Will the degradation expected on solar panels, affect both the voltage and wattage?
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Originally posted by Brian53713 View PostWill the degradation expected on solar panels, affect both the voltage and wattage?
The voltage is pretty well fixed by the choice of semiconductor material.SunnyBoy 3000 US, 18 BP Solar 175B panels. -
The way it was explained to me was that the I-V curve tends to lose definition in its "knee" and tend to flattening out a bit as the cells degrade and generally time goes on, with the MPP shifting downward and to the left, but more downward than leftward, meaning current will probably be affected more than voltage. But, there are several mechanisms at work, and it may be pretty hard to make blanket statements or generalizations about all types of cells, materials and mfg. processes.Comment
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If the main effect were voltage, it would be possible to check temperature and measure the degradation pretty
accurately. If its the current (as I expect), much harder since sun intensity is so variable. And who has a lab
flash tester? Something to do in a decade... Bruce RoeComment
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Originally posted by bcroe View PostIf the main effect were voltage, it would be possible to check temperature and measure the degradation pretty
accurately. If its the current (as I expect), much harder since sun intensity is so variable. And who has a lab
flash tester? Something to do in a decade... Bruce Roe
Also, as it turns out, the array voltage is a fairly accurate way to measure an array's temperature, provided the voltage is measured at reasonably consistent plane of array irradiance levels - and one tool to estimate array fouling - more long boring stories.Comment
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I am going to guess, that the current degradation is pretty much tied to the total amount of sun a panel has received. So
if the panel is kept tied to an MPPT load, the total amp hours, or the total KWH delivered to date, would track degradation.
Bruce RoeComment
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