Apple's announcement of the iPhone 15 lineup at last week's "Wanderlust" event gave us our first official look at the next-generation iPhone before it hits store shelves on September 22. However, Apple has historically avoided revealing the individual specs of its newest models in advance, so some mystery remains and the rumor mill continues to swirl.

The latest leak comes from a Chinese regulatory agency, discovered by MySmartPrice (via Android Authority). According to this regulator, the iPhone 15 series will have slightly improved battery life, but it is not groundbreaking.

The base iPhone 15 is reported to have a battery capacity of 3,349mAh and a wattage of 12.981Wh. Its larger sibling, the iPhone 15 Plus, on the other hand, has a 4,383mAh battery with a wattage of 16.950Wh. At the high end, the iPhone 15 Pro and iPhone 15 Pro Max have the largest batteries at 3,274 mAh (12.70 Wh) and 4,422 mAh (17.109 Wh), respectively.

This translates to battery life of up to 20, 26, 23, and 29 hours for the iPhone 15, Plus, Pro, and Pro Max, respectively, Apple says in the listing. At least when handling low-load tasks like video playback.

Compared to last year's iPhone 14 series (see below for a breakdown of each generation's battery capacity by model), it is clear that these are not significant advances. In Apple's current models, the base model has 3,279 mAh, the 14 Plus has 4,325 mAh, the 14 Pro has 3,200 mAh, and the 14 Pro Max has 4,323 mAh.

Previous leaks had suggested that the iPhone 15 series, especially the iPhone 15 Pro, could have significantly improved battery capacity. And while those rumors did not come to fruition, the iPhone 15 will have the longest-lasting battery of any iPhone to date.

Of course, it is important to remember that the numbers behind a phone's battery capacity can only tell you so much. How long a cell phone's battery lasts each day depends on a number of factors, including the size and brightness of the screen, the efficiency of the internal modem, and what tasks it is used for.

Reservations for the iPhone 15 series are live, having started after Apple's September event, and the handsets hit store shelves on September 22. But if you're thinking of grabbing one of the high-end models, you may have to wait a bit depending on where you shop. For more information, see our update on the iPhone 15 Pro shipping delay.