Development of an EV Battery Management Display with CANopen Communication

Abstract

The increasing adoption of electric vehicles (EVs) presents a growing demand for efficient, real-time battery monitoring systems. Many existing Battery Management Systems (BMS) with built-in Controller Area Network (CAN) communication are often expensive or lack user-friendly interfaces for displaying data. Moreover, integrating such BMS units with standard Human–Machine Interface (HMI) displays remains a challenge in cost-sensitive applications. This article presents the design and development of an interface for integrating the BMS of electric vehicles with the ATD3.5-S3 display using the CANopen protocol. The system enables the real-time visualization of essential battery parameters, including voltage, current, temperature, and state of charge (SOC) percentage. The proposed system utilizes a JK BMS, an ESP32 microcontroller, and a TJA1051 CAN transceiver to convert UART data into CAN Open messages. The design emphasizes affordability, modular communication, and usability in EV applications. Testing under various load conditions confirms the system’s stability, reliability, and suitability for practical use in electric vehicles.

1. Introduction

EVs have become increasingly popular as a sustainable solution to reduce greenhouse gas emissions and dependence on fossil fuels [1,2]. At the core of EV performance is the BMS, which ensures safe and efficient battery operation [3,4]. A major challenge in EV development lies in implementing cost-effective and reliable systems for real-time battery data visualization and communication [5,6]. This study presents the development of a low-cost and modular BMS interface using CANopen communication for use in EV applications [7,8].

Literature Review

Numerous studies have addressed the integration of BMS with various communication protocols [3,5,9]. Traditional BMS solutions typically utilize CAN communication but lack compatibility with modern graphical user interfaces (GUIs) [6,7]. Some commercial systems offer high integration but come at a significant cost, limiting their feasibility for low-budget EV projects [1,4]. Research has also explored protocols such as Modbus and UART-based communication [6,9,10], though these often require custom development and are not modular [8]. However, most existing solutions do not focus on low-cost, open-source implementations that integrate easily with HMI displays like the ATD3.5-S3 [11,12].

Despite advances in BMS communication, few studies address the need for an affordable, open, and flexible system that supports real-time visualization using standard HMI hardware [8,13]. Existing commercial options are either costly or closed-source, making them difficult to adapt for educational, prototyping, or budget-sensitive projects [1,3]. Moreover, CANopen—though widely used in industrial automation—remains underexplored in EV BMS display applications [7,11].

This study introduces a CANopen-based communication interface between a JK BMS and an ATD3.5-S3 touch display using an ESP32 microcontroller [8,12,14]. The novelty lies in the implementation of a low-cost, open-source solution that bridges UART-to-CANopen conversion for real-time battery parameter monitoring [7,10,11]. This modular design facilitates easy integration, scalability, and cost-efficiency, making it highly suitable for academic research and small-scale EV development [5,15].

2. CAN Communication Between BMS and Display Units

CAN Communication Between BMS and Display Units Communication between a BMS and an HMI display through the CAN protocol has become a key approach in modern EV architectures [1,6,16]. This method enables real-time monitoring and visualization of critical battery parameters, such as voltage, current, temperature, and state of charge [5,7,17]. CAN’s robustness in data transmission, coupled with its noise immunity and arbitration mechanisms, ensures the reliability and accuracy of information exchanged between the BMS and the display unit [9,18]. By employing CAN transceivers—such as the TJA1051 module—and microcontrollers like the ESP32 [10,19,20], data can be retrieved from BMS devices via UART [10,14,19] and subsequently transmitted to the display using standardized CAN frames [6,21]. This architecture not only enhances system integration but also reduces communication latency and increases diagnostic capabilities [9,18], making it an effective solution for EV battery monitoring systems [19,22].

2.1. CAN

The CAN is a digital communication protocol originally developed for use in automotive systems and has since been widely adopted in industrial and medical applications. It enables communication between ECUs [9,21] without the need for a centralized controller, allowing each node within the network to communicate independently. CAN is known for being dependable, strong, and effective at handling real-time data [9,18], making it suitable for applications requiring high accuracy and stability, such as automotive control systems [9,21], industrial automation, and critical medical devices [18].

