailer in Mexico. She is one half of DashboardDrifters.com and the founder of RVSpotDrop, a web service for full-time RVers. Jennifer Jennings has been RVing for 2+ years and writing about the RV and Van Life for 2+ years. Jennifer specializes in topics such as Lifestyle, van life, campgrounds features, destination features, and product lists.