Solar Power For Your RV - What you need to know

have you been considering a solar install on your RV, but just aren't sure what is involved or where to start? You are certainly not alone. The price of solar continues to come down and more RV owners (especially full timers) are trying to understand what their options are. In this article I'll address some farely common misconceptions and questions people have.

Having electrical independence is awesome! Solar has greatly enhanced our RVing experience and expanded our camping options.

How Can You Benefit From Solar?

The only time you will benefit from solar is when your RV is disconnected from shore power. There is no reason to have solar on your RV if you primarily stay in full-hookup RV parks. If you prefer to camp in areas where there are no power hookups, then solar may be worth considering.

When not on shore power or generator, your batteries become your primary source for DC power. Onboard or portable generators do a good job powering your RV but require a steady supply of gasoline to run. They are also known to be a bit noisy. A solar charging system requires no gas, makes no sound and can charge your batteries for hours and hours unattended as long as the sun is shining. In fact the sole purpose of solar panels on an RV is for battery charging.

A common misconception is that solar panels will power your RV. While this is not entirely false, it is a mistake to think of solar panels in that capacity. As I've stated the primary purpose for solar panels on an RV is to recharge your battery bank when your RV is not connected to shore power or powered by generator.

Why don't RVs Come With Solar?

Solar charging systems are not standard equipment on most RVs as they only benefit RVers who camp for days at a time in areas where there are no power hookups. So solar remains a custom option like having a satellite dish installed. Many RV manufacturers will pre-wire for solar panels to simplify the process of running cable from the roof into the RV.

How will I know if solar is right for me?

If you are a new RV owner, I recommend using your RV for a while before making any major upgrades. Over time you will figure out what your camping preferences and limitations are. You'll then be in a better position to decide whether an investment in solar is something you'll benefit from. Seasoned RV owners, on the other hand, will probably know whether solar is a necessary feature for them to have when purchasing a new RV.

If you think camping off-the-grid is something you're interested in, then I encourage you to try it out first before making any kind of significant investment in solar or generators.

Our Story

When we first started RVing, we primarly stayed in RV parks. We usually didn't even consider locations that did not have full-hookup sites. Over the years, our preferences have changed. We still stay at RV parks periodically, but prefer to seek out more scenic locations.

There are many beautiful campgrounds located on public, National Park, or State owned land. Camping at these campgrounds is inexpensive and often free. However, what you gain in beautiful scenery and solitude you lose in amenities. So having a totally self-contained and self-sufficient RV prevents us from having to sacrifice much. In fact we can function quite well off-the-grid without campsite amenities. This has allowed us to expand our camping options, be more spontaneous, and even save money in the process.

Do I still need a generator if I have solar?

Don't ditch your generator for solar. You will still have an occaisional need for a generator. For instance, you may need to fire up your air conditioner, heater or other power hungry appliance. Your solar array isn't going to generate much power when when sun exposure is limited by tree cover or on stormy days. In those instances you may need a generator as a backup to recharge your battery bank. In place of an on-board generator, some keep a small portable generator on-hand (like this one) solely for the purpose of battery charging.

There are limited cases of folks who have abandoned their generator completely and have made the necessary adjustments for living solely off of solar. As for us, we have less of a need for a generator since installing solar, but we still rely on it at times. We enjoy having solar as our primary source of battery charging, but still enjoy the security of knowing the generator is ready and waiting when we need it. We also boondock only in locations with a moderate climate. Extremely hot and humid climates are generally not optimal for boondocking with solar.

What can I power with solar?

The solar panels on your RV are used mainly for battery charging. Therefore, the amount of power (electrical load) you can draw is determined primarily by the capacity of your battery bank and inverter, and NOT by the amount of solar on your roof. This is a common misconception people have when they ask "how many solar panels to I need to run my whatever?" Instead they should ask "how much battery capacity and what size inverter do I need to run my whatever?"

The short answer

Lights (preferably LED), laptop computers, radios, fans, TVs, water pump and other small items can be used while on battery/inverter power. In some cases small coffee makers, low power microwave ovens, toasters, and low power hair dryers can be used for very short periods depending on your battery's state of charge and size of your inverter.

I put my inverter to the test to see if I could make coffee and microwave popcorn. Watch the video and see what happened.

High power consuming components like air conditioners, heat pumps, space heaters, or water heaters generally require too much power for a standard RV solar/battery/inverter system to sustain. Power hungry components such as these will rapidly drain your RV batteries if used on battery power alone. For this reason, most RVers who rely on solar relocate throughout the year to sunny locations that have moderate climates where keeping cool means opening windows and/or turning on an electric fan.

The RV Geeks show us how to keep cool in the desert and still extract as much solar energy from sun as possible. Watch The Video

The long answer (Determine how much power you need?)

You first need to estimate what your power needs are. Size your battery bank to match your estimated daily power consumption. Consider a typical 24 hour period. What electrical items will you use and for how long? Determine the amount of current (in amps) that each piece of electrical equipment uses. Finally add it all up and compare it to the capacity (in Amp Hours) of your battery bank at full charge.

Once you've determined the size of your battery bank, you can determine how much solar you need to adequately charge it. A simple way to do this is to apply the 1 Watt to per Amp Hour rule. Simply put, make sure you have as many watts of solar as you do amp hours of battery capacity.

For example: A 400 Amp Hour battery bank will need roughly 400 Watts of solar. This is just a rough measure to get you in the ball park. You should also take into account the efficiency of your panels, amount of sun in your area, cable size/length, and power loss between your solar panels and batteries (i.e Voltage Drop). I add 20 percent to the solar estimate to account for the fact that I live in Pacific Northwest where it is cloudy much of the time.

That should get you off to a good start. When you are ready for more, these articles will help you take it to the next level.

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