If you've ever needed to charge your phone but known you had
to leave an outlet behind in just a few minutes, here's a way to get the most
possible charge for your precious time at a charger: Put your phone in Airplane
Mode first.
Putting your phone into airplane mode turns off all of the
wireless radios inside, so while you won't be able to receive calls, use data,
or use GPS, you also won't be fighting background processes that use those
radios for power while your phone is plugged in. The end result is your phone
will charge a little faster, and you'll walk away with a bit more power in your
battery than you would otherwise. Of course, you could get a similar effect by
just turning your phone off (sans power required to shut down/start up), but
this is a bit easier.
Source
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