Samsung is reportedly preparing a significant battery and charging upgrade for the Galaxy S27 Ultra: leaks indicate a larger cell of around 5,700mAh combined with an optimized charging curve that could sustain higher power for longer while retaining a 60W peak limit.
Galaxy S27 Ultra battery size and charging curve
According to tipster @WalleGalaxy on X, the Galaxy S27 Ultra may break Samsung’s long-standing 5,000mAh ceiling with a battery near 5,700mAh — roughly a 14% increase over the Galaxy S26 Ultra. Rather than increasing maximum charging wattage, Samsung is said to be exploring a more efficient charging curve that maintains higher charging speeds for a longer portion of the cycle. This strategy could shorten real-world charging times without advertising a higher peak power figure.
Current baseline: S26 Ultra and competitor tests
Samsung’s current Galaxy S Ultra models use a 5,000mAh battery and support Super Fast Charging 3.0 up to 60W. Samsung states the Galaxy S26 Ultra can reach approximately 75% after 30 minutes of charging. In an independent test, a tester named Victor recorded 76% after 30 minutes and a full charge in about 49 minutes. By comparison, the iPhone 18 Pro Max reportedly reached around 71% after 30 minutes and required about one hour and eight minutes to reach 100%.
Market context and battery technologies
The reported changes come as Samsung trails several Chinese Android makers on raw battery capacity and charging speed. Chinese brands have pushed larger cells and charging capabilities that exceed 60W, and some are researching combinations of metal-can designs with silicon-carbon technology. Apple reportedly adopted metal-can battery technology in the iPhone 18 Pro models — a method Apple has patented and previously used in the Apple Watch Series 5. Rumors also cite devices such as the Xiaomi 18 Pro Max with a reported 8,500mAh battery as examples of the higher-capacity trend.
User expectations and long-term performance
Online discussions on Reddit show mixed reactions: some users welcome the reported 5,700mAh increase, while others want Samsung to adopt silicon-carbon cells and pursue substantially larger capacities to match Chinese Ultra-branded flagships. The coverage notes that larger capacity alone does not guarantee a better ownership experience; processor efficiency, charging behavior and how a battery retains performance after two or three years are equally important. Samsung’s reputation for stable battery health is highlighted as a relevant factor if the Galaxy S27 Ultra’s rumored upgrades prove accurate.
If the leaks are correct, the Galaxy S27 Ultra will need to demonstrate not only a larger battery but also faster practical charging and durable battery health to validate the change.
