Connecting External Sources
SMA America, LLC
114
SI5048U-TUS121440
Technical Description
14 Connecting External Sources
The Sunny Island supports the integration of external energy sources. Here a distinction is made
between the integration of a generator and the integration of the public grid.
Both the generator as well as the public grid are integrated through the AC2 connection of the Sunny
Island. A single-phase, split-phase and 3-phase connection can be established. In the case of single-
phase parallel operation the transfer relays are operated in parallel, making it possible to use a
correspondingly larger current, which in turn allows for a generator or grid connections with a higher
capacity
The Sunny Island has separate parameters for the grid and generator. This generally allows both
operating modes to be used without making additional adjustments. The parameter settings and
display values distinguish between settings or values which are generator-specific or grid-specific and
settings or values (EXT) common to both grid and generator.
14.1 Generator
The Sunny Island can start or stop a generator depending on consumer power or battery state of
charge. In this case, different limits and times are taken into consideration (see section
14.1.5 ”Automatic Generator Operation” (page 120)).
Expanded Generator Management System
If necessary, the Sunny Island and the generator can supply loads jointly; the sum of (nominal) power
of both energy sources is available via the off-grid power system.
14.1.1 Parallel Connection
In the case of Sunny Island inverters connected in parallel which operate on the same phase and in
the same cluster, the internal transfer relay is activated simultaneously. It is thus possible to multiply
the generator current and therefore to connect a larger generator or a higher grid current.
The maximum current in the system is limited to 150 A:
Connection in a Single-phase Parallel System
When installing parallel single-phase systems, the connection cables for AC1 and AC2 of
all Sunny Islands must have the same cable cross-sections and cable lengths.
Number of Sunny Island inverters
Maximum current
1 Sunny Islands
56 A
2 Sunny Island inverters
112 A
3 Sunny Island inverters
150 A
