Solar Electric Panel Shading

If one panel is shaded it will not affect the entire solar array.

Solar electric panel shading.

What we learned about shading. When shade hits them the first thing that happens is the current goes down. Intuition suggests that power output of the panel will be reduced proportionally to the area that is shaded. However this is not the case.

Depending on the exact circumstances even if only 1 of a photovoltaic solar panel is in the shade it is possible to lose 50 80 of power production from your entire solar array. Because of partial shading one part of the solar panel generates lower amount of energy as compared to the other non shaded part. Many residential properties are situated in green spaces and constantly growing trees and foliage can encroach on solar panel setups. Shading tests serial vs parallel panels actually solar panels are current sources.

Solar panels in parallel and series is a really important topic though especially if they re shaded so we ll leave the best till last. A solar panel consists of a number of cells in series which makes up a total voltage of around 17 to 23 volts for a 12volt panel. What fewer people understand however is just how important it is to avoid shading as much as possible. For this reason it is hugely important that your solar energy system remains out of shade throughout the day wherever possible.

In his book renewable energy and efficient electric power systems stanford university s gil masters demonstrates how shading just one out of 36 cells in a small solar module can reduce power output by over 75. Shade on your solar panels can come from several sources. But this is not always possible. It is possible for a panel to put out quite high voltage and no significant current.

Setting up the solar panel where there is no shade is the best way to avoid the loss of output. When a solar cell is shaded it loses power. A shadow cast on even just part of one solar panel in your solar array can potentially compromise the output of the whole system. As the amount of power generated in shaded non shaded parts differs it leads to overheating which in turn reduces the total power output of the solar panel.

When there is shade on solar panels it will reduce the current of that panel. That loss of power increases electrical resistance within the cell which in turn blocks the flow of electricity coming from upstream solar cells. Perhaps most obviously trees near your solar array can cause shading issues. Each panel works independently.

Let s say you have a panel that has a rating of 17 5 volts and 5 8 amps it will produce 100watts. Now if shade comes over the panel the current could drop to 3 amps but the voltage stays the same resulting in 52 5 watts 3 amps x 17 5 volts. Diodes regulators and solar panels.