A Guide to Solar Tracking

Solar Trackers have been around a long time, but there are a lot of misconceptions about them and most people don't know about their practical applications. More people than ever before are using solar power, and while grid-tied solar installations greatly outnumber off-grid solar, the number of off-grid users is still steadily growing. Depending on your situation, solar trackers have a number of possible benefits. Choosing the right kind of tracking mount is important. Unfortunately there aren't a lot of packaged tracking mount solutions. They tend to be either very expensive, or too cheap and inadequate, so DIY mounts are still very common. Fortunately just about anyone with a welder and simple tools can make a decent tracking mount from commonly available materials, and controllers and motors can be purchased online separately.

Types of Tracking Mounts
There are two broad categories of solar tracking mounts: single-axis and dual-axis. Each of these can be broken down into sub categories. Common single-axis mounts are polar , azimuth , and horizontal mounts, but we can see how these are all the same thing depending on where you are. The axis of rotation for a polar mount is ideally parallel to the earth's axis of rotation, which means it is tilted to match your latitude. At the equator, a polar mount becomes a horizontal tracker. At the north pole it becomes a vertical axis azimuth tracker. If you are at a very low latitude then choosing a simple horizontal design makes a lot more sense than an azimuth tracker. Likewise, if you're near the arctic circle then you really need an azimuth tracker, not a horizontal tracker.
By adding an elevation control on a polar axis, a dual-axis equatorial mount is created. This is the same type used by most telescopes because it simplifies accurate tracking with the earth's rotation. Many people change the angle of the polar axis itself, instead of the elevation of the panels on the axis. The order of rotational operations is important though, so those mounts don't trace the path of the sun with just the primary axis moving. Adding elevation (altitude) movement to an Azimuth system creates what is known as an Alt-Azimuth mount. These are probably the most popular due to the many simple ways they can be fabricated.