SMA SUNNY ISLAND 4.4M Operating Manual page 95

SMA Solar Technology AG
• Set the parameter Limit battery state of charge for start load shedding 1 in add time range to the
lower SOC threshold for the first level of load shedding.
• Set the parameter Limit battery state of charge for stop load shedding 1 in add time range to the
upper SOC threshold for the first level of load shedding.
• Select Device > Load shedding 2.
• Set the parameter Limit battery state of charge for start load shedding 2 in add time range to the
lower SOC threshold for the second level of load shedding.
• Set the parameter Limit battery state of charge for stop load shedding 2 in add time range to the
upper SOC threshold for the second level of load shedding.
6. Ensure that the multifunction relay used for controlling the first level of load shedding is set to 1-stage load
shedding or 1st stage with 2-stage load shedding (see Section 7.10.2 "Setting the Functions of the
Multifunction Relays", page 108).
7. Ensure that the multifunction relay used for controlling the second level of load shedding is set to 1st stage with
2-stage load shedding.
Relevant for off-grid systems
Cell voltage
Target value
of the cell voltage
in the constant
voltage phase
Figure 22: Switching-on time and switching-off time for utilization of excess energy during constant voltage phase
The Sunny Island controls the utilization of excess energy during the constant voltage phase depending on the cell
voltage of the battery. During the constant voltage phase, the battery is charged with a constant charging voltage.
When the setpoint of the cell voltage in the constant voltage phase is reached, the multifunction relay is activated. The
multifunction relay remains in this position for the minimum time 241.07 ExtPwrDerMinTm. If the cell voltage differs
by more than 241.08 ExtPwrDerDltVtg from the setpoint of the cell voltage, the multifunction relay is deactivated.
The setpoint of the cell voltage depends on the charging process during the constant voltage phase.
Charging Process Parameter
Boost charge Battery > Charge > Cell charge nominal voltage for boost
charge
Full charge Battery > Charge > Cell charge nominal voltage for full charg-
ing
Equalization charge Battery > Charge > Cell charge nominal voltage for equaliza-
tion charge
Operating Manual
Time of activation
Minimum time
7 Commissioning
Time of deactivation
Time
Default value
2.40 V
2.45 V
2.45 V
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