I noticed this on my iPad since 11.4 update too. Without using it at all the battery is still draining. The usage time in the stats is always about 1/6 of standby time with no app is showing up there. Turning off WiFi, bluetooth, location, background refresh, hand off, mail fetching, WiFi-calling, messages syncing and photos syncing all didn't help. Tried erasing everything and setting it up again without restoring from backup, still the same. I found that it might be related to my iCloud account. If I do a fresh install, the battery drain is not there. Sign in to iCloud and it's back. Also if I remove the iPad from my iCloud account with another device, the battery drain immediately stops. But other devices with the same account don't have this issue.
My phone did have battery drain on 11.4 too but I believe it was a bit different. It drops by 50% overnight (the iPad only drops by about 5% to 10% per day) and usage time in battery stats did not increase. Turning off WiFi also stops it. 11.4.1 fixed the battery drain for the phone but not for the iPad.
My phone did have battery drain on 11.4 too but I believe it was a bit different. It drops by 50% overnight (the iPad only drops by about 5% to 10% per day) and usage time in battery stats did not increase. Turning off WiFi also stops it. 11.4.1 fixed the battery drain for the phone but not for the iPad.
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