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Old Apr 9, 2012, 10:06 PM   #1
PracticalMac
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How long does it take to charge "New iPad" (iPad 3)

Have not charged from fully drained state, but did 48% in just over 3.5 hours, suggest about 8 hours to charge from 0% (stand by mode almost entire time).

Actually boggle my mind, all that battery power. 25 W·h(!).

...Considering the charger is 2.1Amp, for 25W-h, suggests over 10 hours to charge from 0%. (musing)
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Old Apr 9, 2012, 10:22 PM   #2
Chris Blount
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Mine takes 6 hours.
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Old Apr 10, 2012, 01:36 AM   #3
donnaw
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Mine takes about 6 hrs too. This is from around 10% to 100%.
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Old Apr 10, 2012, 01:47 AM   #4
richpjr
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Another one here with around 6 hours - just plug it in before bed and it's ready in the morning.
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Old Apr 10, 2012, 01:54 AM   #5
Mikekan
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6 hours and 15 minutes
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Old Apr 10, 2012, 02:03 AM   #6
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Yes, between 6 and 7 hours seems to be the norm.
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Old Apr 10, 2012, 02:39 AM   #7
markie
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Quote:
Originally Posted by PracticalMac View Post
Have not charged from fully drained state, but did 48% in just over 3.5 hours, suggest about 8 hours to charge from 0% (stand by mode almost entire time).

Actually boggle my mind, all that battery power. 25 W·h(!).

...Considering the charger is 2.1Amp, for 25W-h, suggests over 10 hours to charge from 0%. (musing)
The battery is 42.5 watt-hours.

The charger is rated for 2.1A, 5.1V. 2.1*5.1=10.71. So, in THEORY, you get 10.71 watts but with the voltage loss on that flimsy wire, you'll never see more than the 10watts total power the charger is marketed as (4.76 volts at 2.1A, and technically it's not a charger, it's a power supply, the actual charger is in the iPad, but still...). So we'll run with Apple's 10 watt figure, also because it's a nice number.

That means that theoretically, assuming 100% efficient charging, the battery COULD charge in 4 hours, 15 minutes (4.25 hours). Nothing is 100% efficient, and the last 10% or so of a lithium ion battery charge must be done very slowly. Still, with the device off, you should get at least mostly charged in 5-6 hours in paper. If you're using it at all, this goes down.

Now, if you use a smartphone charger... 1A at 5V is 5 watts. Theoretical minimum charge time would be 8 hours, 30 minutes. Again, assuming non-existant 100% efficiency. Also again, the device is OFF in this assumption and any use is even more likely to prevent the iPad from charging at all, and making it more likely to drain (just more slowly) while connected.

Finally, with a computer USB port or standard phone charger... 0.5A at 5V is 2.5 watts. Theoretical minimum charge time becomes 17 hours (100% efficient charging again, not realistic). In reality, the chances of this charging the device are slim, but at least the battery will drain a bit slower...
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Old Apr 10, 2012, 08:33 AM   #8
h1r0ll3r
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7-ish from 0 - 100%
About 6 hours or so for regular charging. I seem to have an issue with the battery percentages displaying inaccurate info like some others have noted. I charged mine overnight and it went from 45% to 58%? How random is that. Anyhoo, after hard reset, it went back to 100% but then stayed there for about 6-7 hours. After another hard reset, it dropped to 30%. Had to recalibrate the battery a couple times but I think it's working properly now.
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Old Apr 10, 2012, 09:16 AM   #9
D.T.
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Yeah, I’m seeing about 6 hours or so too.

The longer charge period hasn’t been an issue for me. I have a charger at my desk, so I just connect it when I’m done for the day or occasionally while I’m using it (for video for example) - also have another charger upstairs, so if I’m using it at night, when I’m done I just connect it right at my nightstand.

So in the morning it’s at 100%, and given my use, I don’t even have to charge it but every 2-3 days anyway.
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Old Apr 10, 2012, 11:25 AM   #10
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6.5 hrs for mine. I charge up every night. Usually end the day at about 20% remaining.
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Old Apr 10, 2012, 11:54 AM   #11
spiderman0616
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I've said it before and I'll say it again:

Who cares? Don't people mostly charge at night while they're sleeping? And if you do need to charge it during the day, charge it for a couple of hours and leave!
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Old Apr 10, 2012, 02:55 PM   #12
PracticalMac
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Quote:
Originally Posted by markie View Post
The battery is 42.5 watt-hours.

..
Thanks for all that! Explains it.

I likely over estimated total time, probably less then 7 hours on my end too.
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Old Apr 10, 2012, 03:04 PM   #13
Mikekan
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We all know that it is not good to leave the iPad on the charger when it is fully charged! So this is one good thing about taking so long to charge, when you charge over night you wake up the iPad has not been left fully charged on the charge for a long time!
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Old Apr 10, 2012, 03:14 PM   #14
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We all know that it is not good to leave the iPad on the charger when it is fully charged!
This is simply not true:
Quote:
“That [charging] circuitry is designed so you can keep your device plugged in as long as you would like,” [Apple VP Michael] Tchao said. “It’s a great feature that’s always been in iOS.”
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Old Apr 10, 2012, 11:33 PM   #15
Mikekan
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Thanks for clarifying this!
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Old Apr 11, 2012, 02:17 AM   #16
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Mine takes.... I don't know. Plug it in when I to to sleep.... Wake up and it's fully charged.
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Old Apr 11, 2012, 04:04 AM   #17
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All I know is that if I plug it in before bed and it's still not charged by morning I've had a crappy night's sleep
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Old Apr 11, 2012, 09:19 AM   #18
sofasurfer
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Interesting to see how people's iPads take differing amounts of time to charge. Mine takes about 12 hours from 1%-100%. I have it currently charging and in 5 hours it has charged less than 50%.
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Old Apr 11, 2012, 10:46 AM   #19
Mikekan
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Are you using the supplied iPad charged or an iPhone one? It is normal to have small variations due to the different losses that each charger has but 12 hours is double the time!
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Old Apr 11, 2012, 10:50 AM   #20
verwon
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Honestly, I've never sat down and timed mine. If it's low, I plug it in and don't worry about it. Usually, that's at night, when I'm going to sleep, anyway.
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Old Apr 12, 2012, 02:37 AM   #21
sofasurfer
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Originally Posted by Mikekan View Post
Are you using the supplied iPad charged or an iPhone one? It is normal to have small variations due to the different losses that each charger has but 12 hours is double the time!
I am using the supplied charger. Is there a difference in charger between the iPad2 and New iPad charger as the wife has an old machine and I use her charger sometimes.
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Old Apr 12, 2012, 02:56 AM   #22
MrXiro
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Are you plugging it into a computer or an outlet? No way should it take 12 hours from an outlet.
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Old Apr 12, 2012, 03:48 AM   #23
sofasurfer
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Are you plugging it into a computer or an outlet? No way should it take 12 hours from an outlet.
Straight into a wall socket.
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Old Apr 12, 2012, 03:53 AM   #24
MrXiro
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Straight into a wall socket.
I would take it to the apple store or exchange it.
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Old Apr 12, 2012, 03:55 AM   #25
sofasurfer
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I would take it to the apple store or exchange it.
Shame...as the iPad is perfect apart from this.
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