BQ27546-G1: RSOC=0% when charging lasts for more than 30 minutes

zheng dingsong

Part Number: BQ27546-G1
Other Parts Discussed in Thread: BQSTUDIO

At present, we have two projects: 1 series of 1 and 1 series of 2 and use BQ27546-G1, the voltage corresponding to 0% is 3.0V. During cycling, discharge to the overdischarge protection of the battery pack, and after standing for 10 minutes, charge the battery pack. It is found that RSOC=0% lasts for more than 30 minutes, and the voltage of the battery pack has reached 3.0V or more. What is the cause of this?

over 1 year ago

0 Jonny over 1 year ago

TI__Mastermind 24751 points

Hello,

Can you please provide the log and gg file for this?

Regards,

Jonny.

0 zheng dingsong over 1 year ago in reply to Jonny

Prodigy 30 points

2727.RL003_log.xlsx 6765.RL_GS.gg.csv

hello，Attached are the log and gg files

0 Jonny over 1 year ago in reply to zheng dingsong

TI__Mastermind 24751 points

Hello,

I am not sure that I fully understand your question here, can you please elaborate on what you are asking here and the test?

Regards,

Jonny.

0 zheng dingsong over 1 year ago in reply to Jonny

Prodigy 30 points

We set the discharge terminate voltage at 3.0 V. When testing, we discharge the battery to the over-discharge protection voltage of 2.8 V, and then start charging. Sometimes the RSOC of the battery will remain at 0% for a long time.In the log file. Line 3626 to 3803 is where the problem occurs, line 3626 starts charging, RSOC has been showing 0%, but the voltage of the battery has reached 3.4 V. The 0% we set corresponds to a voltage of 3.0 V.

0 Jonny over 1 year ago in reply to zheng dingsong

TI__Mastermind 24751 points

Hello Zheng,

In your first post you mention using the gauge for 2 different packs, 1sip and 1s2p. Are you using the same gauging configuration for both packs?

Regards,

Jonny.

0 zheng dingsong over 1 year ago in reply to Jonny

Prodigy 30 points

Different configurations are used, and we have adapted the most appropriate ID according to the actual battery core. The previously uploaded file indicated one of the batteries, but the same problem occurred with both batteries

0 Jonny over 1 year ago in reply to zheng dingsong

TI__Mastermind 24751 points

Hello,

How was the chemID matched for the cells you are using? Did you use the GPCCHEM tool and ensure that there is a DOD % error less than 3% for your cells? Additionally, can you please provide me with the bqStudio log files for both cells?

Regards,

Jonny.

0 zheng dingsong over 1 year ago in reply to Jonny

Prodigy 30 points

RL003B-log data.xlsx

Hello, the attachment is the complete charge-discharge cycle data. From the 18466 line to the 18467 line in sheet9, the passcharge data jumps from 4813 to 4949. We want to know the reason for this jump. Passcharge and Fullcharge capacity data seem to affect the time it takes for the SOC to go from 0% to 1% on the next charge.

0 Jonny over 1 year ago in reply to zheng dingsong

TI__Mastermind 24751 points

Hello,

I don't think you have mentioned this, but how was the chemID matched?

Regards,

Jonny.

0 zheng dingsong over 1 year ago in reply to Jonny

Prodigy 30 points

This is a picture of the matched chemID. We used three batteries to match the chemID, and the final chemID was 7477.

0 Jonny over 1 year ago in reply to zheng dingsong

TI__Mastermind 24751 points

Hello Zheng,

Thank you for providing the chemID match information. From your results, the chemID 7477 is indeed a good match here.

The reason the gauge takes a while for the SOC to go from 0% to 1% can be seen with the passed charge. Once the Passed charge reaches the FCC value, then you can see that Rem Cap is updated and the SOC is also updated. Additionally, it looks like you have the load mode incorrectly configured for your application. You have Load Mode configured for a constant power load when in reality your load is constant current. Please change the load mode to equal 1 so that the gauges is configured for constant current. An incorrect configuration for load mode and load select can cause an unexpected gauging behavior.

Regards,

Jonny.

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BQ27546-G1: RSOC=0% when charging lasts for more than 30 minutes