Electrical Connection SMA Solar Technology AG
32 SI5048-TEN093630 Technical Description
6.2.1 Safety Precautions/Conditions
Connect a suitable battery to the DC side (see section 22”Technical Data” (page205)). The DC
connection must observe all applicable local ordinances and guidelines.
6.2.2 Cable Sizing
Be sure to observe all standards applicable to the installation site. The DIN VDE 0298-4 applies in
Germany.
Use as short a battery cable as possible. Long cables and insufficient cable diameters reduce the
system efficiency and the overload capabilities.
Example of Cable Layout
At an AC output of 5000 W and a battery voltage of 48 V, a curret of up to 140 A flows through
the battery cable.
The current flowing through the battery cable causes a power loss and a drop in voltage with every
meter of simple battery cable. You can use the following table to find the power loss and voltage drop
associated with different cable cross sections.
This means that:
For a 10-meter distance between the Sunny Island and the battery, at least 20 m of cable are needed.
Using a cross section of 50 mm
2
, 140 A (current flowing through the battery cable) cause a power
loss of 170 W in total and an effective voltage drop of 1.2 V.
DANGER!
Death hazard due to inappropriate handling of the battery. Death or serious
chemical burns.
• Obasrve all safety and maintenance instructions provided by the battery
manufacturer!
• Use special (insulated) tools to mount and install the battery.
Cable cross-section power loss Voltage drop
35 mm
2
12 W/m 90 mV
50 mm
2
8.5 W/m 60 mV
70 mm
2
6 W/m 45 mV
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