[Tfug] Laptop battery charging time

[Jude Nelson]

Claude,

Is this one of those "smart" batteries, that have a built-in sensor on
them?  If so, the kernel has a config option for that, which will get
better readings than the usual ACPI daemon.

Otherwise, the ACPI daemon on your system may be checking the battery
charge in too short/long intervals:  too short, and the calculation
sample size is too small for any meaningful output; too long, and the
calculation is inaccurate due to too general sampling.  I'm pretty
sure there's a way to change the interval, but I'm not sure how it
could be done.  If it exists, it's probably some obscure option in
/etc/sysctl.conf.

Regards,
Jude

On 11/9/07, Claude Rubinson <rubinson at u.arizona.edu> wrote:
> Okay, here's a bit of an odd one.  I switched out the batteries on my
> Thinkpad T40 this morning. (I don't see why it would matter but I use
> those large, long-life ones.  What is that?  9 or 12 cells?)
>
> Anyway, I keep the acpi command constantly running under watch so that
> I can observe expected charge time/remaining battery life/etc.  I
> hadn't used the batter in a number of months and it was almost
> completely dead when I put it in this morning.  It starts charging and
> in an hour and a half or so (maybe more, maybe less, I wasn't really
> paying attention), it gets to "99% charged" with less than 1 minute of
> charging time remaining.  Except that it never hits 100%/fully
> charged.  Instead, throughout the day, the minutes until charged
> counter has slowly (very slowly) been INCREASING.  An hour or so after
> it hit 99% charged, the timer had increased to just over 1 minute
> until fully charged.  Now, many, many hours later, it reads 4:27
> (minutes:seconds) until charged.
>
> I've removed and reinserted the battery in case it was a bad
> connection but to no avail.
>
> Anybody got any idea what might be going on here?  Am I about to
> overcharge my battery, make it explode, and burn my house down?  Or is
> this something that I shouldn't worry about?
>
> Thanks,
>
> Claude
>
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