2.2. CANopen

CANopen is a communication protocol developed on the foundation of CAN to support automation control, particularly within industrial domains such as manufacturing systems, robotics, and medical devices [7]. It is designed to be highly flexible and easily extensible, enabling efficient communication between devices within a network [18]. CANopen includes specialized control functions such as parameter configuration and device status monitoring, enhancing the usability of CAN-based systems in complex and scalable applications [21].

Although traditional CAN is sufficient for simple EV battery systems with limited nodes and custom message formats, it lacks standardization at higher layers, which can lead to integration issues across devices from different vendors [18,21]. CANopen, by extending the CAN protocol with standardized communication profiles, offers enhanced interoperability, structured data handling through Object Dictionaries, and built-in support for diagnostics, synchronization, and real-time communication via Process Data Objects (PDOs) and Service Data Objects (SDOs) [7,11]. These features make CANopen more suitable for complex, modular EV systems where safety, performance monitoring, and multi-device coordination are critical [8,11]. However, it introduces greater complexity and may not be ideal for resource-constrained systems [9]. Therefore, the choice between CAN and CANopen should depend on system requirements for scalability, diagnostics, and vendor interoperability [11,21].

2.3. PCAN-USB

The PCAN-USB is a hardware interface device that enables the connection between a CAN and a computer via a USB port [9,18]. It functions as a signal converter, allowing users to monitor, analyze, and interact with data transmitted over a CAN bus [9,21]. This device is particularly valuable in automotive development environments or any applications requiring CAN-based communication [9,18], as shown in Figure 1.

2.3.1. D-Sub Pin Configuration

The PCAN-USB device employs a 9-pin D-Sub connector to facilitate CAN communication. The standard pin assignment is detailed in

Table 1. PCAN-USB D-Sub pin assignment [23].

Pin	Connection Type
1	Not connected/optional + 5 V
2	CAN-L
3	GND
6	GND
7	CAN-H
9	Not connected/optional + 5 V

and typically adheres to the layout specified by the manufacturer, as shown in Figure 2.

2.3.2. Key Features of PCAN-USB

The device connects directly to a computer or laptop via a USB interface, allowing easy integration with analysis and diagnostic software. The PCAN-USB also allows direct communication with CAN-based systems, including reading sensor data and sending control messages to other devices on the CAN network.

2.4. Lithium-Ion Battery with Nickel Manganese Cobalt Oxide (NMC)

NMC lithium-ion batteries are a class of rechargeable batteries that combine lithium with nickel, manganese, and cobalt (LiNiMnCoO₂) as cathode materials [24,25]. This formulation provides a well-balanced combination of high energy density, safety, and operational versatility [24,26], making NMC batteries highly suitable for applications that demand high performance, particularly EVs [8,24] and energy storage systems (ESS) [27].

2.5. Lithium Battery Pack Assembly

The assembly of lithium battery packs is essential for ensuring the safety, reliability, and performance of energy storage systems [27,28]. It involves configuring multiple cells in series or parallel to meet voltage and capacity requirements [25], integrating a BMS for monitoring and protection [18,25,28], as shown in Figure 3, and using protective materials to prevent potential hazards. Effective thermal management is crucial for dissipating heat and maintaining performance, while a robust mechanical structure with durable enclosures ensures physical protection [15,28].

In this study, 20 lithium-ion cells (3.7 V, 25 Ah) were connected in series. The total voltage and capacity of the battery pack are calculated using the following equations:

$$V_{total}=N\times V_{cell}$$

(1)

$$Ctotal=Ccell$$

(2)

where

• V_total is the total voltage of the battery pack;
• C_total is the total capacity of the battery pack;
• N is the number of cells connected in series;
• V_cell is the voltage of a single cell;
• C_cell is the capacity of a single cell.

