BQ34z110 Confirmation of Design steps and Optimization Cycle Process for Impedance Track. 12V 7.2Ah Battery (Lead-Acid)

Greetings TI,

I would like to confirm my the Setup Procedure for the bq34z110 Impedance track to create aGolden Image.

The Below information is a combination of the Data-sheet and the forum information i found. Please correct me if you see a mistake. I Know this might have allot of excess information but I hope that this will be of use to others in the future as well.

Battery: Koyosonic Valve-Regulated Lead-Acid Battery NP7.2-12 (12V 7.2Ah/20HR)

6-Cells, 1200mAh per Cell, 2V per Cell.

Keywords:

Located: This is the place were to find the parameters in the bq Gas Gauge Evaluation Software.

Battery C value= 7.2 derived from from 7200mA (BIG QUESTION MARK HERE is this correct?)

DESIGN STEPS : Step 1:

1. Design Capacity: 7200mAh
   Design Capacity is for all cells together in your battery (e.g. 1200*6=7200mAh )
   Located: (Data Flash)->(Configuration)->2nd column, third row from the top.(Design Capacity)

2. Design Energy: 8640mWh (Design energy scale = 10x)Design Energy for all cells together. (E(mWh) = battery[mAh] x battery[V]) 
   (e.g 7200*12V = 86400mWh)Located: (Data Flash)->(Configuration)->2nd column, forth row from the top.(Design Energy)

3. Cell Charge Voltage (T1-T2): 2250mV (default value)

4. Cell Charge Voltage (T2-T3): 2450mV (default value)

5. Cell Charge Voltage (T3-T4): 2350mV (default value)singe-cell charge voltage for each JEITA temperature range.Located: (Data Flash)->(Configuration)->2nd column, seventh row from the top.

DESIGN STEPS : Step 2:

1. Number of serrie cells: 6Located: (Data Flash)->(Configuration)->3rd column, under the registers heading sixth row from the top.(Number of serries cell).

DESIGN STEPS : Step 3:

1. Voltage Divider: 20000mVThe maximum expected battery voltage. (All Cells included)Located: (Data Flash)->(Calibration)->3rd column, first row from the top.(Voltage divider)Note: After calibration, a slightly different value will appear in the Voltage Divider parameter.

DESIGN STEPS : Step 4:

1. CC Gain (mohm): 10mohm

2. CC Delta (mohm): 10mohm
   The value of the current sense resistor should be entered into both CC Gain and CC Delta
   (e.g 10 mohm)

Located: (Data Flash)->(Gas Gauging)->1st column, third row from the top.(Load Mode)

DESIGN STEPS : Step 5:

1. Load Mode: 0 Const-Current (default)Load Mode is used to select either the constant current or constant power model for the Impedance Track(Load Mode = 0 (Constant Current), Load Mode = 1 (Constant Power))Located: (Data Flash)->(Gas Gauging)->1st column, third row from the top.(Load Mode)

2. Load Select: 1 (Const-Current Default)Load Select defines the type of power or current model to be used to compute load-compensated capacity in the Impedance Track algorithm. If Load Mode = 0 (Constant Current) then the options presented in Table 8(pdf) are available. 
   Located: (Data Flash)->(Gas Gauging)->1st column, second row from the top.(Load Select)

3. Cell Terminate Voltage: 1850mVThe theoretical cell voltage where the system will begin to fail for a single-cell
   (e.g. normal voltage=12000mV system fail=11000mV, cell fail voltage = 11000mv / 6cells = 1833mV),

   Note: use a higher level than the calculated value to have some reserve capacity.Located: (Data Flash)->(Gas Gauging)->1st column, sixth row from the bottom.(Cell Terminate voltage)

4. Quit Current: 45mAThis value should be slightly higher than the expected idle current of the system. (e.g. 45mA)
   Located: (Data Flash)->(Gas Gauging)->2nd column, last row from the top.(Quit Current)

5. Qmax Cell 0: 1200mAh (BIG QUESTION MARK HERE is this correct?)Enter the C-rate value of your battery.
   The initial Qmax value is taken from a cell manufacturers' data sheet multiplied by the number of parallel cells. 

