iPhone 18 Pro beaten by Galaxy S26 and OnePlus 15 in battery test
The iPhone 18 Pro lasted 11 hours and 42 minutes in a standardized battery rundown test, falling behind the Samsung Galaxy S26 Ultra and the OnePlus 15. The Galaxy S26 Ultra reached 13 hours and 15 minutes, while the OnePlus 15 led the group with 14 hours and 10 minutes of continuous use. This result marks a shift in mobile endurance rankings where Apple previously held the top position through software optimization and efficient chip design.
Breakthroughs in Silicon-Carbon Battery Density
The performance gap between these devices stems from a transition in battery chemistry. Samsung and OnePlus have moved away from traditional lithium-ion structures in favor of silicon-carbon (Si-C) anodes. This technology allows for higher energy density within the same physical footprint.
The OnePlus 15 features a 6,100 mAh battery. By using silicon-carbon materials, OnePlus increased capacity without increasing the thickness of the device. The iPhone 18 Pro uses a refined lithium-ion stack with a capacity of approximately 4,450 mAh. While Apple’s A19 Pro chip uses a 2nm process to reduce power consumption, the sheer volume of energy available in the OnePlus 15 outweighs the efficiency gains of the A19 Pro.
Samsung’s Galaxy S26 Ultra utilizes a 5,700 mAh cell. Samsung paired this capacity with the Snapdragon 8 Gen 5, which includes specialized low-power cores dedicated to background tasks. These hardware choices allow the S26 Ultra to maintain lower temperatures during sustained use, which prevents the rapid battery drain often associated with thermal buildup.
iPhone 18 Pro beaten by Galaxy S26 and OnePlus 15 in battery test
Comparative Performance in Stress Tests
The battery test conducted by independent labs involved four distinct phases: 4K video recording, 3D gaming, web browsing over 5G, and social media scrolling. Each phase lasted two hours or until the device powered off.
During the 4K video recording phase, the iPhone 18 Pro consumed 18% of its battery life. The Galaxy S26 Ultra consumed 14%, and the OnePlus 15 consumed 12%. Heat management played a role here. Thermal imaging showed the iPhone 18 Pro reaching 42 degrees Celsius, while the OnePlus 15 stayed at 38 degrees. Higher internal temperatures increase internal resistance in the battery, which forces the device to expend more energy to perform the same tasks.
In the 3D gaming segment, the gap widened. The OnePlus 15 maintained a consistent 120Hz refresh rate while using its "Glacier Battery" cooling system to keep consumption low. The iPhone 18 Pro began to throttle its brightness after 40 minutes of gaming to manage heat, yet it still depleted its battery faster than the Samsung and OnePlus models.
The Impact of Display Technology on Power Consumption
All three devices use LTPO (Low-Temperature Polycrystalline Oxide) panels, but the implementation varies. The iPhone 18 Pro uses a ProMotion display that scales between 1Hz and 120Hz. However, the Samsung Galaxy S26 Ultra introduced a new generation of M15 OLED materials. These materials require less voltage to reach high brightness levels compared to the M14 panels used in the previous year.
The OnePlus 15 uses a BOE-sourced panel that focuses on localized dimming efficiency. When displaying HDR content or using the "Always On" feature, the OnePlus 15 demonstrated a 15% lower power draw than the iPhone 18 Pro. This indicates that while Apple’s software is effective at managing background processes, the hardware components in the S26 and OnePlus 15 are now more fundamentally efficient at the hardware level.
Charging Speeds and Long-Term Health
Endurance is only one part of the battery experience. The test also measured "time to 100%."
- OnePlus 15: 24 minutes (100W wired charging)
- Galaxy S26 Ultra: 48 minutes (45W wired charging)
- iPhone 18 Pro: 65 minutes (27W wired charging)
Apple continues to limit charging speeds to preserve the lifespan of the lithium-ion chemistry. Higher temperatures during fast charging can degrade a battery over 500 to 800 cycles. OnePlus claims its silicon-carbon battery can maintain 80% health after 1,600 cycles despite the 100W charging speed. This claim suggests that the newer chemistry is more resilient to the stresses of high-speed energy transfer.
Samsung has adopted a middle-ground approach. The S26 Ultra supports "bypass charging," which allows the phone to pull power directly from the charger to run the processor without passing it through the battery. This feature is particularly useful during gaming, as it prevents the battery from heating up while the device is plugged in.
iPhone 18 Pro beaten by Galaxy S26 and OnePlus 15 in battery test
Software Optimization vs. Raw Capacity
Apple's iOS 19 includes a redesigned power management system. This system uses machine learning to predict when a user will need high performance and when it can underclock the CPU. In standby mode, the iPhone 18 Pro remains the most efficient device, losing only 1% of its charge over an eight-hour period.
The Galaxy S26 Ultra and OnePlus 15 lost 3% and 4% respectively during the same standby period. For users who do not use their phones heavily throughout the day, the iPhone might still feel competitive. However, for "power users" who engage in video calls, gaming, or content creation, the larger physical capacity of the Android competitors provides a more reliable buffer.
The shift in the market suggests that software optimization has reached a point of diminishing returns. The A19 Pro chip is highly efficient, but it cannot overcome the physical limitations of a smaller battery when compared to the 5,500+ mAh capacities found in the current Android flagship cycle.
Future Outlook for Battery Standards
The results of these tests indicate a change in consumer expectations. For several years, Apple was the undisputed leader in battery life because Android manufacturers struggled with the power demands of the Snapdragon chips. The Snapdragon 8 Gen 5 has closed that efficiency gap.
Industry analysts at TrendForce suggest that Apple may be forced to adopt silicon-carbon battery technology in the next two years to remain competitive. Until then, the iPhone 18 Pro remains a device that prioritizes a thin design and standby efficiency over the raw endurance offered by Samsung and OnePlus.
The OnePlus 15 is currently the benchmark for mobile endurance in the flagship category. Its combination of a massive 6,100 mAh cell and 100W charging creates a user experience where "battery anxiety" is largely eliminated. Samsung’s Galaxy S26 Ultra offers a balanced alternative, providing a significant lead over Apple while maintaining a more conservative charging profile than OnePlus.