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Can I safely charge my iPhone 4 overnight on a regular basis?

Is leaving the phone on the charger overnight really really bad for your iPhone?


3 Answers 3


Nah. Electricity is PULLED to devices that use it, not PUSHED from the plug. The phone is smart enough to stop pulling when its battery is full.

EDIT: However, an adapter can provide incorrect voltage for a device. Don't take what I said there and wire your iphone power adapter to a 220 source, for instance. You can OVERDRIVE a device with too many volts, but you can't send it "too much" of the right voltage, because the amperage is a function of the device's draw. I know I just said that assuming that you understand the difference between volts and amps, but there it is; they're different.


No, leaving it charging overnight will not have any adverse effects. All you need to do with the iPhone's lithium battery is be sure to drain it once a month for longevity.

Read Apple's iPhone Battery page.

[Similar answer for Apple's lithium laptop batteries, iPad batteries, etc.]

Also see Apple's Lithium-Ion Batteries page for more info.


The answer is it's just like an laptop: If it's left plugged in all the time, then the battery WILL eventually die. So the answer is yes, it's OK to leave it plugged in, but not all the time.

  • 2
    This is not correct. If you leave a laptop plugged in, it is not continually charging the battery - if it was, it would explode! Once the battery is charged, the charging circuit will cut out (or at least cut to a drastically lower voltage). One of the worst things to do to a lithium battery is to continually discharge/charge it, keeping it topped up at 100% will keep it working longer. (For the longest life, discharge it to about 40%, and store it in a cold place)
    – ZoFreX
    Commented Dec 2, 2010 at 16:19
  • Tip 8. But then again, I have been known to misunderstand answers. cl.ly/3Tq4
    – jrg
    Commented Dec 2, 2010 at 16:31
  • Tip 8 is correct ("Do not leave a charged battery dormant for long periods of time."). My comment wasn't totally clear: if you are using the battery, then you should be keeping it charged. If you are not using the battery, you should drain it to 40%. You should try to avoid draining it completely as much as possible.
    – ZoFreX
    Commented Dec 3, 2010 at 9:29
  • Alright. Sorry about being a stickler about this, but I just want to have clear answers here. :)
    – jrg
    Commented Dec 3, 2010 at 11:49

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