The iPhone 18 Pro Max ships with part of its battery capacity temporarily locked in software to comply with aviation and transport regulations. At full capacity, the battery exceeds 20 watt-hours, triggering extra shipping requirements. Apple uses firmware to keep the battery below this threshold while the phone moves through its factory and shipping network.

The restriction disappears automatically once the owner activates the device, restoring access to the battery's full rated capacity. Customers began receiving devices on September 18. An Apple support document published the same day explains the reason for the restriction.

The iPhone 18 Pro Max is rated for up to 45 hours of video playback, six hours more than the iPhone 17 Pro Max. The process also works in reverse when an activated iPhone 18 Pro Max needs to be mailed for repair, trade-in, return, sale, or gifting. Apple's Prepare to Ship feature lowers the battery below the shipping threshold and temporarily limits how much it can recharge.

Open Settings, tap General, tap Transfer or Reset iPhone, then tap Prepare to Ship. Users choose whether the device is being sent for repair, trade-in, return, or another reason. If the battery is too full, the phone discharges itself until it falls below the required level.

A red Ready to Ship badge appears in Settings once the process is complete. For repairs, trade-ins, and returns, Prepare to Ship limits charging to 80% for 14 days. Unopened iPhone 18 Pro Max units do not need the extra step because the factory restriction is still active.