High Voltage / Relay BMS

High Voltage BMS Relay 400V 800V 500A 1000A with CAN/RS485

The master-slave battery management system can monitor the cell voltage, battery pack total voltage, cell temperature, charge and discharge current and other parameters of the lithium battery system in real time and with high precision, and perform rapid analysis and processing to provide the corresponding lithium battery overcharge , over-discharge, over-current, over-temperature, short-circuit and other protection mechanisms to ensure the safe and reliable operation of the lithium battery system and prolong the service life of the lithium battery.

Application: large vehicle starting power, solar energy storage, engineering vehicle, low speed four wheeled vehicle, RV or any other device you want to place it in.

Product Detail

Product Tags




Product Information

Brand Name: HeltecBMS
Material: PCB board
Origin: Mainland China
Warranty: One year
MOQ: 1 set
Battery Type: NCM/LFP/LTO
Balance Type: Passive balancing


  • Customized logo
  • Customized packaging
  • Graphic customization


  • 1. Master-Slave High Voltage BMS *1 set. (Other parts according to your needs)
  • 2. Anti-static bag, anti-static sponge and corrugated case.


Purchase Details

  • Shipping From:

1. Company/Factory in China

2. Warehouses in United States/Poland/Russia/Brazil

Contact Us to negotiate shipping details

  • Payment: TT is recommended
  • Returns & Refunds: Eligible for returns and refunds

Example of Package Details

128S 500A split port BMS package includes:
1* Master BMS-BMU with harness
1* Hall Sensor
3* Relay
1* Pre-amp resistance
128S slave boards (quantity and each number of strings can be customized)

128S 500A same port BMS package includes:
1* Master BMS-BMU with harness
1* Hall Sensor
3* Relay
1* Pre-amp resistance
1* 500A Anti-reverse diode
128S slave boards (quantity and each number of strings can be customized)

Frame Schematic



The interior of the product adopts modular design, which is divided into master control module-BMU master control module, slave control acquisition unit-BCU voltage and temperature acquisition equalization module, BTU temperature acquisition expansion module, and BIU insulation detection module. According to the requirements of the charging and discharging operating conditions of the lithium battery pack in different application scenarios, the appropriate selection of the slave control module unit effectively improves the compatibility of the product for various terminal applications.

It supports 500A continuous current output, and the peak current can reach 2000A. It is not easy to be heated and damaged. If damaged, the main control will not be affected. You only need to replace the relay to reduce maintenance costs. Current relay power consumption: 250mA.

The relay is a main circuit switch. You can choose different currents, but the maximum current does not exceed 500A. It is recommended that the working power consumption be less than 500mA. BMS only provides 12V control voltage to control the introduction of relay.


  • With SOC estimation function.
  • Consistency and extend battery life.
  • With charge and discharge control function.
  • Features automatic balance management to improve battery pack.
  • Has complete fault level alarm function, including voltage, current, temperature, insulation and other fault alarms.
  • Functions of single voltage data acquisition, total voltage data acquisition, current acquisition, temperature acquisition, and battery pack insulation state detection.




Power supply

18-150V (Note, if the battery pack is lower than 96V, the total voltage of the battery can be used for power supply, no external DCDC)

System power consumption

Working mode: <10ma;

Sleep mode: <1ma;

OFF mode: <50uA

System startup method

External passive switch signal (default self-locking switch)

Number of cell collection strings



Number of temperature acquisition


The default is 1/4 of the number of cell strings, which can be supported by the BTU temperature expansion module

Single cell voltage

Collection range

0~5V,support all lithium battery monitoring

Detection error


Battery pack

total voltage

Collection range


Detection error


Charge and



Collection range

Hall detection method, typical ±600A range. Optional 100A, 300A, 600A, 1200A.

Detection error

±1 %


Collection range


Detection error


SOC Estimation error

≤5 %

Cell balance (Passive balance)

Typical equalizing current 80mA

Number of relay control circuits

6, 12V high side drive control

Communication method

Up to 6 isolated CAN2.0B interfaces,

vehicle communication: V_CAN,

charging communication: C_CAN,

internal communication I_CAN;

debugging communication: D_CAN;

reserved CAN: R1_CAN;

reserved CAN: R2_CAN.

2 isolated RS485 interfaces,

support Modbus protocol, and VCU or display.

2-way UART, can be used to connect to bluetooth module, GPS remote management or display screen, etc.





Relative humidity

10~90 %RH, no condensation, no corrosive gas



Different applications, electrical connection and networking methods are different, please confirm with the company's technical personnel according to specific needs.

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