A solar inverter's maximum output is like a car's top speed. Imagine you're driving a car that can go up to 120 mph, but most of the time, you won’t be driving that fast- unless you borrow your uncle's 1969 Mustang trying to impress the second runner-up of the 4H pageant on a double date. Hypothetically speaking.
Traffic, road conditions, speed limits, and knowledge of the sheriff's whereabouts (whose daughter is the second runner of the 4H pageant) all affect how fast you actually go.
Similarly, a solar inverter might have a maximum output of 11.4 kW, but real-world factors like the amount of sunlight, the number of solar modules, and weather conditions usually mean the system produces less than that. Like with a car, you rarely reach the maximum speed, and your solar system won't often hit its peak output either. As with most things, it depends.
One of the easiest ways to hit peak production, at least in the summer months, is to load up that roof with as much PV as possible. This affects the DC to AC-ratio, or the amount of solar array wattage divided by the PV inverter max AC output.
For example, if you put 11.4kW of modules on the roof and connect that array to an 11.4kW inverter, then that system has a DC-to-AC ratio of 1:1. If you wanted to really load up that roof and go with a 2:1 ratio, then you would have a 22.8kW array, equivalent to fifty-seven 400W modules, feeding that inverter.
"Whoa, whoa, man, that is crazy talk! That inverter will start clipping and never use that much of array!"
Yes, this is true; however, the industry is challenging this concept of clipping. I have been for years, so it is nice to see people really taking a closer look at it, particularly when installing an energy storage system. In my Amazon bestseller, The Battery Powered Home, I dig into the concept of clipping. The Reader's Digest Condensed version (is that even relatable anymore?) is that clipping isn't necessarily a bad thing. I always promote it with energy storage systems since homeowners will use every watt and every watt-hour you give them. Load that roof up and fill that battery up as quickly as possible.
It's not 2010, and a 260W module doesn't cost $1200. You can get a 400W module for a little over $100. Go crazy with that glass and fill up that roof, especially if you have an energy storage system.
"But I don't want to give PG&E any free solar!"
Ok, cranky pants, I know they suck, but who cares if you get less than a nickel per kWh (thanks, Newsome and California PUC)? You still get to charge your battery and save money on your electric bill, plus disaster resiliency from the occasional storm or earthquake and the PG&E shutdowns when the winds hit 35 mph. Still a pretty good deal!
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