All About Your RV, Motorhome or Campervan’s Electrical System

electrical system rv and motorhome

A handy guide to basic motorhome electrical maintenance

Your camper van’s electrical system may not be the most exciting part of owning a travel vehicle. However, knowing some basics can really come in handy when (not if) you experience an outage.

Just like your car, RVs, motorhomes and campervans have a complex electrical system. At times, problems can emerge, leading to inconvenient and uncomfortable issues that crop up while you’re on the road or at a campsite. The good news is that these problems can usually be avoided with a basic preventive maintenance routine.

Buying a new or used motorhome means having access to many of the comforts and conveniences of taking your home with you on the road. But many of these features require a solid working electrical system, which is why prior to taking off on your next road trip you should get acquainted with some of the basics regarding your motorhomes electrical system.

Importance of routine maintenance of your RV electrical system

The electrical system of your RV or motorhome is pivotal in enabling you to enjoy modern technology. It allows you to utilize functions such as overhead lighting, microwave and refrigeration. It also powers the fans for your HVAC system. Keeping your electrical system in great shape saves you from inconveniences and expensive repairs.

Motorhome Electrical System Basics

First, let’s begin by talking about the three different electrical systems within most RV and motorhome electrical system:

  1. 12-volt DC* automotive system – This system is responsible for how your RV operates (drives you from destination to destination).
  1. 12-volt DC coach system – This system is responsible for the fans (furnace, restroom, fan over the range), overhead lights, water pump, stereo and refrigerator (when it’s in the LP gas mode). This system gets its power from a 120-volt external power source hook up (home outlet or campground). The 120-volt DC/AC** will take in the power from the external source and convert a portion of it for your items requiring a 12-volt source. Your RV has a battery, which takes in the 120-volt DC/AC power and stores it for these items when the coach is not hooked up from an external source.
  1. 120-volt DC/AC coach system – This system is responsible for linking power to your RV’s refrigerator, microwave, roof air conditioner, and your 120-volt outlets (any appliances you bring to plug into your RV). This system gets power from an external source such as a home outlet or a campground.

*DC stands for “Direct Current”; this is the manner in which electrons flow. Certain appliances/fixtures in your RV will require power in the form of DC.

**AC stands for “Alternating Current.” In this type of flow, electrons will pump and contract power into a system. Certain appliances/fixtures in your RV will require power in the form of AC.

The basics of AC vs. DC

Your rig likely has 2 electrical systems. 

The alternating current (AC) is similar to the one at your home. Direct current (DC) works similarly to the one in your car. Your AC power is derived from an external source while your DC power is generated from the battery. The DC system powers mild functions like lighting and powering your fans. However, big appliances like microwaves and refrigerators are run by the AC system.

Your rig may have a converter that enables the AC system to charge the DC system. Also, it is common to find inverters in an RV. Inverters convert DC power into AC power.

RV Battery Basics

RVs and class B motorhomes have battery systems that can operate in areas without hookups (also known as “boondocking,” or camping in remote areas). These “house” batteries hold a power charge so you can operate your appliances and fixtures.

There are several different types of house batteries you can have installed in your vehicle. Depending on your patterns of use, you may use the manufacturer’s battery (the one that comes with the RV), or you may find yourself wanting another type.

The most common type of motorhome battery is a 12-volt RV/marine flooded cell lead acid battery. This type of battery holds a decent charge and will be just fine for the “vanlifer” who mainly uses their motorhome in campgrounds with hookups. These batteries can last you around two years, depending on your usage needs and preferences.

Pro tip: Just in case you find yourself in a situation where your battery is no longer working, we recommend storing an extra battery when traveling long distances in your campervan, RV or motorhome.

If you plan on spending a lot of time in your campervan without being hooked up to a power source, you may find that two 6-Volt deep cell batteries maintain a longer charge.

How to Care for Your Motorhome Batteries

Most rigs are outfitted with 1 or more batteries. Batteries are limited in terms of power in that they can’t run for long when multiple appliances are switched on.

Shore power becomes a source for your RV or motorhome when you plug your rig into an electrical grid. The amount of power to draw is measured in amps. Mostly, it is either 30 or 50 amps. Generators also act as alternative sources of power for your RV. The amount of power you draw from generators depends on their size.

