I sell iPhones, and the first iPhone 18 Pro Max sold at my store was a 256GB black model with a physical SIM. The customer was initially happy, but after a few days said the battery lasted only about 19 hours—roughly the same as their iPhone 15 Pro Max. Apple lists up to 43 hours for this version, so even allowing for real-world usage, I expected at least 30 hours. Aside from reducing screen brightness or enabling Low Power Mode, what could be causing this? Could the phone still be completing setup or dealing with an iOS issue?
3 Answers
The advertised number is based on specific conditions, such as offline video playback, not ordinary mixed use. A normal day of use may be much closer to one full day than 30–40 hours. New-phone excitement can also lead to heavier usage, and weak 5G reception, frequent 5G connections, high brightness, and outdoor use can all reduce battery life compared with an older phone.
If the phone is only a few days old, it may still be restoring data, updating apps, indexing files and photos, and processing Siri or search data. Those background tasks can use a surprising amount of power, sometimes for a week or two. It is best to check the Battery settings again after setup has fully settled.
Have the customer compare the Battery settings after several more days, including which apps are using the most power and how much screen-on time they are getting. Once background setup finishes, a restart may help clear anything stuck. If the battery is still poor after a week or two, then it would be worth checking for an iOS bug or possible hardware issue.
That makes sense. I was comparing the advertised figure with real-world expectations, but I’ll have the customer wait until indexing and setup are finished before judging the battery.