The iPad Pro comes with a 18 watt USB-C Charger. It’s light and portable and a great step up from the chargers that came with the previous generations of iPads. But I wondered if 17 watts was the maximum that my new 2018 iPad 11″ could consume during charging so decided to run some tests to find out.

I happen to have a bunch of USB-C chargers handy. I also have a MacBook Pro 15 which has USB-C ports that can provide power, just like a portable battery pack. I purchased a USB port ammeter that measures the amount of power flowing through the ports. The power sources I included in this series of tests are:

The 18 Watt USB charger that came with the iPad

An Apple 30 watt USB charger

An Apple 80 watt USB charger

My 2016 MacBook Pro 15

An Anker PowerPort 5+ USB-C power adapter

To run the test I purchased a universal USB ammeter that supports both USB and USB-C. I used the 2M cable that I purchased from Apple for my MacBook Pro. I discharged the iPad’s battery down to 10% and then measured each charger by connecting the iPad to the meter and plugging it into each charger. Below are the results.

Test 1 – 18 Watt Charger that came with the iPad

You can see that the small and portable USB-C charger delivers 1.9 amps at 9v, almost exactly 18 watts as advertised.

Next up is the MacBook Pro 15″ 2016.

It supplied almost 3A at 5V for around 15 watts of power. Since I lug the MacBook around with me I use it as a portable battery pack for my phone and tablet, so it’s good to know it can provide a decent amount of power, pretty close to the included 17 watt adapter.

Now to the Apple USB-C power supplies.

First up is the Apple 30W adapter that comes stock with a MacBook 12″.

‘This is supplying almost 2A at 15 Volts so powers the iPad at almost the 30 watts that are advertised.

Now I tested the monster 87 watt Apple USB-C adapter that comes with the MacBook Pro.

Interestingly enough this is providing around 3A at 9V for 26 watts of power. This is 8% less than the 30 watt adapter. It made me wonder how these devices decide what voltage and amperage to use.

Next I tested my Anker PowerPort 5+ USB-C power adapter. This device advertises itself as outputting a maximum of 45 watts.

This device send 2.2 amps at 15V, for a total of around 35 watts. This was the highest power delivery out of them all and double the power of the supplied Apple 17 watt adapter. Surprising that this beats out the 87 watt adapter.

Conclusion:

The clear winner here was the Anker charger which provided 35 watts of power to the iPad, double the 18 watt adapter that comes in the box. Surprisingly, the Apple 87 watt adapter was outperformed by just a bit by the Apple 30 watt USB charger.

The Lithium based batteries found in most portable devices like the iPad can run on their full charge rate until they are getting full. Once this happens the charge rate slows. This means that a 2x increase in wattage when the battery is dead doesn’t equal a 50% reduction in charge time, but getting from zero to around 70-80% should be roughly double. If there is interest I’ll measure the charge rates over time and publish them.

Either way the iPad is clearly able to take more power to charge than the 17 watt USB-C charger is comes with is capable of. It makes me wonder if there are any other devices out there that can charge the iPad faster.