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Last Updated on August 24, 2024 by Paul Clayton
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Easily Get RV Solar Power On Cloudy Days
Many RVers are increasingly turning to solar energy as the main power source or a complementary option.
And it’s easy to see why. Solar power is free; it provides the freedom to camp anywhere and makes dispersed camping off-grid much easier.
Solar energy, however, also has its fair share of downsides. The biggest one, according to most RVers, is its efficiency, especially in cloudy, overcast weather conditions.
But how bad can it be?
In this article, I’ll share everything you need to know about the performance of RV solar panels in cloudy weather. I’ll also expound more on how you can improve the RV solar power efficiency in less desirable weather conditions.
Read on!
Do RV Solar Panels Work on Cloudy Days?
Yes, RV solar panels work on cloudy days but only generate 10 to 25% of the typical energy output. They don’t “work just fine” and generally produce less current on cloudy days, but they’ll still produce some energy.
For example, my RV solar panels “work” even at night when I’m parked under Walmart streetlamps, but it’s nowhere near the amount they would generate in full sun. They also generate less energy during winter, when there’s less direct sunlight.
You must understand that it’s usually daylight, not sunshine, which usually powers solar cells. Modern RV power cells are incredibly sophisticated in technology and can work through different weather conditions, such as hail, rain, snow, and sunshine.
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Even then, I must reiterate that while most portable RV solar panels can work throughout the year, they usually decrease performance if the conditions are cloudy.
The reason is the solar cells on each panel usually absorb energy from the sun, and therefore, when the conditions are cloudy, they receive less amount of energy it creates. My rule of thumb regarding solar remember is that the less the shadow over a solar panel, the better.
Edge-of-Cloud Effect
Many RVers usually assume RV panels function optimally in hot, sunny weather. It’s true to some extent, but too much heat may compromise the efficacy of the RV solar panels by 10-25%.
Extreme conditions may even degrade the panels, especially when temperatures go past 25°C. And this is why most manufacturers usually specify their solar panel output at a panel temperature of 25°C.
There’s a phenomenon known as the “Edge of Cloud Effect,” which can see your RV solar power spike in overcast conditions.
The Edge of Cloud Effect, also known as Cloud lensing, occurs when the sun’s irradiance is higher as a cloud passes than it would be on a clear sunny day.
It happens for two main reasons: The first one is that the water and ice molecules inside the clouds reflect and refract the sun rays for extra irradiance, more than direct sun rays. Therefore, the sun’s rays are magnified as they break through a cloud, creating a much higher electrical output.
The other reason is solar panels will generally perform optimally when shaded. Shaded solar panels are cooler, and the cooler the panel, the more efficiently they operate.
A perfect example of this effect is the comparison of solar efficacy in different US cities. For example, San Francisco is known for its foggy, cooler weather, while Las Vegas is known for the hot sun.
Yet, RV solar is generally more effective in San Francisco than in Las Vegas. The clouds in San Francisco magnify the sun’s rays more intensely. Plus, the cooler conditions mean the solar panels are likely to function much better than in hotter, warm conditions.
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Edge of Cloud Effects is also evident in other cloudy American cities such as Portland and Seattle.
To sum up, even if you’re RVing in cloudy, cool weather locations, you can still purchase and benefit from a solar power system. Sunshine is only part of the bigger story.
How to Improve the Efficiency of RV Solar Panels on Cloudy Days
While RV solar panels will generally work on cloudy overcast days, there’re several ways to improve their efficiency.
The section below will look at ways to improve your RV solar power efficiency in not-so-desirable weather conditions.
Consider your RV Solar Panels (What are the Best Types of RV Solar Panels for Cloudy Weather?)
Most RV solar panels will work in cloudy conditions, some work better.
There’re three main types of solar panels on the market, Monocrystalline PV, Polycrystalline PV, and Amorphous (or Thin Film).
