October turned out to be a much better month than September, particularly in terms of system stability. Whatever was plaguing the inverter seems to have settled down and after a reboot the panel monitors/optimizers seem to be humming right along. Production for the month was right on track with estimates, though it was noticeably lower than October of last year. Compared to last month production was, not unexpectedly, down considerably.

September was a rough month for my solar panels. On several days the inverter failed and shut down, which meant no power was produced. In the last 10 days of the month the monitoring and control unit for the individual panels also froze, reducing efficiency (and giving me some holes in my data).

My solar numbers for August turned out pretty well, though it's clear that summer is starting to wane. Compared to last August use was down and production was up, though only slightly. More noticeable was the drop in production compared to last month as the days are getting shorter and the weather cloudier.

July was a fairly typical summer month, with production coming in just a bit (half a percent) shy of the estimate for the month. As expected production was a bit lower than last month although it was better than last year.

This month got off to a strong start with a string of sunny days, but around mid-month the traditional Seattle "June Gloom" rolled in early and put a real damper on production. The month ended up just a little shy of estimates, about 6 kWh short of the expected 469 kWh.

April turned out to be a very good month for my solar panels, handily beating the estimate for the month as well as last year's performance. I finished the month with a surplus of about 250 kWh sent to the grid, having generated just short of 400 kWh.

March turned out to be a good month for my solar panels, with production beating both the estimate and last year's production. I sent a surplus of power back to the grid, and am rapidly closing in (already!) on having a surplus of power for the year.

This post is a bit overdue, but I'll make up for it with a slew of new charts. I've started collecting solar radiation data from a nearby weather station and am using that to estimate the efficiency of my panels on a daily basis. I've also incorporated some additional comparisons between past data (yearly and monthly) to see how my system performance may be changing over time.

Fall is definitely here. I only had one day this month with a surplus of power, and total production dropped under 100 kWh. On the bright side the panels still produced more than estimated, about 48% of my power use for the month.