I updated to iOS 18 a couple weeks ago. I find that my iPhone 15 pro will now have up to 20% battery drain overnight in sleep mode. In iOS 17, it would only drain a few percent, if at all. My battery health currently indicates 100% capacity. Please fix in the next iOS update as this unexpected battery drain will affect the lifespan of my phone.
iPhone 15 Pro
This is happening to me as well and I have tried EVERYTHING including a full reset and waiting a week for things to even out. I have tried putting the phone in airplane mode, batter saver mode, but nothing works. I recently paid for a battery replacement service through an Apple store. I believe this is a bigger problem than is being reported as many people simply charge their phone overnight and wouldn't detect it but there are plenty of complains about overall shorter battery life and hotter phones after the 18.0 update.
Battery Drain in iOS 18 While Idle
