BQ34Z100-G1 : SOC freeze to 100%

Please find the LOG for these runs here.

TI_2016-06-09.zip

I forgot one discharge that I added now.

Loïc

In BQ34Z100-G1 datasheet's there are : SOC = TrueRC()/TrueFCC(). 

Why is not this case in real use?

Look my diagram:SOC_BQ.pdf

When I calculate SOC = TrueRC/TrueFCC, I have a better result with RSOC_True !
Can you provide me the good parameter to change for done a good result?

Thank you for your Help,
Loïc

Loic

I see a couple of issues with the log files. First, the Control Status register shows that IT is not enabled. The reason that you see a delay in SOC counting down at the beginning of discharge is that charge is accumulating during rest and the same amount of charge must be removed before the Remaining Capacity will start decrementing. It is possible for charge to continue to accumulate during charging after SOC = 100%, but the pack has to rest until a DOD point is set to allow the gauge to clear this excess charge. In your case, charge is still accumulating during rest and the gauge will not be able to clear this excess charge and prevent SOC from holding at the beginning of discharge.

Tom

Tom,

I am going to retry with IT ENABLE. I shall hold you informed about the results

Loïc

IT not being enabled is not what is causing the delay. It is caused by the accumulated charge during rest. You will have to eliminate that to allow RM to start decrementing at the start of discharge.

Tom,

It's not possible to eliminate the accumulated charge during rest period because my battery is a NiMh and I must overcharge for balancing cells and after compensate self discharge.

Why SOC is not egal to TrueRC/TrueFCC (like in sheet 33 of BQ34Z100-G1  data sheet)? In this case I have a better result that actual calculation of bq =>

SOC = RemCap/FullChgCap

Look explanation diagram below:

2553.SOC.pdf

Loïc

I Tom,  I have a better result with IT ENABLE.

For resume, my error is : I had forgotten to send IT ENABLE at the end of optimisation cycle....

Now, you can check the result on diagram below:

SOC_With_ITENABLE.pdf

Thank you for your help,

Loïc