JBD BMS incorrect SOC

[@DrAuwal]

Hello, my JBD BMS (AP20S006 20S 200A 7-21S) is not reading the SOC correctly. It was recently coupled with an EVE LF280K cells in a 24V configuration. It rapidly drops around from 80% to 60% abruptly. The system is new and yet to do the first cycle.
What do I need to do to correct this?
Thanks folks.

 

[Bob B]

You have answered your own question.

Until one cell has reached the "cell full voltage" setting is tracks SOC based on the "cell xx% cap voltage" settings .... which is only a guestimate based on cell voltages.
Once you reach the cell full voltage, the BMS should reset to 100% and begin tracking SOC based on current in and current out.

If you write any setting change it will revert to the voltage guestimate again til cycled.

 

[MisterSandals]

What do I need to do to correct this?

Stop counting on your BMS to correctly report SoC. Its a safety switch primarily. They are notoriously inaccurate for SoC.

 

[Bob B]

Hello, my JBD BMS (AP20S006 20S 200A 7-21S) is not reading the SOC correctly. It was recently coupled with an EVE LF280K cells in a 24V configuration. It rapidly drops around from 80% to 60% abruptly. The system is new and yet to do the first cycle.
What do I need to do to correct this?
Thanks folks.

If you charge the battery til 1 cell reaches the cell full voltage .... It will start counting amps instead of guestimating based on voltage.

 

[@DrAuwal]

You have answered your own question.

Until one cell has reached the "cell full voltage" setting is tracks SOC based on the "cell xx% cap voltage" settings .... which is only a guestimate based on cell voltages.
Once you reach the cell full voltage, the BMS should reset to 100% and begin tracking SOC based on current in and current out.

If you write any setting change it will revert to the voltage guestimate again til cycled.

Thanks for this explanation.

 

[@DrAuwal]

Stop counting on your BMS to correctly report SoC. Its a safety switch primarily. They are notoriously inaccurate for SoC.

Noted.

 

[@DrAuwal]

If you charge the battery til 1 cell reaches the cell full voltage .... It will start counting amps instead of guestimating based on voltage.

Thank you.

 

[740GLE]

Stop counting on your BMS to correctly report SoC. Its a safety switch primarily. They are notoriously inaccurate for SoC.

Agreed.

Which is another reason I’m happy not having closed loop communication between my inverter and BMS.