iPad Pro fast charging feature gone?

Short answer: Yes, there should not be any significant difference between a smaller and a larger adapter.

Longer answer: USB-C chargers and devices can negotiate a voltage. The voltage can be 5, 9, 15 or 20 Volts. Typically the devices decide on the highest one that both support. In theory, a larger adapter might support more voltages and thus affect the charging time very slightly. In practice I don't think this would be measurable.

I made a few tests with the 29 Watt adapter, the 61 Watt adapter and the Satechi 75 Watt adapter. The results are a bit surprising to me. I tested with the iPhone X, the iPad Pro 10.5", and a Macbook 12".

• 29 Watt: All devices charge with 15 Volts. Highest current was with the Macbook at 1.4A (about 21 Watts).
• 61 Watt: iPhone X and iPad charge with 15 Volts, Macbook with 20 Volts (1.4A, about 24 Watt). iPhone and iPad take about the same current as with the 29 Watt adapter, so the charging time would be identical.
• Satechi: The iPhone charges with 9V, iPad with 15V, and Macbook with 20V.

I find two things interesting:

1. The iPhone clearly supports 15V, and so does the Satechi Adapter. Still, they negotiate only 9V.
2. The 29 Watt adapter apparently does not support 20V, even though the Macbook 12 does (the 29 Watt was included with the Macbook).

Now on to the new 30 Watt adapter: My theory is, they "fixed" the problem that their smallest adapter does not support 20V. They needed a new "name", so they added one Watt (which won't be really measurable, IMO).

So you should be fine with the 30 Watt adapter.

And yes, you must buy an original Apple cable. So far, no 3rd party certified USB-C to Lightning cables are available, so you don't have a choice in this matter. I would never risk a bootleg cable, it might easily fry your charger and/or the iPad.

Last question is about the battery size. The bigger a battery is, the larger can the charging current be. In the RC world, one charges with "1C", which means the current is the same as the charge of the battery. In your case, a "1C" charge would be charging with 41 Watts (e.g. 15 V, 2.8A). However, "1C" is considered damaging to the battery, so I am sure Apple goes way below this. If my 30.4 Wh battery is charged at about 18W then yours would be charged at 24W, which is still below the 30W adapter's maximum. So I think there is no point in getting a bigger adapter.

We are only users here, but appears during the course of iOS 10, Apple eventually did away with the fast charging ability in the 12.9 inch screen size iPad Pro models.

The 9.7 and 10.5 inch iPad Pro models never supported fast charging ever.

The removal of this feature, like Apple does sometimes, happens without Apple ever “officially” documenting the removal of previous iOS features.

Apple loves to promote new hardware and iOS software features to promote new products, but seems to be less than forthcoming to never in announcing or documenting any feature removals.

"Fast charging" essentially means using more than 5 Volts when charging the device.

The 12 Watt regular charger uses 5V 2.4A, which multiplied gives 12 Watts.

When I charge my iPad Pro 10.5" on an Apple 29W charger, then charging starts at 5V 1.7A. The charger and the iPad then negotiate a higher voltage and quickly shift to 15.3V, 1.5A. This is a little more than 20 Watts, almost double of the 12 Watts of the regular 5V charger. My USB-C measuring device can't really keep up with the rapidly fluctuating current, so the 1.5A is only guess. It might be more or less on average.

At about 80% the current starts to go down. This means that from 0-80% the fast charge is almost twice as fast compared to the regular charger (if the 20 Watts are accurate). From 80-100% there is little (if any) difference.

This has been the case with every iOS release that I had on my iPad, including the up-to-date iOS 11.4.

One more thing: 20 Watts is of course less than the 29W maximum that the charger can deliver. When I use a non-apple 75W charger, I still get only 20 Watt. The iPad itself limits the current to a safe value, regardless of the theoretical maximum of the charger. I suppose that Apple chose a safe charging current that will not destroy the battery. I can't see any reason not to use fast charge; I use it every night when recharging the iPad.

Based on the support article you referenced, I seem to be in error.

So, go out and purchase everything you need and try it!

If it works, great!

If not, you have 14 days to return everything.

Good Luck!