Supplementary Information; Determining The Battery Capacity - SMA SUNNY ISLAND 4.4M Operating Manual

9 Configuration of the Inverter
Data security during activated Modbus interface
If you activate the Modbus interface, there is a risk that unauthorized users may access and manipulate the data
or devices in your PV system.
• Take appropriate protective measures, such as:
– Set up a firewall.
– Close unnecessary network ports.
– Only enable remote access via VPN tunnel.
– Do not set up port forwarding at the communication port in use.
– In order to deactivate the Modbus interface, reset the inverter to default settings or deactivate the
activated parameter again.
Deactivate the dynamic active power limitation for the PV inverters when controlled via Modbus
If the PV inverters and the battery inverter are controlled in a PV system via Modbus, the dynamic active power
limitation of the PV inverters must be deactivated.
Procedure:
• Activate the Modbus interface and adjust the communication ports if necessary (see the technical information
"SMA Modbus® Interface" at www.SMA-Solar.com).
9.8

Supplementary Information

9.8.1

Determining the Battery Capacity

Manufacturers state the battery capacity depending on the discharge time. In the installation assistant and in
parameter Rated battery capacity, always specify the battery capacity for a ten hour electric discharge (C10).
Procedure:
• Determine the battery capacity C10 specified by the battery manufacturer.
☑ You could determine the battery capacity C10.
✖ You could not determine the battery capacity C10?
• Estimate the battery capacity C10 from other discharge times. This will provide a value that is probably
sufficient for commissioning.
Discharging time
120 h (C120)
100 h (C100)
20 h (C20)
10 h (C10)
5 h (C5)
1 h (C1)
• Contact the battery manufacturer, request the C10 battery capacity and set the correct battery capacity in
the installation assistant as soon as possible. Proceed as if you were replacing the battery (replacing the
battery, see Sunny Island operating manual).
122 SI44M-80H-12-BE-en-10
Estimation
C120
C10 = /
1.28
C100
C10 = /
1.25
C20
C10 = /
1.09
C10 = C10
C5
C10 = /
0.88
C1
C10 = /
0.61
SMA Solar Technology AG
Operating Manual