A new leak suggests that Samsung is preparing a significant battery upgrade for its upcoming Galaxy S27 Ultra, potentially exceeding 5,500mAh and surpassing the expected capacity of Apple’s iPhone 18 Pro Max. If confirmed, this would mark Samsung’s most substantial battery increase in the Ultra series since the Galaxy S20 Ultra debuted in 2020.
What’s Changing Inside the Galaxy S27 Ultra
According to tipster @phonefuturist, Samsung is testing 5,600mAh and 5,800mAh cells from its in-house battery unit, Samsung SDI, after initially settling on a smaller 5,200mAh solution. If the testing holds, the Galaxy S27 Ultra could ship with a battery exceeding 5,500mAh, marking Samsung’s first meaningful battery increase in the Ultra lineup since the Galaxy S20 Ultra launched in 2020.
Notably, Samsung appears to be achieving this transition without switching to silicon-carbon batteries, which many Chinese phone manufacturers have adopted for their superior energy capacity. Instead, Samsung is focusing on improving its current lithium-ion technology.
How It Stacks Up Against the iPhone 18 Pro Max
Apple’s next flagship is also expected to grow its battery this cycle. Leaked reports suggest the eSIM-only model available in the United States will feature a 5,425mAh cell, while the version with a physical SIM card in other regions will offer a smaller 5,235mAh one. The latter would be the largest ever seen in any iPhone, but Samsung’s 5,500mAh+ battery will surpass it in size.
Capacity Isn’t the Whole Story
Samsung has traditionally packed larger batteries than Apple’s Pro Max models, though the iPhone 17 Pro Max’s eSIM variant briefly broke that pattern. However, mAh values don’t always directly correlate to actual performance time, as iPhones and Galaxy phones use different operating systems with drastically different power efficiencies.
For context, flagship models from China, such as the OnePlus 15 and Oppo Find X9 Pro, carry batteries ranging from 7,300 to 7,500mAh, leaving Samsung and Apple behind in pure capacity. As with any pre-release information, these numbers remain speculative until confirmed by Samsung and Apple.