Is it bad for an iPad pro M1 to charge it with my Mac charger?

Your Mac Power Adapter is presumed to be an OEM Apple USB-C Power Adapter. If so, it is USB PD (Power Delivery) compliant - and is fully compatible with your iPad Pro.

The USB PD charging protocol allows your iPad to actively “communicate” its power needs to the Power Adapter. The Power Adapter and connected device actively “negotiate” the highest mutually supported power profile - allowing the iPad to charge at its maximum supported charging rate - this obviously being within the maximum supply capabilities of the source Power Adapter.

The power adapter will only supply the power that the iPad requires. A Power Adapter of higher wattage will cause no harm. Other than convenience, a higher power availability from the Power Adapter provides no other benefit to the connected device.

There are proprietary charging standards used by other manufacturers which are not compliant with the USB PD Specification.

Unless the Power Adapter specifications explicitly state that the Power Adapter supports USB PD (Power Delivery) you use it with your iPad entirely at your own risk. Your iPad Warranty, if you have one, will not cover damage caused by an incompatible charging source.

Yes, no harm to your iPad.

The charger doesn’t “push” power; it just supplies the power “drawn” by the device.

Regards

Giulio

You will need to check that your Acer Power Adapter supports USB PD (Power Delivery). If not, you might be best advised to avoid the risk of causing damage to your iPad.

If you purchase an Apple USB-C Power Adapter, you will be assured that it is compatible with your iPad.

Your 2021 iPad Pro M1 was supplied with an Apple 20W USB-C Power Adapter. This will charge your iPad at its maximum supported charging rate.