PV Inverters module strings [RE-wrenches]

[Eric Smiley]

Use the MPP voltage and derate for the highest expected module
temperature.

Eg. A 36 cell module at 65 degrees C (40 degrees above STC)

0.002 V/cell/degree C  (typical temp. coef.) x  36 cells/module = .072
V/ module/degree C
.072 V/module/degree C x 40 degrees = 2.88 V/ module

If Vmp = 17 then 17 V - 2.88 volts = 14.12 Volts

300 V / 14.12 V = 21.3 modules in series minimum.

Now look at the Voc and "derate" for the lowest temperature according to
the NEC table.

Eg. Voc = 21 Volts x 1.25 (worst case) = 26.25 Volts

600/26.25 = 22.9 modules in series maximum..

I don't have the specs for the SR100, but as you can see there isn't
much room to play.



----------------------------------------------------------------------
Eric Smiley
Project Leader - BCIT Technology Centre
Photovoltaic Energy Applied Research Lab (PEARL) - BCIT
ph: (604)432-8657 www.bcit.ca/~tc/pearl/index.htm

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