When you roll up to the RV park and go to plug into shore power, you might ask yourself: do I need to disconnect my battery first? Your RV already has a battery bank after all, is it dangerous to have two sources of electricity at once?
You usually don’t have to disconnect your battery when plugged into shore power. But there are a few unique cases where you might want to disconnect.
First, let’s learn a bit more about your RV’s electrical systems. Then we’ll take a look at when you should disconnect your RV battery.
Your RV’s Two Electrical Systems: AC and DC
Your RV has two separate electrical systems, one for AC power and one for DC power. But what’s the difference?
DC stands for “direct current.” With DC power, the electricity flows in only one direction. Most batteries, including the ones in your RV, use DC power. And in most cases, DC power has a voltage of about 12 volts.
Your RV’s DC power system is powered by your RV’s battery bank. This system powers important things in your RV like lights, slideouts, and certain appliances.
AC stands for “alternating current.” With AC power, the current changes directions rapidly back and forth 50 to 60 times a second. In North America (and in much of South America), AC power has a voltage of about 120 volts.
AC power is what comes out of the wall outlets in a typical home. Most consumer electronics require AC power to run properly.
Your RV’s AC power system is most commonly powered by a shore power connection. This system can power your consumer electronics and any non-DC appliances in your RV.
Converts & Inverters
Converters change AC power to DC power, and most RVs come with one installed. When plugged into shore power, your converter can charge your batteries and provide power to your DC devices.
Inverters change DC power to AC power. They don’t come standard on most RVs but are still common and very useful. The inverter lets you use the power from your batteries for your AC devices, even without a shore power connection.
When Should I Disconnect My RV Battery?
So, should you disconnect your RV battery when you connect to shore power? Generally speaking, no.
There are some reasons to disconnect your RV battery, but being plugged into shore power usually isn’t one of them.
When you connect to shore power, your RV’s converter makes use of that power to charge your batteries. It also provides DC power directly to devices, preventing your battery from discharging.
3 Reasons to Disconnect Your Battery
There are only three real reasons you’d disconnect your battery when on shore power:
- Your RV has an old, inefficient converter without overcharge protection. In this case, disconnecting the battery can prevent overcharging.
- You want to charge the battery with a separate smart charger.
- After your battery is charged, disconnecting it while you’re on shore power can slightly improve the battery’s lifespan.
In any other situation, your batteries should stay on with a shore power connection.
But that doesn’t mean there’s never any reason to disconnect your batteries. In fact, many RV batteries come with a battery disconnect switch or have one installed aftermarket. But why would you use a battery disconnect switch?
The main reason is to reduce battery discharge when you won’t use your RV for a while. Your electronics still draw a small amount of charge, even when they’re off. Disconnecting the battery prevents this, although the batteries will still discharge, just much more slowly.
So, if you expect to be away from your RV for a long period, such as when you put it in storage, disconnect your batteries.
Bottom Line: You Don’t Need to Disconnect Your RV Batteries While Plugged Into Shore Power
Your RV’s electrical system can be a bit intimidating and it never hurts to have an abundance of caution. But in this case, there’s no need to worry. There’s no danger or issue with keeping your batteries connected while you’re plugged into shore power.
In fact, it’s perfectly normal, and your RV is probably already equipped to handle this situation. Your RV’s converter will take the AC power from your shore connection to charge your batteries and power your DC devices.