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BQ20Z90: Asus battery UnsealKey/FullAccessKey

eric etienne
Prodigy 80 points
Part Number: BQ20Z90
Other Parts Discussed in Thread: BQ29330

I have a laptop battery from Asus (AS0104M43E) with device name (T12--24). Could you send UnsealKey/FullAccessKey at my mail  ?

Another question, I can't get voltage at the output header of the battery although I can get good results with bus interface : for instance I read about 11V directly at the pack, 10948mV with 0x09 command but  no voltage at the header.

Thank you.

  • 0
    Expert 2475 points
    The default unseal codes are 0414 3672 and the default full access codes are ffff ffff. The codes will not work if the user has changed them.

    I am not clear as to the difference in the "11V directly at the pack" and the "header". Can you clarify as to how these differ physically, since you measure voltage on one, but not the other?
  • 0 in reply to TEC
    Prodigy 80 points
    Many thanks for your reply. Well on this battery there's a 9 pins connector normally used by the laptop (I would expect to see the voltage here). I also measured the voltage directly between the cells between the lowest potential and highest potential. From the bus I can read the correct value, then I wonder if there's some FET to switch on to actually get the voltage at the 9 pins connector / regular output.
  • 0 in reply to eric etienne
    Expert 2475 points
    There are FETs and probably a fuse between the cells and the pack connector. One or both of them could be open preventing voltage from reaching the connector. If the fuse is blown, then it will be a permanent failure. If you can open the pack, then you can probe the circuit and determine what is interrupting current flow. If you are trying to repair your battery, then I doubt that you will be able to unseal the pack and reset or update anything on the gauge. The unseal keys have probably been changed.
  • 0 in reply to TEC
    Prodigy 80 points
    As far as I know this battery never had a break or some kind of overvoltage/overcharge . There's a FETControl register but I can't access it within SealedMode. I've tried the keys this morning but it didn't pass, do you think FETControl register could lock/unlock the output ? You may have UnsealedMode Battery to test. In case this helps P/N of my battery is : 08G21UF10107.
  • 0 in reply to eric etienne
    Prodigy 80 points
    One more thing, I had a look at BatteryStatus : I've found EC0,1,2 flag were raised which mean : EC3 EC2 EC1 EC0 0,1,1,1 = UnknownError bq20z90/bq20z95 detected an unidentifiable error. Probably it has to do with the fact the output is disabled.
  • 0 in reply to eric etienne
    Expert 2475 points
    The unknown error code means that some fault occurred and it is not a typical defined event. The device does not disable the FETs arbitrarily, so some fault must have occurred to cause the FET to open. I don't know how much else you can do without opening the pack and probing some nodes.
  • 0 in reply to TEC
    Prodigy 80 points

    Isn't there a reset procedure which would clear EC flags and put it back to normal ?

  • 0 in reply to eric etienne
    Prodigy 80 points
    On more thing, there's another chip in my case bq29330 which handles FETs, how can I know the address of this chip on the management bus ?
  • 0 in reply to eric etienne
    Prodigy 80 points
    ok I've found it forget my last question - I'll give a try with this chip. So no ideas for the keys, do you think Asus might have changed them ?
  • 0 in reply to eric etienne
    Expert 2475 points
    The AFE does control the FETs and it also supplies power to the gauge. The gauge contains the control parameters and it should clear the AFE after the safety recovery conditions have been met. If the gauge gets stuck, then you can hold the MRST pin low for a few seconds and this will reset the gauge and firmware. Yes, most pack manufacturers change the unseal codes to protect themselves from people accessing their packs.
  • 0 in reply to TEC
    Prodigy 80 points

    Well, I've read the AFE chip, with these values :

    0x00 00
    0x01 08
    0x02 00  
    0x03 00
    0x04 04
    0x05 06
    0x06 0f
    0x07 f0     
    0x08 f2

    I've tried to write registers 01-08 with zeros, and made the mrst reset. I'm not sure if it's related but I manage to get about 9V on the output pins (there's actually two pins / 9 for the ouput). But the voltage is not very stable, it should be about 11-12V and EC2-0 flags are still raised. Anyway I think there's an electrical break somewhere on the broad, and I've decided not to go further for repairing it.

    Do you know any battery type/brand I can be sure keys are unchanged ? Thank you for your replies.