https://wccftech.com/iphone-13-pro-max-battery-capacity-massive-upgrade/

Given its size, it was obvious that the iPhone 12 Pro Max would have the biggest battery out of all the three models, and its successor, the iPhone 13 Pro Max, could top that limit, according to a new leak. In fact, all the iPhone 13 models reported to arrive in late September could have larger cells than their direct predecessors, and that is excellent news for a number of reasons, which we will discuss shortly.

On Weibo, Digital Chat Station has shared what appears to be the battery capacities of all the iPhone 13 models, and unsurprisingly, the iPhone 13 Pro Max is said to sport the biggest cell, at 4352mAh. With the iPhone 12 Pro Max featuring a 3687mAh cell, its successor will have an 18 percent bigger battery, assuming the leak is true. This info suggests the upcoming flagship will have a thicker chassis, and the same goes for the rest of the iPhone 13 family, whose battery capacities are listed below.