AEK-POW-BMS63EN voltage measurement error

[trishuynh]

Dear experts,

I am facing an issue when measuring a pack of 14 batteries Fenix ARB-L18-2600. When fully charge 4.23 Volt, the BMS63EN return around 4.0x Volt. When the batteries reduce to 4.12 Volt, the BMS63EN return ~3.98 Volt. Could experts tell me where and how to modify or calibrate the BMS63EN Board?. (I used the Autodevkitstudio-2.4 with both SPC58EC - AEK_POW_BMS63EN_SOC_Estimation_14Cells_GUI application for discovery and SPC58EC - AEK_POW_BMS63EN_SOC_Estimation_Single application for discovery example to measure but they still return same measurement error).

I am really appreciating for your help.

Best regards,

Tri Huynh.

[Max VIZZINI]

Hi,

Assuming the IC is still operational (not broken), normally wrong voltage readings are due to incorrect connection of the pin for sensing, balancing, and GND. All IC pins should be well connected in the 14 cells series connection.

Best Regards,

AutoDevKit Team

[trishuynh]

Dear Max VIZZINI,

The current reading is correct but voltage of all the 14 pins still returned errors with the actual is 4.12 and BMS63EN return is 3.98. Do you have any idea or solutions to guide me with this problem?

Thank you so much.

Best regards,

TH.

[Max VIZZINI]

Hi,

IC pins are NOT well connected with your battery.

Please check AEK-POW-BMSHOLD for connecting suggestions.

https://www.st.com/en/evaluation-tools/aek-pow-bmshold.html 

Best Regards,

AutoDevKit Team

[trishuynh]

Dear Max VIZZIN,

I've already checked he connection and also changed the BMS board but the error is the same. May be due to the protection circuit embedded inside the batteries? Could you have any idea to solve this problem?

Sincerely,

TH.

[SRomeo]

Hi Tri Huynh,

• This voltage shift may happen if Jumper JP1 is not inserted.
  
  For more details take a look to this thread: (post 2025-02-18 3:57 AM) 
  Solved: BMS Chain Setup Assistance - STMicroelectronics Community
  

Hope this helps,
Best regards
AEK Team

[trishuynh]

Dear SRomeo,

on 24/4/2025, When I changed the Jumper to pin 1 and 2, the voltage measurement is correct again. Before that, ASTROI suggest me to place the jumper at 2 and 3 but it still corrects.

However, the jumper on pin 2 and 3 is not correct so I have to replace the jumper to pin 1 and 2 as your instruction. 

Could you please explain me clearly about the different between jumper on pin (1,2) and (2,3) and why now it is incorrect on jumper at pin (2,3)?

Updated: on 25/04/2025, the error happens again on both jumper on pin (1,2) and (2,3). Do you have any idea about this?

Thank you so much for your instruction.

Sincerely,

TH.

[trishuynh]

Dear Sromeo and Max VIZZINI,

All of the connection from the holder to the board are ok and when I measure by using VOM on pin CELL 1 to 14 with GND_EXT the VOM returned 3.62 volt however the BMS still returned 3.51 volt. I dont understand that I have done something wrong or not?

 

 

Best regards,

TH

[SRomeo]

Hi Tri Huynh,

When your board perceives a consistent shift, the device is actually missing the ground reference.
Please follow this procedure:

 1) Disconnect the BMS holder connector
 2) Check both your BMS boards and place each Jumper JP1 in the 1/2 position:

  3) Reconnect the BMS holder connector.

Note: Sometimes, even with the jumpers, this problem happens. That's because the BMS connector is not inserted correctly. Try to reconnect it by pushing along the borders, uniformly, as in the picture:

To check if the measurement are right I suggest to compare voltages as in the picture:

If you have any doubts please take a look to the schematic.
You can find it on the UserManual

Best regards,
AEK_Team