Solis inverter upgrade, performance decreased?

[Hedges]

Shade on a cell, still produces relatively high Voc, but any attempt at pulling current causes voltage to drop.
Bypass diodes are supposed to let current from other panels get past a shaded cell. But, diodes can fail.
Was there any shade on the panels?

An infrared camera is the ideal way to observe hot spots, but decent ones are expensive.

 

[DrPhil]

Shade on a cell, still produces relatively high Voc, but any attempt at pulling current causes voltage to drop.

It was a crap day, so shade everywhere. But I'll still usually be generating 400w in that weather.

 

[DrPhil]

Case in point, currently it looks fine.

This is the weather/cloud cover at the back of my house. One string is on the back roof (above where this picture was taken and facing that cloud), the other on the garage roof to the right of this picture.

Total cloud cover.

And yet I'm generating what I would expect, and the voltages look as they should.



So why the random voltage drops yesterday?

 

[Solar Guppy]

What is the configuration of your solar panels strings?

Based on the Voltage it looks like one string on the home and one on the garage roof?

Also I assume you are in a high latitude, so many hours with low irradiance, meaning its dawn/dusk like? add in cloudy conditions and that could explain the voltages. The human eye is not a good judge for marginal light conditions and the irradiance available.

Here is a sunny day on my 2 inverters, notice that 5G with the battery comes alive earlier than the one without as it need enough energy on the GT one to power the inverter.





My Arrays, 4 strings of 7 panels, two strings to each inverter



Full dashboard Yesterday