Inverter Communication & Protocol Selection


The JK‑PB2A16S inside your AmpBox is an “Inverter‑Smart” BMS. Unlike basic batteries that only provide voltage, your AmpBox can communicate with your inverter via CAN or RS485. This closed‑loop communication allows the inverter to adjust charging behavior based on real‑time cell data.

1. Preparing the Physical Connection

Before selecting a protocol in the app, you must connect the data cable between the AmpBox and your inverter.

  • The Port: Most modern inverters (Victron, Deye, Sol‑Ark, EG4) use the CAN port.
  • The Cable: A standard RJ45 (Ethernet) cable is used, but the pinout must match.
  • Note: Some inverters (like Victron) require a custom pinout using pins 7 & 8 for CAN. Always check your inverter manual before plugging in.
2. Selecting the Protocol in the JK App

To enable communication, you must tell the BMS which “language” to speak.

  • Open the JK BMS App → Settings → enter password 123456.
  • Scroll to Protocol Selection or Inverter Brand.
  • Select your brand:
    • Victron: Choose Victron or Pylontech.
    • Deye / Sol‑Ark: Choose Deye or Luxpower.
    • Growatt: Choose Growatt.
    • Goodwe / Sofar: Choose Pylontech (universal CAN protocol).
  • Tap Set to save. The BMS may reboot its communication module.
3. Setting the Communication Interface

Depending on your AmpBox model (15P, 20P, 30P), you may need to specify the hardware port:

  • CAN: Use this for modern inverters supporting closed‑loop CAN control.
  • RS485: Use this for older inverters (e.g., Voltronic/PIP) that lack CAN support.
4. Verifying the Connection

How to confirm everything is working:

  • On the Inverter Display: Check the “Battery Information” or “Li‑BMS” menu. SOC %, Voltage, and Temperature should match your AmpBox.
  • Charge/Discharge Limits: The inverter should now automatically follow the limits set in Article 2.3.
  • If a cell warms up or voltage rises too quickly, the BMS will tell the inverter to reduce current — before a protection trip occurs.
5. Troubleshooting “Comm Loss”

If your inverter displays a BMS Communication Loss error:

  • Check Baud Rate:
    • CAN: 500k
    • RS485: 9600 or 19200
  • DIP Switch Check: Ensure the Master AmpBox has DIP Switch 1 ON. The inverter only communicates with ID #1.
  • Cable Pinout: Most communication issues come from using a standard Ethernet cable when the inverter requires a crossed CAN‑bus cable.

Summary: Closed‑loop communication is the gold standard for AmpBox safety and performance. It prevents overcharging, improves efficiency, and allows the inverter to react before the BMS needs to shut down for protection.

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