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[Discuss] [ OT ] iPad battery

I promise you battery circuits are smarter than that these days.  We
monitor battery voltage.  If it drops too much, we start charging again.

I'm really having trouble picturing a EE doing it any other way.

Drew Van Zandt
Cam # US2010035593 (M:Liam Hopkins R: Bastian Rotgeld)
Domain Coordinator, MA-003-D.  Masquerade aVST

On Fri, Dec 28, 2012 at 9:21 PM, Rich Pieri <richard.pieri at> wrote:

> On Fri, 28 Dec 2012 20:04:42 -0500
> Jerry Feldman <gaf at> wrote:
> > 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 with shut down
> > at about 20%
> Actually, this is the second worst thing you can do with a Lithium
> battery pack. The worst is to leave it charging all the time:
> * Plug into charger. Monitoring circuit charges battery.
> * Battery reaches full charge. Monitoring circuit stops charging
>   battery.
> At this point if you don't disconnect mains power then the battery is
> not used to power the device. The battery pack will still self
> discharge all the way to zero given sufficient time, typically 2 to 3
> months. The battery monitor circuit detects no drain on the battery so
> it must still be at 100% and, since there is no power in the battery to
> operate the device it will remain that way forever. Irreparably
> destroyed battery pack.
> The last time I saw this in action was about 8-10 years ago. Had a
> little notebook playing firewall. Left the battery pack connected as an
> ersatz UPS. When the power really did fail, so did the notebook.
> Monitoring circuits are supposed to be "smarter" these days but better
> safe than sorry. Don't leave it plugged in all the time. Use the
> battery. That's what it's for.
> --
> Rich P.
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> Discuss mailing list
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