SMA Off-Grid Systems User Manual
Installation - Quick Reference Guide
Off-Grid Systems
Off-Grid Systems with SUNNY ISLAND 3.0M / 4.4M / 6.0H / 8.0H
Off-Grid-IS-en-30 | Version 3.0 ENGLISH
Legal Provisions SMA Solar Technology AG
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You can download the current warranty conditions from the Internet at www.SMA-Solar.com.
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2 Off-Grid-IS-en-30 Installation - Quick Reference Guide
SMA Solar Technology AG Table of Contents
Table of Contents
1 Information on this Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Content and Structure of this Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Target Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 Additional Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Symbols for Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 Typographies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Intended Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Information on Off-Grid Systems and System Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1 Off-Grid System Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Modular Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.2.1 Single System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.2.2 Single-Cluster System (Single-Phase) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
3.2.3 Single-Cluster System (Three-Phase) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.2.4 Multicluster System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.3 Information on Off-Grid Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4 Optional Devices and Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4 Single System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 Circuitry Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2 Connecting the Sunny Island . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3 Connecting RS485 to the Sunny WebBox. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.4 Basic Configuration of the Sunny Island Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5 Single-Cluster System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.1 Circuitry Overview Single-Phase Single-Cluster System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.2 Circuitry Overview Three-Phase Single-Cluster System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.3 Connecting the Sunny Island inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.3.1 Connecting the Master . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
5.3.2 Connecting the Slaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
5.4 Connecting RS485 to the Sunny WebBox. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.5 Basic Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6 Multicluster System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.1 Circuitry Overview and Connection of the Sunny Island Inverters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6.2 Basic Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
7 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.1 Switching to Installer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.2 Commissioning the Multifunction Relays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7.3 Starting the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
7.4 Testing the Battery Current Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
7.5 Testing the Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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Table of Contents SMA Solar Technology AG
7.6 Testing the Load Shedding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.7 Commissioning the Sunny WebBox. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7.8 Commissioning the PV System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7.9 Completing Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
8 Contact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
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SMA Solar Technology AG 1 Information on this Document
1 Information on this Document
1.1 Validity
This document is valid for off-grid systems with the following Sunny Island inverter device types:
• SI3.0M-11 (Sunny Island 3.0M) from firmware version 3.2
• SI4.4M-11 (Sunny Island 4.4M) from firmware version 3.2
• SI6.0H-11 (Sunny Island 6.0H) from firmware version 3.1
• SI8.0H-11 (Sunny Island 8.0H) from firmware version 3.1
1.2 Content and Structure of this Document
This document summarizes the specific information on off-grid systems with Sunny Island inverters. Circuitry overviews of
selected off-grid systems provide the basis as to how an off-grid system can be designed. The structure of the document
specifies the chronological sequence for configuration and commissioning. This document does not replace the
documentation of the individual products. You will find details and help in the event of difficulties in the documentation of
the respective product.
1.3 Target Group
The tasks described in this document must only be performed by qualified persons. Qualified persons must have the
following skills:
• Training in how to deal with the dangers and risks associated with installing and using electrical devices and batteries
• Training in the installation and commissioning of electrical devices
• Knowledge of and adherence to the local standards and directives
• Knowledge of and compliance with this document and all safety precautions
1.4 Additional Information
Links to additional information can be found at www.SMA-Solar.com:
Document title Document type
Sunny Island System Guide Brochure
Off-Grid Systems Planning guidelines
PV Inverters in Off-Grid Systems Technical information
Sunny Island "Generator - Whitepaper" Technical file
External Energy Sources Technical information
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1.5 Symbols for Information
Symbol Explanation
Indicates a hazardous situation which, if not avoided, will result in death or serious injury
Indicates a hazardous situation which, if not avoided, can result in death or serious injury
Indicates a hazardous situation which, if not avoided, can result in minor or moderate injury
Indicates a situation which, if not avoided, can result in property damage
Information that is important for a specific topic or goal, but is not safety-relevant
☐ Indicates a requirement for meeting a specific goal
☑ Desired result
✖ A problem that might occur
1.6 Typographies
Typography Use Example
bold • Display messages
• Parameters
•Terminals
•Slots
• Elements to be selected
• Elements to be entered
> • Several elements that are to be
selected
[Button/Key] • Button/key on the inverter to be
selected or pressed
• Connect the grounding conductor to
AC 2Gen/Grid.