   The parallel value is also used for the value programmed in Design Capacity. If Design Capacity = 7200mA then 

   Qmax Cell 0 = 7200mA / 6Cells = 1200mA)Located: (Data Flash)->(Gas Gauging)->3rd column, fisrt row from the heading State.(Qmax cell 0)

DESIGN STEPS : Step 6

Determine and Program the Chemical ID, Use the bqChem feature in the Evaluation Software to select and program the chemical ID matching your cell. use the procedure defined in TI's
“Chemistry selection.pdf” document. (SLUC138)

If no correct ChemID is found Send battery's to TI for characterization or create log data.

Creating Log Data:

1. In the bq Gas Gauge Evaluation Softwareyou will need to monitor(select) the cell voltage, cell temperature, current and set the time to log every 1 second.
   Note: 1. You can log additional data, but that is all that is needed. 2. You can also have several cells in series, but it is more accurate to use the voltage for one of the cells. 
   3. The bq34z100 series does not monitor individual cell voltages, so you can use the stack voltage and the MathcadTM tool will allow you to select number of series cells in the setup section.

2. Charge the battery until FULL.Note: The VOK and QEN flags should automatically get set during the charging operation.We normally charge the battery without a load attached.The device will count coulombs and report SOC during charging.What you may notice it that it reaches 100% SOC, before charge is complete.The battery needs to remain on the charger until the charging current has dropped below the taper current to insure that all of the cells are fully charged.Full battery: Make sure that you let it taper to to C/100. (C(7.2)/100 = 0.072A)

3. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery. (about 2 hours)(OCVTAKEN bit8): Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relaxed mode.

4. Discharge it at a C/10(or more e.g C/8) rate to discharge is Empty (C(7.2)/8 = 0.9A)
   (Empty  = 500mV below the Cell Term Voltage * # of cells).Important Note: Never discharge to zero, Cell Termination Voltage is cell based.
   E.g. Cell Termination Voltage = 1800mV.
   (1800mV  x 6Cells = 10800mV) then Discharge voltage equals (10800mV – 500mV = 10200mV).

5. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery. (about 5 hours)

6. (OCVTAKEN bit8): Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relaxed mode.

7. Calculate with Mathcad or ask TI for help.

DESIGN STEPS : Step 7

1. Calibrate. Follow the steps on the Calibration screen in the Evaluation Software. Achieving the best possible calibration is important before moving on to STEP 8: Run Optimization Cycle. For mass production,calibration is not required for single-cell applications. For multi-cell applications, only voltage calibration is required. Current and temperature may be calibrated to improve gauging accuracy if needed.

DESIGN STEPS : Step 8

Optimization Cycle STEP 1:

1. Remove all external power from the battery and your device.

2. Disable the FConvEn bit in the Pack Configuration B register.

3. Make sure that the Flash Update OK voltage is set to 1000mV. (BIG QUESTIONMARK HERE Why what sould it realy be?)

Data flash can only be updated if Voltage() ≥ Flash Update OK Voltage. Flash programming current can cause
 an increase in LDO dropout. The value of Flash Update OK Voltage should be selected such that the bq34z110
 Vcc voltage does not fall below its minimum of 2.4 V during Flash write operations. The default value of 2800 mV
 is appropriate.

1. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery.(OCVTAKEN bit8): Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relaxed mode.

Optimization Cycle STEP 2:

1. Temporarily Adjust(lower) the Cell BL Set Volt Threshold so as not to affect a full discharge.(BIG QUESTIONMARK HERE What is theCell BL Set Volt Threshold and what should it be ??)
    (I lowered Cell BL Set Volt Threshold to 1600mV was (1800mV))

Optimization Cycle STEP 3:

1. Send the IT Enable(0x0021) and RESET(0x0041) command.
   Note:You should NOT have to RESET and send IT ENABLE,if QEN and VOK are set.
   The VOK and QEN flags should automatically get set.

