JKBMS B & BD Series Smart BMS Interface Guide (JK-BXXXX / JK-BDXXXX)

Overview

This article covers the interfaces and connectors available on the JKBMS B Series (JK-BXXXX) and BD Series (JK-BDXXXX) Smart BMS protection boards. It is intended to help users correctly connect and operate their BMS unit.

Note: Interface availability varies by version suffix. Please refer to the naming convention and version comparison table below to confirm which interfaces are included on your specific model.

Naming Convention

JKBMS model names follow a structured suffix system. Each letter in the suffix indicates a specific hardware feature built into the board:

Letter	Feature
A	ACC (Accessory Power Output)
H	Heating Control
C	CAN Bus
R	RS485
P	Parallel (Enhanced Hard Parallel Interface)
B	Buzzer Alarm
T	4-Channel Temperature Sensor
M	Dry Contact / Buzzer Alarm
D	Charger Detection
O	One-Wire Communication
E	Pre-charge Circuit

For example, the suffix HCRPB indicates the board includes: Heating + CAN + RS485 + Parallel interface + Buzzer alarm.

Applicable Models

• B Series: JK-B1A8S10P, JK-B1A16S10P, JK-B2A8S20P, JK-B2A16S20P, JK-B2A24S20P, and other JK-BXXXX variants
• BD Series: JK-BD6A8S, JK-BD6A17S, and other JK-BDXXXX variants

1. Communication Interfaces

Bluetooth

All B and BD Series boards include a built-in Bluetooth module, supporting wireless parameter configuration and real-time monitoring via the JKBMS App (iOS / Android).

UART

All B and BD Series boards include a UART serial interface for wired communication with host controllers or external devices such as inverters and energy storage controllers.

• Default baud rate: 115200 bps
• Logic level: 3.3V TTL
• Pins: TX, RX, GND

RS485 (HCRPB Version Only)

Available exclusively on HCRPB-suffix models within the B/BD Series. Supports Modbus RTU protocol, suitable for industrial-grade remote monitoring and multi-unit communication.

• Pins: A+, B−, GND
• Maximum communication distance: 1200 m
• Supports multi-device networks (up to 247 nodes)

CAN Bus (HC / HCRPB Versions)

Available on HC and HCRPB suffix models. Enables communication with compatible inverters or energy storage systems.

• Pins: CANH, CANL, GND
• Default baud rate: 500 kbps (configurable)
• Supports mainstream ESS CAN protocols (e.g., Pylontech, SMA, Victron)

2. Functional Interfaces

Heating Control (HC / HCRPB Versions)

Available on HC and HCRPB suffix models. Allows connection of an external heating pad to automatically warm the battery pack in low-temperature environments, preventing cold-charge damage to cells.

• Trigger temperature: configurable via App
• Connector type: 2-pin connector

Temperature Sensor Interface (NTC)

Multiple NTC temperature sensor ports are provided for real-time monitoring of cell and ambient temperature.

• Sensor type: NTC 10kΩ (at 25°C)
• Quantity: varies by model (typically 2–5 channels)

Balance Leads

The balance lead harness connects to each individual cell for active or passive balancing, ensuring uniform cell voltages across the pack.

• Connector: JST or solder terminals
• Important: Connect in strict cell order — incorrect wiring may permanently damage the BMS

Main Circuit Terminals (B−, P−, C−)

• B−: Battery negative input — connects to the battery pack negative terminal
• P−: Load/discharge negative output — connects to load or inverter negative terminal
• C−: Charger negative terminal — connects to charger negative (some models combine C− and P−)

3. Parallel Expansion Interfaces

Soft Parallel (PLINK Module)

HC and HCRPB versions of the B/BD Series support soft parallel expansion via the optional PLINK Module (sold separately).

Hard Parallel Interface (Parallel Module — HCRPB Version Only)

The HCRPB version features an enhanced hard parallel interface, compatible with the optional Parallel Module for multi-pack hard parallel expansion in large-capacity energy storage systems.

4. Interface Comparison by Version

Applies to B Series (JK-BXXXX) and BD Series (JK-BDXXXX)

Interface / Feature	Standard	HC	HCRPB
Bluetooth	✅	✅	✅
UART	✅	✅	✅
CAN	❌	✅	✅
RS485	❌	❌	✅
Heating Control	❌	✅	✅
Soft Parallel (PLINK Module)	❌	✅	✅
Hard Parallel (Parallel Module)	❌	❌	✅
Buzzer Alarm	❌	❌	✅

5. Safety Notes

• Always disconnect all power sources before wiring to avoid short circuits or electric shock.
• Do not hot-plug UART, RS485, or CAN interfaces.
• Balance leads must be connected in strict cell sequence — incorrect wiring may permanently damage the BMS.
• If in doubt, contact JKBMS technical support or refer to the user manual for your specific model.

6. Definition of the Port and the Wiring of the Parallel and Heating