iPad Pro charging issues

You don’t require a Thunderbolt cable to charge your iPad - however, your iPad will charge at its maximum supported charge rate when charged using a 20W USB-C Power Adapter and USB-C charging/data cable (both as supplied with your iPad Pro).

For future reference, these support pages should help with troubleshooting battery and charging issues:

Charge and monitor the iPad battery - Apple Support

If your iPad won't charge – Apple Support

Troubleshooting generally requires substitution of the Power Adapter and cable for another known-good item. Most models of iPad require a Power Adapter rated at 12W (i.e., 2.4A @5V) or greater to reliably charge. 5W Power Adapters (1.0A @5V) intended for older models of iPhone are inadequate to charge an iPad; if the iPad charges at all, charging will be very slow. Recent models of iPad are supplied with a 20W USB-C Power Adapter.

Some third-party USB-C power adapters (and portable PowerBanks) may not support USB PD (Power Delivery). Power Delivery mutually negotiates the charging voltage; the source, load and cable are all elements involved in the negotiation protocol. Unless the Power Adapter explicitly supports USB PD, it will almost certainly fail to charge the iPad; proprietary charging standards, such as QC (Quick Charge), are not supported.

Many computer USB ports also cannot source sufficient power to charge an iPad. Unless explicitly designed for charging connected devices, computer USB ports are typically limited to 0.5-1A @5V (i.e., 2.5-5.0W).

If you continue to experience difficulties when using an appropriate Power Adapter of 12W or greater, you might be best advised to seek assistance directly from from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively, you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:

https://apps.apple.com/app/apple-support/id1130498044

You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad, Power Adapter and cable(s):

Genius Bar Reservation and Apple Support Options - Apple

Well, if the iPad charges with a cable that you have, Thunderbolt or otherwise, then you have a working solution. That said, you iPad should successfully charge with the supplied Power Adapter and USB-C cable.

If the iPad won’t charge with the Apple 20W USB-C Power Adapter and supplied cable - there are three possibilities:

1) The iPad itself has an undetected fault.

2) Either the Power Adapter or cable are defective.

3) Your iPad has a system software issue. Ensure that you have updated to the most recent version of iPadOS - at time of writing, this being iPadOS 16.6.