My solar panel has been in constant use from the day it was installed (2011). These are pictures of the fully automatic installation, with the controller in the cab.
The SP and the controller were both purchased from Ramsond (http://www.ramsond.com
). The SP carried a 25 year power warranty, which covered the output of the panel. If the output dropped below 80% of the peak rated power of the panel then it would be covered under the warranty.
All was well until I noticed that things were not working like they once did. In the beginning, it was little things , like the battery voltage taking a dip, under a load (which was below the rated output of the SP) when the panel was getting full sun. Progressively, the problem became worse to the point where I had to get the amp meter out to see what was going on. Under identical conditions as when I first installed the panel, I now found that instead of getting the usual 5.2 amps of output, I was lucky to be getting 3.5. Clearly less than 80% of rated power.
A quick visual of the SP revealed an interesting situation. Dark lines had developed on the panel cells with some going completely from margin to margin. Here is a picture of the lines.
These pictures were taken a few months before the panel was returned, and in the months between the pictures and the shipment back to Ramsond, the lines grew worse. I was advised that these lines were called “snail trails” and it seems to be a problem with panels from 25 or more different manufacturers, not just Ramsond. If you do some research on this condition, it appears that this is a new phenomenon and the manufacturers are still searching for an answer as to what causes the problem. Even more concerning is there seems that there is no one “theory” that is accepted by everyone and no one seems to know for sure if this has any effect on the performance of a panel.
Ramsond assured me that "the snail trails shouldn't affect performance
". Despite this, they were very good about exchanging my original panel for a new one. Whether the problem with my original panel was due to snail trails or something else, I don’t know, but I do know that the new panel performs perfectly. Ramsond customer service is excellent.
Moral of the story:
1. If you have a SP mounted on your vehicle, keep an eye open for snail trails and periodically check the output from your panel to make sure it is performing as advertised;
2. If you buy a SP, do your research and select a company that offers a good warranty on SP performance. (25 years is a good warranty!)