How does shade affect solar? This one should be a simple answer, right? Well yes and no. Shade will render solar inoperable while it is being shaded; however, systems can be oversized to take advantage of times when it is not shaded. But the general consensus is trim trees, place the solar in the sunniest location possible, and keep it out of the shade.
We have touched on this subject in the past with our post Location Location Location: Why Shading is Bad for Solar Systems. In this post we explain how solar can be remotely mounted in a non-shaded area to ensure the power assembly will operate correctly, or how trimming trees is a great way to eliminate the problem all together. Installing the system on a roof can also ensure that the solar doesn’t become shade when tall buildings are in the area.
But let’s take this a step further. I found a video that shows real time what shading can do to a solar panel:
Crazy, right? Just a little bit of shade already affects the solar panel and drops the production of power. It doesn’t require the panel to be completely shaded to render it inoperable. This is because solar arrays are divided into strings. Shade one section of the panel and the whole string will stop working. Shade across all the strings and the panel will completely stop working.
Increasing the panel size can compensate for this a little, but it isn’t the best solution. Since there is no telling how much the shade is going to affect the panels without field testing, it is always better to make sure your solar is not shaded at all, facing south, and sitting around a 45° angle. This is the best installation method for almost all applications, especially off grid installations.
If you follow the above and keep your solar panels away from shade, you will ensure that your solar is producing enough power during the day to charge the batteries completely. This will ensure that your solar lighting and power systems are able to operate at night as required.