2.6. BMS

A BMS is an essential component designed to monitor, regulate, and optimize the performance of rechargeable batteries, especially lithium-ion types that require precise control due to their electrochemical complexity [1,3,22]. The BMS performs several core functions, including monitoring cell voltage and temperature to prevent overcharging, overheating, and thermal runaway; managing current flow to avoid overcurrent damage; and balancing cell voltages to ensure consistent performance and maximize battery lifespan [4,17]. It also detects faults and alerts users to abnormal conditions while activating protective measures to prevent failure [4,18]. Key components of a BMS include sensors for real-time monitoring [5,29], a microcontroller unit (MCU) for processing data and executing control strategies [14,20], and balancing circuitry to maintain voltage uniformity across cells [4,22,25]. The BMS offers significant benefits, such as enhanced safety, extended battery life, and improved overall performance [1,4,16]. Its applications span a wide range of industries, including EVs [2,3], where it supports stable and efficient operation, and ESS [17,27] that rely on renewable sources like solar and wind. In conclusion, BMS is a critical technology that ensures the safe, reliable, and efficient use of lithium-ion batteries in modern energy and mobility solutions [1,2,4].

2.7. JK BMS (JiKong Battery Management System)

JK BMS, or the JiKong Battery Management System, is a widely used BMS solution designed for various energy applications [14,22], particularly in EVs [2] and ESS [17], where reliability and efficient power management are essential [22], as shown in Figure 4. JK BMS is recognized for offering comprehensive features for monitoring and managing lithium-ion batteries [14,29] while also demonstrating robust compatibility with other electronic systems [21].

While the JK BMS is chosen in this study due to its affordability and functionality, it is essential to recognize that other low-cost alternatives, such as the LTT BMS and SmartBMS, also exist. However, the JK BMS offers specific technical advantages that align well with the goals of this study [14,22,30]. For instance, it provides a highly stable UART communication protocol that can be adapted to CAN through hardware-level conversion (e.g., using the TJA1051 transceiver) [14,21,31], whereas some other budget BMS options may lack detailed documentation or support for communication scalability [29].

2.8. UART

UART is a serial communication protocol used for data transmission between two devices, such as a microcontroller and a sensor or computer [18]. It operates asynchronously, without requiring an external clock, using two primary lines: TX (Transmit) and RX (Receive). Data transmission involves a structure with a start bit, data bits, an optional parity bit, and stop bits, with the sender and receiver agreeing on a baud rate for synchronization. UART supports various operation modes, including simplex, half-duplex, and full-duplex, and is commonly used in microcontrollers [14,20], computer interfaces, and embedded systems like BMS [5,22] and electric vehicles [2,10]. It offers advantages such as simplicity, low cost, and full-duplex communication, but it has limitations, including lower speed compared to other protocols like SPI and I2C, as well as limited multi-device support.

2.9. TJA1051 Transceiver Module

The TJA1051 is a CAN transceiver module designed to interface CAN systems with external embedded devices [21]. This device is manufactured by NXP Semiconductors, which is headquartered in Eindhoven, The Netherlands. It is widely utilized in automotive and industrial applications, particularly within electric vehicle systems [2], to facilitate efficient communication between internal components such as ECUs [18] and various sensors, as shown in Figure 5. The TJA1051 acts as a bridge that converts differential CAN signals into logic-level signals usable by microcontrollers [14,20] and other control units.

2.10. ATD3.5-S3 Display Module

The ATD3.5-S3, manufactured by Artron Shop Co., Ltd. (ArtronShop), with operations based in Nonthaburi, Thailand, is a 3.5-inch TFT capacitive touch display designed for integration with the ESP32-S3 board, manufactured by Espressif Systems (Shanghai) Co., Ltd. from Shanghai, China [14,20]. which offers high-performance processing and wireless communication capabilities, including Wi-Fi and Bluetooth, as shown in Figure 6. This display module serves as a practical solution for embedded systems that require interactive graphical user interfaces [11], particularly in applications such as the Internet of Things (IoT) [32], automation systems, and smart home devices [20].

2.11. CAN Bus Expansion Module for ATD3.5-S3

The CAN bus expansion module for the ATD3.5-S3 display serves as an auxiliary interface designed to enable microcontroller-based systems—such as those utilizing Arduino boards—to communicate over a CAN [18,21]. CAN is a widely adopted communication protocol in automotive and industrial systems [1,9,16], providing robust and efficient data exchange between distributed devices within the same network, as shown in Figure 7.

