Verifying Solar Panel Output
If the solar panel is unobstructed, unshaded, at the correct tilt
angle, and in full light between 10 a.m. and 3 p.m., you can verify
the solar panel's performance per the nameplate ratings for Voc
and short circuit current (ISC) as follows.
To verify the solar panel output, complete the following steps.
1. Set the
PV(+)
breaker to
OPEN (OFF)
position.
2. Using a volt meter, measure the Voc voltage between the
PV(+)
and
PV(-)
terminal blocks. It should measure within 5%
of the nameplate rating in LOW to HIGH sunlight.
3. Set the
PV(+)
breaker to
CLOSED (ON)
position.
4. Using an ammeter rated for a maximum system ISC value,
measure the charging current through the
PV(+)
terminal.
In LOW sunlight, it should measure approximately 30% or
less of the rating shown on the nameplate: 60% or less of
nameplate rating in MED sunlight; and 60% or greater in
HIGH sunlight. The degree of sunlight is based on cloud
cover and height on the horizon for that time of day in winter.
Table 27 provides the degree of sunlight at various times on a
clear, sunny day in the winter.
Degree of Sunlight
Time
Sun Capacity
LOW
7:00 a.m. - 9:00 a.m.
10 - 30%
MED
9:00 a.m. - 11:00 a.m.
30 - 60%
HIGH
11:00 a.m. - 1:00 p.m.
60 - 100%
MED
1:00 p.m. - 3:00 p.m.
30 - 60%
LOW
3:00 p.m. - 5:00 p.m.
10 - 30%
Table 27 – Sunlight by Time of Day in Winter
96
R900 Gateway Installation and Maintenance Guide
Appendix A Solar Power Information
Summary of Contents for 13458-000
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