JIKONG JK-B2A8S20P Smart BMS User Manual

1. Introduction

The JIKONG JK-B2A8S20P is an intelligent Battery Management System (BMS) designed for large capacity series lithium battery packs, including Lifepo4, Li-Ion, and LTO types, supporting configurations from 4S to 8S. This smart BMS offers comprehensive battery management with features such as voltage acquisition, high current active balancing, overcharge/over-discharge/overcurrent/over-temperature protection, coulomb meter, Bluetooth communication, and optional GPS remote functionality.

The core of the JIKONG BMS is its energy transfer active balancing technology, which ensures maximum battery consistency, extends battery life, and delays aging. It supports a continuous balancing current of 1A or 2A, depending on the model variant. The compact size and full functionality make it suitable for a wide range of applications, including electric bikes, tricycles, low-speed quads, forklifts, cleaning cars, tourist cars, industrial drones, scooters, RV energy storage, and various lithium battery and power bank systems.

JIKONG JK-B2A8S20P BMS with key features — Figure 1: JIKONG JK-B2A8S20P BMS highlighting its functions, type, balancing current, battery strings, and charge/discharge current.

BMS integrated into an electric scooter, highlighting interfaces and features — Figure 2: JIKONG BMS integrated into an electric scooter, showcasing its six major interfaces and multi-interface display capabilities.

2. Specifications

The JIKONG JK-B2A8S20P BMS offers robust performance and protection. Below are the detailed specifications:

2.1. Basic Parameters

Index	Parameter	Unit
Supply Voltage	10-36	V
Operating Power Consumption	<900	mW
Operating Temperature	-30-70	°C
Max. Number of Collection Strings	8	String
Max. Balancing Current	2	A
Max. Charging Current	200	A
Max. Discharge Current	200	A
Max. Instantaneous Current	400	A
Max. Internal Loop Resistance	0.4	mΩ
Finished Weight	349	g

Product Parameters table for JIKONG BMS models — Figure 3: Detailed product specifications for various JIKONG BMS models, including battery strings, balance method, currents, and protection features.

2.2. Dimensions

The dimensions of the JK-B2A8S20P series protection board are 153mm × 126mm × 17.6mm.

JIKONG JK-B2A8S20P dimensions diagram — Figure 4: Dimensional drawing of the JK-B2A8S20P BMS.

3. Setup & Installation

3.1. Packing List

Upon receiving your JIKONG BMS, please verify the contents of the package:

BMS x 1
Sampling line x 1 (70cm long)
NTC x 1 (40cm long)
Switch x 1 (50cm long)

Packing list for JIKONG BMS — Figure 5: Visual representation of the items included in the JIKONG BMS package.

3.2. Interface Definition

The BMS features various connectors for different functionalities. Refer to the diagram below for a visual guide to the product's appearance and interface definitions.

Rich interface options on JIKONG BMS — Figure 6: Overview of the rich interfaces available on the JIKONG BMS, including CAN, RS485, BT, NTC, Soft Switch, SOC Indicator, Key Switch, and Active Equalizer.

Key connectors and their definitions:

P1 (Balance Acquisition Interface - XH-10AW 10-pin): Connects to individual battery cell positive terminals (B1-B8) and the total negative (B-) and positive (B+) terminals for voltage acquisition and balancing.
P2 (Heating Interface - A1254WF-7A): For connecting optional heating elements (HT-) and charge indication (CD+/CD-).
P3 (Display Interface - A1254WF-6A): For connecting external display screens (VCC, A) and RS485 signal (A).
P4 (GPS Interface - 1.25T-4PWT): For optional GPS module connection (VGPS, TX, RX, GND).
P5 (Communication Interface - A1254WF-3A): For CAN/RS485 communication (DN, DP, GND).
P6 (Temperature Interface - HY2.0-4P): For NTC temperature sensors (T1A, T1B, T2A, T2B).
D1 (Bluetooth Connection Indicator): Steady on when Bluetooth is connected, blinking when disconnected.
P- (Main Negative Terminal): Connects to external load or negative terminal of charger, equipped with M6 screws.
B- (Battery Negative Terminal): Connects to the negative battery terminal, equipped with M6 screws.

