6 Electrical Connection
SMA Solar Technology AG
Operating manual
35
SI44M-80H-13-BE-en-15
2. Ground the battery at the positive terminal or negative terminal using a conductor with the calculated cross-
section.
3. Also ground the Sunny Island enclosure using a conductor with the calculated cross-section, as follows. To do this,
first strip the insulation from the grounding conductor.
4. Place the clamping bracket over the conductor. Position the
conductor on the left.
5. Fasten the clamping bracket with the M6x16 hexagon socket
screw and a serrated conical spring washer (AF 5, torque: 4 Nm
to 5.7 Nm). The teeth of the conical spring washer must face the
clamping bracket.
6.5
Connecting the Components
6.5.1
Connecting the Battery Fuse to the Sunny Island
Selecting the battery fuse
The battery fuse protects the DC cables and the battery against a short circuit. The battery fuse must be designed
according to the maximum short-circuit current of the battery, the conductor cross section of the DC cables and the
technical data of the Sunny Island (see Section 16.3, page 176). The locally applicable standards and directives
must be complied with.
If a battery fuse is already available, no further fuse is necessary.
Tip: Install a battery fuse of the type enwitec BAT FUSE HERITAGE 01 or enwitec BAT FUSE HERITAGE 03.
Maximum cable length for the DC connection
Long cables and insufficient conductor cross-sections reduce the efficiency of the system and the overload
capacity of the inverter.
• The length of all DC cables from the battery via the battery fuse to the Sunny Island must be smaller than
10 m.
Connection of DC loads or DC energy sources
The DC connection of the inverter is primarily intended for connecting a battery. When DC loads or DC energy
sources are connected, electromagnetic interference may temporarily interfere with operation. Therefore, DC
loads or DC energy sources that are immune to electromagnetic interference should be used. This is the case if DC
loads and DC energy sources have interference immunity for industrial environments (e.g. according to EN
61000-6-2).
SMA recommends the Sunny Island Charger of MSTE SOLAR GmbH as DC charge controller.
The recommended minimum conductor cross-section depends on the battery voltage, the power and the length of the
cable:
