Why do phones take so long to charge enough to turn on after dying?



I don’t know if this is exclusively an iPhone thing or not, but every smart phone I’ve had takes a ridiculous amount of time to charge to the point of powering up after it dies. Anyone know why?

In: Technology

What other phone you had ?

Rechargeable batteries do not like being completely discharged. If the battery is discharged enough that the phone has to power itself off, the phone is designed to charge up to a certain percent above “dead” before it allows itself to be powered back on. That way, if the phone is unplugged, it does not have to shut down right away.

Also, forcing the phone to stay off allows it to charge up to the “power on” threshold more quickly, since all the power from the charger can go to the battery, and not be split with running the phone as well.

Well for one, lithium batteries can’t charge as fast when they are super low. It’s just a quirk of the battery chemistry. Below 10% and above 90% (ish) they need to charge slower.

The other part is that your phone will wait till you get at least a couple percent so that it doesn’t just die halfway through, or immediately after booting up.

Even when it’s plugged in to an adapter if the adapter is, say, just plugged into an old 100mA USB port it’s entirety possible that your phone is using more power than the charger can supply and is still draining battery.

Most phones will also save a bit of reserve below 0% where it has enough power to safety show you a quick low battery image before blinking off several times. Then below that it will just not respond to the power button press, but this can make people think the phone is bricked when they might just have a bad charger.