• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 227 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ34Z100: BQ34Z100

Sandor Toth
Prodigy 60 points
Part Number: BQ34Z100
Other Parts Discussed in Thread: BQ2040,

Hi!

We wanted to replace in our multi cell and multi chemistry battery gauge design the old BQ2040 chip with the new BQ34Z100 offered by TI. So, to be familiar with the new one, we used a TI development kit, picked up a brand new 12V 7Ah battery which commonly used in UPS, downloaded a very similar chemistry profile (0800 chemistry ID, Leoch 7200mAh valve regulated Lead-Acid) and started charge/discharge cycles monitored with the TI Battery Studio. 

After 3 complete cycle, there are strange data (for me... :), and I can not get correct answer about the battery fully charged and remained capacity. The "DOD0 Passed Q" and the "Qmax Passed Q" data counting up and down in one discharge/charge cycle, but never overwrite the "Remaining Capacity" or "Full Charge Capacity" fields. The Full Charge Capacity is always 965mAh (State Of Health = 14% ?????), despite both Qmax Passed Q and the DOD0 Passed Q is over 7000mAh on full charge (charge current drops below 0.1A from the initial 2A CC/CV charging method) or full discharge (cell voltage drops below 1800mV).

On charge, the Remaining Capacity counts up until 965mAh, and stops while the Qmax carry on counting. If I cut the charge current at fully charged state, and leave the battery without load, the Remaining Capacity immediately falls to zero.

The "True RC" and  "True FCC" values follow the DOD0 Passed Q and Qmax Passed Q values while the charge or discharge is active, but when the cycle is finished (charge current or load current is zero) they change to the mysterious 965mAh..

In the old battery gauge chip (BQ2040) simply I had to read the FCC and RC registers, and I got acceptable values. So, can anybody tell me the algorithm how I can detect the actual FCC and RC of the battery in the BQ34Z100, because based on the test I don't find exact method for it.

Thank you.

Sincerely, Sandor

So, where can I find the actual

  • 0
    TI__Genius 12215 points

    Hi, Sandor

        I think there might be more data need to be modified. but at present, I guess below data may still be default, which is 1000mAh and hence limited your FCC and RemainingCapacity, you need to change it to the actual value of your battery which seems to be 7000mAH, a nominated value from SPEC would be OK, since this value could change in following learning cycle

       Please be noted that after you downloaded your desire Chem ID, and configured other data like charging voltage, taper current and terminate voltage base on the default configuration data which comes with a new bq34z100 device, you need to enable the IT algorithm by sending IT enable command and do leaning cycle to update the Ra table.

       After these are done you will be able get expected result for SOC and Remaining Capacity

  • 0 in reply to Steven Yao
    Prodigy 60 points

    Hi Steven!

    Thank you for your quick answer.

    I modified all data mentioned above, and changed the "Design Capacity" to 7000mAh. But indeed, I did not enabled the IT algorithm. I just did it now, and started a new discharge/charge cycle, and I'm waiting for the result.

    Thank you for your help again.

    Sincerely:

    Sandor