This CAN bus shield acts as a bridge between the main ATD3.5-S3 system and the CAN network, allowing the system to both transmit and receive data reliably and securely [18]. It converts electrical signals and manages protocol-level communications to ensure compatibility with other CAN-enabled components, such as BMS [14,22], sensors, or ECUs [21].

By integrating this module, the ATD3.5-S3 platform can function not only as a display and control interface [11] but also as a node within a distributed embedded system [14,32]. This expands its applicability to fields requiring real-time communication and diagnostics—particularly in smart energy systems, electric vehicles [2], and factory automation [18].

2.12. ESP32 Module

The ESP32 is a high-performance microcontroller developed by Espressif Systems. It is equipped with integrated Wi-Fi and Bluetooth capabilities [10,14,19] and is designed for a wide range of applications, including automation systems [32], the IoT [20], and intelligent control systems [10,14,32], as shown in Figure 8. Its versatility and adaptability for interfacing with various sensors and peripherals make it a popular choice in embedded system development [10,14,19].

2.13. Buck Converter or Step-Down Converter

A buck converter, also known as a step-down converter, is a type of switching voltage regulator designed to efficiently reduce a higher input voltage to a lower output voltage. It belongs to the family of DC-DC converters and is widely utilized in applications requiring regulated DC power. Unlike linear regulators, the buck converter uses high-frequency switching to control and regulate the voltage conversion process, offering significantly higher efficiency.

3. Methodology

This article focuses on the development of the JK Battery Management System (JK BMS) [14] and its connection to a display interface, allowing users to monitor battery status in real time [22]. The BMS and the display communicate via the CANopen protocol [21], a standard widely used in the automotive industry [1,2]. In this study, an ESP32 module is used to receive UART signals from the BMS [14,20] and forward them to a TJA1051 transceiver module [14,20]. The UART signals are then converted into CAN signals and transmitted to the display [18]. The system presents key battery parameters, such as voltage, current, temperature, and SOC for user monitoring [17].

An overview of the battery monitoring system architecture is shown in Figure 9. The JK BMS communicates via UART to the ESP32 [14,20], which then sends CAN messages via the TJA1051 transceiver [21,31] to the ATD3.5-S3 display [12].

3.1. Electrical Circuit Design

The electrical circuit design in this study was carried out using EasyEDA version 2.2.40.3, a popular software for circuit and printed circuit board (PCB) design. EasyEDA is user-friendly and supports the complete workflow, including schematic drawing, PCB layout, and direct export of files for manufacturing [15]. The prototype circuit was created as shown in Figure 10. The details of each component are shown in

Table 2. Component details.

Number	Name
1	ESP32 Microcontroller
2	Buck Converter
3	TJA1051 CAN Transceiver
4	Fuse
5	CAN Bus Communication Port
6	Battery Management System (BMS) Communication Port

.

The ESP32 was selected for this research due to its cost-effectiveness, sufficient computational power, and built-in Wi-Fi/Bluetooth capabilities, making it ideal for cost-sensitive EV prototyping [10,14,20]. With its dual-core 32-bit Xtensa LX6 processor running up to 240 MHz, the ESP32 can efficiently handle real-time data parsing, CAN frame processing, and GUI control without the need for additional hardware [13,14]. Compared to STM32F series MCUs, which offer strong real-time performance but often require more complex setups and lack native wireless interfaces, ESP32 provides a more integrated and developer-friendly solution [32]. Its large open-source ecosystem, support for libraries like LVGL, and low power consumption in sleep modes further enhance its suitability for embedded EV monitoring applications [20,32]. While STM32 may be preferred for applications demanding strict real-time control and industrial-grade support, ESP32 offers a well-balanced alternative that simplifies development and meets the performance needs of this project [14].

3.2. Testing and Evaluation Method

The communication system, implemented through CANopen, is tested to ensure accuracy and stability in data transmission [21] and to verify the correctness of the data displayed on the monitor [11]. The results are analyzed, and the system is improved to achieve optimal performance [8]. Data analysis is performed by comparing the test results from the PCANView program version 4.2.2.55 with the data from the JK BMS application. The parameters compared include voltage, current, temperature, and SOC values measured by the battery system sensors [35]. The testing begins by connecting the test circuit between the BMS and the PCANView program, as shown in Figure 11. Data is acquired from PCAN-View, as shown in Figure 12, and this data is compared with the JK BMS application, as shown in Figure 13.