3.3. Wiring Diagrams

The JK-B2A8S20P series protection board is suitable for 3-8 series lithium battery packs. The specific wiring method varies depending on the number of cells in your battery pack. Always ensure all balance cables are properly connected before powering on the BMS.

Wiring method for 8-string cells — Figure 7: Wiring diagram for an 8-string cell configuration, showing connections for B-, P-, and individual cell taps (1S-8S).

Wiring method for 4-string cells — Figure 8: Wiring diagram for a 4-string cell configuration, showing connections for B-, P-, and individual cell taps (1S-4S).

3.4. APP Installation

The JIKONG BMS is managed via a mobile application compatible with Android and iOS operating systems. To install the APP, scan the QR code below. An Android version 7 or higher is required for Android devices.

QR code for JIKONG BMS mobile APP — Figure 9: Scan this QR code to download the JIKONG BMS mobile application.

3.5. Device Activation

Before activating the protection board, ensure all balance cables are correctly connected and the P- and B- terminals are securely wired. Confirm the protection board is firmly fixed to the battery pack. Once these checks are complete, power on the protection board.

The BMS does not have a physical power-on switch. It is designed for charging activation: connect a charger with a voltage 2V higher than the battery voltage to activate the BMS. Alternatively, if you have an optional display screen and button, you can activate the device by connecting the display cable and pressing the button.

4. Operating Instructions

The JIKONG BMS offers a range of intelligent functions for optimal battery management. Most settings and monitoring are performed via the mobile APP or optional display.

4.1. Active Equalization

The BMS uses active equalization to transfer energy from higher voltage cells to lower voltage cells, ensuring battery consistency. Before using, set basic battery parameters (cell count, capacity) in the JIKONG APP. You can adjust the balance trigger pressure difference (mV) in the APP settings. Balancing automatically starts when the voltage difference between any two strings exceeds the set value and stops when it falls below. The default balance current is 2A for the JK-B2A8S20P. It is recommended that the balance current not exceed 0.2C of the battery capacity. If not needed, disable balancing in the BMS control page of the APP.

Active Balancing (Lossless Balancing) diagram — Figure 10: Diagram illustrating the principle of active balancing, where energy is transferred between cells to achieve voltage equilibrium.

Table showing excellent balance effect — Figure 11: Comparison table demonstrating the reduction in pressure difference across cells (1S-8S) before and after active balancing.

4.2. GPS and Display Interface

The BMS includes reserved GPS and display interfaces. Users can connect an optional GPS module for battery location tracking or an external display screen to monitor battery information. These options can be selected based on individual needs.

Multi-screen display and data connection options — Figure 12: Examples of multi-screen display options, including mobile APP, PC software, and JIKONG home storage display, showing real-time battery data.

4.3. Heating Function

The BMS supports an optional heating function to prevent battery performance degradation in low-temperature environments. This feature uses a resistance heater or heating film to warm the battery. The designed heating current is 4A. Users can control this function via the BMS control page in the APP. For secondary protection, it is recommended to series a temperature control switch (45°C to 65°C normally closed type) in the heating circuit to prevent thermal runaway.

4.4. Overcharge Protection and Recovery

The BMS provides standard overcharge protection. Users can set the single cell overcharge protection voltage and recovery voltage in the APP. If any cell voltage exceeds the set overcharge protection voltage during charging, the BMS will stop charging. Charging resumes when all cell voltages drop below the recovery voltage.

4.5. Overdischarge Protection and Recovery

Standard overdischarge protection is included. Users can set the undervoltage protection voltage, recovery voltage, and automatic shutdown voltage in the APP based on battery type. If any cell voltage falls below the protection voltage during discharge, the BMS will stop discharging. Discharge resumes when all cell voltages rise above the recovery voltage. If any cell voltage drops below the automatic shutdown voltage, the BMS will automatically shut down.

4.6. Overcurrent Protection (Charge/Discharge)

The BMS features standard overcurrent protection for both charging and discharging. Users can set continuous charge/discharge current, overcurrent delay, and overcurrent release time in the APP. If the current exceeds the set value for the specified delay, the BMS will trigger protection and stop the respective operation. The operation resumes after the overcurrent release time. Note: The maximum continuous discharge current should not exceed 200A.

