Compared to what? Before? A different iPad? A previous model iPad?
The 'new iPad' has a significantly higher capacity battery than previous models, therefore takes longer to charge than previous models.
If you are attempting to charge it with anything other than the suppiled charger plugged into a wall outlet, then it will take longer to charge.
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%.
How to Calibrate Your Mac, iPhone, or iPad Battery
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
Apple Batteries - iPad http://www.apple.com/batteries/ipad.html
Extend iPad Battery Life (Look at pjl123 comment)
New iPad Slow to Recharge, Barely Charges During Use
Tips About Charging for New iPad 3
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips
iPhone, iPod, Using the iPad Charger
Install and use Battery Doctor HD
In rare instances when using the Camera Connection Kit, you may notice that iPad does not charge after using the Camera Connection Kit. Disconnecting and reconnecting the iPad from the charger will resolve this issue.
I own an iPad Air 1 and have always noticed it takes a REALLY long time to charge as compared to my perception, having never measured in any scientific way, to my earlier model iPads, iPhones and even various Macbooks Over the years. These all seemed to just charge at what felt like a "normal" rate. So much so that I never gave it any thought, other than perhaps, needing to top off and having the sense I could plug in anywhere using almost any charger or cable. Unless it was a bad cable, charging just happened. Even with those pesky messages that the charging device wasn't authentic and might not function, but they always did. Well until they stopped completely.
But that was in the days when all Apple supplied was a way too short cable that was hard to use your device and charge simultaneously so many started hunting for longer cables that often worked but also evoked the warning messages.
WIth it's the new iPads, what we're experiencing is different. Simply stated the new generation of iPads use more power. Specifically the screen. HD comes at a cost as does the stronger processors. If you use your iPad while charging even with the supplied Apple 10-watt charger, and shortest Apple cable, if you have brightness up, you may see the message that your iPad isn't charging and you can be using more power than Apple's charger can replace simultaneously.
when your iPad rests however, charging will commence and/or charge at a faster desired rate.
WHats eats odd to me, is that as of last week I didn't know all this and finally found the time to visit an Apple Store and they replace my still under AppleCare but nearly 2 years old iPad Air.
It's been several days and it charges just as slowly! So this morning I started reading and learned the above. Knowing what I do now, Apple shouldn't have replaced my iPad as there was nothing wrong. My charging habits need to change not my iPad
sincentive the monitor is such a drain, first thing is to turn brightness down as low as possible, and use the best charging hardware possible. My next research will be to see if there are chargers and cables capable of faster, stronger charging. For all I know, Apple designed the device to max out input wise, so it might not be possible to charge faster than with supplied Apple gear. TBD.
BUt monitor brightness and keeping only the apps needed open seems the only options currently Until Apple finds a way to charge iPads faster which will no doubt only work on future models. I'm assuming if I can charge my Macbook Pro faster than my iPad, surely Apple can find a way to speed charging up on a tablet. Right? We'll see... In the meantime there are many great articles out there. I liked this one from MacWorld.