3.3. Conversion of Hexadecimal (HEX) Values from PCAN-View Software to Decimal (DEC)

Example 1: CAN ID 0x355 (State of Charge)

The conversion process for CAN ID 0x355, bytes 0–1, is demonstrated as follows. Referring to Figure 12, the data obtained for these bytes is the hexadecimal value 0x005D. This value was converted to its decimal equivalent using the programmer mode of a calculator, yielding the decimal number 93, as depicted in Figure 14. According to

Table 3. Definition for CAN ID 0x355.

Byte Number	Parameter Name	Value/Unit
0	State of Charge	1%
1

, CAN ID 0x355, bytes 0–1, represents the SOC. Therefore, the battery’s SOC is calculated as 93 × 1% = 93%. This calculated value was then compared with the “Remain Battery” value displayed in the JK BMS application (shown in Figure 13), which also indicated 93%, confirming the equivalence of the values [36].

Example 2: CAN ID 0x356 (Battery Terminal Voltage)

Similarly, for CAN ID 0x356, bytes 0–1, the data from Figure 12 is the hexadecimal value 0x0050. Converting this value to a decimal using the programmer mode of a calculator results in 80, as illustrated in Figure 15. Based on

Table 4. Definition for CAN ID 0x356.

Byte Number	Parameter Name	Value/Unit
0	Battery Terminal Voltage	1 V
1
2	Total Pack Current	1 A
3
4	Battery Temperature	1 °C
5

, CAN ID 0x356, bytes 0–1, represent the battery terminal voltage. This indicates that the total battery voltage is 80 × 1 V = 80 V. Upon comparison with the total battery voltage displayed in the JK BMS application (Figure 13), the value was confirmed to be identical at 80 V [36].

4. Discussion

Following the design and fabrication procedures outlined in Chapter 3, the researchers successfully constructed a functional circuit prototype. This prototype interfaces with the BMS via its UART port, converts the signals to the CAN protocol, and transmits them to a display unit [26]. The PCB was fabricated using a copper etching process, and components were mounted according to the schematic designed in EasyEDA software, as depicted in Figure 10 [15]. Upon completion of component installation and control system programming, the display unit accurately presented key data acquired from the BMS, namely voltage, current, temperature, and SOC.

The development and implementation of the proposed battery monitoring system represents an important contribution to the design of affordable and scalable EV diagnostic tools. The integration of CANopen communication and real-time display enables enhanced system observability for low-cost EV platforms [1,5,6,8]. Through detailed testing across a range of operational scenarios—such as fast charging, high-current discharge, and idle states—the system demonstrated high data fidelity, stability, and robustness [5,15,24].

The consistent matching of data between the prototype system, PCAN-View, and the JK BMS application underscores the accuracy of the data transmission process. This validates the correctness of the hexadecimal-to-decimal conversions and the proper assignment of CAN IDs to specific battery parameters [23,30]. Notably, the system maintained accurate and real-time performance without packet loss or delay even under rapid current fluctuations and thermal changes during high-load conditions [5,13].

One of the technical highlights is the successful use of the ESP32 to decode UART messages and generate CANopen-compliant frames. This lightweight microcontroller reliably parses, formats, and forwards data, with no noticeable delays throughout the testing period [10,13,32].

4.1. Data Communication Test Results via CAN Bus

To verify the accuracy of the data presented on the display unit, the researchers conducted system testing by comparing data from three distinct sources: PCAN-View software version 4.2.2.55, as depicted in Figure 16; the JK BMS mobile application, as depicted in Figure 17; and the prototype system’s display unit, as depicted in Figure 18 [35].

The test results indicated a high degree of consistency between the values shown on the prototype display and the data obtained from both the PCAN-View software and the JK BMS application. It was necessary to convert the HEX values associated with specific CAN IDs captured by PCAN-View into their DEC equivalents to achieve direct correspondence with the values presented on the prototype display and within the JK BMS application.

