Problem! BQ34Z100 "Passed Charge" is resetting itself every 30 sec

Ilja,

It is not uncommon to see SOC jumps during the learning cycle. We have also found that having FConvEn set to 1 can seem to make it worse. You can try setting this bit to 0 in the Operation Configuration B register to see if it helps.

Regards
Tom

Hi Tom,

Thank you! It really helped. I don't only understand, why it should be set to 0. Could you explain in details?

1. Now the problem is following :
 During learning cycle SOC is going to zero 10 times faster and reaches zero when battery actually should be 90%. I am using X10 Mode and Design Capacity is set to 6000 (cAh, but Evaluation Software still shows in mAh), as you recommended me in this topic
http://e2e.ti.com/support/power_management/battery_management/f/180/p/251974/887046.aspx#887046

2. Should I change Design Energy Scale to 10?

3. And the last one. Can I use I2C bus and Write I2C Data Block in Evaluation Software to make step 2 "Send SMB command 46, word 0006 to turn on the FETs"?(Creating Pre-Learned Defaults in the document SLUA334B)

Thanks in advance,
Ilja

Ilja,

Did you calibrate the current to 1/10 the actual value with the device in X10 mode? e.g. You would enter 1A for the current, if you had 10A applied. The bqEVSW does not change the units in the program. You have to keep track of that. The Design Energy Scale only takes effect, if you have the Load Mode set to 1. I thought that you had it set to 0 which is constant current mode.

The bq34z100 does not control FETs, son the 46 command does not work. You have to apply the charge and discharge current to the pack.

Regards
Tom

Hi Tom,

Thanks for your answer. I calibrated the current to 1/10 the actual value and changed Load Mode to 0. This part is works now!

Today I discharged the battery till 11.4V, but  BATHI (Battery High) flag is still RED (set to 1) and BATLO is 0. What do they depend? Cell Terminate Voltage?

In previous thread you suggested not to multiply Number of Cells, so I changed this parameter to 1.
http://e2e.ti.com/support/power_management/battery_management/f/180/p/251974/887046.aspx#887046

Should I take care about these flags when I am on step 3 of Creating Pre-Learned defaults in SLUA334B?

As I understand design is based on current now. Do I need Energy based parameters at all? If not, why I can't set Number of Cells to 4?

Thanks in advance,

Ilja

Here is GG-file and DataRAM screenshot!

4628.2.05.13_Learning_cycle.gg.zip

Ilja,

There must have been a misunderstanding. You must set the Number of Series Cells parameter to the number of series cells in your pack. I was saying that you do not multiple the Design Capacity by the number of series cells to set the Design Energy. The device will take care of that. You will need to set the Number of Series Cells to 4 and re-calibrate the pack. That should take care of you BATHI problem. It is dependent on the Cell BH Set Volt Threshold and it multiplies it by the number of series cells.

If you have Load Mode set to 0, then the device does not use the energy parameters.

Regards

Tom

Hello Tom,

Thank you for your reply.
I already though that solution is found, but the following thing is happened:

1. I discharged battery til BATLO flag was set. Evaluation software showed SoC 0%.
2. I left battery to relax for 12 hours and then connected it to 20A Automatic charger for LiFePO4
3. I started Logging every 5 sec in Evaluation software and came home for a weekend
4. When I arrived Evaluation Software showed SoC 2% and I started examining LOG-file and I saw the following:

bq EVSW Version: 0.9.86 for bq34z100 v0.06   
Device:100,Ver:0.06
03/05/2013 12:12:08   
          
Sample    Stamp       Elapsed(s)    SoC    RemCap    Passed Charge
1                12:12:13           0                 10            585              -560
2                12:12:18           5                 10            588              -564
3                12:12:23          10                10            588             -564

.... 3h 5min later evaluation software reaches SOC 100%

2203    15:17:17    11104    99    5911    -5886
2204    15:17:24    11111    100    5913    -5889
2205    15:17:31    11118    100    5916    -5892
2206    15:17:38    11125    100    5919    -5895

..... 1H 3 MIN later automatic charger shows 100% and turns charging off

2775    16:22:03    14990    100    5972    -7093
2776    16:22:10    14997    100    5972    -7093

..... Evaluation program shows "Passed Charge" absolute value very slow decreasing
...... 2 days 1 hour 5 minutes later "Passed Charge" is resetting to zero value and SOC is falling from 100 to 2%

34692    17:27:21    191708    100    5972    -6509
34693    17:27:27    191714    100    5972    -6509
34694    17:27:34    191721    2    94    0
34695    17:27:41    191728    2    94    0

"Past charge" is decreasing in positive value from 0 to 12
and after 1 hour 0 min is resetting to zero again

35220    18:27:32    195319    2    82    12
35221    18:27:38    195325    2    95    0

THE SAME THING! "Past charge" is decreasing in positive value from 0 to 11
and after 1 hour 0 min is resetting to zero again

36284    20:27:56    202543    2    84    11
36285    20:28:03    202550    2    95    0

RESETTING "PAST CHARGE" TO ZERO WAS HAPPENING EVERY 1 HOUR!!!

FConvEn set to 0 as you suggested.

Question 1.What is happening? What is wrong now?

Question 2. What to do if SoC shows 100% but battery actially is now full (automatic charger continues charging)? Will Impedance Track enabling solve this problem?

Thanks in advance,
Ilja

P.S. GG and DataRAM screenshot are attached
1832.07.05.2013_2 percents.zip

bq EVSW Version: 0.9.86 for bq34z100 v0.06    
Device:100,Ver:0.06
03/05/2013 12:12:08    
           
Sample    Stamp       Elapsed(s)    SoC    RemCap    Passed Charge
1    12:12:13    0    10    585    -560
2    12:12:18    5    10    588    -564
3    12:12:23    10    10    588    -564
4    12:12:28    15    10    592    -568
5    12:12:33    20    10    596    -571

.... 3h 5min later evaluation software reaches SOC 100%


2203    15:17:17    11104    99    5911    -5886
2204    15:17:24    11111    100    5913    -5889
2205    15:17:31    11118    100    5916    -5892
2206    15:17:38    11125    100    5919    -5895


..... 1H 3 MIN later automatic charger shows 100% and turns charging off


2775    16:22:03    14990    100    5972    -7093
2776    16:22:10    14997    100    5972    -7093


..... Evaluation program shows "Passed Charge" absolute value very slow decreasing
...... 2 days 1 hour 5 minutes later "Passed Charge" is resetting to zero value and SOC is falling from 100 to 2%


34692    17:27:21    191708    100    5972    -6509
34693    17:27:27    191714    100    5972    -6509
34694    17:27:34    191721    2    94    0
34695    17:27:41    191728    2    94    0

"Past charge" is decreasing in positive value from 0 to 12
and after 1 hour 0 min is resetting to zero again

35220    18:27:32    195319    2    82    12
35221    18:27:38    195325    2    95    0

THE SAME THING! "Past charge" is decreasing in positive value from 0 to 11
and after 1 hour 0 min is resetting to zero again

36284    20:27:56    202543    2    84    11
36285    20:28:03    202550    2    95    0

RESETTING "PAST CHARGE" TO ZERO WAS HAPPENING EVERY 1 HOUR