https://wccftech.com/magic-keyboard-for-ipad-pro-reportedly-causing-battery-drain/

A few users have been reporting increased battery drain when using the new Magic Keyboard for iPad Pro. Compared to the Smart Keyboard, the battery drain is much higher - as high as 3% every 10 minutes during normal usage.

Many users have taken to Twitter to share their experience of massive battery drain with both 11-inch and 12-inch variants of the Magic Keyboard. Normal usage in many scenarios has been defined as typing something while listening to music, not including any gaming or videos. A few prominent Twitter users such as Jon Rettinger and Mark Gurman have shared their concerns with the issue.