My ipad shuts down even when battery power remains
My ipad shuts down completely when there's still 40% power left. It won't turn on again until it's plugged into a power source. Please help.
iPad Air, iOS 12
You might be best advised to seek assistance directly from Apple Support - and request a remote battery diagnostic.
The Contact Support link is at top-right of this page. Alternatively, you can initiate a support case using the excellent Apple Support App: