There are two ways to quote DC watts. One is called STC, or Standard Test Conditions, also known as “nameplate rating.” This is the most simple and easy to grasp way to quote, because you just take the wattage of the panel and multiply it times the number of panels. For example, if you had 10 SPR230. .
You get to AC watts by multiplying the PTC DC wattage by the inverter efficiency. Many inverter efficiencies can run around 95%. so just take the DC rating an multiply by .95. This will be the lowest number of the three. .
The answer is that it doesn’t really matter, as long as when comparing quotes, you’re looking at the same number. In Northern California, the.
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