4.7. Overtemperature Protection and Recovery

Standard overtemperature protection is provided for charging and discharging. Users can set the overtemperature protection and recovery values (°C) in the APP. If the BMS detects a temperature above the set protection value, it will stop the corresponding operation. The operation resumes when the temperature drops below the recovery value.

4.8. Low Temperature Protection and Recovery

Standard low temperature protection is included for charging. Users can set the low temperature protection and recovery values (°C) in the APP. If the BMS detects a temperature below the set protection value, it will stop charging. Charging resumes when the temperature rises above the recovery value. For extremely cold regions, using the optional heating function is recommended.

4.9. Short Circuit Protection and Recovery

The BMS is equipped with standard short circuit protection. Users can adjust the short circuit protection delay (µs) and recovery time (S) in the APP. If a short circuit occurs, the BMS will trigger protection. Adjusting the delay can help prevent false triggers due to high peak currents from chargers or loads during initial connection.

4.10. Discharge Precharge Function

An optional discharge precharge function is available. The default precharge time is 5 seconds. Users can enable or disable this function and adjust the precharge time in the APP. Setting the time to 0 disables the function.

4.11. Emergency Switch

The standard emergency switch function allows the BMS to operate for 30 minutes in critical situations (e.g., over-temperature, over-discharge, over-charge, or dropped cell). Activating this in the APP's BMS control page will enable both charging and discharging for 30 minutes, even if a single cell voltage reaches the automatic shutdown level, to provide emergency use time.

4.12. Intelligent Sleep

The intelligent sleep function is standard. When enabled in the APP, the BMS will enter a low-power sleep mode if the charging/discharging current is less than 1A for 26 consecutive hours, reducing self-consumption. The BMS can be reactivated by pressing a button (if connected) or by connecting a charger.

4.13. Communication Function

The BMS supports optional CAN/RS485 communication. Users can select the desired communication protocol and set the BMS address in the APP's BMS control page. Refer to the JIKONG Protection Board communication protocol document for specific details.

Protocol docking and compatibility with inverters — Figure 13: The BMS supports various mainstream inverter communication protocols, configurable via the mobile APP.

PC software for setting inverter communication protocols — Figure 14: The host computer software allows for setting inverter communication protocols, with a table of supported CAN protocols.

5. Maintenance

To ensure the longevity and optimal performance of your JIKONG BMS, follow these general maintenance guidelines:

Regular Inspection: Periodically check all wiring connections for tightness and signs of wear or corrosion.
Cleanliness: Keep the BMS clean and free from dust and debris. Use a soft, dry cloth for cleaning. Avoid using liquids or harsh chemicals.
Environmental Conditions: Ensure the BMS operates within its specified temperature range (-30°C to 70°C) and avoid exposure to excessive moisture or direct sunlight.
Firmware Updates: Check the JIKONG official website or APP for any available firmware updates to ensure your BMS has the latest features and bug fixes.
Physical Handling: Handle the BMS gently. Avoid dropping or subjecting it to strong impacts, as this can damage internal components.

For detailed maintenance procedures and troubleshooting, please refer to the official PDF user manual: JIKONG Lithium Battery Active Balance Protection Board Maintenance Manual (PDF).

6. Troubleshooting

The JIKONG BMS is designed with multiple protection features to safeguard your battery. If you encounter issues, the mobile APP or display screen will often provide error codes or status indications. Here are some common issues and their potential solutions:

