Your New iPhone Will Unlock Extra Battery When You First Turn It On

Apple is shipping the iPhone 18 Pro Max with its battery temporarily locked below full capacity to meet shipping rules. The full capacity comes back automatically the first time you turn the phone on and activate it. The Verge

International rules set a 20Wh limit for shipping a single battery cell by air. Wh, or watt-hour, is simply a measure of how much energy a battery holds. After activation, the U.S. model without a physical SIM card goes back to about 21.75Wh. The European model with a physical SIM slot goes back to about 21.06Wh. Both are over the shipping limit, which is why the temporary lock is needed.

Apple describes the same lock in its support article titled 'Prepare your iPhone 18 Pro Max to ship'. It says a new phone that has not been taken out of the box or activated has its battery temporarily limited to under 20 Wh. Apple Support

For phones people already own, Apple added a "Prepare to Ship" button in iOS 27 for the iPhone 18 Pro Max. 9to5Mac It drains the battery to below 20Wh and sets a charging limit to keep it there during shipping. Think of it like putting a temporary stop on a fuel tank for the trip.

You find it at Settings > General > Transfer or Reset iPhone > Prepare to Ship. Once turned on, it caps charging at 80 percent for 14 days. Apple says the battery may need time to drain before the process finishes and may feel warmer than usual. You can turn Prepare to Ship off at any time in settings.

The broader context here is a shift in how Apple handles the shipping rule. Instead of using a smaller battery or running a separate shipping system for this model, it put the limit in the battery software. The phone counts as an under-20Wh device for shipping, then becomes a 21Wh-class device once you power it on.

In my view, this moves the work from the factory to software. Resale, warranty returns, and repairs now have one extra step. Any used iPhone 18 Pro Max sent by air without Prepare to Ship turned on would travel above the limit it was shipped under. For large company fleets and shipping firms, that settings switch matters as much as the box. It is a practical fix that other makers will likely copy. As phones hold more energy, this kind of software switch allows bigger batteries without rewriting world shipping rules. For users, nothing is lost. You get more battery on day one, with the shipping part handled quietly in the background.