6 Electrical Connection
SMA Solar Technology AG
Operating manual
45
SI44M-80H-13-BE-en-15
2. Attach the battery temperature sensor in the center of the battery-
storage system, in the upper third of the battery cell. As a result,
the battery temperature sensor measures the temperature at the
warmest point in the battery-storage system.
3. Thread both insulated conductors of the sensor through a ferrite included in the scope of delivery and connect to
the terminals
BatTmp
on the Sunny Island (see Section 6.6.6, page 61). In this case, the polarity is arbitrary.
6.5.9
Connecting the Battery Current Sensor in the Off-Grid System
When using lead-acid batteries, a battery current sensor can be installed for precise measurement of the battery
current. SMA Solar Technology AG also recommends installing a battery current sensor when connecting DC loads or
DC energy sources. When connecting DC loads or DC energy sources, the SOC calculation can only work correctly
with the measured data from the battery current sensor.
Relevant for off-grid systems
BatCur −
SUNNY ISLAND
DC +
DC −
BATTERY
BATTERY
CURRENT SENSOR
BATTERY FUSE
Figure 10: Connection of the battery current sensor to the Sunny Island.
Cable requirements:
☐ Conductor type: copper wire
☐ Maximum cable length: 3 m
☐ Conductor cross-section: 0.2 mm² to 2.5 mm²
☐ A measuring cable with intrinsically safe current circuits must be used. For this purpose, "intrinsically safe" means
that the cable is double-insulated and that, in the event of a short circuit, the conductor melts but the insulation
remains intact. In addition, the cable is not combustible.
☐ Insulated conductors in the measuring cable must be twisted.
Procedure:
1. Install the battery current sensor in the
DC
power cable between the battery and the battery fuse.
