New iPhone 14 Pro Max bad battery drain even when not used

Hi abed162,

Is this happening on the latest version of iOS 16? iOS 16.1 is the latest version of iOS. Was your device restore from a backup when set up? Is it possibly that the data is still restoring in the background? You can tap Settings > your name > iCloud > iCloud Backup to see if data is still restoring. This may be expected behavior until the data is fully restored.

Since you mentioned the battery is decreasing while sleeping, check and see if the behavior is due to an app using data in the background, which could be also be expected behavior for losing battery life unexpectedly. Check out those steps here: Batteries - Maximizing Performance - Apple

"Background Activity. This indicates that the battery was used by the app while it was in the background — that is, while you were using another app.

• To improve battery life, you can turn off the feature that allows apps to refresh in the background. Go to Settings > General > Background App Refresh and select Wi-Fi, Wi-Fi & Cellular Data, or Off to turn off Background App Refresh entirely.
• If the Mail app lists Background Activity, you can choose to fetch data manually or increase the fetch interval. Go to Settings > Accounts & Passwords > Fetch New Data."

Reach out to Apple Support directly for further assistance if additional help is needed: Contact - Official Apple Support

Kind regards.

There is never a time when an iPhone is doing nothing, unless you shut it off completely. And even then some circuits remain on to support Find My and battery status. But when the phone is on, even when you are not using it, the phone receives notifications that must be filed, receiving new email and text messages, weather updates (whether you have a weather widget or not), stock updates, App Store updates, syncing to iCloud, etc. And it also communicates with the cellular network periodically so the network knows where to find it if you get a call. A drop of 16% just from background processes like these over a 10 hour period is normal.

But you should be plugging the phone in when you go to sleep. The absolute best way to get maximum use on a charge, as well as slow the decline of battery capacity long term is to enable Optimized Battery Charging (Settings/Battery/Battery Health) and charge the device overnight, every night. The battery will fast charge to 80%, then pause. During the nighttime pause the phone will use mains power instead of battery power, allowing the battery to “rest”, and thus reducing the need to charge the battery quite as often. The phone will resume charging to reach 100% when you are ready to use your phone; it will “learn” your usage pattern. If you enable iCloud Backup (Settings/[your name]/iCloud - iCloud Backup) the phone will back up overnight also, assuring that you can never lose more than the current day’s updates. Here's more information→About Optimized Battery Charging on your iPhone - Apple Support

iPhone 14 pro, iOS 16.1.2, low power mode ON, (and not on a charger), all apps closed, went to bed at 12:30 last night, 91%, woke up at 9:00 this morning, 46%. No use overnight.

its odd, but this doesn’t happen all the time. Many days I get through normal usage for the full day using only about 50% of a full charge.

abed162 wrote:

I keep my battery percentage between 50% and 80% its a hassle to focus on keeping my battery percentage in that range

That is NOT a good strategy, because it means that line power never runs the phone, so all energy to run the phone comes from the battery. If you charge overnight for most of the night line power operates the phone, so the battery is not used.

Why did you STOP using optimized charging? 99% is good. On average, ANY smartphone will lose about 1% of its capacity per month.

That is NOT what Apple recommends. Apple recommends charging overnight, with Optimized charging enabled. You’ve had the phone less than a month, and it’s at 99%. The calculation truncates, so as soon as it drops below 100%, even to 99.9%, it will display 99%. You haven’t had it long enough to see the trend, and a new phone will use more energy for the first week or two as it updates its databases in background.

Actually, there is very little you can do that will significantly affect battery longevity either positively or negatively, except let it drain to zero routinely (which will significantly shorten battery longevity). But charging overnight will slightly extend battery longevity, and never letting external energy power the phone will slightly shorten battery longevity. And external power ONLY operates the phone when it is either at 100% or at 80% due to Optimized Charging.

Had the same problem after the IOS 16 update. I erased the phone with the exception of the esim now I can leave my phone overnight and only lose 1 to 2 percent and daytime runtime has increased tremendously. Phone runs just as good as the day I got it.

I'm having the exact same issue

This drop is not normal. It shouldn’t do that on non low power mode, let alone low power. It dropped faster than when in heavy use.

It was low power mode. Restricted mail fetch, background activity, phone was face down, so display was off, too.