I've noticed that if the iPhone 4S battery is completely empty and the phone won't turn on, then even if I plug it in to the charger, it still won't turn on for a few minutes. Shouldn't it be able to turn on immediately once I plug it in?
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Why doesn't the iPhone turn on when you plug it in?
- Thread starter slapple
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Nope. Not enough power to even run the os. It takes a few minutes to get enough charge to barely work...
It should. But for some reason it doesn't. I don't buy the not enough power argument. Even half an amp from a regular usb port should be enough to run the phone, and charge the battery. Let alone the wall charger.
Because if the power just shuts off during boot up it could really bork up your phone.
Of the millions of iPhones out there certainly some people will be dumb enough to just unplug the phone the instant they see the boot-up logo. Since that phone (in that universe) was running off the wall, it just instantly dies again during the boot up process. This is bad.
So Apple decided to not let the phone boot up until the battery has enough charge to do the entire boot up from battery power and, if it needs to, a proper shut down by battery as well.
So, basically, you have to wait for the battery to charge about 4 or 5% before the phone will turn on. It's just safer that way.
Of the millions of iPhones out there certainly some people will be dumb enough to just unplug the phone the instant they see the boot-up logo. Since that phone (in that universe) was running off the wall, it just instantly dies again during the boot up process. This is bad.
So Apple decided to not let the phone boot up until the battery has enough charge to do the entire boot up from battery power and, if it needs to, a proper shut down by battery as well.
So, basically, you have to wait for the battery to charge about 4 or 5% before the phone will turn on. It's just safer that way.
I agree. Let's say you plugged an iMac into the wall. You wouldn't need to wait a few minutes before you can turn it on, right?
That's not quite a valid comparison because the iMac doesn't have a battery it runs off of.
Yeah and I don't think it'd be a disaster if the iMac were to lose power in the middle of the OS booting up.
But what about an MBP with an empty battery? Does it need to wait a few minutes after being plugged in before you can turn it on?
Well, the alternative here is to just have the iPhone die and shut off earlier. (I think that's the Macbook's solution.)
Is that what you'd prefer? To have the phone just die sooner? I wouldn't care for that solution. When I'm away from a plug I'm more concerned with how much time I can get out of my phone than I am with how fast it will turn on once I get home.
I think we can have the iPhone use as much battery as possible before it dies, but then it can start up immediately when someone plugs it in. You seem to be concerned about someone plugging in their dead iPhone and then immediately unplugging it once it turns on. Not sure why anyone would do that - if they are dumb enough to do that, let them live with the consequences (which I don't think would be that bad anyway).
You and I are not designing the iPhone. We're not here talking about how to build this thing. It's already been done. No, we are trying to guess what reason Apple has for doing things the way they did.
I like my hypothesis. If you disagree with it you need to come up with another guess. For what reason do YOU think Apple has made the phone work this way?
If you have a better guess I'll consider it. But right now you're disliking my reason and in its place the only thing you have is "I don't know."
Until you have a better guess I'm gonna stick with mine.
I'm not saying your explanation is wrong, it is probably right. I'm just saying I don't know why Apple would design it that way. If OS corruption due to a loss of power is the reason, then I don't think it's a big deal if the power were to get cut off during bootup. It could happen to an iMac, but I don't think an iMac would become a doorstop if it were to happen. Apple could improve the design for the iPhone 5. 
This was one of the reasons I switched away from the iPhone. I would regularly need to use my phone but would have to wait 10mins for it to decide it was ready to be switched on.
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Mine does.
Well, firstly let me admit that I don't have more than an 'I don't know' either, but frankly, your explanation doesn't seem all that plausible to me. After all, is booting up anything more than loading stuff into memory? It's not like data on the SSD gets corrupted or changed if that process were to be interrupted.
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The phone runs DIRECTLY off the battery at all times.
There is no pass-through with a direct wired power connection.
Therefore, the iPhone won't power up until the battery itself has enough charge in it to start up the phone - even if it's plugged into the wall or a USB wire.
There is no pass-through with a direct wired power connection.
Therefore, the iPhone won't power up until the battery itself has enough charge in it to start up the phone - even if it's plugged into the wall or a USB wire.
i thought that once it hits 100% it runs directly off the connection so it doesn't harm the battery?
It has anything to do with fear of people unplugging and dying during boot, the phone would not be permanently harmed in that any ways.
Instead it's all about power available... the usb connection, even from AC adapter is not capable of providing the hardware with enough energy to run at full speed, which is what is taking place during the boot process.
Because of this, and because the phone is incapable of bypassing the battery to pull directly from the adapter, it has to wait for enough charge to build up for this process to complete with depleting the battery completely.
Instead it's all about power available... the usb connection, even from AC adapter is not capable of providing the hardware with enough energy to run at full speed, which is what is taking place during the boot process.
Because of this, and because the phone is incapable of bypassing the battery to pull directly from the adapter, it has to wait for enough charge to build up for this process to complete with depleting the battery completely.
This sounds like the most plausable explanation. There's no point in designing and implementing a pass through power system on a device that's primarily going to be used on batter power. It would probably take up space needlessly.
No. It stops charging the battery altogether and lets it run down a bit before topping the charge off again. This is why sometimes you'll see that your percentage drops a little quicker than normal when you unplug your iPhone.
http://www.apple.com/feedback/
If running the phone to empty and the couple of minutes after plugging in are a burden then you were correct to change phones. But it is a choice to let it run down that far and there are battery extenders.