My Tesla Solar Roof is underperforming by at least 20% – Tesla Motors Club

I’m a little confused, as earlier you said you have a 10.6 kW DC system, but various sites say Solar Roof v3 is 58.25W per tile, which would be a 13.3 kW DC system.

Also, what size is your inverter?

PVWatts, based on the above, and using 10% system losses (PV Watts defaults to 14%, not sure what’s appropriate but have the impression that’s very pessimistic), thinks the maximum hourly AC production on a 10.6 kW DC should be 9400W for the first month of May. That would be perfect conditions and assumes no clipping.

It also thinks that with a 1.2 DC/AC ratio (8.8 kW inverter), you wouldn’t actually lose any annual production–even though AC production would be curtailed this time of year, apparently its inverter model says that the greater inverter efficiency at other times of the year would make up for it. Not sure if that is true for Tesla’s inverter.

Cheers, Wayne

Source: https://teslamotorsclub.com/tmc/threads/my-tesla-solar-roof-is-underperforming-by-at-least-20.227531/page-2

May 10, 2021 sally Wood