2. After IT ENABLE, Update Status should automatically get set to 4. 

RESET: Forces a full reset of the bq34z110.IT ENABLE  Forces the fuel gauge to begin the Impedance Track algorithm, sets Update Statusto 4 and causes the [VOK] and [QEN] flags to be set in the CONTROL STATUS register. [VOK] is cleared if the voltages are not suitable for a Qmax update. Once set, [QEN] cannot be cleared. This command is only available when the fuel gauge is UNSEALED and is typically enabled at the last step of production after system test is completed.Optimization Cycle STEP 4:1. Connect a LOAD to the battery (Note: C/10 (or more e.g C/8)) (C(7.2)/8 = 0.9A)2. Discharge the battery until the battery is Empty (500mV below the Cell Term Voltage * # of cells).Important Note: Never discharge to zero, Cell Termination Voltage is cell based.
E.g. Cell Termination Voltage = 1800mV.
(1800mV  x 6Cells = 10800mV) then Discharge voltage equals (10800mV – 500mV = 10200mV).CAUTION :It may be necessary to stop the load, check the rebound, then apply the load again to ensure that the rebounded voltage will not be significantly higher than the Cell Termination Voltage. For example, a Cell Termination Voltage of 1800mV will be 10800mV for a 12 V/six-cell battery. After stopping the load at 10500mV, it can bounce all the way up to 11500mV, which is too high for this procedure. However, if the load is continued until the battery voltage is 10000mV, the resulting bounce back will be close to the intended termination voltage. Optimization Cycle STEP 5:

1. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery.

2. Wait for the VOK flag to clear.

3. Wait until Update Statusautomatically gets set to 5.

(OCVTAKEN bit8): Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relaxed mode.

Optimization Cycle STEP 6: 

1. Charge the battery until FULL.Note: The VOK and QEN flags should automatically get set during the charging operation.

charge the battery without a load attached.The device will count coulombs and report SOC during charging.What you may notice it that it reaches 100% SOC, before charge is complete.The battery needs to remain on the charger until the charging current has dropped below the taper current to insure that all of the cells are fully charged.We normallyFull battery: Make sure that you let it taper to to C/100.  (C(7.2)/100 = 0.072A)Optimization Cycle STEP 7:

1. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery.Note: the VOK flag will remain set.

(OCVTAKEN bit8): Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relaxed mode.Optimization Cycle STEP 8:

1. Connect a LOAD to the battery (Note: C/10 (or more e.g C/8)) (C(7.2)/8 = 0.9A)

2. Discharge the battery at C/10 (or more e.g C/8) until the battery is Empty (500mV below the Cell Term Voltage * # of cells).Important Note: Never discharge to zero, Cell Termination Voltage is cell based.
   E.g. Cell Termination Voltage = 1800mV.
   (1800mV  x 6Cells = 10800mV) then Discharge voltage equals (10800mV – 500mV = 10200mV).

CAUTION :It may be necessary to stop the load, check the rebound, then apply the load again to ensure that the rebounded voltage will not be significantly higher than the Cell Termination Voltage. For example, a Cell Termination Voltage of 1800mV will be 10800mV for a 12 V/six-cell battery. After stopping the load at 10500mV, it can bounce all the way up to 11500mV, which is too high for this procedure. However, if the load is continued until the battery voltage is 10000 mV, the resulting bounce back will be close to the intended termination voltage.Optimization Cycle STEP 9:

1. Wait until the OCVTAKEN flag gets set, this indicates a relaxed battery.

2. Wait for the VOK flag to clear.

3. Update Status should automatically get set to 6.

Optimization Cycle STEP 10:

1. Restore the Cell BL Set Volt Threshold to the desired value. (1800mV)

2. FConvEn bit needs to be restored to 1. (Question??)
   
   
   Great Thanks for taking the time to read through my extremely long post
   I Really hope you can clarify on some of my questions.(and hopefully help others as well)
   
   Regards 
   Jacques.