The quickest way (and really the only way) to charge your iPad is with the included 10W USB Power Adapter. iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter (5W). When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge very slowly (but iPad indicates not charging). Make sure your computer is on while charging iPad via USB. If iPad is connected to a computer that’s turned off or is in sleep or standby mode, the iPad battery will continue to drain.
Apple recommends that once a month you let the iPad fully discharge & then recharge to 100%.
At this link http://www.tomshardware.com/reviews/galaxy-tab-android-tablet,3014-11.html , tests show that the iPad 2 battery (25 watt-hours) will charge to 90% in 3 hours 1 minute. It will charge to 100% in 4 hours 2 minutes. The new iPad has a larger capacity battery (42 watt-hours), so using the 10W charger will obviously take longer. If you are using your iPad while charging, it will take even longer. It's best to turn your new iPad OFF and charge over night. Also look at The iPad's charging challenge explained http://www.macworld.com/article/1150356/ipadcharging.html
Also, if you have a 3rd generation iPad, look at
Apple: iPad Battery Nothing to Get Charged Up About
Apple Explains New iPad's Continued Charging Beyond 100% Battery Level
New iPad Takes Much Longer to Charge Than iPad 2
I also have an iPad 1 and an Ipad 3. Both on iOS 5.1. A few observations:
I have also noticed worst relative battery life. I'm probably getting half the life out of a battery. Down from perhaps 14 hours of wifi use to a consistent 7 hours. I essentially went from charging the 1 a few times a week to charging the 3 just about every day when the battery dies.
Navigation kills battery life. I have 3G on the 1 but not the 3. On the 1, use of any navigation app on 3G ***** the battery. Its the same on any phone. If you have 3G on both, then this is probably not your issue. I've seen less than 3 hours when using nav apps. I don't think you're seeing anything out of the ordinary. If you are using a 5 watt car charger, its quite possible the nav app is sucking juice out of the battery faster than the charger can replenish it. I use a 10 watt charger and do not have this issue on a boat where the iPad is running all day long.
If you are in Europe, charging over 220 takes longer than 110. We live in both Europe and the USA and have always noticed this. So don't follow all the wisdom on the web re charging times. Overnight is best.
The 1's screen is much brighter at a given brightness setting. To get the same level of brightness on the 3, you have to crank up the brightness. I believe this is the main culprit with my shorter battery life as the brightness slider is set materially higher than on the 1.
Just for the record, my ipad 3 screen started to fail. Whole lines of dead pixels appearing over a period of 24 hours.
Got a new replacement ipad 3 on Friday and the battery life is noticeably better. 2 days later and still at 16% and thats from the initial 81% when i picked it up from the store. On my original ipad 3 i would have had to charge it twice by now.
For me, there is no doubt my original ipad had a battery drain fault. The dodgy screen seems also to have highlighted some quality control issues?
Responses indicating how to extend battery life are welcome and do show good practice which i adopted, however there clearly is an issue somewhere and with some tablets leaving the factory.
Fyi you are supposed to get roughly 6 minutes per 1%. 6*10*10=10hrs. Is you battery using between 4 and 5 min per percent? That means you should still get around 5+hrs. This is hypothetical of course. My battery lasts about 6-7min per 1% while doing 2d games and surfing the web. With e-reading i get about 12hrs of reading time total. With demanding games i get roughly 7hrs. My battery lives pretty close to ten hours so something must be up with yours. If you have the 4g, turn it off when not in use,same for wifi, they are far too demanding of power especially when they are not in use. I would suggest doing a full cycle charge weekly as well, it helps keep your battery alive and well :)
Brightness has a big influence on battery life so if you can turn your brightness down, you will get longer battery life.
Not much you can do to improve charging time. This is my biggest complaint with the iPad 3.
This is a good article on the battery.
My new iPad 3 had the drainage problem when I used it for browsing etc. not the sleep problem.
I had it replaced but the replacement did the same thing. Even though I only read text on a simple page in Safari, or used my RSS app if would get a little hot on the back, and the battery steadily came down.
I am very fond of my iPad 2 and never experienced anything like it.
The new iPad was restored from my iPad 2 iCloud backup.
Reading this forum I tried a Restore from iTunes that installed the newes iOS and I then did a restore from iCloud.
This gave same result; Background battery drainage.
I then finally gave in, losing all my App settings, and again did an iTunes restore and now set it up as a new iPad.
So far, this seems to cure the background battery drainage.
Some things I noticed on the iCloud restore;
1) The restore from iCloud/iPad2 comtained Apps from different accounts. Since I had forgot about buying from two other iTunes accounts that my primary, I canceled the app installation from those.
2) The only App I use all the time is my RSS reader. I noticed that when it was re-installed on my iPad 3 from iCloud it kept notifying me on how to use the app. This is natural, the first time you use it, but it shouldn't keep reminding you. This made me think of somthing as trivial as user rights on files. Yes, good (I should say bad) old ownership problems on files. It seemed like the RSS app was unable to save certain settings. Maybe some of the files from the iCloud restore had the wrong permissions. Well, just at thought.
So far the drainage problem has gone, but it is definitely a pity if you can not use an iCloud restore!
I am sad to report that the problem is back.
Even though I close all apps except for the one I am using, for instance Mail, reading wikipedia in safari or my rss reader. I notice that the iPad gets slightly hot on the back, and the battery drains. My wifes and childrens ipad 2 stays ice cold while they surf, plays music in itunes or watch youtube. My retina iPad just gets warm and needs to be charged, even though what I do most is read articles and news.
Something in the background is not right, and it makes me sad, since I want to sell my iPad 3 and get back my faithfull iPad 2.
Apple if you are listening: fix this background thing on the iPad retina that drains the battery!
And no, it is not sleep/lock related. When locked, the battery is rock solid.
With my ipad 2 I never thought about which app or process the drained my battery, but now I want to know.
This is a great article for the new iPad and its battery life, it made a lot of sense to some customers I have had who have had similar battery issues.
Although in some occassions yes there has been issues with some batteries. Best way to test this is to head into a Apple Authorised Repairer or an Apple Store so they can run diagnostics or test for themselves (be prepared to leave your iPad for a day or two for thorough testing! At least you will know definitely how your battery is)
Although this is for a macbook pro screen It will look exactly as in the article above.
You may have one dead pixel or a small cluster both are usually covered by warranty,
If your not sure call up Apple Care (1300 321 456 - Australia) and they'll confirm with you.