We find that more and more people are reconsidering their RV solar needs. Call it a result of the cultural shift towards green energy, perhaps a function of adding flexibility to travel itinerary’s, or possibly just because its neat to power your stuff for “free”. There is a growing interest in RV solar technology, the equipment, and what it means to you as a RV’er. There really are two main ways to think about RV solar. First is the idea of trickle charging to keep your on board batteries ready to go regardless of how long you may have been sitting idle. The second is gaining faster in popularity and that is to install a system of components or a RV solar kit to create and store enough power to see a significant reduction in the need for a generator.
For anyone new to RV solar, it easiest to think of a RV solar system as a battery charger more or less. Anything that can run off your batteries can be run from a RV solar system. As you can imagine, RV Solar systems are especially helpful for boondockers and dry campers. A RV solar panel is much like a battery in that it supplies electricity at a certain voltage. A RV solar panel needs the sunlight to make electricity while batteries require a chemical reaction to do the same.
How Much RV Solar Power Do I Need?
When you wander around your local retailer looking for battery chargers, you may notice that many of them offer about ten amps. The good news is this is around the minimum necessary to charge a normal RV battery. You can expect a ten amp RV solar panel to offer a hundred watts in most cases. Going lower than that will typically mean lackluster charging performance. If you go higher then you should be able to charge additional batteries or charge the existing batteries you have at a more rapid pace.
The maximum power that can be derived from the sun is around 1 kilowatt per square meter of panel. When you consider that there are losses from clouds, angle, and other atmospheric factors you can expect a significant loss of efficiency. The math comes out to something around 100 watts per square foot is available for the taking. Then looking at the efficiency of a RV solar panel in general, it cant capture but a portion of that energy. You will find that it takes around a square yard of solar panels to get 100 watts in good conditions. When you measure up the space you have available on your roof or elsewhere you may find it difficult to capture the power required.
What is Trickle Charging?
When your RV sits for a prolonged period of time the battery systems typically begin to lose power. Regardless of if they are used or not. For many car owners this is the reason a battery is dead after letting it sit in storage for too long. The same principle applies to your RV. Its also important not to leave the batteries dead for long periods of time as this could cause permanent battery damage. All that is needed to avoid much of the pain associated with this battery phenomenon is a RV solar trickle charger. Not to mention that it will keep your batteries fully charged and ready to go when the time comes to use them.
You can take a small panel no larger than a dinner plate and connect the wires and battery clips. After a connecting it to your battery you will have it fully installed. Place the panel in the sun and voilà! There is a chance that if you have a more modern RV that you may already have one of these installed from the manufacturer. All this for the cost of an oil change.
If You Need RV Solar on Steroids
If you consider yourself a full-timer, boon-docker, or dry-camper then the chances are a standard trickle charger setup wont get you excited. Your left with the typical generator or you can integrate your RV solar needs in a way that offers more potency. You wont always be able to replace your generator as the sun has a way of being absent from duty when you need it most. But on those nice sunny days you can replace the generator depending on your usage needs.
As many RV’ers are quite frugal with their power needs, in some cases all that may be needed is 100 or so watts of RV solar panels and a few extra batteries. This should allow for moderate lighting, TV, and other electrical needs. These folks often use propane to do the heavy lifting of the fridge, heat, and any cooking. These days you can find these types of systems in a portable package to be used on demand. Permanent installations are also available.
Alternatively, you may have seen RV’s with multiple solar panels on their roofs that are producing upwards of 800 watts of power. Under these configurations you will typically find a half dozen or more additional batteries and an inverter producing a few thousand watts of AC power. These systems are powerhouses, quite literally. They are built to capture huge amounts of power from the sun, store it, and then convert it as needed in order to run all the gadgetry, appliances, and other power hungry devices your RV may house. These types of RV solar systems are not what you may call cheap, at $5,000 or more in many cases. Yet, these systems can enable you to spend many days without the need for power hookups or a generator.
Many look at the RV solar system decision from a “break-even” standpoint. Curious how long it take to make back their investment in savings from RV park costs and fuel. The answer sadly is a moving target. Rest assured however it doesn’t take much time at all at todays rising fuel and park rates.
This is debated in RV solar discussions but many consider solar panels a commodity. Purchase high quality brand names and try to get panels that have not been sitting for a long time (1yr). This allows you to compare panels based on watts alone. Many people compare by looking at the dollars it takes per watt or Dollar-per-watt. Take the cost and divide by the wattage and you have a simple number in which to compare RV solar panels. Try not to mix and match panels unless they have the same voltage. This can cause issues for your solar charge controllers.
Solar Charge Controllers
The controller is the command center for your RV solar system. At the most basic level it simply decides if the panel should be connected to the battery. In order to do that the controller will figure out if the solar panel is producing energy to be useful and that the battery is ready to store the energy. The solar charge controller’s purpose to to connect the panel to the batteries at the right time for both the battery and the panel.
They can read battery voltage, adjust the voltage, optimize power flow, figure solar panel production, and overall keep the RV solar system running efficiently.
The MPPT or maximum power point tracking controllers have improved the the way controllers interact with the different RV solar components. Essentially the MPPT controller is not only able to charge the batteries efficiently but they also control how to pull the most energy from the solar panel. You should consider it as an option if your serious about building a quality RV solar setup.
Who doesn’t like to know what’s going on? The ability to monitor your RV solar system varies widely with the quality and cost of the setup. Some systems use indicator lights, others list the voltage. Some even show the voltage of the batteries and panels. Even fancier versions can keep track of usage and provide the remaining capacity of your batteries.
Wiring is the backbone of your RV solar system. Luckily with the typical RV solar setup the amps are between 10-20 amps and the run is only 15 feet or so. That being said heavy duty wiring isn’t always necessary. Try to utilize 6-10 gauge wire which many would consider mid to heavy duty. Any wires that are exposed to the elements should be well insulated and secured to avoid movement or rubbing. Wires that are outside, such as the wires connecting the panels, need to have an insulation that can withstand the elements. All wires need to be tied down so they don’t flap and chafe.
It goes without saying that mounting your RV solar panels should be done with the highest quality hardware so that they are absolutely secure. Also worth considering are flexible solar panels that simply peel and stick. They come highly recommended by many RV’ers. Some choose to mount their panels flat, some on tilt brackets. To each his or her own we say. Just be sure to consider the loss of efficiency if the panels don’t face directly toward the sun. Leaving one or more panels loose or easily detachable also is a strategy used to alleviate the need to park in a certain area or facing a certain direction. All methods work, but each have trade offs.
This RV Solar Guide is meant to be general information. If you want to continue your research we encourage you to visit the links below to learn more.
- Trailer Life – RV Solar Power
- GoneWithTheWynns.com – What Can Solar Power Do For an RV?
- MarxRV.com – The 12 volt Side of Life
- MacSlab.com – Optimum Tilt of Solar Panels
- Good Sam Club – Do-It-Yourself RV Solar: What you need to know.
- JackDanMayer.com – RV Electrical and Solar