900-00272-01-001 Rev A
13
Harnessing the Sun
SkyBox can harvest up to 5 kW of power from a solar array and send this power to the battery, your home, the
utility, or any combination of these three places.
Usually, you will see the SkyBox
Producing
on the solar tile. At night, or when the sun is exceptionally weak,
the SkyBox home screen will display
Sleeping
on the solar tile. The SkyBox “wakes up” once the array
voltage reaches 250 Vdc. At this point, it runs three self-tests to ensure it is safe to connect to the array. If you
stand next to the SkyBox during these tests, you’ll hear the PV relay click closed and open again. The
descriptions of these tests can be found in
PV Self-Tests
on page 26.
Once the self-tests have passed, SkyBox closes the PV relay. On the SkyBox home screen, the
S O L A R
tile changes to a yellow bar with the title
Sweeping
. To “sweep” the array means the SkyBox searches for the
voltage point where the most power is produced. While it would seem like this would be the highest voltage,
it’s usually not. The “maximum power point voltage” is closer to the middle of the voltage range for the array.
Since the SkyBox is looking for the most power throughout the whole range of voltage, you’ll see the power
displayed on the home screen go up and down. This operation occurs when one of the following conditions
is met:
o
Solar startup (morning)
o
Forced (button push)
o
Every hour off-grid if a 200 W or more deficit exists between PV and load
o
If significant change to the maximum power point occurs while on-grid
In most applications, SkyBox continually harvests as much solar power as it can to provide power to the loads
and to charge the battery. However, when operating in
Non-export
or off-grid (grid relay is open), the SkyBox
only harvests as much power as necessary. In either of these cases, if you have a 5 kW array and the day is
sunny, but you only have 500 W of load with a full battery, SkyBox will only produce 500 W of solar power.
This means the array is not under producing, it is just being under-utilized.
Solar Gotchas
Many installers who have used OutBack Power products in the past are very familiar with how to set up an
array for a charge controller and inverter system. However, since the SkyBox is a completely different platform
these rules no longer apply. The SkyBox needs to be treated as a brand new system.
Two commonplace items CANNOT be used on a SkyBox array: optimizers and lightning arrestors or other
surge protection. Both of these hardware items can cause interference with the IRD and AFCI self-tests
(see
PV Self-Tests
on page 26). This completely prevents the SkyBox from connecting to the solar array.
Maximum Power Point Tracking
Maximum power point tracking (MPPT) is the technology used by the SkyBox to optimize the harvest of power
from PV arrays. At this time, SkyBox only supports one MPPT array. This just means you can’t have two
different arrays facing in completely opposite directions connected to the SkyBox and expect to get full power
out of either.
Содержание OutBack Power SkyBox
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Страница 27: ...900 00272 01 001 Rev A 27 NOTES...
