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RV Electrical Systems: Knowing Your RV 101

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RV Electrical Systems: Knowing Your RV 101

Camping with a recreational vehicle is a great way to experience nature and explore the wilderness without leaving behind the comforts of modern technology. 

Your RV is truly like a house on wheels. But this means you might experience some of the same maintenance issues with your RV that you might have in your home or even your car.

Don’t let this concern intimidate you, though. With little preparation and education, any camper can understand their RV electrical system and be ready to solve minor issues that might come up.

This quick and easy tutorial will explain your camper electrical system for you and make sure you’re prepared for a stress-free and hassle-free vacation.

Understanding Your RV electrical systems includes:

  • Electricity safety.
  • How electricity works in an RV.
  • How to plug into the campground pedestal.
  • Estimating the power demands of your rig.
  • Choosing the right components.
  • Basic RV Electrical maintenance to "keep your lights on".

How to Work With Electricity Safely

Before you begin any electrical work, it’s critically important to understand the dangers of electricity and how to keep yourself safe while working on your motorhomes power system.

Most of us, if we’re lucky, have only seen electrocution in movies and TV shows. The consequences of being shocked can range from a small tingling buzz to complete heart paralysis

Risks With Electrical Systems

Working on a travel trailers electrical system is unlikely to cause complete heart paralysis, which usually only occurs when the voltage is greater than 600 volts. Even so, there are dangers and potentially deadly risks when working with electricity, so be sure to take proper precautions.

The primary danger is the risk of electrocution. Electrocution means injury due to shocks, ranging from very minor to severe. But a secondary danger that comes with working with any electrical power source is the risk of electrical burns.

Both electrocution and electrical burns can result in death if you’re not careful, so be sure to heed all the advice provided by your motorhomes manual, as well as licensed mechanics and electricians. If these sources aren’t available, the Canadian Centre for Occupational Safety and Health (CCOSH) has excellent advice and safety procedures.

Safety Procedures for Working Electrical Systems

Conductors and Insulators

Electricity can only pass through materials called conductors. Conductors include wires, metal objects, water (in most cases), and, most importantly, the human body. 

Materials called insulators can stop the electrical current. Insulating materials include rubber, wood, glass, and plastic, among other things.

The most basic method to protect yourself from electrical dangers is through the use of insulators.

In most cases, electricity is trying to find a pathway from the source to the ground. If your body provides this pathway for the electricity, you’ll most likely suffer some electrocution or injury.

Many electrical injuries occur when the rubber casing around the wires and cables becomes frayed or split, and the wires underneath are exposed. Touching those exposed wires can result in electrocution.

Before beginning to work, check the cables for any exposed wires. Connectors, covered in electrical tape or wire caps, will also need checking. 

You can also protect your body from becoming a conductor with insulating protective gear. Rubber gloves and rubber-soled boots will provide protection, as well as standing on a rubber mat or a wooden ladder. You should be particularly careful not to stand in puddles or any other water.

Circuit Interruption

If you accidentally become a conductor, and the electricity finds a path to the ground through your body, most systems will have a breaker or circuit interrupter. These are designed to interrupt the pathway of electricity.

It’s important to understand that sometimes a breaker is designed to protect equipment and not for personal safety. If the breaker is designed to protect you, it will be called an arc-fault circuit interrupter (AFCI) or ground-fault circuit interrupter (GFCI).

Whether you’re working with the internal appliances of your electrical circuits or connecting your RV to external power outlets, you should first check to make sure it has an appropriate circuit interrupter for your safety.

How Does RV Electricity Work?

An RV most often draws power from its highly engineered “deep charge” battery. These 12-volt batteries are designed to power a limited number of appliances overnight. The battery then recharges during the day as the vehicle’s alternator converts mechanical energy from the engine into usable electric energy.

If the RV isn’t moving during the day, it’s usually connected to a campground pedestal, or “shore power.” These pedestals typically provide 220-volt, 50-amp electricity to quickly recharge the battery and even power many of the energy-intensive appliances inside, such as air conditioning.

Measurements

Without a background in electrical engineering, or training as an electrician, perhaps it’s difficult to understand the difference between these common electrical terms. A brief explanation might be helpful to describe what these terms mean.

Voltage is also known as “electrical potential.” It describes the difference in electrical charge between two points, typically between a power source and the neutral ground charge. A greater difference means a larger voltage, and this indicates a greater potential to drive the electrical current.

Amps, which is short for “amperes,” is the unit that measures electric current. Electric current is the movement of electric charge, and this is what causes electrical appliances to work. 

