Can anyone tell me what current should be pulled by the ipad whilst charging at various levels of battery capacity? Is it the same no matter what level of charge the battery is at or does it increase/decrease depending on the level of the battery.
iPad 2, iOS 5.1.1
The power brick plugged into the wall is not a charger. it is a power supply, nothing more. The charger itself and all charging control systems are built directly into the iPad (or iPhone, or Mac, or Apple Pencil, or whatever lithium battery device you’re discusssing) itself. The device regulates and controls its own charging, and will not draw current higher than its maximum programmed limit.
There is nothing novel in that either. Every industry standard SMART lithium power device has been that way for decades, and every single device Apple has ever produced with lithium ion or polymer batteries has been that way.
The plastic brick you plug into the wall does nothing more than convert household voltage and current to industry standard USB output (for Apple iPad and iPhone power supplies, that is 5v and either 1A or 2.1A). This is why you can use an iPad 12w power brick to safely charge any iPhone as well. The iPhone itself will regulate the current it charges with (up to fairly recent models, that was a max. of 1A). Similarly, no iPad model will ever pull more than 2.1A for charging, no matter how much more you offer it.
P.S. This is also why cheap knockoff Chinese and other batteries burst into flames on cheap items like some hover boards and such (or cheap eBay iphone or iPad “replacement“ batteries) - those sweat shop knock off lithium batteries do NOT conform to SMART industry standards and thus often fail to properly regulate their own charging, draw too much current, overheat and explode.
The power brick plugged into the wall is not a charger. it is a power supply, nothing more. The charger itself and all charging control systems are built directly into the iPad (or iPhone, or Mac, or Apple Pencil, or whatever lithium battery device you’re discusssing) itself. The device regulates and controls its own charging, and will not draw current higher than its maximum programmed limit.
There is nothing novel in that either. Every industry standard SMART lithium power device has been that way for decades, and every single device Apple has ever produced with lithium ion or polymer batteries has been that way.
The plastic brick you plug into the wall does nothing more than convert household voltage and current to industry standard USB output (for Apple iPad and iPhone power supplies, that is 5v and either 1A or 2.1A). This is why you can use an iPad 12w power brick to safely charge any iPhone as well. The iPhone itself will regulate the current it charges with (up to fairly recent models, that was a max. of 1A). Similarly, no iPad model will ever pull more than 2.1A for charging, no matter how much more you offer it.
P.S. This is also why cheap knockoff Chinese and other batteries burst into flames on cheap items like some hover boards and such (or cheap eBay iphone or iPad “replacement“ batteries) - those sweat shop knock off lithium batteries do NOT conform to SMART industry standards and thus often fail to properly regulate their own charging, draw too much current, overheat and explode.
@Thom: It is nice that you want to answer questions but if your answer is poorly informed it might be better that you don't.
1. The OP specifically asks about current not watts.
2. Current is measured in Amps not Volts. Current is NOT 110 Volts!
3. The Apple charger as you call it (power supply or brick as some others have called it) can provide 10.5W of energy, which equates to a maximum current of 2.1 Amps. USB 3.0 and 3.1 both support the USB Power Delivery specification which supports a maximum of 20 volts at 5 amps for a total of 100 watts of power. This means that if you have a computer that supports the 3.0-3.1 protocol and provides a 5V USB output, it can also provide 10W which is the same as Apple's wall charger and therefore it can charge your iPad just as quickly as the Apple charger. You need to find out just what the specs are on your computer USB ports before you can say they are necessarily worse or better than the Apple charger.
4. The iPad patently does not "pull the full charge until the meter reaches 100%". It pulls full current (2A) for part of the charge and a diminishing charge as it approaches 100%.
Watts = Volts x Amps, that is, Power is Voltage times Current
Therefore: Amps = Watts/Volts
Regardless of the Voltage in the wall (110 V AC or 220 V DC or whatever), the chargers for most phones and tablets are designed to convert it into an OUTPUT of 5 Volts and some given current (0.5 Amps, 1 Amp, 2 Amps, etc.). This is what the devices receive.
Each device is rated at some given Power, or wattage. An iPad has a rating of 10 Watts. Hence, by simple math we have: iPad Current = 10 Watts / 5 Volts = 2 Amps. This is the current "drawn" by an iPad.
The safest thing is naturally to use the iPad charger, which has been taylored to work for the iPad. But if not available and one must resort temporarily to another charger, the best option is to use one with an output of 5 Volts and 2 Amps.
What happens is we use a charger with less than 2 Amps? -- It takes longer to charge or might not charge at all, and if it takes too long the battery might heat up.
What happens if we use a charger with greater than 2 Amps? -- If the charger is well designed, the iPad will draw the 2 Amps it needs and that would be OK. However, if the charger is cheap, old, badly designed, or sensitive to current surges in the wall, then there is a risk that under certain conditions it could heat up or even burn the battery of the iPad. Naturally the risk is less if the charger is rated at say 2.1 or 2.5 Amps, than say, at greater Amperage.
I am not sure if you mean current or watts. Current would be 110 volts in the US and I think 220 volts in some other areas of the world.
If you are talking about watts the iPad pulls 10 Watts which is why you want to use the included wall charger to charge an iPad not a computer USB port or an iPhone wall charger.
And yes the iPad pulls the full charge until the meter reaches 100% then the circuitry in the charger/iPad drop the draw to a trickle to allow the battery to get a full charge without damaging anything.
Volts is potential, current is amps. Watts = volts x amps. Solve as required.
But any answer is academic, because there's nothing the user can do about it.
The charger is rated at 10W. The output is 5VDC @2A.
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
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
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 - iPadhttp://www.apple.com/batteries/ipad.html
Extend iPad Battery Life (Look at pjl123 comment)
https://discussions.apple.com/thread/3921324?tstart=30
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
Tips About Charging for New iPad 3
http://goodscool-electronics.blogspot.com/2012/04/tips-about-charging-for-new-ip ad-3.html
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips
http://thehowto.wikidot.com/prolong-battery-lifespan-for-ipad
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 😉
What is the charging current of ipad?
