Why does the iPhone take so long to start up after it dies?

I fully understand what you are talking about, I get annoyed with this all the time. It's strange that when my Mac or Vape are completely flat I can plug it into the wall or a computer and it turns on straight away. If someone could explain the difference then I would greatly appreciate it.

I doubt that Apple is working on it, as it's how the hardware is implemented. Basically, external power is never used to power the phone. Instead, the phone always gets its power from the battery. So if the battery has insufficient charge to power the phone the phone won't come on. When the phone shuts off due to low battery the only way to bring it back is to put sufficient charge into the battery to power the phone. For me this takes a couple of minutes using a 10 watt Apple USB adapter, or 5 minutes with an Apple 5W cube adapter on an iPhone 6 (the 10W adapter will not speed up a 5 series or earlier model, but it will for the iPhone 6). If your need is that critical get an external battery powered USB adapter. The Mophie Juice Pack is popular choice, as some models are built into a case for the phone. I use a MyCharge (http://shop.mycharge.com/collections), which I've been very happy with. In almost 8 years I've only had one occasion where my phone actually shut off due to low battery (I run it down intentionally every month or 2).

Or get a phone that better meets your unusual need.

ascho078 wrote:

Full discharges are required to re-calibrate the battery, and apple actually recommends doing it once a month. (as do almost all other Lithium battery manufacturers).

Apple dropped that recommendation a couple of years ago. And, it wasn't to calibrate the battery, it was to calibrate the battery sensor.

You can read Apple's recommendations here:

Batteries - Maximizing Performance - Apple

A single study is not "confirmation".

If the battery is completely drained then - yes - it will take a few minutes if charging before it has enough juice to start working again. Is this really a surprise? It might work quicker if you plug into the wall rather than a computer.

Have you had an iPhone before? If so, you're in denial. If not, then you should know that it takes on average 7 min, and as much as 10....STILL! This is 5 years after the original post.

Why (when, if the user were to plug in their iPhone one second before it powered down, it'd stay on) does it take 10 minutes to power back up?

Much better if it's on iOS 10. My grandma gave me her iPhone 5, and it had servere battery issues. It was running iOS 8. When we updated it to iOS 9 there was no change. At iOS 10, a dead battery meant 10 seconds on the charger before bootup. Issues? Upgrade to iOS 10 if compatible.

Full discharges are required to re-calibrate the battery, and apple actually recommends doing it once a month. (as do almost all other Lithium battery manufacturers).

Lithium ion batteries also aren't designed for consistent shallow discharges, which is one of the reason it's so important to calibrate monthly. because thats the typical usage scenario (shallow discharge). the lifetime of a Lithium battery is affected most by Temperature changes, and Loading (the amount of draw). High Loading will kill a battery faster than anything else (and while loaded the battery will raise temperature dry quickly).

ideally they are discharged to around 50% with medium draw in consistent temperature, and month drawn to 0% will low draw - left off (no draw) and fully trickle recharged (rapid charging actually affects battery life too, and it's a feature built into most apple batteries).

Memory Effect has been confirmed recently in Lithium Ion batteries, Lithium-Iron Phosphate which is used to positive electrodes in Lithium-ion batteries. there exists a condition where the voltage of the terminal remains relatively unchanged over a large range of the state of charge, which make anomalies in readings of the charge voltage look like major changes in the charge. the micro controller typically determines the state of charge by measuring terminal voltage. during study it was discovered: "The memory effect only vanished if one waited a sufficiently long time after a cycle of partial charging followed by full discharge. In such cases, the two particle groups were still separated after the full discharge, but were found on the same side of the potential barrier." (note this basically requires a full discharge over a given period).

study was done by Petr Novak of Paul Scherrer Institute

Frankly, almost everything in your post is BS. Apple has a whole team of battery experts, and I'm sure that both individually and collectively they know a lot more about it than some outsider working with a different technology and set of assumptions.

Memory effect has not been confirmed in Li chemistry batteries. Quite the opposite. The fact that there exists a condition where the voltage remains unchanged over a large range of state of charge is true, which is why Apple's microcontroller does not measure terminal voltage to determine state of charge. If Herr Doktor Novak did measurements this way they are completely invalid with respect to batteries in Apple devices (as well as Samsung, LG, and virtually every other electronics manufacturer who uses Lithium chemistry batteries). The U2 charging chip that virtually all manufacturers use determine State of Charge from end points. The battery voltage shows an uptick near the full charge point, and a downtick near the full discharge point. These are used to determine the endpoints of "full" and "flat." Note that neither of these are true "full" and "flat" - they are near these points, but show as 0% and 100% on the gauge to prevent the user from fully discharging the battery. The charging circuit stops charging at the 100% reading, which is not actually the full capacity of the battery, to prevent overcharging.

State of charge is determined by monitoring current out and current in and calculating SoC from careful measurements. Occasionally this results in small, cumulative errors; if they get too large the problem can be resolved by draining the battery until the device shuts off as determined by the downtick, then charging to the uptick, which identifies 100%. Earlier iPhones needed this gauge "recalibration" fairly frequently, which is why Apple used to recommend doing this on a monthly basis. They dropped that recommendation about 3 years ago, however.

You are also wrong in your statement "rapid charging actually affects battery life too, and it's a feature built into most apple batteries." Apple does not use rapid charging over the full charge cycle; they charge at the full rate until 75% SoC is reached; the rate of charge then tapers rapidly. This is why an iPhone will reach 80% in under an hour, but will take another 2 hours to reach full charge. As you haven't noticed this, perhaps you don't even own an Apple device. Is this the case?

A Mac has a lot more room that a phone to fit in fancier charging circuitry.

A "Vape" charger probably just puts out enough power to overpower the small battery and force the voltage high enough to activate the unit even if the battery is dead. They don't seem to be very concerned about exploding batteries, based on the number of reports of fires and burned faces. They also aren't concerned about battery life since the whole unit is so cheap. People would be upset if phones had to be replaces frequently due to battery failure.

A phone has a large battery and not much space for elaborate charging circuitry. The main concerns are having the battery last a few years, and not catch fire. Having to wait a few minutes to use the phone after a fully discharged battery is not considered a major problem for most people. It would be easy to make the phone shut off while there was still some charge left, so it could start aa soon as the charger was connected, but most people would prefer more use time rather than a few minutes waiting in the rare cases when it is completely dead.

AKRBTN wrote:

It remains a mystery to me why people who appear to have access to a power supply let their phone die and then complain because it takes a little while to start up again.

Exactly what I was thinking. I can't remember the last time I turned my phone off.

This is normal with a depleted battery. Exactly why does it "really ****"? Do you have the patience of a 2-year-old?

Good thing you don't have a Blackberry. Restarting those things, even with a full battery takes about 10 minutes.

As I said, it might be a bit quicker if you connected it directly to a power source rather than through a computer.