Surprisingly, there isn’t a comprehensive guide to RV electrical systems and what to expect. Fear not, you can still have your Netflix. Here’s a nice, simple breakdown for you.

For the most part, any full-time rig is going to have two different electrical systems; the 12V system and the 120V system.

The 12V DC System

This half of your RV electrical system runs off of a battery (or multiple batteries). It’s basically the same as your car.

What Runs Off The 12V system?

  • Lights
  • Slide outs
  • The furnace fan
  • Your fridge (if it’s gas)
  • Your water pump

Once your battery dies, so do all of the above until you recharge the battery.

What charges the battery?

  • Your truck, via the trailer wiring harness (if pulling a trailer)
  • Solar panels (if you have ’em)
  • Your generator (if you have one)
  • Shore Power (when you plug in to an external power source)

The 120V AC System

This part of your RV electrical system is just like your house. You’ll have the same kind of wall outlets you’re used to plugging things into at home. Typically, your big energy-sucks run off this system. Usually, it does not run off your batteries and is the big reason many folks are constrained to RV parks. When you roll up to a campground, you basically have a big extension cord that runs from your RV to an outlet that the campground provides. They call this Shore Power. Different systems have different amperage, and that goes for both RVs and campgrounds alike.

What Is Amperage?

Think of it like a garden hose. The wider the diameter of the hose, the higher the rate that water can push through, right? Well, that’s amperage. A 50amp service would be a fire hose, and a 30amp service would be a garden hose. If your rig has two AC units, it’s probably a 50amp rig because you need enough throughput to run both AC units at the same time. Typically, you’ll either see 50 amps or 30 amps. So, if you have a 50A RV, but the campground you’re staying at only offers 30A, you’ll need an adapter for the plug that connects the RV to the shore power.

Can I hook up to someone’s house?

Yep. They make little adapters that’ll allow you to plug in to a common extension cord coming from a house. However, keep in mind that you’ll be limited with what you can run, because the hose isn’t wide enough. Want to run your AC unit? Sure, go ahead but be ready to trip the house breaker every time your compressor turns on.

What Runs Off The 120V System?

  • Your AC Unit
  • Your fridge (if electric)
  • Your fireplace (if you have one)
  • Your television

What if I don’t have shore power?

This is where your generator comes in to play. You fire up the generator and plug the RV into that instead. Many motorhomes come with an on-board generator that’s all rigged up, and that doesn’t require anything more than the push of a button.

The other option is solar. With a proper solar setup, your 120V system does actually run off the batteries. You’ll need what’s called an inverter and a boat load of batteries to pull it off. Checkout our Solar Guide for a deeper explanation.