Electric current is also what causes burns and muscle paralysis, which has led to the famous phrase, “Current Kills.” Because of this fact, electrical fuses, breakers, or circuit interrupters are designed to break the electric connection if too much current is passing through.

Watts are the unit of electrical power. Electric power is calculated by multiplying voltage by current; or, more typically, current is calculated by dividing power by volts, since voltage is relatively constant and the appliance specifies the power requirements.

Watt-hours are a unit of energy, and RV batteries are usually rated by watt-hours. You calculate this by multiplying the power demand of your appliance by the time you need to use that appliance. For example, a 10-watt appliance, used for two hours, would consume 20 watt-hours. A typical RV battery stores between 100–1000 watt-hours.

Electrical Systems Within the RV

The first key point to recognize when working with fifth wheels or motorhomes is that your RV runs on two different systems: an external power system and an internal power system. 

When parked and plugged into shore power, whether, at home or a campsite, this external power is 120 volts AC power. When you’re camping, your RV runs off of your 12-volt DC system via the house battery.

This handy RV electrical wiring diagram shows RV wiring for dummies:

120-Volt or 12-Volt?

As we mentioned earlier, voltage is the electrical potential that motivates current. As you’d expect, a municipal connection to shore power provides a much stronger electrical current motivation. Your standard outlets at home, as well as shore power connections at a public campsite, both provide 120-volt electricity. 

But, this is only true in the United States and North America. If you travel to South America or somehow get your RV to an overseas location such as Europe or Asia, you should know that most of the other countries in the world use 220-volt power outlets. If you’re planning any overseas camping, it’s advisable to rent an RV in that country.

Regardless of your location around the world, though, your house battery will typically be 12-volts dc power. The only exception you may encounter is when someone has wired an electrical system with two or more 6-volt batteries (golf cart batteries) in series.

AC or DC?

AC stands for alternating current, while DC stands for direct currentAlternating current means that the current and voltage cycle between positive and negative very quickly (in the US, it switches 60 times per second). This type of current is more efficient to send over long distances.

Alternating current is only produced in power plants or generators, while solar panels produce direct current and store it in batteries. If you’re charging your RV battery from AC power, such as shore power, you’ll need a charger or converter (called a “rectifier”) to change this AC power to DC power.

Typically most of your RV electrical systems will be designed to operate from either AC power or DC power, with power outlets dotted around the interior for your appliances. There are two exceptions; (1) the water pump and interior lighting systems will (typically) be powered by the 12-volt DC system, and (2) for specific high-load requirements such as your air conditioning system (the other “AC”—don’t get them confused!) will be hooked up to the 110 AC system .

30-Amp or 50-Amp?

Depending on the power demands inside your RV, it might be either a 30-amp or 50-amp camper. 

Smaller RVs are usually 30-amp, and larger RVs may be 50-amp. You can quickly tell what kind of RV you have by the plug attachment – an RV 30 amp plug has three pins, while a 50 amp plug has four.

In a pinch, you can always plug your power cord into either type of amp service. All it requires is the proper dogbone adapter.

You can plug your 30-amp power cord into 50-amp service without any concerns. However, if you plug your 50-amp RV into 30-amp service, you should limit your electricity usage. If your combined appliance usage exceeds 30 amps, you run the risk of overheating and starting a fire.

Plugging In at the Campground

At some point, you’re sure to find yourself in front of one of these campground pedestals, also called a “shore power station.” If you’re looking at one for the first time, you might be confused about the different RV electrical outlets and switches. This section should help explain the pedestal and any other equipment.

Power Outlet Adapters

Campground shore power provides a variety of different current levels. To differentiate amps at the station, RV’s use various electrical outlets, these outlets may not fit your RV’s power plug, so you may need an adapter to plug in.

The adapters are often referred to as “dog bone” connectors because the two heads on a short cable resemble a dog bone.

Camco (55165) Heavy Duty RV Dogbone Electrical Adapter with Innovative 180 Degree Bend Design and Easy PowerGrip Handle - 15 Amp Male to 30 Amp Female, 12'

Now, dogbone adapters are safe for use as long as you aren’t exceeding the amp draw of the outlet. For example, if your RV has a 50 amp plug, and you use a dogbone adapter to connect it to a 15 amp power source (this is what your house outlets provide), you’ll be safe as long as you don’t draw more than 15 amps with your RV.

The power and current requirements for various RV appliances will be discussed later in this article.

Using Surge Protectors

Hughes Autoformer BX4370 Power Watch Dog 30 AMP Surge Protector (PWD30)

One of the most significant risks associated with RV power systems (other than shocking yourself) is that when you’re out in nature, there is a greater possibility of damage caused by lightning strikes. A lightning strike near a campsite can cause brief and powerful power surges that can damage or destroy your power system entirely. For this reason, surge protection is vital.

