solar harvest - slouching toward winter solstice
Having a larger house battery bank now means I get more days where the solar cannot get out of Bulk stage. On those days we can see what the setup is capable of producing.1
In the last two weeks I’ve had 5 days where it stayed in bulk all day. Note the downward trend (and one completely overcast/rainy day):
- 2.84kWh
- 2.70kWh
- 0.48kWh <- 100% overcast, d’oh! :-\
- 2.66kWh
- 2.59kWh <- today
The average of those is 2.2kWh/day, a little lower than the 2.44kWh/day PVwatts predicts for November. If the downward trend holds average harvest should bottom out at 1.97kWh/day on Winter Solstice, December 21st.
If we factor in all days (including days when the system was loafing after meeting loads) the average for the past two weeks is 1.47kWh/day. This suggests on average the system has somewhere between 0.7kWh and 1.0kWh more grunt than I am using on a daily basis. The margin will continue to get thinner until we reach winter solstice and have a 0.5kWh buffer with my current usage.
Digression: surprisingly (to me), in December ELP has 3.4% more insolation in than American Girl BLM, CA and 8.4% more than Quartzsite, AZ. Maybe my reduced snowbirding circuit has benefits other than the purely fiscal.
-
because it never backs off in Absorption or Float. Full pull, bay-beeeeee! ↩