It's the middle of March, the sun is rising higher in the sky each day. That means we can do our bi-annual adjustment of the solar panels to get the maximum amount of power possible.
There are a number of factors that affect the efficiency of your solar panels, and one of those is the angle at which the solar rays hit the panel. The ideal angle would be perfectly perpendicular (90°). And while it is impossible to keep a perpendicular angle all day without an expensive tracker, we can set our panels at an average that maximizes their potential. The problem for those of us who don't live on the equator, is that the sun's position in the sky changes throughout the year. The further one moves from the equator, the more drastic this variation is.
In the summer, the sun arcs high in the sky. The winter months see the sun skimming much lower on the horizon, particular in northern latitudes (if you are located in the northern hemisphere). But don't despair, there are two simple rules to follow when aiming your solar panels. And for those of you who want to generate the maximum amount of power with the minimal amount of work throughout the year, you need only make one simple adjustment twice per year to achieve that.
The Horizontal Azimuth
First we will deal with the horizontal azimuth of the solar panels. This would be the equivalent to you standing up and looking straight ahead while spinning in a circle. You could be facing North, South, West, or East. This is your horizontal azimuth. For maximum efficiency, the panels should be aiming at 180° true south (not necessarily magnetic south).
If you are in an area where magnetic south (what your compass reads) is significantly different than true south, you should do a quick search on Google to learn how to compensate for this magnetic deviation. Once we set the horizontal azimuth, we will not change it. This will always be the best location for the panels to face whether summer or winter.
There is one exception I must mention to the above rule. If your location has a significant obstruction to the south that cannot be moved, you may want to turn the solar panels slightly so they are perpendicular to the portion of the southern horizon where they are able to get direct sunlight. An example could be a location where a mountain range is blocking significant sunlight from the southeast. In that situation, it may make sense to angle the panels more to the southwest to maximize what direct sunlight is present.
Next, the Vertical Tilt
Next, we need to set the vertical tilt of the solar panels. If you are going to be setting up a solar array this summer, here is a simple rule of thumb for determining the optimum vertical angle: Your latitude minus 15°. Here is a simple online tool to help you find your latitude. If your latitude is 30°, take 30 - 15° = 15°. This is assuming that 0° is horizontal and 90° is vertical.
You can buy a clinometer (aka inclinometer) or build one yourself. Another option is to use a protractor, speed square, or even a tape measure. However that takes someone who is geometrically inclined. If you were setting up the solar panels in the winter, the rule of thumb changes to this: your latitude plus 15°. Back to our example, latitude of 30° + 15° = 45°. If you get confused, just remember that the solar panels should be more horizontal (pointing high into the sky) during the summer and more vertical (pointing towards the southern horizon) in the winter.
One could get carried away with this adjustment business and make a 1° adjustment every week. But the amount of additional power produced would not be worth the work required. In my opinion, the best balance between effort and efficiency may be found by making an adjustment two times per year. Adjust the solar panels once in the spring and once in the fall. When spring arrives (usually March/April) move the panels to their summertime position. When fall arrives (Sept./Oct.) adjust to the winter position.
By placing your solar panels in a more vertical position it increases the ability for them to shed snow in the winter. There may be a few times every year when you'll need to brush them off. Be sure your solar panels are mounted in an accessible location (not on the roof). However you may find that they shed the snow quite well as soon as the sun comes out.
The obvious caveat here is that your solar panels must be mounted in such a way that the vertical tilt may be easily adjusted. There are a number of ways to accomplish this. We have had good success with these mounts mounted to a false wall. A false wall is a number of large pressure treated posts set in a row. Then connect them with 2x6's.
If you are having difficulty picturing this, take a look at our video Urban Danger. You will see a solar setup like this approx. 50 minutes into the video. An even better (albeit more expensive) option would be heavy duty post mounts. And for the creative person with more time than money, the sky is the limit! I have heard of everything from mattress rails (also on Urban Danger) to a homemade tracker utilizing an old c-band satellite dish motor.