A surge protector is usually integrated into the dogbone adapter.

Check the Campground Wiring

Here is a diagram of the possible outlets you might find at a campground.

For safety reasons, you should always make sure that the outlet is clean and free of debris. You especially need to check the ground connection, shown with a “G” in the above diagram, to make sure it’s not obstructed or corroded. To be extra cautious, you can buy a Non-Contact Voltage Tester to ensure the station is grounded.

After checking the outlet box on the pedestal, you should check the connecting power cord for any damage or wear.

Don’t Have an RV Power Hookup?

If you aren’t camping near a campground with RV power sources, then you have a few limited options to keep your RV powered-up:

  • You can carry a diesel or gas generator with your RV. Generators like these usually consume about a gallon of fuel per hour and can be somewhat noisy.
  • You can recharge your RV battery using solar panels. Determining how many panels you need will be covered later in this article.
  • Your alternator will recharge your RV battery as you’re driving, so if you drive for long distances between camping nights, your battery may be charged when you arrive.

Electrical Demand: Estimating Your Needs

Before you set off for a camping adventure in the wilderness, it’s good to predict or estimate your daily power consumption. This way, you can make sure your battery is large enough to meet your needs, and avoid overloading your electrical connections in your RV electrical panel.

Know Your RV’s Appliances

Air conditioning, clothes washers/dryers, microwave ovens, space heaters, and water heaters are usually the most significant power-consuming appliances in your RV. You should only use these appliances when connected to shore power, or very sparingly when running on battery power.

Some of your appliances can draw 15 amps or higher. When using these appliances, it’s essential to know how many amps your shore power is providing. 

When connected to a house electrical outlet (15 amps), you may only be able to use one of these appliances at a time. Some electrical pedestals provide 30 or 50 amps, in which case you can operate a few appliances simultaneously.

The appliances that hog the most electricity (and their current requirements) are:

  • Air Conditioner (12-16 amps).
  • Water Heater (9-13 amps).
  • Electric Skillet (6-12 amps).
  • Hair Dryer (5-12 amps).
  • Microwave (8-13 amps).
  • Space Heater (8-13 amps).
  • Washer/Dryer (14-16 amps).
  • Furnace (12-13 amps).

Working Out Your DC System Power Requirements

Before traveling, you should check the power requirements of the appliances and equipment that you expect to use regularly during your trip. You should also estimate how many hours you plan to use each appliance.

Your battery will probably be rated between 30–200 amp-hours. The most expensive luxury RV batteries can be as high as 1200 amp-hours. The amp-hour rating of your battery indicates how much energy the battery contains.

By multiplying the amp requirement of each appliance by the number of hours that you plan on using it, you can calculate your battery capacity requirements. Keep in mind that you should only discharge your battery to 50 percent, and thus should have a battery with twice as much capacity as you require.

Example:

You have two interior light bulbs (1 amp each) that you’ll run for 2 hours, and a fan (4 amps) that you’ll run for 8 hours. You also have a small refrigerator (5 amps) that is running off of battery charge for 12 hours per day, and you use your microwave (12 amps) for 15 minutes each night.

Your battery system requirement is:

  • Lights: 2 * 2 = 4 amp-hours.
  • Fan: 4 * 8 = 32 amp-hours.
  • Refrigerator: 5 * 12 = 60 amp-hours.
  • Microwave: 12 * 0.25 = 4 amp-hours.
  • Total: 4 + 32 + 60 + 4 = 100 amp-hours.
  • You need at least a 200 amp-hour battery to safely power your RV.

Selecting Components for the Electrical System

Choosing the right components for your RV electrical system can be the first step in simplifying your RV maintenance, and even make possible RV wiring for dummies.

RV Deep Cycle Batteries

The house battery is the life and heart of your 12-volt direct current electrical system. It’s essential to choose a quality battery with enough capacity to meet your daily energy needs.

Battery Capacity

RV battery capacities are measured in amp-hours, and a 200 amp-hour battery will usually cost you around $350–$400.

A 100 amp-hour battery is much more affordable, usually around $170 from your local car parts store. Keep in mind, though, that you should only use 50 of the available amp-hours to maintain the battery’s full lifespan, and 50 amp-hours per night will severely limit what you can use your electricity for.

You can buy a 35 amp-hour battery for around $75–$80. With this limited capacity, you probably won’t be using anything electrical inside your RV other than interior lights and maybe a small fan.

