When RVgoers first realize they have a battery disconnect switch, the first question usually is: “Should I disconnect my RV battery when plugged in?”
And that is a valid question. Since RV manufacturers install a battery disconnect switch, it must mean that you need to use it. Right? The truth is, sometimes you want your disconnect switch “on,” and other times, you want it “off.”
This post will review when you want your battery disconnect switch on or off, including:
- When the disconnect switch should be ON
- When the disconnect switch should be OFF
- Advantages and disadvantages
Below is your quick guide on the different scenarios into whether you will want your battery disconnect switch on or off. Since each switch setting has its own advantage or disadvantage, check what you want to accomplish to determine whether to leave it on or off.
Table of Contents
- Shore Power
- RV Converter
- Solar Panel
- Tow Vehicles
Most of us start at the RV park by leveling our travel trailer, extending our slides and awning, and then plugging into shore power. All those tasks, such as extending the slide or the awning, are powered by DC power from your battery. In fact, most of your RV gadgets and safety features are all run by your RV battery or DC power. For a complete list, visit my post on what runs on a battery in a travel trailer.
Shore power is AC power. This is just like your household power. It will run RV appliances such as your air conditioner or microwave. But for things like your lights and slide, that is all powered by your RV house battery in DC power.
Switch ON: Operate RV Battery
When you want to function any 12 volt power from your RV battery, you must have the RV battery disconnect switch in the ON position. By keeping the switch on, you are allowing power flow from the RV battery to the RV. This will allow the DC battery to power things such as your lights, slide, inverter, and power awning.
An RV converter is simply a battery charger or battery tender. It takes the AC power from Shore Power and “converts” it to DC power for your battery. As you use lights and other battery items, the RV battery starts to drain, and you will eventually have a dead battery.
However, an RV converter acts as a smart charger or a trickle charger to the correct battery voltage. It keeps providing the power flow to your deep cycle battery to keep it fully charged and avoid that dead battery.
Another note is that your converter will operate the DC-powered items in your RV without a battery. This is helpful if you have a battery failure and need to operate things like slide on shore power. For more information, visit my post on whether a converter works without batteries.
Switch ON: Battery Charger
Leaving your RV disconnect switch on allows your coach battery to be charged and stay fully charged. Keeping your RV battery fully charged always gives you the battery voltage needed. The advantage is that it reduces the chance of battery failure and can extend battery life.
I recently upgraded my RV to have a solar panel. I boondock a lot, and having that solar panel has really reduced my need to run my generator for DC power. My setup was pretty easy: a solar panel, controller, and plug-in adapter connecting to my battery.
To harness that solar power, I needed to ensure that the power from the solar panel was making its way to my battery. As I double-checked my positive and negative lead to ensure I was getting power, I noticed the negative lead connected to the battery cut-off switch. Realizing this, had I had the disconnect switch off, it would have cut the power to the battery terminal, and all that energy would have been lost!
Switch ON: Solar Power
If you have a solar panel, you will need your disconnect switch on to get that power to your battery. The power will go from the panel to the battery by leaving it on. By turning it off, the negative battery cable will be disconnected and won’t charge your battery or have power from the solar panel.
Did you know that your tow vehicle provides power to your RV when on the road? As you plug in your 7-pin or 4-pin connector to your tow vehicle, DC power is provided while you drive. For more info on how this works, visit my post on charging your trailer battery from 7 pin connector.
I really like this advantage because as I drive to the RV park, my RV battery gets fully charged, and I can set up my travel trailer quickly without needing to plug into shore power.
Switch ON: Tow Vehicles
As you tow your travel trailer or RV, keeping the battery switch on will allow your battery to charge while you are driving. This is a great advantage for starting your trip with a fully charged battery.
We reviewed a lot of why you should leave your disconnect switch on. But when is a situation that I would want to turn it off? It is a switch, so there should be a time and place when you would want to have your battery cut off.
The main situation in which you want to have your switch off is during any period of storage. This can be between trips or for any off-season or winter storage.
You would want to disconnect the battery during storage to avoid a dead battery. Even when your RV is just sitting there, not being used, power is still being consumed – this is sometimes called a parasitic battery drain. An appliance such as your CO2 detector, radio, and thermostat all continually draw power whether you are using the RV or not. After a while of this power draw, you will eventually end up with a dead battery.
This is especially true for any off-season storage. I noticed that it takes my RV just about two weeks for my battery to drain down just by sitting there. Keep in mind, I have a second RV battery and they are fairly new. So for any off-season storage, you definitely want your disconnect switch in the off position.
Switch OFF: Storage
Whether you have a regular lead acid battery or a longer-lasting AGM battery, you will have a dead battery eventually when your RV is stored for a period of time.
Turning your RV disconnect switch off during storage will save your battery from draining when not in use. I suggest that the battery cut-off switch be placed in the off position for even short storage periods (at least a week).
One disadvantage to this is that it cuts off all power to your RV. So if you have a clock radio with the time, you must reset every time you use your cut-off switch …sorry!
The best practice is to remove your battery from your RV for long periods and keep it on a battery tender or trickle charger. Extreme hot or cold is not good for a battery. And if you are not using the RV for a while or season, I suggest you take the time to remove and store the batteries in a conditioned area.
Another time you want to turn the switch off when you are doing electrical repairs. Safety is a top priority when working on your RV, and you should cut the power off when doing any electrical work on the travel trailer.
Switch OFF: Repair
When performing any repairs, put your switch in the off position. This will disconnect the negative side or ground and cut the power to any electrical device you work on.
So, should your battery disconnect switch be on or off? The short answer is, “It depends.”
When connected to shore power, having the switch “on” is crucial to operating the 12-volt functions powered by the RV battery, such as lights, slides, and power awnings. Similarly, keeping the switch on during travel charges your battery via the RV converter, ensuring a steady power supply to critical devices.
Furthermore, if equipped with a solar panel, leaving the switch on enables the panel to recharge the battery effectively. On the other hand, turning the switch off is recommended during storage periods, including off-seasons or breaks, to prevent the battery from draining due to continuous power consumption by devices like CO2 detectors and thermostats. Disabling the battery disconnect switches is also essential during electrical repairs to guarantee safety by cutting power to the components you are working on.
Tony is an avid camper and RV traveler. He fell in love with camping on his first RV trip with his wife over 25 years ago. Tony loves sharing lessons learned and tips about RV maintenance and safe traveling.