Thursday, May 19, 2022


Solar RVing in the shade

By Bob Difley
If you like to boondock away from the beaten track, summertime camping often means looking for a bit of shade to help keep cool. But if your power comes by way of solar panels, you’ll be in the world of trade-offs — shade means less solar power.

Most winter desert campsites are open to the sky, so your panels charge when the first rays of the morning sun hit your panels until it has passed out of view in the western sky. But since the angle of the sun is lower in the winter, you will not get full charging unless you tilt your panels toward the sun’s trajectory across the sky, and position your RV horizontal to the sun’s movement. In winter with shorter days, fewer amps will make their way into your batteries. Therefore, you may have to schedule more electricity-using hours (meals, showering, computer use) during daylight so as not to deplete too much from your batteries overnight.

But when you move from the desert to a Ponderosa pine-forested campsite, your challenges change. Since the sun during the summer months passes more directly overhead, your panels do not have to be elevated to take advantage of the sun’s rays throughout the day. Days are longer so you have many more charging hours every day than in the desert, and since the number of nighttime dark hours roughly equals the eight hours of sleep needed, most electricity usage can be accomplished while the panels are charging to some degree. If you coordinate your sleeping and rising times with the sun’s, you will not draw excessive juice from the batteries.

But now comes the hard part. Since you are camping in a forest, you will undoubtedly have periods of the day when the sun is blocked from reaching your panels by the magnificent (and tall) trees surrounding your campsite. Short of camping out in the middle of a meadow (which is nice, too) you will have to hazard a guess at how many daylight hours the sun is actually reaching your panels — without any part being shaded, which reduces the amount of amps that pass into your batteries — and calculate accordingly so you don’t find yourself with batteries that have not recharged.

The remaining consideration in both desert and forest is the number of overcast or rainy days which will produce far fewer amps. It is therefore a good idea to oversize your system to account for all the variables. And sweep off the pine needles from time to time.

You can find Bob Difley’s e-books on Amazon Kindle.



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1 year ago

Another thing to consider is series connecting 12V Panels such as 2ea 12v panels which provides 24V (Open voltage is more like 40VDC). Many MPPT controllers are 12/24VDC. The advantage is in lower light the voltage will stay above MPPT normal cut off voltage and still provide power.

BILLY Bob Thronton
1 year ago

So, what was the point of this article. The title sure was deceiving. Then I saw at the end, he’s hawking a book.

John R Crawford
1 year ago

Thanks for this article, I’ll just keep using my generator.

Sink Jaxon
1 year ago

I have 340 watts on the roof (2- 170 watt panels), but I also have a 120w panel on the ground with a 25′ wire I can move around in the day to chase the direct sunlight in a shade situation like that. There’s always holes in the trees that let direct sunlight in. We always seem to have enough power to run what we need. But we don’t run a TV, or inverter of any kind either. Two 85Ah AGM batteries. Have never been to the East coast either, where sunlight may not be in as much abundance than the West, sooo that may make a difference.

1 year ago

We sometimes also use our Noiserator (propane fueled) while on route between camping areas to charge the bike battery, electric toothbrushes, laptops and anything else that needs 110v to charge.

Alan Wolfe
1 year ago

Very good points. Many folks have read all of the promises of going Solar, and only afterwards learn the lessons you highlight.
I for one have a wife that only loves deep wood camping. We have no conflict there, I also love the deep woods, but its shadows hinder the 300 watt solar setup on my roof.
We sure don’t want to run that noisy generator, but there are times it is a necessity when there is no shore-power.
I picked up a secondary small Honda 2200iu quiet generator, even that disturbs the wonderful quiet of the woods, but again, there are times when we do need power. (note: our installed 3000 watt generator is just plain LOUD)

1 year ago

We boondock with a Lance 11.5′ camper and a 100w rooftop panel that came with the rig from the factory in 2002. 115ah group 31 battery. In the Oregon Fir and Cedar forests we sometimes resort to our 100w Renogy panel that I made into a portable with 60′ leads. (in 3 20′ sections to use as needed) We watch tv on a 12v 24″ flat panel occasionally and use a small 110v dvd player through our 400w inverter. Occasionally I overdraw the battery down to 11.9 but rarely as we don’t watch that much tv anyway.

1 year ago

Ummmmm… Isn’t this why we have generators?

Sink Jaxon
1 year ago
Reply to  Don

Generators are obnoxious!

1 year ago

One thing many overlook is that solar panels do provide shade on the roof in their own footprint. So, the more panels you have the more shade you get when out in the open.

John R Crawford
1 year ago
Reply to  Steve

Very good point!

Tommy Molnar
1 year ago

We oversized our system (700 watts, which I think is oversized anyway) for just this reason. The only time we couldn’t get a charge was when the panels were completely snow covered.