Charging Magic Mouse 2 from iPad

As you have a fourth generation iPad Pro (with USB-C connector), you may find that your Magic Mouse 2 will successfully charge.

I don’t have the means by which to test and verify charging behaviour for your combination of hardware - so am unable to confirm that you’ll be able to charge the Mouse with the iPad in Sleep mode. However, all technical information suggests that the 2018/2020 iPad Pro device can charge an iPhone - so a Mouse shouldn’t be significant challenge.

I hope this information and insight proves to be helpful. Please let us know how you get on - as this information would be useful to inform our body of knowledge.

Unlikely, but unverified. Whilst unable to provide a definitive answer, the following might be informative.

USB-C, as used with 2018/2020 models of iPad Pro, is designed to provide power to external devices.

By contrast, the Lightning port of other models of iPad and iPad Pro is considerably more limited in its ability to provide power. Whilst the Magic Mouse2 should require very little power, the iPad does not supply power to the Lightning port whilst the iPad is in a Sleep state; this will very likely impact the ability of the iPad to charge an external device.