Interesting.  Well when I pull the plug it does drop out immediatley.  So
I'm not sure what to make of all this really.  I'll post what happens with
the new battery when I get it.

Thanks again,
-Pete

On Wed, Apr 6, 2011 at 3:43 PM, Bob Proulx <b...@proulx.com> wrote:

> Peter Rapisarda wrote:
> > cat /proc/acpi/battery/BAT0/info
> > present:                 yes
>
> This information is in conflict with the previous information that you
> posted saying that you didn't have any battery directories but just AC
> directories.  Perhaps between then and now your battery became
> connected?  Because at boot time if the battery is detected then it
> should provide this directory of information.  If it isn't then it
> doesn't.  It is fully dynamic with every boot.  The /proc isn't really
> a filesystem but an interface to the kernel.  It is a memory only
> filesystem presenting an interface of information and controls.
>
> > design capacity:         4400 mAh
>
> The battery says it has a vendor new rating of 4.4 amp-hours.  (It can
> supply one amp of current for 4.4 hours.  Or two amps of current for
> 2.2 hours.  A typical machine pulls between 1-2 amps during running
> and that would normally provide between 2-4 hours of runtime.)
>
> > last full capacity:      3334 mAh
>
> The battery says that when last charged it was able to hold 3.3 amp
> hours of charge.  That is a degradation of 75% from new.  That isn't
> terribly terrible.  My own main battery is sitting at around 90% at
> the moment.  (I have a big extended capacity 9 cell 7.7 AH battery.
> The standard 6-cell for my machine has around 4.6 AH standard
> capacity.)  Batteries age over time as they are used.  If it were
> really very bad then I would expect it to say something down in the
> one amp-hour range.
>
> The rest of the information is vaguely interesting data about the
> battery and was pretty much as expected.  But there was something that
> seemed a little odd to me.
>
> > battery technology:      rechargeable
> > design voltage:          14800 mV
> > design capacity warning: 440 mAh
> > design capacity low:     133 mAh
> > capacity granularity 1:  44 mAh
> > capacity granularity 2:  44 mAh
> > model number:            DELL53LSN
> > serial number:           678
> > battery type:            LION
> > OEM info:                Sanyo
> >
> > cat /proc/acpi/battery/BAT0/state
> > present:                 yes
> > capacity state:          ok
> > charging state:          charged
> > present rate:            1 mA
> > remaining capacity:      4400 mAh
> > present voltage:         16748 mV
>
> Here it is showing that while the battery is charged that it is still
> charging the battery at a rate of 1 milli-amp.  If it is charged then
> I would expect the rate to be zero.  Otherwise it will continue to
> charge (although at a very slow rate) which will eventually "cook" the
> battery.  Excess charge can't be stored after the battery is fully
> chemically converted and the excess energy will be converted to heat
> energy.  This is a topic that everyone has an opinion upon and my
> opinion is that this often results in out-gassing of battery chemicals
> resulting in reduced battery capacity.
>
> > Does this mean anything to you?  And just to be clear this is the old,
> > presumably non-functioning, battery.
>
> That data doesn't look like a non-functioning battery.  It looks like
> it has 3.3 AH of capacity.  If you removed the AC power it should
> provide power to your laptop for at least some while.  If you could
> see the rate that it was discharging at that time then you would be
> able to calculate an approximate runtime for that battery.  However I
> have found that in practice the firmware calculating these values may
> be wildly optimistic and the values may change wildly during
> operation.  In other words...  You have to try it and see how well it
> actually performs and even though it says 3.3 AH it may result in
> something much different after a few battery cycles.
>
> But if you remove AC power and the machine drops out immediately
> without any sign of battery being used then something bad is
> happening.  Perhaps the firmware is lying to you.  It wouldn't be the
> first time.  Or something else must be wrong.  At that point I don't
> know.
>
> Bob
>

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