iPhone 18 Pro Max Real-World Charging Test: 55% in 15 Minutes Beats Galaxy S26 Ultra

For years, slow charging speeds have remained the primary critique leveled against Apple’s flagship smartphones. While rival Android flagships raced past 100W, iPhones consistently hovered around 27W to 30W, taking close to two hours to reach a complete top-up.

That dynamic has changed with the release of the iPhone 18 Pro Max. Independent lab benchmarks published by prominent tech testing outlet Xiaobai’s Tech Reviews (小白测评) reveal that Apple’s new 60W charging architecture and 5,391mAh (5,400mAh nominal) battery deliver unprecedented speed, outperforming Samsung’s flagship Galaxy S26 Ultra in real-world recharge intervals.

30-Second TL;DR

• The Benchmark: Xiaobai’s Tech Reviews tested the iPhone 18 Pro Max with Apple’s 40W-60W Dynamic Power Adapter in a 25°C controlled room.
• Rapid Charging Curve:
  • 10 Minutes: 34%
  • 15 Minutes: 55%
  • 55 Minutes: 100% (Foreground display)
  • 76 Minutes: Complete trickle cutoff
• Larger Battery: Achieved with an expanded 5,391mAh (5,400mAh nominal) battery, nearly 700mAh larger than previous generations.
• Beating Samsung: The 15-minute 55% benchmark outpaces the Samsung Galaxy S26 Ultra (5,000mAh, 60W), completing the 0-100% curve nearly 30 minutes faster than the iPhone 17 Pro Max.
• Peak Power Delivery: Reached an observed peak of 52W, sustaining high-wattage power for approximately 12 minutes thanks to the phone’s new internal vapor chamber cooling system.

Real-World Charging Benchmarks: 10, 15, and 55 Minutes

Conducted at a standard ambient room temperature of 25°C, Xiaobai’s Tech Reviews drained the iPhone 18 Pro Max to 0% and connected it to Apple’s official 40W Dynamic Power Adapter (bursting up to 60W via USB PD 3.1 AVS):

• 10 Minutes (34%): In just 10 minutes of wall power, the device recovers over a third of its capacity-providing enough power for roughly 12 to 14 hours of moderate calling, messaging, and navigation.
• 15 Minutes (55%): Passing the halfway mark at the 15-minute threshold, the iPhone 18 Pro Max comfortably delivers on Apple’s promotional fast-charge claims.
• 55 Minutes (100% UI): The phone’s status bar reaches a full 100% indicator in 55 minutes flat.
• 76 Minutes (Complete Full Charge): Following the initial 55-minute sprint, the device spends 21 minutes in an ultra-low trickle-charge phase to protect anode longevity and prevent dendrite formation, completing the full electrical saturation cycle in 76 minutes.

Compared directly to the iPhone 17 Pro Max, which required over 105 minutes to reach full saturation, the iPhone 18 Pro Max cuts total charging time by nearly half an hour while filling a noticeably larger battery.

Peak Power and Thermal Management: 52W Sustained for 12 Minutes

The technical key to this charging leap lies in sustained power delivery rather than short, cosmetic bursts:

• 52W Real-World Peak: While rated for a theoretical ceiling of 60W under the USB PD 3.1 Adjustable Voltage Supply (AVS) protocol, the phone drew a continuous, measured ~52W during its initial charging state.
• 12-Minute Plateau: Most smartphones that advertise high peak wattages throttle down within 2 to 3 minutes due to excessive thermal build-up. The iPhone 18 Pro Max sustained its 50W+ draw for approximately 12 continuous minutes, explaining why 34% was reached in just 10 minutes.
• Upgraded Vapor Chamber: This prolonged high-wattage intake is made possible by Apple’s redesigned internal architecture, which pairs a laser-welded titanium chassis with an expansive graphite-and-copper vapor chamber to channel heat away from the battery cells.

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iPhone 18 Pro Max vs. Flagship Charging Curves

How It Bests the Samsung Galaxy S26 Ultra

The most surprising takeaway from Xiaobai’s testing is how the iPhone 18 Pro Max stacks up against Samsung’s top-tier Galaxy S26 Ultra:

• Efficiency Advantage: Although the Galaxy S26 Ultra also upgraded to a 60W wired charging standard this year, its charging algorithm steps down wattage more conservatively to manage thermals on its 5,000mAh pack. As a result, the S26 Ultra reaches roughly 44% to 46% in 15 minutes.
• More Milliamps in Less Time: In that same 15-minute window, the iPhone 18 Pro Max reaches 55%, replenishing nearly 2,965mAh of active capacity compared to Samsung’s ~2,250mAh.
• Under-the-Hour Benchmark: Reaching 100% displayed battery in 55 minutes places Apple ahead of Samsung’s flagship in practical emergency top-ups, marking a rare reversal in fast-charging hierarchy between the two tech giants.

The Requirement Reminder: You Need USB PD 3.1 AVS

To replicate these benchmark speeds, users must be mindful of their charging accessories:

• MacBook Charger Incompatibility: Standard Apple 96W and 140W MacBook power bricks lack the necessary USB PD 3.1 AVS (Adjustable Voltage Supply) handshake, causing the iPhone 18 Pro Max to fall back to older ~27W profiles (taking over 20 minutes to reach 50%).
• Required Hardware: Achieving the 15-minute 55% milestone requires Apple’s new 40W Dynamic Power Adapter ($39) or any certified third-party multi-port GaN charger that explicitly supports USB PD 3.1 with AVS.

With the iPhone 18 Pro Max, Apple has effectively neutralized one of Android’s longest-standing competitive advantages. A 5,400mAh battery that hits 55% in 15 minutes and displays a full charge in under an hour sets a new benchmark for Apple’s hardware lineup.

Via