Q: How low should the battery be before I put my iPad to charge?

Charge when you want for as long as you wish.

It is advised to let the iPad run totally down to where it shuts off once a month to calibrate the meter. That said, my rule of thumb is charge it when you don't think you have enough to get through the day. IMHO, it's best to leave it on until it's full, but if you have to pull it off earlier, you won't hurt it.

the 2 charges in 4 hours or so, the 3 5-6 hours

You can (and should!) put it on charge whenever you can / find it OK. Thing is: as opposed to what some (not necessarily very informed) people state, it's not needed to discharge it as much as you can every single time.

We aren't living the Nickel-Cd/MH times any more, there isn't "memory effect" in today's batteries.

That is contrary to Apple's recommendation. Once charged the device should be disconnected and run until it's down to zero and shuts off or until you know it you will need more battery than what is showing as available for in a given time period. There is a finite number of charges to any battery. The more times you charge the battery, the faster you will need to replace it.

Source?

Apple. I just replaced my battery and the Apple Genius people told me. It's also in their documentation.

The quickest way (and really the only way) to charge your iPad is with the included 10W or 12W (5W on Mini) 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 (2.5W, 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

http://www.macblend.com/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

http://allthingsd.com/20120327/apple-ipad-battery-nothing-to-get-charged-up-abou t/

Apple Explains New iPad's Continued Charging Beyond 100% Battery Level

http://www.macrumors.com/2012/03/27/apple-explains-new-ipads-continued-charging- beyond-100-battery-level/

New iPad Takes Much Longer to Charge Than iPad 2

http://www.iphonehacks.com/2012/03/new-ipad-takes-much-longer-to-charge-than-ipa d-2.html

Apple Batteries - iPad http://www.apple.com/batteries/ipad.html

iPhone: Hardware troubleshooting (Power/Battery section also applies to iPad)

http://support.apple.com/kb/TS2802

Extend iPad Battery Life (Look at pjl123 comment)

https://discussions.apple.com/thread/3921324?tstart=30

iOS 7 Battery Life Draining Too Fast? It’s Easy to Fix

http://osxdaily.com/2013/09/19/ios-7-battery-life-fix/

New iPad Slow to Recharge, Barely Charges During Use

http://www.pcworld.com/article/252326/new_ipad_slow_to_recharge_barely_charges_d uring_use.html

iPad: Charging the battery

http://support.apple.com/kb/HT4060

Best Practices for iPad Battery Charging

http://www.ilounge.com/index.php/articles/comments/best-practices-for-ipad-batte ry-charging/

Tips About Charging for New iPad 3

http://goodscool-electronics.blogspot.com/2012/04/tips-about-charging-for-new-ip ad-3.html

How to Save and Prolong the battery life of your new ipad

https://discussions.apple.com/thread/4480944?tstart=0

Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips

http://thehowto.wikidot.com/prolong-battery-lifespan-for-ipad

iPhone, iPod, Using the iPad Charger

http://support.apple.com/kb/HT4327

Install and use Battery Doctor HD

http://itunes.apple.com/tw/app/battery-doctor-hd/id459702901?mt=8

To Extend a Device’s Battery Life, Get to Know It Better

http://tinyurl.com/b67c7xz

iPad Battery Replacement

http://www.apple.com/batteries/replacements.html

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.

 Cheers, Tom

lola839 wrote:

 

That is contrary to Apple's recommendation. Once charged the device should be disconnected and run until it's down to zero and shuts off or until you know it you will need more battery than what is showing as available for in a given time period. There is a finite number of charges to any battery. The more times you charge the battery, the faster you will need to replace it.

Completely false, and not even what Apple says - see http://www.apple.com/batteries/ipad.html

Deep discharge cycles will degrade any Lithium battery much more rapidly than shallow cycles.  Since partial discharge and partial charge cycles are completely harmless, it is far better to charge more often or more frequently and avoid deep discharge cycles as much as possible.  Since overcharge protection is also built in, once charged, if it is convenient to work with the device while plugged in, it is fine to use while plugged in and avoid unnecessary discarge cycles.

There is no set point that one need pay attention to for charging - plug it in and charge it, and unplug it and use it, as is convenient to do so.  Simply try to avoid deep discharge cycles as much as you can by plugging it back in whenever it is convenient to do so.

I went to the site you referenced. I don't get you "completely false..." pronouncement at all...but thanks for your expert input there. The site clearly says once charged, the device should be disconnected from the charger. If you don't want to run it all the way down, fine but it should be run all the way down at least once a month.

lola839 wrote:

...The site clearly says once charged, the device should be disconnected from the charger....

Nowhere on the page I linked to does it say anything like that at all.