Connecting the Battery Current Sensor in the Off-Grid System
Qualified person
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.
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:
- Install the battery current sensor in the DC power cable between the battery and the battery fuse.
- Connect the BatCur+ insulated measuring conductor to the side for connecting the battery fuse on the battery current sensor.
- Connect the BatCur- insulated measuring conductor to the side for connecting the battery on the battery current sensor.
- Thread both insulated conductors through a ferrite included in the scope of delivery and connect to the terminals BatCur+ und BatCur- on the Sunny Island ( > Connecting BatVtgOut, DigIn, BatTMP and BatCur).
