Solar and Wind Power for RVs
The use of solar panels, and to a lesser degree wind turbines, has taken off in the recreational vehicle community. There is interest in renewable energy to charge batteries for a variety of reasons. But DIYers are clamoring for more cost-effective products catered uniquely to the RV community.
Here, we run over some of the important considerations to make before opting for an alternative energy solution for your RV, including solar and wind power.
Why are people using renewable energy on RVs?
Renewable energy is a viable means to charge batteries because:
- It is cheaper than burning gasoline to run a generator, especially when you only need to draw a small amount of power for just a few appliances.
- If you are using solar/wind power, you don't have to worry about plugging into the grid at a campground to charge your batteries – so you can truly be out in the "boondocks"
- Generators are noisy
Solar for RVs – So how are people doing it?
For very detailed information on using solar panels to charge batteries on an RV, go to Handy Bob's blog and read "The RV Battery Charging Puzzle." What follows is a summary of Handy Bob's key recommendations and limitations regarding the use of solar panels to charge batteries on RVs. On Handy Bob's blog he goes into great detail about the components of his system, from types of batteries he uses to preferred charge controllers.
There is a lot of misinformation out there about RVs and solar panels, and some of the biggest purveyors of that information are those who are doing the wiring and set-up of solar panel systems. According to Bob, "If you can’t use your lights and appliances whenever you want to, day or night, your system does not work." However, based on his extensive documentation about the finer points of setting up a solar panel system on your RV, your system can work if you adhere to the recommendations summarized below.
- Measure your power needs first
- Make sure your batteries are fully charged!
- Use big enough wires, bigger than recommended.
- Think about where to put things
- Locate the panels so they are NEVER shaded.
- Buy a three-stage charge controller and set it to whatever the recommended voltage is from the battery manufacturer.
Buy a recording meter (Handy Bob recommends a Trimetric 2020 battery monitor, $190) and find out how much power you actually need to run various appliances. That way, you will not drain your batteries (because you can tell how many amps are going in and out) and you'll be able to properly size your solar system to your energy needs. For a lower cost solution, consider the WindyNation 100 Amp DC Watt Meter.
Use a recording meter to know how much charge your batteries have. Be sure you and your recording meter agree on what (how many volts) a fully charged battery is.
Handy Bob says that, "it is good practice to use one or even two sizes bigger wire than recommended to limit voltage drop."
Consider where to place charge controllers and inverters in relation to batteries. The closer, the better, and always use wire run length as the unit of measurement.
Be careful of air conditioners, antennas, and other things on your rig that might block the sun. If you choose to get hardware to tip your panels (which would be very helpful in the winter), make sure you purchase hardware that will allow your panels to tilt at least 45 degrees.
Consider our Xantrex C-Series Charge Controllers, including the C-35, C-40 or C-60. They are durable three-stage charge controllers perfectly suited for this application.
Solar for RVs – What are the limitations and common set-backs
- Undersized wires
- Wiring that is too strung out
- Inadequate charge controllers
- Extended periods of rain/clouds
A weakness mentioned by several people in the RV community is the use of undersized wires to carry electricity from the PV panels to the batteries.
The charge controller should be as close to the batteries as possible (in terms of wire-run length). Keeping charge controllers (and inverters) closer to the batteries minimizes losses in the system.
Many of the solar charge controllers out there are set at too low of a voltage to properly charge batteries or there is voltage drop in the wiring between the charge controller and the batteries.
If you are spending all of your time RVing in, say, the Pacific Northwest, you may want to consider wind power.
What about wind for RVs?
Wind is currently less popular in the RV community than solar power, but the high cost of gasoline in recent years is driving people to seek out alternate ideas, including increasing interest in deploying wind solutions. We believe it will become an increasingly popular option for a variety of reasons, not the least of which is that gasoline prices are not going down--ever.
- Set-up & take-down
A primary concern about wind turbines as a power source for RVs is that they are noisy and difficult to set up. There is reason to believe that with recent advances in wind turbine design, the noise and set-up problems can both be resolved. Pat Bosnich, of Every Miles a Memory blog says that, while parked in Cedar Key, Florida, with the turbine "spinning like mad" no one could hear it. The turbine made "less noise than the sound of the wind blowing through the palm trees."
Pat was also in the process of designing a mast that could be set up and taken down in under 10 minutes, so wind that might help get over the set-up concern.
- Cheaper per watt than solar
- When it's not sunny, it is often windy
Whether you choose wind or solar (or wind AND solar), there is energy to be gained from renewable sources to help you avoid using a generator and maintain your off-the-grid "boondocking" lifestyle in your RV.