SMA Off-Grid Systems - Manual (Page 7)

SMA Solar Technology AG 2 Safety
Installation - Quick Reference Guide Off-Grid-IS-en-30 7
2 Safety
2.1 Intended Use
Off-grid systems with Sunny Island inverters are self-sufficient utility grids that are being fed with energy from several AC
sources in the stand-alone grid (e.g., PV inverter), from a generator, and/or with DC charge controllers (e.g., Sunny Island
Charger). The Sunny Island forms the stand-alone grid as a voltage source. The Sunny Island regulates the balance
between the energy fed-in and energy used and has a management system with battery and generator management and
load control.
The Sunny Island can synchronize with a generator and connect directly, if necessary. When the stand-alone grid is
connected to the generator, the voltage in the stand-alone grid is regulated by the generator.
Off-grid systems with Sunny Island inverters are single-phase or three-phase AC distribution grids. The local standards
and provisions must be observed. Loads in off-grid systems are not protected against power failure. An off-grid system is
not suitable for supplying life-sustaining medical devices.
Multiple Sunny Island inverters can be operated in an off-grid system. Three Sunny Island inverters are connected in
parallel on the DC side and form a cluster. A cluster can consist of the following device types:
The circuitry of the Sunny Island inverters forming a cluster and the circuitry of several clusters in a system must be carried
out in accordance with this documentation (see Section 3 "Information on Off-Grid Systems and System Description",
page 11).
The output power of the AC sources in the stand-alone grid is controlled via the frequency and voltage of the stand-alone
grid. The AC sources must be suitable for stand-alone mode with Sunny Island (see Technical Information "PV Inverters in
Off-Grid Systems" at www.SMA-Solar.com). The maximum output power of the AC sources in a stand-alone grid must be
observed (see the Sunny Island inverter installation manual).
The Sunny Island uses lead-acid batteries or lithium-ion batteries for energy storage in off-grid systems. Ensure that the
battery room is sufficiently ventilated when using lead-acid batteries (see battery manufacturer's documentation). If a
lithium-ion battery is connected, its battery management must be compatible with the Sunny Island. The lithium-ion battery
must be able to supply enough current at maximum output power of the Sunny Island inverter (for technical data see the
Sunny Island inverter installation manual). The individual products in the off-grid system must be used for their intended
purpose (see documentation of each product). Any use of the system other than that described in the Intended Use section
does not qualify as appropriate.
DC loads, up to four Sunny Island Charger charge controllers per cluster, or charge controllers from third-party suppliers
can only be connected in off-grid systems with lead-acid batteries. The battery management must record the DC current
during battery charging and electric discharge. If charge controllers from a third-party supplier or DC loads are installed
in an off-grid system, an additional battery current sensor must be installed. The Sunny Island is not suitable for
establishing a DC distribution grid.
The enclosed documentation is an integral part of the products. Keep the documentation in a convenient place for future
reference and observe all instructions contained therein.
Device type Potential device types within a cluster Explanation
SI3.0M-11 SI3.0M-11 A cluster must consist of the same device types.
SI4.4M-11 SI4.4M-11
SI6.0H-11 SI6.0H-11 or SI8.0H-11 A cluster can consist of different device types.
If the device types within the cluster are different,
the master must be device type SI8.0H-11.
SI8.0H-11 SI6.0H-11 or SI8.0H-11