BMS Not Activating: Ensure all balance cables are correctly connected and the main P- and B- terminals are secure. Activate by connecting a charger (voltage 2V higher than battery) or by pressing the button on an optional display.
Balancing Issues: Check the active equalization settings in the APP. Verify the trigger pressure difference and ensure the balancing function is enabled. Confirm battery parameters (cell count, capacity) are correctly set.
Overcharge/Overdischarge Protection Triggered: Review the overcharge/overdischarge voltage settings in the APP. Ensure they are appropriate for your battery type. The BMS will automatically recover once cell voltages return to safe levels.
Overcurrent Protection Triggered: Check the continuous charge/discharge current settings and delay times in the APP. Ensure your load or charger current does not consistently exceed the BMS's limits.
Overtemperature/Low Temperature Protection Triggered: Monitor battery temperature via the APP. Ensure the BMS is operating within its specified temperature range. If in a cold environment, consider enabling the heating function.
Short Circuit Protection Triggered: Inspect all wiring for actual short circuits. If no physical short is found, consider increasing the short circuit protection delay in the APP, especially if using a charger or load with high inrush current.
Communication Problems (Bluetooth/RS485/CAN): Ensure the APP is correctly installed and Bluetooth is enabled on your mobile device. For RS485/CAN, verify the wiring, address settings, and communication protocol in the APP or host computer software.

For more complex issues or specific error codes, consult the detailed troubleshooting section in the official PDF user manual.

7. User Tips

Inverter Compatibility: If connecting to an inverter via RS485, always verify compatibility with your inverter's specific RS485 protocol. Refer to the JIKONG Protection Board communication protocol document for detailed wiring and settings.
Initial Setup: Take extra care during initial wiring. Double-check all connections, especially balance leads, before applying power to prevent damage.
APP Monitoring: Regularly use the mobile APP to monitor your battery's status, including individual cell voltages, temperatures, and current. This helps in proactive maintenance and identifying potential issues early.
Parameter Adjustment: When adjusting protection parameters (voltages, currents, temperatures), do so incrementally and observe the battery's behavior. Always understand the implications of each setting.

8. Warranty & Support

JIKONG Technology Co. LTD is committed to providing high-quality products. This product is covered by a manufacturer's warranty against defects in materials and workmanship under normal use. For complete warranty terms, conditions, and support information, please refer to the official PDF user manual.

For technical assistance or further inquiries, please contact JIKONG Official Store customer service.

Official User Manual (PDF): JIKONG Lithium Battery Active Balance Protection Board Maintenance Manual

	JK SMART ACTIVE BMS Product Specifications and Features Comprehensive details on JK SMART ACTIVE BMS products, including technical specifications for various models, security protections, operational modes, and connection diagrams. Features include active balancing, heating function support, and mobile app connectivity.
	JK Smart BMS JK-B1A8S20P/JK-B2A8S20P User Manual - Technical Specifications and Operation Guide This user manual provides detailed information on the JK Smart BMS models JK-B1A8S20P and JK-B2A8S20P, covering technical specifications, connection diagrams, app operation, parameter settings, and safety precautions for Li-ion, LiFePO4, and LTO battery packs.
	JIKONG BMS: Advanced Battery Management Systems - Models, Specs, and Features Explore the comprehensive range of JIKONG Battery Management Systems (BMS) including JK-BD, JK-B1, JK-B2, and JK-BD6A series. This document details specifications, features like active balancing, superior heat dissipation, communication protocols, installation guides, and diverse application scenarios for lithium battery systems.
	JIKONG JK-B2A24S-30P Lithium Battery Active Balancing Protection Board Manual Comprehensive maintenance and user manual for the JIKONG JK-B2A24S-30P Lithium Battery Active Balancing Protection Board. Details product overview, functional characteristics, selection guides, detailed function descriptions, main parameters, interface definitions, installation methods, and APP operation instructions. Supports various lithium battery chemistries and configurations.
	JK-BD4A24S-4P Lithium Battery Active Balancing Protection Board User Manual Detailed user and maintenance manual for the JK-BD4A24S-4P Lithium Battery Active Balancing Protection Board by Chengdu Jikong Technology Co., LTD. Covers product overview, features, selection guide, functions, parameters, interface definition, installation, and APP operation.
	JK-BxA8S-20P Lithium Battery Active Balancing Protection Board User Manual This document provides a comprehensive user manual for the JK-BxA8S-20P Lithium Battery Active Balancing Protection Board manufactured by Chengdu Jikong Technology Co., LTD. It covers product overview, functional characteristics, selection guides, detailed function introductions, main parameters, interface definitions, and APP operation instructions.