• Select the parameter 235.01 GnAutoEna
and set to Off.
•Select 600# Direct Access > Select
Number.
•Press [ENTER].
1.7 Nomenclature
Complete designation Designation in this document
Sunny Boy, Sunny Mini Central, Sunny Tripower PV inverter
Battery charge controllers not supplied by
SMA Solar Technology AG
Charge controllers from a third-party supplier
AC voltage source that can form a stand-alone grid
(e.g., diesel generator)
The term parameter includes parameters with configurable values as well as parameters for displaying values.
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Generator
SMA Solar Technology AG 2 Safety
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 gen erator, 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:
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.
SI8.0H-11 SI6.0H-11 or SI8.0H-11
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 Section3 "Information on Off-Grid Systems and System Description",
page11).
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.
If the device types within the cluster are different,
the master must be device type SI8.0H-11.
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2.2 Safety Precautions
This section contains safety precautions that must be observed at all times when working on or with the system. To prevent
personal injury or property damage and to ensure long-term operation of the system, read this section carefully and follow
all safety precautions at all times.
Danger to life due to incompatible lithium-ion battery
An incompatible lithium-ion battery can lead to a fire or an explosion. With incompatible lithium-ion batteries, it is not
ensured that the battery management is intrinsically safe and will protect the battery.
• Ensure that the battery complies with the locally applicable standards and directives and is intrinsically safe.
• Ensure that the lithium-ion batteries are approved for use with the Sunny Island.
The list of lithium-ion batteries approved for the Sunny Island is updated constantly (see Technical Information
"List of approved lithium-ion batteries" at www.SMA-Solar.com).
• If no lithium-ion batteries approved for Sunny Island can be used, you should use lead-acid batteries.
Danger to life due to explosive gases
Explosive gases may escape from the battery and cause an explosion. This can result in death or serious injury.
• Protect the battery environment from open flames, embers, or sparks.
• Install, operate, and maintain the battery in accordance with the manufacturer's specifications.
• Do not heat the battery above the temperature permitted or burn the battery.
• Ensure that the battery room is sufficiently ventilated.
Danger to life from electric shock due to circuit breakers that cannot be tripped
In the off-grid system, only the circuit breakers that can be tripped by the Sunny Island can be tripped. Circuit breakers
with a higher operating current cannot be tripped. Under fault conditions, there may be a voltage that poses a danger
to life present on accessible parts for several seconds. This can result in death or serious injury.
• Check if a circuit breaker has a higher trip characteristic than the following circuit breakers which can be tripped:
– SI3.0M-11 and SI4.4M-11: circuit breaker with trip characteristic B6 (B6A)
– SI6.0H-11 and SI8.0H-11: circuit breaker with trip characteristic B16 (B16A) or circuit breaker with trip
characteristic C6 (C6A)
If a circuit breaker has a higher trip characteristic than the specified circuit breaker which can be tripped, you
should also install a residual-current device of type A.
Danger to life from electric shock due to damaged devices
Operating a damaged device can lead to hazardous situations that can result in death or serious injuries due to electric
shock.
• Only use the off-grid system when it is technically faultless and in an operationally safe state.
• Regularly check the off-grid system for visible damage.
• Ensure that all safety equipment is freely accessible at all times.
• Make sure that all safety equipment is in good working order.
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Danger to life from electric shock due to live voltage
High voltages are present in the off-grid system. When covers (e.g., an enclosure lid) are removed, live components
can be touched, which can result in death or serious injury due to electric shock.
• When carrying out any work on the electrical installation, wear suitable personal protective equipment.
• Turn off or disconnect the following devices from voltage sources in the given order:
– Loads
– Generator
–Sunny Island
– In the distribution board, the circuit breakers of the Sunny Island inverter and of the generator
– Load-break switch of the battery
• Ensure that the off-grid system cannot be reconnected.
• Open the enclosure lid on the Sunny Island inverter and ensure that no voltage is present in the device.
• Ground and short-circuit the AC conductors outside the Sunny Island inverter.
• Cover or isolate any adjacent live components.