Your RV or motorhome batteries are able to charge and discharge hundreds of times. However, people can damage their batteries and have to replace them prematurely. Avoid these common mistakes to help extend the lifespan of your battery:

  • Failing to charge your house batteries frequently or not charging them fully. This is the top reason why batteries need to be replaced. When batteries are discharging, acid and lead can create sulphate. This sulphate can slowly create a hard substance covering the positive and negative plates. Sulfation is the number one enemy to your battery. Keeping your batteries charged and watered when stored can avoid this process from happening.
  • Not adding water. Your lead acid batteries need water to avoid outgassing or electrolysis. Your battery will have vents to let out excess gas and water vapor. Submerging your battery’s lead plate will help prevent a breakdown. But be careful not to overfill beyond the split-level marker. Only use distilled water when adding water to your batteries (distilled = no salt or electrolytes).
  • Letting your battery fully discharge. When your battery reads 10.5 on the voltmeter, the battery is likely inoperable. Avoid letting your battery fully discharge by recharging every several weeks.
  • Neglecting battery terminals. Make sure that all terminals and cables are tight and clean. Be sure not to overtighten as well. Battery terminal protector spray can be purchased at an auto parts supply store and is helpful in keeping batteries clean and in good working order. You can also use a mixture consisting of diluted baking soda and water. Be sure to lightly rinse off with water after.
  • Overcharging your battery. While letting a battery fully discharge is bad, constant charging will deplete your electrolyte levels in your batteries and also contribute to an early failure. Try to find the perfect balance between overcharging and fully discharging your battery.

General motorhome electrical system maintenance tips

Now that we understand how the electrical system and batteries function, we are better placed to carry out a preventive general electrical maintenance routine for RVs and motorhomes. Below are some pointers.

Check fuses

When blown, fuses lead to loss of power. Keep some spare fuses around your van in case the need for replacement arises. Constantly check the state of your fuses and whether they are resettable or replaceable.

Choose your power cord wisely

Your RV or motorhome will likely either come with a 30-amp or 50-amp electrical system. The 50-amp electrical system is generally preferred as it protects the long-term durability of your appliances. It also facilitates quick charging.

However, some campsites may not have electrical hookups for 50-amp cords. In that case, you could invest in a “50-amp to 30-amp” adapter.

While connected to a power source, keep your cords as short as possible to avoid power drops. Also, ensure they are tightly fitted into the power source to avoid sparks. Before plugging your cord into the power source, you might want to consider using a polarity tester to confirm that the campsite wiring is safe to use.

Invest in surge protection

Some RVs and travel vehicles come with a built-in surge protector. If yours is missing, invest in an external surge protector. A surge protector guards your vehicle against power surges and helps you maintain the integrity of your electrical system.

Motorhome Converter & Inverter Basics

To recap:

Your RV, motorhome or campervan has important electrical systems that give you the ability to use appliances and other devices. For starters, your vehicle uses batteries to store power that’s taken from external sources (campgrounds, your home).

Your vehicle also has a converter to take power from the external source and send it to the proper battery system. Your campervan’s converter is an essential part of this process by doing the following tasks:

  • Taking incoming 120-volt power and converting it into 12-volt DC power
  • Distributing power to AC and DC systems in your vehicle
  • Keeping the house battery charged when your vehicle is connected to shore power

In addition, an inverter will take power from your house batteries (12-volt DC) and change it to 120-volt AC power. When no generator power or electrical source is available, your inverter can store power from your batteries to run appliances and fixtures.

Motorhome Amperage: An Overview

Depending on which motorhome or RV you have, your vehicle will have either a 30-amp electrical system or a 50-amp electrical system. Typically, if your vehicle is smaller and has lower load requirements, it has a 30-amp system. For larger rigs and coaches, a 50-amp system is more common.

Here are the important differences between 30 and 50-amp systems:

  • 30-amp – This system uses three prongs: a neutral wire, a ground wire, and a 120-volt hot wire. This system can take in enough power for smaller appliances (i.e. convection oven, small refrigerator, one roof air conditioner). This will give you 3,600 watts*** of power for your appliances and fixtures.
  • 50-amp – This system uses four prongs: a neutral wire, a ground wire and two 120-volt hot wires. This system can take in enough power for larger appliances and fixtures such as two roof air conditioners, large refrigerators, TVs, etc.

***Watts refers to overall power. If you’re concerned about blowing out or exceeding your vehicle’s electrical system, remember that watts is equal to amps multiplied by voltage (W=AxV). If you have too many appliances running, your wattage may be too high and you may risk damaging your electrical wiring.


Tackling electrical may seem daunting, but with sufficient research and a thoughtful approach you should have very few difficulties. And don’t be afraid to seek help from a professional if you don’t feel comfortable with attempting electrical system maintenance yourself. When unsure, consult the services of an expert.

Owning a travel vehicle allows you to bring the conveniences of home on the road. By maintaining your electrical system properly, you can enjoy your favorite creature comforts wherever you roam.

Looking for your next campervan? Classic Vans is the nation’s premier dealer of new and used class B motorhomes, conversion vans and other travel vehicles. For over 30 years, we’ve been family-owned and operated, specializing in delivering quality vans to every customer.

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