[Discuss] [ OT ] iPad battery

[gaf at blu.org (Jerry Feldman)]

Thanks guys. My mother does not plug it in when she is using it.
One issue is that she has not been turning the device off, she just lets
it go into standby or hybernate mode.

Based on Richard's and your feedback, I think my advice to her is to use
the device, plug it in when the battery gets low, and at night power the
iPad off and plug it in. Of course iPads don't have removable batteries,
so taking care of the battery is a bit more important than one where you
can remove the battery.


On 12/28/2012 09:23 PM, Tom Metro wrote:
> Jerry Feldman wrote:
>> My question is does it hurt to keep the iPad plugged in even
>> when it is at full charge. AFAIK, most computers and smartphones have
>> circuitry to prevent battery damage and over charging.
> Not having first hand knowledge of the iPad charging circuitry, I can
> only confirm that your assumptions match my expectations for a modern,
> battery powered device. If this were not the case, you'd have heard
> about lots of people complaining about ruined batteries resulting from
> them forgetting to unplug their iPads.
>
>
>> Basically in general the worst thing you can do with a Lithium Ion
>> battery is to run it all the way down, and most systems [will] shut down
>> at about 20%
> Roughly correct.
>
> Additionally, you maximize the life of a Lithium Ion battery by
> minimizing the number of charge-discharge cycles it experiences, which
> is finite.
>
> And adding some confusion, it is recommended that Lithium Ion batteries
> are stored long-term in a partially discharged state.
>
> It's a bit of a compromise, but the easiest way to maximize the life of
> your Lithium Ion batteries is to keep them perpetually fully charged.
>
>
>> One caveat is that the charger is always drawing power, so the electric
>> meter is running even when the charger is not plugged in to the device,
>> which is more of a green issue than anything else.
> Chargers are getting better in this respect. Even an old-school linear
> power supply will draw less power once the battery has charged and the
> charge circuitry turns off charging, but they still use a fair bit
> (relatively speaking) when sitting idle. Modern switching power supplies
> improve upon that, and they make it easier/cheaper for the device being
> powered to tell the supply to shut itself down, reducing idle draw to
> near zero. I'm not sure if any main stream consumer devices make use of
> this latter capability yet.
>
>
>> My mother was told not to keep it plugged in all the time.
> Either obsolete advice or for the green reasons you cited.
>
> Many phones have on-screen messages to not just detach the charger, but
> unplug it from the wall precisely for the power savings. Ironically it
> would have had far greater impact 10 years ago when most "wall warts"
> were inefficient linear supplies.
>
>  -Tom
>


-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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