The three solar technologies are different, including the quality of silicone used. They’ve differing levels of sensitivity to light, cost, and efficiency.
Of the three, I would recommend Monocrystalline solar power for your RV. It’s the best solar technology for cloudy days.
The Monocrystalline uses silicon cells of the highest quality, and the crystals formed are usually from a single item. So, the electrons on the Monocrystalline have the freedom to move freely and thus can create a higher rate of electricity.
And therefore, Monocrystalline are generally more efficient than other RV solar panels. Their efficiency also means they can be used in a smaller space, making them ideal for RVs where space is premium.
Clean your Solar Panels
Not regularly cleaning your RV solar panels could expose them to etching issues, which generally degrade their effectiveness over the year.
Rain helps, but there will still be dust and bird poop, which doesn’t easily come off. Depending on the accumulation of dust and debris, the power efficiency of your RV solar panels may drop between 30% to 50%.
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Of course, this becomes less of a factor in areas with lots of rain.
In other places, you’ll need a soft-bristled brush so you don’t scratch the RV solar glass panels. Plain water is enough, but if you want, use a 1:8 vinegar-to-water ratio. Vinegar should help break the gummed grime, while water clears the minerals.
If you plan to wash your RV solar panels, it’s a good idea not to do it when they’re hot. Thermal shock is a thing. Only clean the panels early in the morning.
Don’t Park in Shade
Shading usually cuts down on the power generation of your RV solar panels. The shading makes the panels generate significantly less power.
Of course, clouds are also a form of shading, but the good thing is that sun rays will, in most cases, penetrate them unless they’re heavy.
However, other forms of shade, especially opaque shades, will make it difficult for the sun’s rays to pass through.
And therefore, you must avoid parking your RV in the shade, especially if you have the roof-mounted type.
Get a Portable Solar Panel
Sometimes, it makes sense to park your RV in the shade, especially in summer when you want to avoid direct sunlight.
In such cases, you could still enjoy the benefits of solar power if you considered portable RV solar panels.
The portable RV solar panels will allow you to grab and transfer them wherever sunlight is available.
Consider a Higher Elevation
The energy output by the sun usually decreases by traveling through the atmosphere. The further away you’re from the sun, the less intensity you can expect.
Therefore, given two locations with different altitudes, I’d recommend one with a higher altitude. The sun travels less to your location, increasing the generated voltage output and higher efficiency.
Off-Grid Electricity Tips
The tips I’ve outlined above will help you optimize the performance of your solar panels, especially in cloudy weather.
However, sometimes, the clouds are too thick, and if they stick around for a long time, my tips won’t be simple enough. And because of that, here’re other electricity tips you might consider.
Good Battery Bank is Key:
Having some nice RV batteries will help you get through cloudy days. The batteries store up energy harnessed on sunny days...
Consider a generator:
You could also consider a generator to provide power when the conditions are cloudy. Consider an inverter RV generator. It’s quiet and efficient..
Go to a campground:
If push comes to shave, and your solar power isn’t sufficient for your power needs, consider going to a campground. Here, you’ll find all the amenities you need.
RV Solar Power FAQs.
Q: Can RV solar power work on a cloudy day?
A: Yes, RV solar panels can work on cloudy days, but their output is generally reduced by about 10-25% depending on the severity of the overcast shadow.
Q: What type of solar panels are best for cloudy days?
A: I recommend monocrystalline silicon cells for climates with cloudy conditions than clear sunny skies. The monocrystalline solar panels are more effective at harnessing energy from the sun, even in less desirable conditions.
Wrap-Up
In an ideal setting, solar panels are usually positioned in a location with plenty of direct sunlight. But for RVers, it’s usually not possible, and depending on the location, it’s easy to find yourself in cloudy spots.
But as we’ve seen, your RV solar panels will still work but won’t be effective as normal.
Cloudy condition significantly affects the performance of your solar panels, but the tips I’ve shared above will help to optimize their performance.
