Solar panels: Difference between winter and summer

April 30, 2010

By Bob Difley
solar_panels The last remaining snowbirds, except for the hardy “desert rats” that won’t head north until successive days of 100-degree plus temps have turned them into brown lizards, have finally started their migration north to the cooler forests of the northern states and Canada. But Boondocking in the national and state forests presents new challenges quite different from those in the southwestern deserts.

One of these challenges is producing enough electrical power from solar panels to meet your daily needs.In the desert, your considerations are:

Because most desert campsites are open to the sky, you get charging from your panels from the first glint of sun over the morning horizon until it has passed out of view in the western sky.
However, since the angle of the sun is lower, 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, and verify that your panels–or other roof top equipment–do not shade the charging (silicon) part of the panel.
Since the days are shorter, your total charging time will be shorter, and your batteries may not have sufficient time to become fully re-charged. 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.

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 full advantage of the suns’ 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 nightime dark hours roughly equals the eight hours of sleep needed, most electricity-using can be accomplished while the panels are charging–though probably not to full capacity–if you coordinate your sleeping and rising times with the sun’s.
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 can be nice) you will have to hazard a guess at how many of the actual 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 re-charged.

The remaining consideration in both desert and forest is the number of overcast or rainy days which will produce minimal battery charging. It is therefore a good idea to oversize your system to account for all the variables.

Check out my eBooks on Boondocking and saving money on the road on my Web site for more information on living the good life of the RV Lifestyle.