Chemical burns and poisoning due to battery electrolyte
If handled inappropriately, battery electrolyte can cause irritation to the eyes, respiratory system, and skin and it can
be toxic. This may result in blindness and serious chemical burns.
• Protect the battery enclosure against destruction.
• Do not open or deform the battery.
• Whenever working on the battery, wear suitable personal protective equipment such as rubber gloves, apron,
rubber boots, and goggles.
• In the case of acid splashing into eyes or on skin, rinse thoroughly with clear water and consult a doctor.
• If acid fumes have been inhaled, consult a doctor.
• Install, operate, maintain, and dispose of the battery according to the manufacturer's specifications.
Risk of injury due to short-circuit currents
Short-circuit currents in the battery can cause heat build-up and electric arcs. Burns or eye injuries due to flashes may
result.
• Remove watches, rings, and other metal objects.
• Use insulated tools.
• Do not place tools or metal parts on the battery.
Risk of crushing injuries due to movable generator parts
Moving parts in the generator can crush or sever body parts. A generator can be started automatically by the
Sunny Island.
• Only operate the generator with the safety equipment.
• Install, maintain, and operate the generator according to the manufacturer's specifications.
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Risk of burns due to short-circuit currents on the disconnected Sunny Island
The capacitors at the DC connection input area store energy. After the battery is isolated from the Sunny Island, battery
voltage is still temporarily present at the DC terminal. A short circuit at the DC terminal can lead to burns and may
damage the Sunny Island.
• Wait 15 minutes before performing any work at the terminal or on the DC cables. This allows the capacitors to
discharge.
Damage to the battery due to incorrect settings
Incorrect settings can lead to premature aging of the battery. Settings of the parameters in the menu 220# Battery
influence the charging behavior of the Sunny Island inverter.
• Ensure that the values recommended by the battery manufacturer are set for the battery (for the battery technical
data, see the documentation of the battery manufacturer).
Destruction of devices due to electrostatic discharge (ESD)
If enclosure parts are removed, the devices (e.g., Sunny Island or PV inverter) can be damaged or destroyed if
electronic components or terminals are touched.
• Do not touch any electronic components in open devices.
• Ground yourself before touching any terminals.
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SMA Solar Technology AG 3 Information on Off-Grid Systems and System Description
3 Information on Off-Grid Systems and System Description
3.1 Off-Grid System Functions
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 an external AC voltage source (e.g., diesel generator), and/or
with DC charge controllers (e.g., Sunny Island Charger). The Sunny Island forms the stand-alone grid as a voltage source
and provides active and reactive power. 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.
In order to be able to distribute the output power of the off-grid system to the loads, several Sunny Island inverters can
be connected modularly in an off-grid system.
Battery Management
Battery management of the Sunny Island inverter is based on precise determination of the state of charge. By combining
the three most common methods for recording the state of charge, the Sunny Island reaches a measuring accuracy of
more than 95%. This way, overcharge and deep discharge of the battery are avoided.
A further feature of battery management is the extremely gentle charging control. It automatically selects the optimum
charging strategy for the battery type and the situation in which it is used. This means that overcharging can be reliably
prevented and that the battery can be fully charged regularly. The available charge energy is used optimally at all times
(see Technical Information "Battery Management" at www.SMA-Solar.com).
Generator Management
The Sunny Island inverter generator management allows for uninterruptible connection of the stand-alone grid to the
generator and uninterruptible isolation from the generator. The generator management controls the generator via a start
and stop signal. A generator current control ensures that the generator always remains at the optimum operating point.
The generator management allows the use of generators that have a low output power in proportion to the nominal load
(see Technical Document "Sunny Island - Generator Whitepaper" at www.SMA-Solar.com)
Load Control
The load control enables control of the AC sources in stand-alone grids, control of a generator, and the specific
disconnection of loads.
The AC sources in the stand-alone grid are limited in their power output by the stand-alone grid frequency. In case of
excess energy, the load control increases the power frequency. This limits the output power of the PV inverters, for
example.
If there is not enough energy available for all loads or the battery is to be preserved, load control can request energy
from a generator by means of the generator management. The generator management starts the generator and the
off-grid system is supplied with sufficient energy.
