The iPhone 18 Pro Max has a battery limitation that exists for a reason no previous iPhone has needed to deal with. Because its single-cell battery exceeds the 20Wh threshold used in shipping regulations, Apple built a dedicated iOS feature that temporarily reduces its capacity before the phone is shipped.
According to a report from MacRumors, Apple detailed the feature, called Prepare to Ship, in a new support document published September 18. It automatically discharges the battery and sets a charge limit so the iPhone stays below the 20Wh threshold during shipping.
Why The iPhone 18 Pro Max Has A Shipping Limit
The iPhone 18 Pro Max is the first iPhone with a single-cell battery rated above 20Wh. That is part of the larger battery capacity increase Apple built into this year’s largest Pro model.
Devices with a single-cell battery above 20Wh have additional shipping requirements in most countries and regions. These rules apply to lithium batteries generally and are not specific to the iPhone 18 Pro Max.
Apple’s solution starts before the phone reaches a customer. A battery-firmware solution limits the iPhone 18 Pro Max’s battery capacity to below 20Wh from the time it is manufactured through its transport from the factory. Once the iPhone is activated, that limit is removed and the battery’s full charging capacity becomes available.
How Prepare To Ship Works
After activation, Prepare to Ship is available when an iPhone 18 Pro Max needs to be shipped for a repair, trade-in, return, or as a gift. You can find it under Settings > General > Transfer or Reset iPhone.
The feature discharges the battery to below 20Wh and sets a charge limit that keeps it below that threshold while shipping. Apple says the iPhone may become warmer than usual while the battery is discharging, which is expected.
The process can take only a few minutes, but Apple says it can take up to a couple of hours when starting with a full battery. You can continue using the iPhone while it discharges, and the device needs a cellular or Wi-Fi connection to complete the process.
Once Prepare to Ship finishes, the Settings app displays a Ready to Ship status with a red badge. If the iPhone has been erased, you can check the status from the Hello screen by tapping the Info button.
The Charge Limit Can Stay At 80 Percent For 14 Days
The temporary charge limit depends on why you are shipping the iPhone. If you are sending it to Apple, a carrier, or a reseller for a repair, trade-in, or return, the battery is capped at 80 percent for 14 days so it remains below the 20Wh shipping requirement.
After 14 days, you can disable Prepare to Ship and restore full charging. If you selected Other because you are sending the iPhone to another person, such as for a sale or gift, you can disable the feature at any time.
Apple also makes clear that the iPhone 18 Pro Max’s battery is safe for shipping and air travel. Prepare to Ship is required only to meet shipping requirements and is not necessary when traveling with the phone or for any other iPhone model.
What Owners Need To Know
If you bought a new iPhone 18 Pro Max and have not activated it or even taken it out of the box, you do not need to enable Prepare to Ship. Apple says the battery is already temporarily limited to below 20Wh during its initial transportation.
For an activated iPhone, the process needs to be completed before shipping it yourself. Apple recommends contacting the company receiving the device first, since it may have additional instructions or packaging requirements.
If Prepare to Ship does not complete successfully or the iPhone does not show that it is ready to ship, Apple says not to send the device until you have contacted the company receiving it for further instructions.
