I am having significant battery drain for the last few days.
Battery usage and standby time are both the same, currently at nearly 20 hours.
No apps running. Restarted the phone, but makes no difference.
What might be causing this?
#1. Go into an Apple Store they are all open tomorrow for a free Battery Diagnostic. Take 10 minutes or less don’t make an appointment.
#2. You can Disable All Find My IPhone, Location Services, And Background App Refresh. No reason why Calendar and Calculator Need Data And Location access all the time.
#3. Update Your PRL, or have Your Carrier ReEstablish you on the Network, sounds familiar the issue you are having and it sounds like you are not properly configured on the cell Network and while No programs are running you Cellular Radio is constantly hunting for Anetnnas or better Signal all the time wasting your battery.
#3. Tell us if you have a GSM att or T-Mobile Device or a CDMA Sprint or Verizon Device. Apple partnered with Intel to supply A GSM Radio Chipset And It’s terrible, owners get proven worse Battery and worse reception.
And thanks to Apples lawsuit with Qualcomm IPhone X models only got a generation behind CDMA Radio Chipset For Sprint And Verizon Phones.
So while Owners May have a way Faster IPhone X, a Galaxy S8 or S8+ will get significantly faster Data and use less power doing so because Qualcomm gave Samsung the latest generation Radio Chipset.