power consumption after shutdown

Gary C Martin gary at garycmartin.com
Sun Feb 15 10:12:32 EST 2009

On 15 Feb 2009, at 05:36, Mikus Grinbergs wrote:

> My apologies for not being clear.  I'll try again:
> I want to feel that the battery that I just put into the XO I'm
> walking out the door with is as "charged up" as it normally can be.
> 1)  If that battery came from an XO that was plugged into the AC
>     24/7 for the past week -- I *think* it is fully "charged up".
> 2)  If that battery came from an XO that had been "shut down" for 48
>     hours; but then that XO had been plugged into the AC until the
>     'power' light went green -- I *think* it is well "charged up".
> 3)  If that battery had been sitting on the shelf (not in an XO) for
>     a month -- what did I need to do to make it "topped off" ?
> --------
>>> What I am now interested in is understanding a "correct" state of
>>> charge value after having my battery out of the XO for one month.
>> Not possible without discharging the battery fully to determine the
>> state of charge it had.  The test is charge destructive; once it is
>> completed there is no usable charge in the battery.
> Sorry - I did not mean that I cared exactly how "charged up" it was
> -- what I want to know is how to ensure to myself, without going to  
> extremes, that the battery was "well charged up".   [Is 94% reported
> by the pop-up for an on-the-shelf battery believable, or is the
> 'true' value half that?  And if do I see 94%, do I need to worry
> that "this is a battery that requires some more charging"?]
>>> the software pop-up says 94%.  But I notice that
>>> after an hour, the software pop-up *still* says 94%.
>> I hope you aren't surprised.  No reason it should change.  Battery is
>> not being used.
> I was under the impression that when the battery charge went
> somewhere below about 97%, the XO would "charge it some more".
> So I was surprised to have it stay at 94%.   [If 94% being shown on
> the pop-up is not low enough for "charging some more", then how can
> I initiate charging being performed by the XO ?]
>>> But when the software pop-up is between 90-96% (for a previously
>>> out-of-case battery), and despite the AC adapter being plugged in
>>> that value does not increase in an hour -- what ought I to do to
>>> find the "state of charge" ?
>> No possible way except a full discharge while measuring the power
>> provided.
> Apologies for being unclear.  I'm not particularly interested in the
> precision of the "state of charge".  What I am interested in is "is
> the battery as 'well charged up' as I can make it be by using the
> XO's 'built-in' charger - I will want to get the most minutes of use
> of my XO when carried to a place that does not have electricity" ?

Have you tried either of the tools/procedures at:


Either olpc-pwr-log (download and run in terminal) or bat-recover  
(download a batman.fth file and use from Open Firmware), display  
actual charge going into (or out of) the battery, so you could use  
either of them to charge and see when your battery stops getting any  
more juice. Of course, without testing full discharge/charge cycles  
occasionally, you could never be quite sure where a batteries max is/ 
was (but that just takes us back to the email loop on precision).


> And if it is not 'well charged up', what do I need to do to make it
>  so?   In particular -- if it *were* 90% "charged up" when I took
> it off the shelf, would I have to fully discharge it in order to
> then "charge it up" (using the XO as the 'charger') closer to 97-99% ?
> mikus
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