JKBMS Inverter BMS (Home Energy Storage) Interface Guide

JKBMS Inverter BMS (Home Energy Storage) Interface Guide

Overview

This article provides a comprehensive interface definition for the JKBMS Inverter BMS series, designed for home energy storage (ESS) applications. It covers all physical ports, communication interfaces, and wiring definitions to help users correctly connect and operate the board.

Note: Interface availability may vary by model. Please refer to the port definition tables and diagrams below, and confirm against your specific model's user manual.

Applicable Models

  • JK-PBXA16SXP-V19

1. Board Layout & Interface Overview

The Inverter BMS features interfaces on both the front panel and the main board. Key areas include:

  • Front Panel: RS485-1, RS485-2, CAN, One-Wire Port 3, RJ45 ports, DIP switches (ON/DP), dry contact terminals, ON/OFF button, RUN/ARM indicator LEDs, and temperature sensor inputs (L1–L6)
  • Main Board (rear): Balance lead connectors (P1–P11), UART port, display board connector, heating interface (P10), battery negative terminal (B−), load output negative terminal (P−), battery positive terminal (BAT+/P11)

2. Front Panel Interfaces

RS485 Ports (RS485-1 & RS485-2)

Two independent RS485 communication ports via 8P8C (RJ45) connectors. Used for communication with inverters, monitoring systems, or multi-unit parallel networks.

  • Protocol: Modbus RTU
  • Connector: 8P8C RJ45
  • Pin definition: refer to the RJ45 pin diagram (when connecting to BMS: RS485A, RS485B; when connecting to CAN: NC, NC, CANL, CANH, GND, NC)

CAN Port

CAN bus interface via RJ45 connector for communication with compatible inverters and ESS controllers.

  • Default baud rate: 500 kbps (configurable)
  • Supports mainstream ESS CAN protocols (e.g., Pylontech, SMA, Victron)
  • Connector: 8P8C RJ45

One-Wire Port (6P6C RJ11)

One-Wire communication interface via 6P6C (RJ11) connector.

DIP Switches (ON / DP)

4-position DIP switch bank for address setting and function configuration. Refer to the user manual for switch position definitions.

Dry Contact Terminals

4-terminal dry contact (relay output) interface for alarm or external control signals.

ON/OFF Button

Main power on/off control for the BMS.

Temperature Sensor Inputs (L1–L6)

Up to 6 external NTC temperature sensor inputs for monitoring battery pack and environment temperatures.

3. Main Board Interfaces

D1 — Balance Lead Connector (P1)

Main balance lead input connector (24-pin). Connects to individual cell balance leads in strict cell order.

P2 / P3 — Display Board & Auxiliary Connectors

Connectors for the display board and auxiliary functions.

UART Port

Serial UART interface for wired communication with host controllers or PC configuration tools.

  • Default baud rate: 115200 bps
  • Logic level: 3.3V TTL

P4 / P5 — Auxiliary Connectors

Additional multi-pin connectors for extended functions (refer to pin definition table below).

P6–P9 — NTC Temperature Sensor Connectors

Multiple NTC temperature sensor connectors for cell-level temperature monitoring.

  • Sensor type: NTC 10kΩ (at 25°C)

P10 — Heating Interface

2-pin connector for external heating pad control. Automatically activates in low-temperature conditions to protect cells during charging.

P11 / BAT+ — 16S Battery Positive Terminal

Battery pack total positive terminal connection point.

B− — Battery Total Negative Terminal

Battery pack total negative terminal.

P− — Load Output Negative Terminal

Negative output terminal for load / inverter connection.

4. Connector Pin Definitions

D1 (P1) — Balance Lead & Communication Connector

24-pin connector including: RUN-LED, ARM-LED, LED3–LED6, RS485-A1, RS485-A2, CANH1, GND, ADDR0–ADDR3, RS485-B1, CANL, INST+, INST−, and related signals. Refer to the pin diagram image below.

P2 — RS232 / RS485 Connector

Includes: RS232-TX/NC, RS232-RX/NC, GND1, GND1, RS485-B2, RS485-A2, NC.

P3 — Multi-function Connector

Includes: RS485-B2, GND0, NC, ON/OFF-LED, LED5, LED6, COM2, COM1, S2, S1, GND0.

5. Interface Comparison Summary

Interface / Feature Inverter BMS (JK-PB Series)
Bluetooth ✅
UART ✅
CAN (RJ45) ✅
RS485 × 2 (RJ45) ✅
One-Wire (RJ11) ✅
Heating Control ✅
NTC Temperature Sensors ✅ (up to 6 channels)
Dry Contact Output ✅
DIP Address Switch ✅
Balance Leads ✅

6. Safety Notes

  • Always disconnect all power sources before wiring to avoid short circuits or electric shock.
  • Do not hot-plug RS485, CAN, or UART interfaces.
  • Balance leads must be connected in strict cell sequence — incorrect wiring may permanently damage the BMS.
  • Confirm RJ45 pin definitions before connecting — RS485 and CAN share the same RJ45 form factor but have different pin assignments.
  • If in doubt, contact JKBMS technical support or refer to the user manual for your specific model.

7. Port Definition Diagrams & Wiring Reference

The following images show the front panel layout, main board interface locations, and detailed pin definitions for all connectors:

Inverter BMS front panel interface layout — RS485, CAN, One-Wire, DIP switches, dry contact terminals

Inverter BMS main board interface layout — balance leads, UART, heating, B-, P-, BAT+ terminals

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