I understand the battery problems. (finally)

[Bert Freudenberg]

On Mar 16, 2007, at 9:02 , Richard A. Smith wrote:

> Here's the 411 on the battery problems.
>
> The gas guage IC in the batteries has EEPROM in it where the EC  
> code stores lots of parameters on the type and state of the  
> battery.  Under certain low voltage conditions when writing the  
> data the timing on the one-wire bus is marginal and the EC ends up  
> writing lots of 0xFF's to the EEPROM.
>
> Recent version of the EC code have a couple of sanity checks when  
> the EC reads this data.  The 0xFF's trip the error handling and the  
> charging state machine restarts, reads out the bogus data again,  
> gets errors, lather, rinse, repeat.
>
> There is currently no method of recovery in EC code.  So once the  
> EEPROM gets corrupted the laptop will will never charge the battery  
> again.
>
> I spoke with quanta about this issue on the phone tonight and turns  
> out they have also discovered this and added some write  
> verification checks.  They released PQB81 a few hours ago.  I will  
> be releasing a new firmware (B81) tomorrow with this updated EC code.
>
> Although B81 may stop future corruption from happening it will not  
> fix all the current broken batteries.  I spoke with quanta about a  
> method of re-initializing the EPROM data to default values so we  
> can recover all the batteries that are dead.  They said they were  
> going to look into it.
>
> In the meantime I'm going to work on a few ideas that I have so  
> that we can recover the batteries in the field.  Stay tuned.

I can confirm that B81 does not seem to have any effect on my dead  
battery. I used the readEC program attached to #1051 but it's all  
zeros, a single byte was 0f I think - anyone interested in the  
output? Note this is not a LiFe.

- Bert -