BQ34Z100-G1 State of Charge Instantly drops to 0% on Load

Christian Haynes

Other Parts Discussed in Thread: BQ34Z100, BQSTUDIO, GPCCHEM

Hi Everyone

I am using the BQ34Z100 EVM Module to analyse a Li-Ion battery but find that after performing a learning cycle the "Update Status" never changes to "05" and as soon as I put a load on it to discharge the state of charge instantly drop back down to 0%.

I am using:

bqStudio Version 1.3.45

bq34z100_G1_v0_16_build_17.srec

EV2300

I have attached the battery datasheet, it is a 2Cell, 7.5V ICR-18650H 2.2AH

I have also attached some of my recent logs and my gg file.

Any help would be greatly appreciated.

Christian Haynes

Battery Documents.zip

over 9 years ago

0 ThomasCosby over 9 years ago

TI__Guru 73830 points

Christian
Your process looks correct, but the Voltage is too low. You are setup for a 2S Li-Ion pack, but the pack voltage is only about 41xx mV. When you log additional data, please run the log file continuously through the charge / rest / discharge and reset cycles to make analysis easier. Also, have you verified that you have a good ChemID match to your cells?
Tom

0 Christian Haynes over 9 years ago in reply to ThomasCosby

Prodigy 70 points

Hey Tom,

I had assumed that you entered cell voltage, not pack voltage when calibrating. It appears to be behaving properly now.

I have chosen Moli ICR18650H (2200mAh) for my ChemID as that has the same model name and specs as the battery I am using. Is there a more comprehensive way of verifying the ChemID?

I really appreciate your help!

0 ThomasCosby over 9 years ago in reply to Christian Haynes

TI__Guru 73830 points

Christian,
ChemID 100 is listed as a match for your cell, but it is very old and the battery manufacturing process may have shifted since then. It would be a good idea to use the GPCCHEM tool to see whether there is a better match.

www.ti.com/.../GPCCHEM

Tom

0 Christian Haynes over 9 years ago in reply to ThomasCosby

Prodigy 70 points

Hi Tom,

I am now having trouble with the learning cycle, I have cycled the battery multiple times but have not been able to get learned status to update to 5. I have had to change battery to something a with a larger capacity and now have a 2S NCR18650BF 3250mAH battery. I performed the ChemID analysis as you suggested I thought that might get it to work but nothing has changed so far. I have attached all my data, would you please check over it when you have the chance.

Thanks for you time.

Christian

NCR18650BF.zip

0 Christian Haynes over 9 years ago in reply to Christian Haynes

Prodigy 70 points

Hi Tom,

Just completed another discharge and the learning status updated to 05. Hopefully when I do another charge on Monday it should update to 06. Not sure what was going on previously but hopefully it should be all sorted.

Thanks,

Christian

0 ThomasCosby over 9 years ago in reply to Christian Haynes

TI__Guru 73830 points

Christian,
If it fails to update to 06, then send the log file to me and I may be able to find the problem or create a set of Ra table values for you.
Tom

0 Christian Haynes over 9 years ago in reply to ThomasCosby

Prodigy 70 points

Tom,

It updated to 06 last night so we are good to go, thanks for your guidence.

Christian

0 ThomasCosby over 9 years ago in reply to Christian Haynes

TI__Guru 73830 points

Thanks for the update.

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BQ34Z100-G1 State of Charge Instantly drops to 0% on Load