Table 5. Sample data conversion and comparison.

CAN ID	Byte	Raw Value (HEX)	Converted Value (DEC)	Parameter/Meaning	Value in JK BMS App
0x355	0–1	0x0054	84	SOC (%)	84%
0x356	0–1	0x004F	79	Battery Voltage (V)	79 V
0x356	2–3	0x000A	10	Total Pack Current (A)	10 A
0x356	4–5	0x001B	27	Battery Temperature (°C)	27 °C

provides examples of this data conversion process [36].

To validate the accuracy of the data presented on the display, the researchers conducted system tests by comparing information from three distinct sources: the PCAN-View software, the JK BMS mobile application, and the prototype system’s display unit.

Figure 18: The prototype system display illustrates the real-time monitoring of key battery parameters—including SOC, terminal voltage, current, and temperature—during a fast charging session (10 A for 1 h). The observed values for all parameters are in precise agreement with those reported by the JK BMS mobile application [30]. This outcome confirms the accuracy of data conversion and synchronization between the BMS and the display interface across multiple critical metrics [5,8,10,13].

Figure 19: The experimental setup during the fast charging test, demonstrating real-time monitoring of terminal voltage, current, temperature, and SOC via the CANopen-based display system under high-rate charging conditions. This setup was used to evaluate the system’s responsiveness and reliability in transmitting and displaying dynamic battery parameters [5,8,13,30].

Figure 20: The experimental setup during the high-current discharge test, illustrating the system’s capability to maintain stable and accurate data communication under conditions of rapid current fluctuation [5,7,8,13,30].

4.2. Results Analysis and System Performance Evaluation

To address the need for broader testing conditions, additional stability tests were conducted under various operational scenarios, including fast charging, high current discharge, and load fluctuation conditions [26,36]. The system demonstrated reliable real-time data transmission, accurate parameter display, and no packet loss or communication delays under all scenarios [13,35]. During fast charging, the display unit consistently reflected the actual values of voltage, current, and temperature reported by the BMS [36]. Figure 19 shows the system setup during the fast charging tests. Similarly, during high current discharge tests, the system maintained stable performance, with accurate real-time reporting of rapid current variations and temperature rise, confirming the robustness of both the BMS and communication modules [22]. Figure 20 shows the system setup during the high current discharge test. These extended tests validate the system’s robustness and suitability for real-world EV operating environments [13].

Testing conducted under various operational scenarios, including under load, during battery charging, and during idle periods, revealed that the system maintained consistent data transmission without interruptions or loss of data packets [13].

The identified advantages of the prototype system include the following:

• Real-time data acquisition from the BMS.
• Clear and accurate display corresponding to the actual system values.
• Scalability for integration with other control systems via the CAN bus.

Nevertheless, certain limitations were observed:

• Potential for signal stability issues over extended CAN bus cable lengths.
• The physical layout and arrangement of components may require further optimization in specific areas to mitigate potential signal interference.

4.3. Limitations and Mathematical Modeling

Despite the system’s successful implementation and stable performance under various operational conditions, several limitations must be acknowledged. First, the system’s communication stability may degrade over extended CAN bus cable lengths or in electromagnetically noisy environments, which could potentially introduce latency or data corruption [18,21]. Second, the current prototype design lacks thermal and electromagnetic shielding, which might be required for deployment in harsh automotive environments [28]. Third, the design and testing were based on a specific BMS model (JK BMS); adaptation to other BMS brands or different CANopen object dictionaries may require significant reconfiguration [11,30].

Moreover, while the system operates based on discrete decoding of CAN messages, it does not yet implement advanced mathematical algorithms such as battery state estimation (e.g., SOC or SOH estimation using Kalman Filters or equivalent models) [17,22,29]. The current implementation uses direct linear conversion from raw hexadecimal values to real-world parameters using scaling equations, such as

$$SOC=HE{X}_{0-1}\times 100\%$$

(3)

$$V_{total}=HE{X}_{0-1}\times 1 \mathrm{V}$$

(4)

$$I_{total}=HE{X}_{2-3}\times 1 \mathrm{A}$$

(5)

$$Tem{p}_{avg}=HE{X}_{4-5}\times 1 °\mathrm{C}$$

(6)

