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Current Sensor

The alternator current sensor is a clamp on hall effect type.

Current sensor and mating plug

Keep this dry

This sensor has no weatherproofing. Mount it in a dry location — inside a battery box, electrical panel, or enclosure. Do not expose to bilge splash, condensation, or excessive moisture.

Mounting and Wiring

  1. Choose the driest, coolest, most vibration free location you reasonably can.
  2. Route the alternator output cable through the sensor jaw. The arrow on the sensor body indicates positive flow direction, but it's invertable with a software toggle if you get it backwards.
  3. Close and secure the jaw with the provided screw, and support it so nothing chafes. The two 316 stainless wood screws in the kit fasten the sensor body down; they are sized for plywood or OSB.

  4. Ethernet Cable 1 (the left RJ5 port, alternator side) contains the wiring for this current sensor. Bring its cut end to the sensor and land four of its conductors in the green 4-pin screw-terminal plug shown in the photo — the same connector family as the XREG-010 board's Power/Field connector:

    Sensor pin Cable 1 wire Cable 1 pin Signal
    1 Blue/White 5 +5 V supply
    2 Green 6 GND — power return
    3 Brown/White 7 Vout (signal to regulator)
    4 Brown 8 GND — signal return

  5. Put dielectric grease in each terminal of the screw plug first, before any wire goes in.

  6. Strip the Cat6 conductors and clamp bare copper under the screws.
  7. Secure both the Cat6 run and the alternator output cable close to the sensor, for strain relief.

The complete pinout for all four cables is in Data Cables & Pinout.

Inside the sensor

One was sawed in half. Teardown photographs and comments on waterproofing: QNHCK1-21 Hall Current Sensor.

Specifications, output scaling, and how the sensor works: Hardware → Sensors → Current Sensor.