Understanding you campers electrical wiring can be very confusing. Use the RV electrical diagram we made below to get an understanding of what powers what and to learn how an RV electrical system works.
Understanding AC vs DC Power
RVs are powered by two electrical systems, AC and DC.
AC, also called alternating current, is what typically powers a regular brick-and-mortar home. We call it alternating current because the flow of the electricity isn’t unidirectional. The electrons rapidly flow back-and-forth. Light bulbs use AC power. Have you ever heard that lightbulbs aren’t a steady source of light? They look steady to the human eye, but in reality, light bulbs rapidly flash like a strobe light. This effect is directly caused by AC power changing directions. This behavior causes brief interruptions in power, which isn’t a problem for electronics with simple circuitry.
However, this type of flow isn’t naturally compatible with more complex electrical systems. For the most part, you can assume that it requires DC if it has a microchip. To make them compatible with AC, many of those systems, such as computers, come equipped with onboard AC to DC converters.
You might be wondering, “If DC is a more stable power source, why don’t we just use it for everything?” The answer is that DC is difficult to transmit over long distances, which is why AC powers the national grid. The specifics of the why aren’t pertinent to the subject of this article, but you can watch this video if you would like to know more.
Converters vs. Inverters
The AC can be transmitted, but it can not be stored in a battery. That’s one reason why we need both. We hook up the DC batteries to the more easily transmitted AC power source, and the AC is converted into DC power.
This conversion happens through the use of the aptly named converter. This is the same type of device that you will find on computers. It is just used on an RV-wide scale rather than a single device.
Many RVs also have inverters. They do the same thing as converters, but it is reversed. Inverters convert DC to AC. You can see examples of this by directing your attention to the RV electrical diagram at the top of the page.
As you know, some devices require AC and some require DC. Provided that there is a sufficient source of electricity, converters and inverters give an RV the flexibility to power all of its devices regardless of the power source, AC or DC.
- Converter: Converts AC to DC
- Inverter: Converts DC to AC
DC is for Priorities – AC is for the Extras
The most observant among you might notice that RV appliances and plumbing are all powered via 12-Volt DC. RVs have house batteries, so DC is the most accessible source of power for an RV. The essential devices pull from those batteries: fridge, slides, water pump, built-in lighting, etc. Of course, there are exceptions to every rule, but this is a reliable guideline.
Anything plugged into an outlet will receive the standard 120 Volts of AC that any household outlet would supply. If the RV is connected to shoreline power or a generator is running, the wall outlets will pull the needed AC power from that source. Otherwise, assuming that the RV is equipped with an inverter, 12 Volts of DC power will be pulled from the house batteries. That power will run through the RV’s inverter, and the produced 120 Volts of AC power will run whatever you connected to the power outlets: microwave, phone charger, laptop, TV, etc.
Sources of RV Power
An RV primarily draws its power from AC sources at “120 Volts.” In reality, the 120 Volts is more of a rounded estimate, so you might see a bit of variation in the stated voltages of shoreline power pedestals. In the past, power companies sent 100 volts through the lines, but the amount has changed a couple of times over the last century. For all intents and purposes, consider 100 volts, 110 volts, and 120 volts to be the same thing.
When hooking up to a pedestal, you will find two basic configurations:
- 30-Amp Socket: Its three-prong receptacle visually defines this socket-type. Only one of the prongs supplies power, and it provides the expected 120 volts at 30 amps. Using the calculation of “Amps(30) x Volts(120) = Watts,” this calculates the total provided power to a rough 3,600 watts of electricity.
- 50-Amp Socket: Due to its four-prong receptacle, the 50-amp socket provides significantly more power. Two of the prongs supply 120 volts each, and both of them deliver 50 amps. Using the same formula, “Amps(50 + 50) x Volts(120),” these pedestals will supply 12,000 Watts.
Unless you purchased an aftermarket DC generator and made modifications to the electrical system, the generator is also going to be a source of AC power. If you plan on doing any boondocking, this is going to be your noisy best friend. It will provide you with the same 120 volts of AC power that you receive from a shoreline connection.
Solar Panels (DC)
Solar panels are a great supplemental and sometimes primary power source for many RVs. They are both economically-wise and environmentally-friendly, and they quietly generate 12 Volts of DC power that can be fed directly into your RV’s batteries. Of course, the one downside is that these systems rely on a sunny day.
If a storm is brewing, those clouds are going to cut off your solar panels from the sun. Wind generators aren’t as popular as solar panels. However, they deserve more attention than they receive. They are a perfect addition to a boondocking setup. They are also cheaper than solar panels, but they are also a bit more challenging to implement.
Using the Engine’s Alternator
Many manuals advise using the generator instead of the alternator whenever possible. This advisement was written because running a high-powered alternator to charge house batteries can generate damaging levels of heat. While the heat can slowly damage the alternators, they are still very durable pieces of hardware. They should hold up for a long time.
Generators are more efficient at producing electricity, so they are an economical choice too. There really isn’t any benefit to using an alternator over a generator. Only rely on the alternator if you don’t have another option.
Energy Management Systems
You can think of these ingenious devices as a more intelligent circuit breaker. They do much more than that, but this works as a simple definition.
The power demands of an RV shift from moment to moment, and sometimes those needs exceed the power available from whatever campground pedestal is supplying the power. If that happens, it will trip the circuit breaker on the pedestal. You might make quite a few trips outside, which is an annoyance that nobody wants.
An energy management system can monitor the power being supplied and temporarily cut power to low-priority devices. When there is enough power available, those low-priority devices will receive that power. This will prevent those circuit breakers from tripping.
A more expensive EMS will measure how much power the pedestal is delivering and compare that to the RV’s electrical demand. If the pedestal doesn’t supply enough electricity, it will drain what it needs from the battery to make up the difference.
Conclusion On Camper Electrical Systems
We hope that the RV electrical diagram we included above is helpful to you and that it was able to answer many of the questions you had. We recommend that you always reach out to a trained RV electrician in order to make any modifications or to troubleshoot any part of your RV.