4.4. Real-World Applications

The developed prototype system demonstrates strong potential for real-world implementation across various EV and energy storage applications. Its modular design, low cost, and communication robustness make it particularly suitable for the following scenarios:

• Low-cost electric vehicles and scooters where space and budget constraints limit the integration of proprietary BMS displays [1,4,8].
• University research platforms and educational labs where modular, open-source monitoring systems help students and developers experiment with CAN communication and battery diagnostics [10,13,15].
• Battery swapping stations where real-time data on pack voltage, SOC, and temperature is needed for safety and charge management [5,6,8].
• Off-grid or solar-powered systems for visualizing and logging battery parameters in small energy storage units [24,26,27].

The modularity and openness of the system also enable integration with IoT gateways, allowing remote monitoring, diagnostics, and predictive maintenance in larger fleet or infrastructure applications [10,13,20,32]. With additional shielding and robustness upgrades, the system could be adapted for deployment in light-duty EVs or commercial delivery vehicles operating in electromagnetically noisy environments [7,9,28].

4.5. Future Work and Research Directions

Although the proposed system demonstrates reliable real-time battery monitoring using CANopen communication, several areas remain for further improvement. Future work may focus on the following directions:

• Enhanced Compatibility: Expanding the system to support a wider range of BMS models with different communication protocols or CANopen object dictionaries will increase its applicability across diverse EV platforms [1,6,8,11].
• Robustness and Environmental Testing: Conducting long-term field testing under harsh environmental conditions, including high electromagnetic interference (EMI) and temperature variations, will help assess durability and communication stability in real-world EV deployments [5,24,26,28].
• Advanced Battery State Estimation: Future iterations of the system may incorporate mathematical models or machine learning algorithms for SOC and state-of-health (SOH) estimation, such as Kalman Filters or neural network-based methods, to provide more accurate battery diagnostics [3,17,22,29].
• GUI Improvements: Enhancing the display interface for better usability, including interactive touch features, customizable dashboards, and multi-language support, will improve user experience, especially in commercial applications [12,37].
• Integration with IoT and Cloud Platforms: Adding wireless connectivity for remote data logging, diagnostics, and predictive maintenance via IoT or cloud platforms will enable real-time fleet management and analytics [10,13,20,32,35].

By addressing these directions, future development can extend the usability, scalability, and intelligence of the system, contributing more broadly to smart energy management in electric vehicles and related applications [1,2,4,16].

Furthermore, the practical applicability of the system was validated through its integration into an electric all-terrain vehicle (ATV), which served as a real-world test platform. This vehicle exemplifies a representative use case for low-cost electric mobility in rural and off-road settings, where continuous and accurate monitoring of battery health is critical [1,4,5]. The system’s compact form factor, robust data transmission via the CANopen protocol, and reliable performance under dynamic load conditions underscore its suitability for deployment in experimental electric vehicle platforms, vocational training environments, and lightweight electric utility vehicles operating in constrained or demanding conditions [7,8,13].

5. Conclusions

This study presents the development of a BMS interface designed to provide real-time monitoring of critical battery parameters, including voltage, current, temperature, and SOC, through a touchscreen display. The system architecture integrates an ESP32 microcontroller for receiving UART signals from the JK BMS, which are subsequently converted to the CANopen protocol via a TJA1051 CAN transceiver and transmitted to the display unit [8,10,30,31].

The circuit was designed using EasyEDA and fabricated through a copper etching process. A fully functional prototype was assembled and subjected to a range of operational tests, including fast charging and high-current discharge conditions. The results demonstrated that the system maintained accurate and reliable real-time monitoring of dynamic battery behaviors, with no detectable data loss or latency. Measurements displayed on the prototype interface were found to be in strong agreement with reference values obtained from PCAN-View software and the JK BMS mobile application [5,23].

Overall, the system exhibited high levels of stability, precision, and robustness under high-load conditions. Its cost-effectiveness, modularity, and ease of integration render it a promising solution for low-cost electric vehicles, academic research, and small-scale energy storage applications that require dependable battery diagnostics and CAN-based communication [1,4,8].