Hi Bob ! Long time no see...
A good sanity check is to note the Voc of the array connected to a specific
controller and then see what the voltage is that the controller is
running it
at. Without shading, the input voltage should be running somewhere
between 75%
to 82% of that Voc. If Voc is 100 volts, then MPP voltage will be
around 80 volts
or so. Much higher than 80% and it usually means that the batteries are
full
or inverter is not selling to grid or the tracking is off.
Too low of MPP V usually indicates partial shading or tracking.
boB
Dear Wrenches:
What am I not seeing with this situation?
Only 133 DCkWH (120 ACkWH) during mid-December through April 6 (at least
that is what the mate and the MX80 CC say). PVWATTS predicted ~600 ACkWH.
Here are the major components of the system:
24 - Silicon Energy 190W solar modules in 8 series of 3 modules for 4560W
nominal
1 - Midnite Solar, Combiner box, MNPV12 with 8 circuit breakers (one for
each string)
1 - MX80 charge controller
16 - Concorde SunXtender Sealed AGM Battery, 6V, 405Ah, L16, PVX-4050HT (2
parallel series of 8 batteries for 48V and 810 AH)
1 - Outback FlexNet DC System Monitor, FN-DC
2 - GVFX3648 inverters
1 - Mate2
1 - HUB10
1 - Remote Temperature Sensor
The insolation this winter has been, if anything, more than usual. The
electrical usage noted on the utility bill was approximately 170 ACkWH more
than the same winter period last winter. No appreciable change in usage
pattern this winter compared to last winter (in fact, if anything, there has
been less use this winter). Everything appears to be functioning (normally,
I think).
What is going on? It cannot just be a malfunctioning utility meter. It
seems to me that regardless of the functionality of the utility meter, the
Mate and the MX80 should show greater production.
What is being overlooked?
Thanks for your help.
Bob Clark
SolarWind Energy Systems, LLC
(509) 826-1259
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