jonnydot
New Member
How do the wattages work? This panel is advertised as 300 watts. Under Power it states 201-300watts but under wattage it states 300-399watts.What is it ?
Wattage query
- Thread starter jonnydot
- Start date
Based on a Google search of the part number (A691036749010), I found an eBay listing and according to that it's a 300W panel. So probably 300W - the site you got that info from (shopusfirst.com.au?) is confusing.
MichaelK
Solar Wizard
There are normally two different wattage standards that most panel companies publish. The STC, which is the standard test conditions of illuminance at 1000W/meter squared at 25 degrees C,
and the NOCT rating for nominal operating cell temperature, which is 800W/meter squared at 46 degrees C.
Manufacturers understand that panels almost never put out their "rated output", which is because you can't guarranty the sun is putting out exactly 1000W/m2 during the day, and also that power output (voltage) goes down as the panels sit in the hot sun all day. So, the NOCT is more of a "worst case" rating that people will always see the panels perform better then.
So, the different values may represent the difference between the STC and NOCT ratings?
and the NOCT rating for nominal operating cell temperature, which is 800W/meter squared at 46 degrees C.
Manufacturers understand that panels almost never put out their "rated output", which is because you can't guarranty the sun is putting out exactly 1000W/m2 during the day, and also that power output (voltage) goes down as the panels sit in the hot sun all day. So, the NOCT is more of a "worst case" rating that people will always see the panels perform better then.
So, the different values may represent the difference between the STC and NOCT ratings?
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