The sensors are smart devices and the 3 wires in the sheath just get paralleled together to the second sensor to create a sensor network. We are working on a more elegant solution but all you need to do is cut the sensor wire and tap in the new sensor leads. The harness is EU spec and the sensors are US colour spec so it goes like this.
Sensor Harness
Red >>> Brown (+5V)
Black >>> white (GND)
Yellow >>> remaining wire (Signal)
Page 19 of the manual talks about it a bit too.
Battery Pack Temperature Measurement:
Battery pack temperatures are measured by Dallas DS18B20 digital temperature sensor/s. Up to two sensors can be used in parallel connected directly to the wiring. Up to 8 sensors may be used with a junction box. BMS should be turned off and main connector disconnected before adding sensors. If the temperature sensors wiring is placed near the power lines shielded cables should be used.
And here are the harness pinout wires for the Active BMS:
The system will automatically find the new sensor on the network and add it to your display.
