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So we’ve all heard that the iPad Pro is slow to charge, but I’ve been doing some research on the actual numbers and have had some interesting findings. I’m the developer of a battery/charging information app on the App Store called Battery Health and so I am often looking at the innards of iOS devices in terms of batteries and power management. This research is based on live stats reported by the internal charger device driver on the iPad Pro.

iOS devices ship with an internal charger chip (that's inside the device, NOT the power adapter that ships with it) that is configured to charge the battery at certain rates, depending on several factors. Battery charging speeds are typically measured by a unit called C, which is basically a fraction of the total capacity of the battery. For example, a 1000mAh battery that charges at 0.5C indicates that we’re charging it with a 500mA current, or half of its capacity. The higher the charging current, the faster the battery gets charged. For most iOS devices, the base charging rate for the constant current stage (the early, fast stage in the charging process) is around 0.55-0.65C.

For example, The iPhone 6 Plus has a 2855mAh battery and it charges at a maximum current of 1730mA, or about 0.60C. The iPhone 6S Plus has a slightly smaller 2725mAh battery, and its maximum charging current is 1790mA, or about 0.65C, so it charges a bit faster than the 6 Plus. Some Android phones will go much faster, up to .80C or even 1C. The catch is that faster charging shortens the overall life of the battery, so quite honestly Apple is playing it very safe with these kind of numbers, which is why their batteries tend to last so long.

Now, the iPad Pro has a gigantic 10,088mAh (38.3W) battery, but its maximum input current at the USB port is only 2400mA (12W, same as all other recent iPads). When you charge an iPad Pro, its charger is configured at 0.55C, same as many other iOS devices. The problem is that with a 10,088mAh battery, that comes to 5560mA, or 28W.

This means that the iPad Pro technically needs a 28W charger to charge at optimal speed — at the INTENDED speed. The 12W charger it ships with is only supplying 40% of the current required to charge it at maximum speed.

What’s more alarming is the fact that if you push the Pro hard (full screen brightness, LTE video streaming, etc.), its current draw sometimes actually reaches 2400mA! This means that you could be plugged in with the 12W Apple brick while using it, and the battery won’t actually get charged.

Note that as best as I can tell, the device is configured for a maximum input current of 2400mA at the Lightening port (again, that’s what the device is reporting), so be wary of any 3rd party chargers that claim to charge it faster than the stock charger. I’ve not seen anything like that, but it seems like a likely scam…

For now, the bottom line is, make sure to charge your iPad Pro while it is in standby with the screen turned off. It will barely charge while being used, even with the 12W charger.


Very interesting!! My Pro charges slow and low when charging and using at the same time. I wil remember this.
What kind of portable charger would you recommend? I have a ANKER with two ports (1A and 2A), and aRAVPower with 2.1A and 2.4A. Which would be the ideal port to use? Both chargers are15000mA. Also, what cable would be the best to get for charging he PRo from the two chargers.
Thanks a million.
 
In 2016 I expect Apple to release a Lighting to USB-C cable that is compatible with the 2015 MacBook's 29W (14.5V at 2A) USB-C Power Adapter. This cable will be able to have data transfer speeds of 5Gbps (USB 3.1 Gen 1) and allow charging times of 2 hours or shorter.

By comparison the bundled 12W power adapter is 5V at 2.4A and allows charging times of 4 hours or longer.
 
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I got an Anker Power Hub which is 24W from Santa this year - iPad Pro charges way faster than the 12W charger you get in the box.

I also noticed that it doesnt get charged faster if you use it while charging, so I usually leave it aside or put it for charge overnight.

I mainly use the device to draw/sketch and the battery does drain quickly if using Procreate app. Not to blame the app for taking advantage of the massive iPad Pro power!
 
My iPad Pro came with a 10W charger. I bought it in Brazil. Is this correct? Should I complain to Apple? Thanks.
 
My iPad Pro came with a 10W charger. I bought it in Brazil. Is this correct? Should I complain to Apple? Thanks.

I confirmed to Apple Brazilian Support, all iPads Pro in Brazil ships with 10W charger.... Should I use a powerfull charger? Thanks.
 
There's only one way to find out. Anyone out there with enough electronics/DIY skills to set up a Lightning connector where each side goes to a separate USB cable (plus the willingness to slightly jeopardize your iPP)? That way you could confirm whether two simultaneous 12W feeds are actually supported.

Hi Echo,
Great thread, and great App.

I bought your app: it's a BIG help to managing my iPad Pro's battery health.

I was REALLY struggling to charge it, and used various chargers, including the main USB on my MacBook Pro.
But i'd put aside the official 12W one: I hadn't realized it was so critical!

And WOW, it is the only one that actually charges it very well.
Although as you say, it is limited to 6W, even though it claims to have a 12W rating.

I want to be able to take my iPad Pro on motorbike trips, and use a Lithium backup battery to re-charge it without having to use AC.
Mine is rated at 10W, but the IPP will only use 5W.

There's a chip inside the Lightning cable itself.
Generic/copy-cat cables don't have it.

http://www.idownloadblog.com/2012/0...ip-policies-against-third-party-alternatives/

I just tested a copy-cat versus the OEM one, using my 12W Apple charger.
HUGE difference.
The Apple Lightning cable charges at 6W.
The copy-cat Lightning charges at 1.6W, even though Echo's App reports the charger is rated at 12W.

That also confused me: I was trying to charge my IPP using the copy-cat cable at times.

I object to this: I think there should be standard cables, unless there's a REAL advantage to be gained.
This is just to maintain a monopoly for Apple.

But won't this chip interfere with the idea of splitting the cable into two USB inlets?
 
