Update with more sun and 2*100W in series.
June 1, 7.30am, battery resting 12.8V.
Clear sky, panel V=35, current 9.3A, load 2.7A.
Disconnected the load, current dropped to 8.5A, i.e. 0.8A decrease.
(Effect is similar to yesterday's single-panel conditions when current dropped by 0.7A from 1.4 to 0.7 after disconnecting 2.5A load).
Note that 9A is 60% of theoretical maximum power of 200W array post-controller, so not a bad solar day.
Haze, panel V=30, current 4.5A, load 4.2A.
Disconnected the load, current dropped to 3.2A, i.e. 1.3A decrease.
(Effect is different from yesterday's single-panel conditions but not much different: yesterday current dropped by 0.5A from 5A to 4.5A after disconnecting 4.5A load).
It should not be doing this, not with LFP battery, this is not a Float, the battery is far from being full. I am losing more than 10% of available energy.
I think this controller has a poor charging algorithm and/or poor firmware. Adding one more panel should help the bottom line but this effect of demand will likely still be there.
