SMA SUNNY ISLAND 3.0M Installation And Quick Reference Manual page 16

3 Information on Off-Grid Systems and System Description
Device
Battery current sensor
Sunny Island offers the following functions for off-grid systems via two multifunction relays (see the Sunny Island inverter
installation manual):
Function
Controlling generators
Control of load-shedding
contactors
Time control for external
processes
Display of operating states and
warning messages
Control of a battery-room fan
Control of an electrolyte pump
Use of excess energy
16 Off-Grid-IS-en-30
Description
Shunt for measuring the battery current
A battery current sensor is required in off-grid systems with DC loads or with charge
controllers from third-party suppliers (see Section 2.1 "Intended Use", page 7).
Description
A multifunction relay activates if a generator request is received from the
Sunny Island inverter's generator management. With the multifunction relay, you can
control generators with electrical remote-start function or connect a signal generator
for generators with no autostart function.
A multifunction relay is activated depending on the state of charge of the battery.
Depending on the configuration, you can install a one-stage load shedding with one
multifunction relay or a two-stage load shedding with two multifunction relays. You
can also adjust the limiting values for the state of charge of the battery depending
on the time of day.
External processes can be time-controlled with a multifunction relay.
You can connect message devices to the multifunction relays to allow operating
states and warning messages from the Sunny Island inverter to be output. One of the
following operating states and warning messages can be displayed for each
multifunction relay:
• The generator is running and is connected.
• A Sunny Island displays an error message of level 2 or higher. Only the error
messages within a cluster are evaluated here.
• A Sunny Island displays a warning. Only the warnings within a cluster are
evaluated here.
• The Sunny Island is in operation in a single system.
• The respective cluster is in operation in a cluster system.
• The Sunny Island is in derating in a single system.
• The respective cluster is in derating in a cluster system.
The multifunction relay is activated when the charging current leads to the battery
emitting gases. A connected battery room fan is switched on for at least one hour.
Depending on the nominal energy throughput, the multifunction relay is activated at
least once a day.
During the constant voltage phase, a multifunction relay is activated and thus
controls additional loads that can put any excess energy of AC sources in the
stand-alone grid (e.g., of a PV system) to good use.
SMA Solar Technology AG
Installation - Quick Reference Guide