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I got an Anker Power Hub which is 24W from Santa this year - iPad Pro charges way faster than the 12W charger you get in the box.

I also noticed that it doesnt get charged faster if you use it while charging, so I usually leave it aside or put it for charge overnight.

I mainly use the device to draw/sketch and the battery does drain quickly if using Procreate app. Not to blame the app for taking advantage of the massive iPad Pro power!

I don't see that it would be any different from the Apple single-port 12W one. The Anker 24W description just mean it has TWO 12W ports.

How do you know it charges faster than the 12W Apple charger you get in the box?
Did you measure it with Echo's App?
 
The slow charging is the only thing that annoys me a bit about my iPP. But since I am using it as a second monitor at the moment, it gets charged at work (even slower than usual as I am using the device) and I can use at home without having to charge much.
 
The slow charging is the only thing that annoys me a bit about my iPP. But since I am using it as a second monitor at the moment, it gets charged at work (even slower than usual as I am using the device) and I can use at home without having to charge much.


I use with Duet app as a 2nd display as well.

And if I use high performance mode, macbook pro 15 retina cannot handle to charge it, it even drains.

I was working on a project over night, and i was shocked when I see low battery error.

Later I played around with brightness and the duet settings, it helped a little but still it is not getting enough juice from MBP. :(
 
Additional data point from the Regulatory information tab on the Pro

It can charge by
14.5v 2A Or
5.2v 2.4A
 
Additional data point from the Regulatory information tab on the Pro

It can charge by
14.5v 2A Or
5.2v 2.4A
That's a good catch (image from the regulatory screen attached). 14.5V at 2A sounds like the MacBook's USB-C 29W adapter. But people have tried using it with the iPad Pro with adapters and got the same charging speeds. So clearly we're missing something from Apple to enable higher powered input.

Again, I'll reiterate the original point from this thread: The battery itself "wants" about 22 watts of power (5500mA), so a 29W adapter would be perfect cause it would charge the iPad significantly faster AND it would have enough juice left to power it during charging.

It would make a HUGE difference to actual charging speeds, and would allow us to actually charge these devices while using them, which the current 12W adapter does not.
iPad Pro Regulatory.png
 
I confirmed to Apple Brazilian Support, all iPads Pro in Brazil ships with 10W charger.... Should I use a powerfull charger? Thanks.

I suggest you get Echo's app to see how fast you are charging.
I have the 12W Apple charger and my max rate is around 5W.
So it might not matter what charger you have, as long as it's an Apple moment.

Echo's app is really useful, and not expensive. If you've paid $1,000 for an IPP it seems silly not to buy the app.
And no, I don't have shares in it...:-}
 
That's a good catch (image from the regulatory screen attached). 14.5V at 2A sounds like the MacBook's USB-C 29W adapter. But people have tried using it with the iPad Pro with adapters and got the same charging speeds. So clearly we're missing something from Apple to enable higher powered input.

Again, I'll reiterate the original point from this thread: The battery itself "wants" about 22 watts of power (5500mA), so a 29W adapter would be perfect cause it would charge the iPad significantly faster AND it would have enough juice left to power it during charging.

It would make a HUGE difference to actual charging speeds, and would allow us to actually charge these devices while using them, which the current 12W adapter does not.
View attachment 616735

Here we go, finally Apple releases a USB-C to Lightning cable that allows iPad Pro users to use the 29W USB-C from the MacBook with their iPad Pros!

https://www.macrumors.com/2016/03/21/apple-lightning-to-usb-c-cable-adapter-ipad-pro/
 
Is it actually going to charge faster? 2.4A for the 12W charger vs 2A for the 29W charger. Isn't charging "throughput" measured in amp-hours?
I could be wrong, not an EE.
 
Is it actually going to charge faster? 2.4A for the 12W charger vs 2A for the 29W charger. Isn't charging "throughput" measured in amp-hours?
I could be wrong, not an EE.
It is absolutely going to charge faster. I will report exact differences once I get mine, but an educated guess would be around 2 hours from empty, assuming the device is not in extreme use at maximum screen brightness and such.

29W means that actual charging amperage could easily reach the maximum supported charging rate of about 5.5A. That would be about 22 watts, leaving another 7 to actually power the device.
 
I would love a widget for Battery Health. I think I sent feedback via the app some time back, but being able to pull down the notification shade for quick details on the charging speed would be immensely convenient. An Apple watch complication / app is also another idea, but I'd be happy with just the notification shade widget.
 
I would love a widget for Battery Health. I think I sent feedback via the app some time back, but being able to pull down the notification shade for quick details on the charging speed would be immensely convenient. An Apple watch complication / app is also another idea, but I'd be happy with just the notification shade widget.
I actually added a widget in the latest version, but Apple is so far refusing to approve that version.

Screen Shot 2016-03-23 at 4.51.26 PM.png
 
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Sadly, Apple has recently decided to remove it from the App Store. :(

I'm working with them to try and reverse that decision but I'm not hopeful...
Oh no! What reasons did they give? Your app was essential when trying to figure out if the new TomTom app is inefficient or my charger was broken.
 
So get the faster charger if you want to (and get a new swanky USB-C to lightning cable)
They've done the same with the iPhone immemorial - heck on the 3G you could be plugged into power, using GPS maps and still drain the batter.
 
I actually added a widget in the latest version, but Apple is so far refusing to approve that version.

Ugh.... This is typical Apple. They'll be very draconian about things like this (I recall PCalc had a similar issue with their Notification Center widget) but they'll let things like that InstaAgent credentials stealing app through.

I really hope your appeal succeeds.
 
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