Comparing the battery life of the iPhone 17 Pro Max and the Asus ROG Phone 9 Pro involves looking at both the rumored specifications of the iPhone 17 Pro Max and the known performance of the ROG Phone 9 Pro.
iPhone 17 Pro Max
The iPhone 17 Pro Max is rumored to have a thicker design compared to its predecessor, the iPhone 16 Pro Max, with a thickness of 8.725mm, up from 8.25mm. This increase in thickness is speculated to accommodate a larger battery, which could potentially improve battery life[1][11]. However, the exact battery capacity and life of the iPhone 17 Pro Max have not been officially confirmed. The iPhone 16 Pro Max, for comparison, has a 4685 mAh battery and offers around 17 hours and 35 minutes of battery life in tests[1].
Asus ROG Phone 9 Pro
The Asus ROG Phone 9 Pro boasts an impressive battery life, thanks to its large 5,800 mAh battery and efficient Snapdragon 8 Elite chipset. In tests, it achieved a remarkable 20 hours and 34 minutes of battery life, significantly outperforming many other smartphones, including the iPhone 16 Pro Max[2][5]. The ROG Phone 9 Pro also supports fast charging with a 65W charger, allowing it to quickly regain battery life when needed[3][5].
Comparison
While the iPhone 17 Pro Max is expected to have improved battery life due to a potentially larger battery, it still faces stiff competition from the Asus ROG Phone 9 Pro. The ROG Phone 9 Pro's combination of a large battery and efficient chipset makes it a leader in battery endurance. If the iPhone 17 Pro Max does indeed feature a larger battery, it might close the gap with the ROG Phone 9 Pro, but it would likely still trail behind in terms of raw battery capacity and overall battery life. Additionally, the ROG Phone 9 Pro's fast charging capabilities give it an edge over the iPhone series, which has been slower to adopt fast charging technologies[4][5].
In summary, while the iPhone 17 Pro Max may offer improved battery life, the Asus ROG Phone 9 Pro remains a top contender for those prioritizing long battery life and fast charging.
Citations:
[1] https://www.yahoo.com/tech/iphone-17-pro-max-rumor-175719296.html
[2] https://www.tomsguide.com/phones/android-phones/forget-iphone-16-pro-max-the-asus-rog-phone-9-pro-has-the-best-battery-life-weve-ever-seen
[3] https://www.phonearena.com/reviews/rog-phone-9-pro-vs-iphone-16-pro-max_id6785
[4] https://www.indiatoday.in/technology/news/story/iphone-17-pro-air-pro-max-launch-soon-leaked-design-battery-camera-display-and-everything-else-to-know-2691711-2025-03-10
[5] https://www.tomsguide.com/phones/android-phones/asus-rog-phone-9-pro-review-gaming-pro-and-battery-life-legend
[6] https://www.phonearena.com/phones/compare/Asus-ROG-Phone-9-Pro,Apple-iPhone-17-Pro-Max/phones/12479,12496
[7] https://istyle.ae/blog/comparing-iphone-14-battery-mah-and-battery-life
[8] https://www.gsmarena.com/asus_rog_phone_9_pro-review-2765p3.php
[9] https://forum.blackmagicdesign.com/viewtopic.php?f=2&t=191338&start=200
[10] https://www.apple.com/iphone-16-pro/specs/
[11] https://www.macrumors.com/2025/03/07/iphone-17-pro-max-thicker-larger-battery/