16
Fig. 17 Specific data history
The cursor can also be used to show specific
data on the history view when you hover over
the main graph area. In this example, the cursor
box shows the date, charging watts (from
solar), consumption watts (from loads and other
appliances, solar inverter production watts, the
battery discharge in watts and the current state of
charge.
The following page dissects a typical historical
graph of a system running in self consumption
mode. By analyzing the behavior of the PV, loads,
battery charging and discharging, the homeowner
can see just how much power throughout the
entire day that they are consuming, at what times
and where their energy is coming from - either
from their PV system, their battery bank, the
utility grid or a combination of all three.
Fig. 18 Typical history graph
• 1
- These spikes throughout the nighttime
hours are caused by the kitchen refrigerator.
This unit has a run time of about 30 minutes,
which is indicative of an older refrigerator that
could probably be replaced with a more energy
efficient model. Typical energy star compliant
refrigerators will run for about 15 minutes an
hour, or 6 hours a day.
• 2a
- There is a spike of consumption during this
time of the morning that the solar production
could not sustain since the tip of the blue spike
is outside of the yellow curve.
2b
- The storage unit recognized the spike
was beyond the PV production value and
discharged a small amount of energy to cover
the spike. Consequently, the homeowner did
not have to pay for that spike of energy.
• Green indicates battery charging. This system
completed the battery charging process
around 3 p.m.
3a
- The state of charge line shows a 100%
capacity at the same time the green line
stopped.
3b
- the state of charge started to go down
as the batteries started to discharge due to
decreased PV production.
3c
- The low state of charge for this day was
28% before the batteries started charging from
solar.
• Since the batteries are full at 3 p.m. and there
is still excess solar production, this 2.5 hours of
yellow indicates that the excess was sent to the
grid.
• At first glance it may appear that the storage
unit did not start discharging to cover this light
blue event in the late afternoon when the solar
production started to decline. Using the cursor
will help to clarify what is being displayed.
Fig. 19 Typical history graph values
At 5:53 the system was no longer charging the
batteries (0W) and the load on the system was
2,211W. There was still 1,084W of solar production
1
3
4
2b
2
3c
3a
3b
5