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Original question:

[FAQ] BQ40Z50 FAQs

BQ40Z50-R2: Learning Cycle Failing as per SLUA903 Instructions

Rohit Panchal
Prodigy 45 points
Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQSTUDIO, GPCCHEM, BQ40Z50, EV2400, BQ40Z50EVM-561

Hi Everyone,

I am a non technical consumer of Li-Ion battery pack product which comes with BQ40Z50-R2 gauge in its BMS.

My Pack existing Configuration is 14.4V 7000mAh (4S2P - LG MJ1 18650 3.6v 3500mAh)  and i am trying to change the capacity of pack to as follows 14.4V 10500mAh (4S3P - LG MJ1 18650 3.6v 3500mAh) 

so after studying a lot about the gauge i understood that i have to do the learning cycle in order to get the best SOC after increasing the pack capacity.

I am using EV2300 via SMB port to communicate with BQStudio software.

As per the SLUA903 Guide I have set the parameters of Design Capacity, Design Voltage, Charge Term Taper Current, Discharge (Dsg) Current Threshold, Charge (Chg) Current Threshold, Quit Current and Term Voltage as per my pack configuration and cells data sheet.

I am doing the learning in following steps as per guide:

1st - Set the QEN bit in IT Status Register ( i have assumed the meaning of setting the bit means to turning it to RED color )

2nd - Set the RDIS bit in IT Status Register by RESET command via commands button on the right side of BQStudio

3rd - Discharging the pack via 5A Current to PACK Cutoff Voltage 10V (this is the term voltage where pack reaches 0% as per cell datasheet)

4th - Let it rest and wait until VOK & RDIS bit is getting cleared in IT Status Register (in my case VOK is already cleared and i am waiting for RDIS to clear it takes about 3 hours), after RDIS is cleared i proceed further.

5th - Charge the Pack at 5A current but i am not able to see the VOK bit getting set when Charging Starts

i am seeking your guidance to go further 5th Step as per mentioned in SLUA903.

After the charging is complete VCT & FC Bit are getting set in registers,

My confusion is While charging / discharging generally REST bit should cleared right?

2626.Desktop.rar

  • 0
    TI__Guru** 105760 points

    Hello Rohit,

    I looked through one of the logs you have shared and see that the DOD0 is above the maximum value it should be (2^14 should be the maximum) have you completed the GPCCHEM process in order to find the closest matched chem ID for your battery?

    The other log appears to show the full learning, but update status is set to 0x14, so no learning will occur, the update status needs to be set to 0x04 to re-do learning.

    REST bit should be cleared during active periods of the gauging as you mention for charging/discharging.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 45 points

    Hello Wyatt,

    Thanks for your reply.

    As per my understanding, I should not be worried about the CHEM_ID as i am not changing the model of cell from original pack, instead i am using same cells as original with increased capacity. please note that i changing pack to 14.4v 7000mAh --> 14.4v 10500mAh with same cell.

    Just to confirm CHEM_ID i checked what is already programmed in Gauge via CHEM_ID command button and I got the following result.

      

    Can you please help with interpreting the result data, as i checked in Chemistry Database, CHEM_ID should be 2059 or 2152 for INR18650MJ1 3500mAh cell, am i suppose to convert the result from hex to decimal or wrong CHEM_ID is programmed.

    Please also guide me how to change the update status to 0x04 and where can we check the status is changed to 0x04.

  • 0 in reply to Rohit Panchal
    TI__Guru** 105760 points

    Hello Rhoit,

    chem ID 0x1210 is the default chem ID, so I do not think it was updated correctly to being with. If the exact model is in the chem ID database already you can use it. If you are trying to do a learning cycle with the wrong chem ID it may never work properly due to the OCV-DOD table being mapped incorrectly.

    You can change the update status manually in the data memory tab to restart learning.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 45 points

    Hello Wyatt,

    Thanks for the reply.

    I am trying to program the CHEM_ID by Selecting the Chemical ID from the Chemistry Database and clicking the Program Selected Chemistry but nothing is happening i tried several clicks on it and reinstalled the bqstudio and updated the chemistry version also. can you please guide me what is the procedure of changing the CHEM_ID. 

  • 0 in reply to Rohit Panchal
    TI__Guru** 105760 points

    Hello Rohit,

    Please share a full screenshot of the BQStudio chemistry page when you try to program the chem ID. There is most likely a small error noted on the bottom left of the window.

    You will not be able to change anything if the gauge is sealed or if the voltage is too low, the gauge prevents flash writes if voltage is too low.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 45 points

    Hello Wyatt,

    Thanks for the reply

    Here is the screenshot of whole BQStudio of initial start:

    https://pasteboard.co/wT4x4nrrRT8V.png

    Here is the screenshot from chemistry and selecting the CHEM_ID and clicking Program Selected Chemistry button, unfortunately i dont receive any feedback or any kind of error from BQStudio or from windows also, after several clicks also it has no effect.

    https://pasteboard.co/Pe4M0W1cCxbb.png

    I dont think gauge is sealed, just for your assurance i have send UNSEAL & UNSEAL_FULL_ACCESS commands screenshot attached below:

    Please guide me further

  • 0 in reply to Rohit Panchal
    TI__Guru** 105760 points

    Hello Rohit,

    It looks like you are using an older BQStudio version, I would recommend using the TEST version for the most recent fixes and features.

    On your main register page it also looks like your device ID is all FF, which means you may have the communication in the wrong port. Make sure you have the SMB port attached. When you click the program selected chemistry nothing occurs?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 45 points

    Hello Wyatt,

    Thanks for your reply.

    As per your guidance i have installed the new beta version of BQStudio ver 1.3.121. 

    My bms have 5pin output in following order: 1:(P-), 2: ID, 3:SMBD, 4:SMBC, 5:(P+) and have i am using EV2300 SMB ports to connect with bms.

    After Installing i have tired again to program the selected chemistry but nothing occurs as said earlier.

    I have attached few screenshot for your reference.

    Please guide me further, if we need to reset the gauge or update the firmware because i have two pieces of same bms and both are having same behavior and showing same as you can see in screenshot

  • +1 in reply to Rohit Panchal
    TI__Guru** 105760 points

    Hello Rohit,

    The EV2300 is no longer supported on newer windows systems, we have some drivers which can get it working but they are not tested. Please use the EV2400 when communicating with the BQ40Z50 EVM. This may be causing communication issues.

    You can also see in the auto detected device session that the numbers are all ff's which indicates communication issues, not just for uploading the chem ID.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 45 points

    Hello Wyatt,

    I have placed and order for EV2400 and bq40z50evm-561 also it will take at least 15days to reach my location.

    I hope as per your suggestion using EV2400, I will be able to program the CHEM_ID, I will be creating new Thread if i am not able to resolve me issue till then i am resolving this issue, I really appreciate your efforts on my issues. Thanks once again.

    Sincerely,

    Rohit Panchal