Or does it make a difference?
This is a discussion on iPad charge faster if turned off? within the iPad General Discussions forums, part of the Apple iPad Discussions category; Or does it make a difference?...
Shutting it down or putting it into sleep mode will allow it to charge faster.
Does anyone have stats on this? I charge my iPad every night and have plenty of juice to make it through a day without charging. And that is with heavy use. I never turn the iPad off, and I suspect charging with the power off doesn't make a very big difference.
Posted from my iPad WiFi 64GB
I also never turn my iPad off, even when I am charging it. Once in awhile I let it drain down to the point where it shuts off, but other than that, I usually put it on the charger (the one that came with it) when the batter level drops below 50%. Supposedly, these batteries don't have a "memory" like the old NiCad batteries used to have.
I haven't seen the specs or taken any measurements, but my guess is the iPad has a Lithium Polymer (LiPo) battery with a capacity of ~6,000mAh. The discharge rate appears to be ~0.1C, and the charge rate ~0.5C.
If that is correct, you would expect charging to take ~20% longer with the iPad left switched on than it would if it was switched off. I stress that is just a guess.
The battery will have integral protection circuitry to prevent overcharging and over-discharging. These batteries have no 'memory effect', and don't mind frequent top-up charging. If you run your iPad down to empty, it is best for the battery to recharge it sooner rather than later, as leaving the battery in a discharged state for a prolonged period will shorten its life.
If you have to store it unused for prolonged period (such as a month or more) store it at 50-75%, rather than full or empty.
Apple seems to force the iPad and iPhone to turn on when you plug them in and it's a nuisance then having to turn them off so I've just given up and leave them on. It probably makes an immaterial difference.
New iPad wifi + 3G 64GB
Paired with Macbook Pro
Backed up to iCloud