bq34z100evm: How can I set the initial capacity

Verify that you have the parameter called "Number of Series Cells" set correctly. After setting it, you should issue the 0x41 reset command by typing 41 into the value field of "Control" on the DataRam screen and hitting Enter. If this doesn't fix it, you may want to post a picture of the scanning DataRam screen and and .gg file, which can be saved from the DataFlash screen.

Hi Doug,

Thank you for the response.  I checked that my number of series cells is set to 12 since this gives a maximum pack voltage of 50.4V   ( the pack that we are designing will have 14 cells for a max voltage of 58.8).  Issuing the reset command allows the state of charge to go to 4%.  There must be some parameter that limits the reset capacity to some percentage of the full capacity?  Do you know what this parameter may be?  I will attach the dataram bitmap image and the .gg file in a separate post.  Let me know what you think.

Regards,

Prestor

trying to attach the dataflash bitmap to this post

here is the .gg file fo the dataflash

I was not able to attach the *.gg file because that extension is not allowed.  I changed the extension to *.123 so if you just rename it you should be able to open it.

Prestor,

The gauge is reporting 4% because of the voltage level. On your screen we see a voltage report of 43896 mV. Dividing by 12 cells, thats 3658 mV per cell. At this stage the gauge has not been tracking your state of charge, but will report it correctly if the cells are resting. 3658 mV on a typical LiIon cell equates to 4% state of charge. If you raise the voltage to 4200 mV per cell and issue the 0x41 reset command you will see 100% state of charge.

Regards,

Doug

Doug,

You were absolutely correct about the voltage level being low.  I increased it to 48.3 V and was able to read back 82% charge after reseting with 0x41.  However, when I pressed the button on the demo board to enable the LCDs, 8 out of 10 LEDs turned on and then the board stopped working.  I debugged it a little and found that D7 is not regulating the voltage to the correct level of 5.6 V.  The voltage on the gate of Q3 is zero.  Do you see failures of D7 ( BZT52C5V6s) very often?  Any idea why it failed at a battery voltage of 48.3V?  The jumpers on the bq34z100evm match figure 8 of SLUU904-april2012 with the exception thta J1 is not populated since it should be open for I2C operation.

Thank you for your assistance as we evaluate the BQ34Z100 for our LEV battery pack.

Prestor

Prestor,

No, I haven't seen or heard of any problems with the zener. I do have a case where the push button isn't working.

Rgds,

Doug