[ltp] Has my battery failed?

[James Holden]

Tony Willoughby wrote:

>My 390E has stopped detecting/using the battery.  
>
>My typical practice when leaving work for the day is to run "shutdown"
>and then pull the power cord to to pack it up.  The system continues to
>shutdown on battery power.
>
>One day last week I did this and the system powered off immediately. 
>Since then it will not power up unless connected to the AC.  "apm"
>reports: "AC on-line", it used to report the % charge of the battery. 
>Reseating the battery hasn't helped.  
>
>apm reports the following when started..
>
>Nov 26 09:06:39 localhost apmd: apmd startup succeeded
>Nov 26 09:06:39 localhost apmd[1845]: Version 3.0.2 (APM BIOS 1.2, Linux
>driver 1.16)
>Nov 26 09:06:40 localhost apmd[1845]: Charge: * * * (-1% unknown)
>
>I always assumed that battery failures would be gradual, not sudden like
>this.  Has my battery failed or is something else wrong?
>
>  
>
Quite likely.

It is often the case that when a Li-Ion battery fails, the electrolyte 
degrades almost instantaneously. It's a kind of avalanche effect and the 
actual failure takes only a few milliseconds. At this point, the battery 
goes short-circuit. It's common for the laptop to crash at this point as 
the now shorted battery crowbars the power rails via the DC-DC converter 
before the current limiting kicks in. People often report that the 
machine crashes, and they won't boot up until they get some mains power 
into it. This is probably what has happenned. the apm utility is 
reporting -1% because the microprocessor in the batter which reports the 
power level is non-functional.

James