iPad Pro 2018 charging bottle neck

For the iPad, the 30W charger (currently, from Apple, the lowest wattage PD-capable charger available in the Apple Store) has some “spare” capacity. The benefit of the USB-C PD-capable chargers are that they are able negotiate a higher supply voltage supply for compatible iPad models and other devices (standard USB is only 5V); higher voltages permit faster charging efficiency.

Independent tests, published on the internet, generally suggest that the iPad Pro (10.5” and 2018 11/12.9”) can consume up to about 18W. It is perhaps, therefore, no coincidence that the 2018 Pro models are now supplied with an 18W charger. At present, the Apple 18W chrger is not offered as a stand-alone purchase.

If you intend to utilise the iPad with additional hardware while powering/charging the iPad (e.g., a camera attached via a suitable adapter), then the additional power capacity of the external charger can permit the iPad to charge at the maximum rate - while also supplying power to additional connected devices.

As you already suggest, unless you already have a 45W (or larger) charger, it would be overkill to purchase one.

If you are looking for a higher wattage charger for you iPad, you must ensure that it is “PD (Power Delivery) compliant”. Ideally, sticking to an Apple charger will preserve you waranty - and make any subsequent conversations with Apple Support much simpler.

I have to respectfully disagree here. When the ipad pro 2018 12.9 is on and at a reasonable brightness, it draws more than 30W. With full brightness, it can reach 40-42W, as shows by my OmniCharge USB-C, which is really useful for stuff like this. So a USB-C charger with about 45+ Watts is recommended.