If there is no generator present in the off-grid system or the energy is not sufficient despite the generator being available,
load control turns the loads off using load shedding. All loads are shed simultaneously with one-stage load shedding.
A load shedding contactor sheds the noncritical loads during the first stage with two-stage load shedding. The remaining
loads are shed during the second stage only when the state of charge declines further. This can further increase the
availability of the off-grid system for critical loads.
Installation - Quick Reference Guide Off-Grid-IS-en-30 11
3 Information on Off-Grid Systems and System Description SMA Solar Technology AG
3.2 Modular Design
3.2.1 Single System
Figure1: Block circuit diagram
In a single system, one Sunny Island forms a single-phase stand-alone grid.
3.2.2 Single-Cluster System (Single-Phase)
Required device types for single-phase single-cluster systems
In single-phase single-cluster systems, the Sunny Island inverters must be device type SI6.0H-11 or SI8.0H-11.
Figure2: Block circuit diagram
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SMA Solar Technology AG 3 Information on Off-Grid Systems and System Description
In a single-phase single-cluster system, up to three Sunny Island inverters are connected to one battery forming a cluster.
The Sunny Island inverters are connected on the AC side to the same line conductor. If the device types within the cluster
are different, the master must be an SI8.0H-11.
3.2.3 Single-Cluster System (Three-Phase)
Figure3: Block circuit diagram
In a three-phase single-cluster system, three Sunny Island inverters are connected to one battery forming a cluster.
The Sunny Island inverters are connected on the AC side to three different line conductors. A cluster that consists of
different device types is only supported by SI6.0H-11 and SI8.0H-11. If the device types within the cluster are different,
the master must be an SI8.0H-11 (see Section3.3 "Information on Off-Grid Systems", page14).
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3 Information on Off-Grid Systems and System Description SMA Solar Technology AG
3.2.4 Multicluster System
Required device types for multicluster systems
In multicluster systems, the Sunny Island inverters must be device type SI6.0H-11 or SI8.0H-11.
Figure4: Block circuit diagram
Multicluster systems consist of several three-phase clusters. The individual clusters must be connect ed 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
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.
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Information on clusters
Device types within a cluster
A cluster can consist of the following device types:
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.
SI8.0H-11 SI6.0H-11 or SI8.0H-11
Clusters in single-phase single-cluster systems
In single-phase single-cluster systems, the Sunny Island inverters must be device type SI6.0H-11 and SI8.0H-11.
If the device types within the cluster are different, the master must be an SI8.0H-11.
Clusters in multicluster systems
In multicluster systems, the Sunny Island inverters must be device type SI6.0H-11 and SI8.0H-11. The clusters can
consist of different Sunny Island device types. If the device types within the cluster are different, the master must be
an SI8.0H-11.
If the device types within the cluster are different,
the master must be device type SI8.0H-11.
Connecting the Sunny Island inverters in single-phase single-cluster systems
In a single-phase single cluster system, the following cable lengths and conductor cross-sections must be designed
the same way:
• From the generator to each Sunny Island
• From each Sunny Island to the AC distribution board
• From the BatFuse to each Sunny Island
The same design is a requirement for stable and symmetrical operation of the off-grid system.
Maximum PV system power
In off-grid systems, the maximum PV system power depends on the total power of the Sunny Island inverters.
• Maximum output power of the PV system per SI3.0M-11: 4,600 W
• Maximum output power of the PV system per SI4.4M-11: 4,600 W
• Maximum output power of the PV system per SI6.0H-11: 9,200 W
• Maximum output power of the PV system per SI8.0H-11: 12,000 W
The maximum output power of the PV system must be observed to ensure stable operation of the off-grid system.
3.4 Optional Devices and Functions
Use of the following devices is optional in an off-grid system:
Device Description
Load-shedding contactor Contactor controlled by the Sunny Island for isolation of loads
Sunny WebBox Remote monitoring and system configuration of the off-grid system
Sunny Island Charger 50 Charge controller for off-grid systems with lead-acid batteries
A maximum of four Sunny Island Charger charge controllers can be connected to a
cluster. In multicluster systems, four Sunny Island Charger charge controllers can be
connected to each cluster. If lithium-ion batteries are used, no charge controllers can
be connected.
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