No Power Off While Charging Up?

[OzRob]

My Android tablet (actually a Kindle Fire HD converted to an Android tablet) turns on when I plug the USB cable in, as does my Lumia 521.

May some Android phones do not turn on when a cable is attached, but I can't speak for them.

ALL phones and tablets turn on when plugged into a charging source. They need to because the phone/tablet must monitor and control the charging process to some extent, because no charging circuitry (except for fault protection circuitry) is built into the battery itself in these devices. Most Android phones, however, don't boot up the Android operating system when plugged in when turned 'off'. They just boot up the charging software. But the phone is still 'on' to some extent.

 

[anon(123856)]

This is true. My last Android phone would go into a charging mode where the screen showed a battery and that it was charging, but the phone was not fully operational. If you unplugged it, it turned off completely.

 

[Paul Verizzo]

The technological/scientific ignorance on this thread is astounding. OTOH, not unlike the general scientific knowledge of most Americans.
That Nokia/MS chose to not let the phone be off during charging is their decision. It has nothing to do with accidental overcharging, blah blah blah. Charging with power off just allows a phone battery to reach full capacity faster.
Lithium-Ion batteries absolutely require a "smart" charging system. A chip, monitoring everything electronic in and out. Can't say for sure, but I think the Sony Infolithium system was the first at consumer level, laet 1990's. Your latest Prius or whatever is no different.

You can't change what Nokia and MS decreed. The downside is minimal. Like many WP "features" I hate, we just all have to live with it.

 

[foxbat121]

HTC switched to charge-while-off mode in GDR3 update. It is too early to tell if it is GDR3 OS feature or OEM firmware feature as my Lumia 920 running GDR3 Dev preview does not behave this way. I

 

[Xellsama]

You need to realize that when you turn off, and then turn on the phone, it uses more battery than if the phone stays on. Therefore, in your 30 min window, the extra amount that got charged (which is minimal if you already turned your phone to flight mode.), would be used up instantly during the start up sequence. In fact, in some scenario it might use up more battery than the "extra amount charged". So overall, it would still be better if you just charge with the phone on.

 

[illidanx]

Here is a scenario you probably never heard of but it is true for quite a few people:
Physical power button is broke, no longer works. The only way to turn the phone on is to plug it in a charger.