[RE-wrenches] Bi-facial Open Circuit voltage testing

[Brian Mehalic]

I second Jay's request for some numbers, I'm curious about this not having
participated directly in any bifacial projects yet.  The difference in Voc
and Vmp ratios is interesting.

Brian Mehalic
NABCEP Certified Solar PV Installation Professional™ R031508-59
National Electrical Code® CMP-4 Member
(520) 204-6639

Solar Energy International
http://www.solarenergy.org

SEI Professional Services
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On Mon, Nov 2, 2020 at 8:55 AM Jay <jay.peltz at gmail.com> wrote:

> Hi Jason,
>
> What are you seeing in terms of measurements?
>
> Temp air/module
> Voc
> Irradiance
> Etc
>
> Jay
> Peltz power
>
>
> > On Nov 2, 2020, at 8:18 AM, Jason Kechijian <solarj at me.com> wrote:
> >
> > Hey wrenches,
> >
> > Does anyone have any guidance to which values to use when testing open
> circuit voltage on bi-facial modules, considering you take the temperature
> reading from the cell vs. the back sheet? Also, what would be the correct
> module Voc to use since there are values for both the front and back?
> >
> > 405W Module: Front/Back
> > Pmpp: 405 / 285
> > Vmpp: 40.89 / 41.10
> > Impp: 9.91 / 6.94
> > Voc: 48.42 / 46.99
> > Isc: 10.38 / 7.28
> > Module efficiency: 19.7% / 13.9%
> > Temp coefficient Pmpp: -0.3528%/ºC
> > Temp coefficient Isc: +0.0400%/ºC
> > Temp coefficient Voc: -0.2769%/ºC
> > Nominal: 44+/-2ºC
> >
> > I was using the front Voc and Voc temp coefficient, but I am getting
> some results which are not in line with the 5% of expected.
> >
> > Jason D. Kechijian, LEED AP
> > NABCEP Certified PV Installation Professional™
> >
> >
> >
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