Have you been considering a solar install on your RV, but just aren't sure what's 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 you may 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. If occaisional boondocking is your thing, then a portable solar panel kit may be all you need to benefit from solar and avoid a potentially costly permanent installation.
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. The noise levels can also disturb nearby campers. 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. Consider starting out with a portable solar panel kit. There is no permanent installation required and they provide plenty of power to keep your batteries charged. Just store it when you don't need it. If you decide to expand to a permanent solar install, your portable kit will still come in very handy.
Solar Has Changed How We Use Our RV
When we first started RVing, we primarly stayed in RV parks. We 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.
At first my wife was a bit uncomfortable with the idea of being off-the-grid and having to sacrifice too many creature comforts. These days we don't have to sacrifice much while off-the-grid and she is totally on-board with boondocking without hookups.
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 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 consumers like air conditioners, heat pumps, space heaters, or water heaters generally require more power than a standard RV solar/battery/inverter system can provide. Power hungry components such as these will rapidly drain your RV batteries. For this reason, most RVers who rely on solar relocate throughout the year to sunny locations that have moderate climates. Keeping cool means opening windows and/or turning on an electric fan, not running an air conditioner.
Is it possible to run an air conditioner off of an RV battery bank? Yes it is. Is it a practical solution? No, not at this time. As the price of off-grid lithium battery systems continue to fall, we may start seeing lower powered AC units for off-grid RVs. For now, I'll stick with a good 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 (Experiment and determine how much power you need?)
The best way to figure out what your needs are is to just go do some dry camping for a few days while measuring your power usage. To get an accurate indication of your state of charge, you will need a battery monitoring system. Without one, you'll simply be guessing and probably guessing wrong. Simply looking at your battery voltage or level gauge installed in your RV will not give you an accurate measure of your battery state of charge. So this is an essential first step to figuring out how much power you need while out camping.
Take your RV out dry camping and watch that battery monitor. You won't need solar panels for this experiment. Simply use your RV and see how long it takes you to get down to 50 percent of available capacity (if using lead acid batteries). Can you make it through a 24 hour period? When you reach 50 percent, well that's all you've got. It's time to recharge your battery bank.
Take note of what equipment you've used and for how long. If you need more power, add more battery capacity and try again. Try to get through a good 24 to 48 hours before you need to recharge. Everybody's needs are different, but having enough battery capacity for one or two days is a good benchmark to start with.
Keep that 50 percent of battery capacity in mind if you are using lead acid batteries. That is your maximum available capacity for lead acid batteries (flooded and AGM). For example, if your 200 amp hour battery bank gets down to 50 percent in 24 hours, then you've used approximately 100 Amp Hours of capacity during that time. So if you need 200 amp hours to live, then you'll need a 400 amp hour battery bank. Once you figure out how big your battery bank needs to be, you will have a good idea of how much solar you will need to keep those batteries charged up.
A simple way to estimate how much solar power you'll need is to apply the 1 Watt to per Amp Hour rule. Simply put, your maximum solar output (in watts) should equal your battery capacity (in amp hours).
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 recomend adding 20 percent to the solar estimate to account for these factors.
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.