Battery Drain Issue on iPhone 16 Pro Max

Hello everyone,

I’m experiencing a concerning battery drain issue with my iPhone 16 Pro Max. Even when I'm not using the phone at all and with Wi-Fi turned off, the battery seems to deplete unusually fast. I have disabled all background app refresh settings and have set my mobile data to 4G, but nothing has changed.

Just yesterday morning, I checked my phone after arriving at work, and it was at 70% battery. I didn't use it at all, and with Wi-Fi off and mobile data on 4G, I checked again 8 hours later in the afternoon, only to find it down to 55%.

My question is: if the batteries in the new iPhones (at least mine) are supposed to be reliable, why is it losing 15% of its charge over 8 hours with no usage?

Has anyone else experienced this? Any suggestions would be greatly appreciated!

Thank you!