SMA Off-Grid Systems - Manual (Page 14)

3 Information on Off-Grid Systems and System Description SMA Solar Technology AG
14 Off-Grid-IS-en-30 Installation - Quick Reference Guide
3.2.4 Multicluster System
Figure 4: Block circuit diagram
Multicluster systems consist of several three-phase clusters. The individual clusters must be connected to a Multicluster Box.
The Multicluster Box is the AC main distribution board in a multicluster system. If the device types within the cluster are
different, the master must be an SI8.0H-11.
3.3 Information on Off-Grid Systems
Required device types for multicluster systems
In multicluster systems, the Sunny Island inverters must be device type SI6.0H-11 or SI8.0H-11.
Information on batteries
Lithium-ion batteries in off-grid systems
In order to meet the requirements of off-grid systems, the Sunny Island has a high overload capacity. The prerequisite
for this overload capacity is that the battery is able to supply sufficient current. With lithium-ion batteries, this ampacity
cannot be taken for granted.
• Check with the battery manufacturer whether the battery is suitable for off-grid systems with Sunny Island
inverters. Pay special attention to the ampacity.
Recommendations for battery capacity
SMA Solar Technology AG recommends the following minimum battery capacities.
• Minimum battery capacity per Sunny Island inverter:
– SI3.0M-11: 100 Ah
– SI4.4M-11: 150 Ah
– SI6.0H-11: 190 Ah
– SI8.0H-11: 250 Ah
• Minimum battery capacity per 1,000 Wp power of the PV system: 100 Ah
The sum of the individual battery capacities is the total minimum battery capacity and applies to a ten-hour electric
discharge (C10). The minimum battery capacity must be observed to ensure stable operation of the system.