Deep Cycle vs. Starter Batteries

Deep cycle batteries provide a smaller electrical demand for more extended periods. Conversely, your starter battery needs to provide an intense and short charge to turn the engine.

Many modern batteries are designed to do both purposes.

Types of Batteries

Traditional lead-acid deep cycle RV batteries are usually one of three types: Flooded, Absorbed Glass Mat, and Gel batteries. Newer lithium-ion battery technology is starting to infiltrate the RV battery market, but these types of batteries are not yet common or economically practical.

Lead-acid batteries hold their electrical charge between sheet lead plates suspended in an electrolyte solution.

Flooded batteries are composed of sheet lead plates fully immersed in an electrolyte solution. These batteries frequently need to have the electrolyte liquid refilled. This liquid is also vulnerable to freezing at low temperatures and also electrolysis, which can separate the water into hydrogen and oxygen gases if the battery is overcharged.

Absorbed Glass Mat (AGM) batteries use glass fiber mats soaked in electrolyte fluid between the electrode plates, instead of suspending the plates in the fluid. This prevents fluid from leaking, freezing, and evaporating.

Gel batteries use a gelling agent in the electrolyte solution to stabilize the fluid. This similarly prevents leaking, freezing, and evaporation. Both gel and AGM batteries are marketed as “maintenance-free” batteries because they do not need any extra fluid refilling.

12-Volt Batteries vs. 6-Volt Batteries

It’s highly recommended to use 12-volt batteries in your RV. This voltage is necessary to turn the engine and also helpful for operating interior appliances.

It’s possible to wire 6-volt batteries (such as golf cart batteries) in series to power your RV, but this is needlessly complicated and not usually a cheap solution.

Discharging and Recharging

To maintain the lifespan of the battery and prevent corrosion damage, you should never discharge your deep cycle battery more than 50 percent.

There are several ways to charge RV batteries:

  • Alternator charging.
  • Direct hookup to a municipal source (using battery chargers or converter).
  • Generator charging.
  • Solar panel charging.

Your converter or charger usually has an indicator light to inform you that the battery is fully charged. At this point, turn off the power and disconnect the battery by performing these steps in reverse order. Undercharging can lead to sulfation, and overcharging can also reduce the lifespan of your battery, so ensure you keep an eye on it.

Inverter/Charger vs. Power Converter

If your rigs system has a converter, then connecting your RV directly to shore power pedestals will charge your deep cycle RV batteries by “converting” the AC power to DC, while simultaneously, also providing power to your RV appliances. A battery charger, unlike a power converter, will only charge the RV battery without powering your RV appliances. 

If you plan to rig up solar panels or want to power anything from the 110-volt AC system while off the grid, then you’ll need to add an inverter to your motorhomes electrical systems. An inverter does the same job as a converter, but just in reverse – it will convert the direct current power into alternating current.

RV Generators

RV generators usually cost around $1000, and typically consume half a gallon to a gallon of fuel per hour. Unlike batteries, which measure energy in amp-hours, generators are measured in watt output. You can use the handy chart to estimate the watt need of your RV.

Monitoring Your Usage

An RV battery monitoring system helps to keep track of your battery’s usage and remaining charge. It functions much like your vehicle’s fuel gauge.

Solar & Wind: Renewable Energy Options

Instead of a generator, it’s becoming popular (not to mention environmentally-responsible) to use solar panels or wind turbines to power your parked RV and charge your RV battery. Sizing and estimating your solar panel requirements is like choosing a generator.

RV Electrical Repair and Maintenance

Troubleshooting your RV’s electrical malfunctions might seem daunting, but there are a few simple steps that even a novice can safely perform before consulting a professional.

  1. Check your fuse box. If any of your fuses have blown, replacing it might quickly solve your problem. Never replace your fuse with a higher-rated fuse.
  2. Check your battery. This includes checking connections, water level, and battery charge.
  3. Check your shore power source. If you’re at a campground, this may need staff attention. If you’re at home, check your outlets and breakers.
  4. Check your generator or solar panels. Your generator might cut off early if you’re low on fuel, and your solar panels might need to be realigned.
  5. Check your power draw. Turn off your most demanding appliances until things start working again. You may have unintentionally tried to draw more current than is available.
  6. Refer to the RV electrical wiring diagram in this article for extra insights.

Conclusion

Hopefully, this article has given you the confidence you need to maintain your RV electrical systems, RV wiring, and troubleshoot minor problems. We’ve found that even this basic understanding can be helpful for campers in almost every situation.

If you found this article useful, please feel free to share it with other campers, friends, and family members. If you have any more advice or questions, please add them in the comment section!

Last update on 2020-09-21 / Affiliate links / Images from Amazon Product Advertising API

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