Information current as of

  FAQs about used panels

1. If space isn't an issue, older and bigger used panels will usually be your most cost effective from the standpoint of dollar per watt.

2. Obviously avoid damaged and broken panels unless you are able to fix them yourself. The most common problems are broken glass, broken connections and condensation.

3. Some older panels have turned a brown color from the sun as they age. This doesn't automatically mean they are bad, just be sure to measure their power output to be sure its enough. Brown or clear, they don't degrade any faster.

4. Testing a used panel requires setting your voltmeter to DC then measuring across the positive and negative terminals which gets you the open circuit voltage.

5. Be sure to look for loose connections between the solar panels themselves. If you are unable to solder and fix yourself the dealer may know a repairman or move on to buy a different unit.

6. New panels will have 10% higher output than the factory print outs will say. Stored panels do not degrade power outage, only those that have been in regular use. Typical loss over a time of 20 years would be about 10% for really good panels.

Is shading a problem? In a word, yes. For best use all the panels must have full exposure to sunlight so you don't want to install them on the side of the house that has lots of tree coverage in the afternoon. If any panels are shaded the entire unit will perform less, not just those shaded units. This is true of used and new panels. The same is true for cloudy days. The units will still work but not at optimum efficiency or output. They will produce less but still function.

What if I cannot mount on my roof, are there other options?

There are ground-mount, trellis or pergola applications that may work for you. Ideal is a roof system though as there is less opportunity for damage.

What about surviving bad weather?

Most panels look fragile but are typically designed to withstand very high winds of 125mph and up to 1 inch hailstones.