Samsung Galaxy S26 Ultra battery could be smaller than expected

Last month, reports surfaced that the Samsung Galaxy S26 Ultra — still a year away, given the Galaxy S25 only went on sale last week — will smash its predecessor in terms of stamina thanks to new battery technology. Korean media put the capacity at 6,000 to 7,000mAh — or a 20% to 40% increase on its predecessor.

If that sounded too good to be true, it may well prove to be so. On X, the leaker @PandaFlashPro — who has been claiming a few Samsung insights of late — has poured cold water on the idea of a big increase, and instead predicted a far more modest gain.

“I’ll delete my Twitter account if Samsung gives the Galaxy S26 Ultra a 7000mAh or even a 6000mAh battery I bet,” @PandaFlashPro wrote, before providing a more modest estimate.

"’Based on my Five Sources, the internal Samsung Test Lab only seem to have a Capacity of Max 5500mAh not more’", the leaker added.

The use of quotation marks is interesting, suggesting a verbatim quote from somebody else, which adds an extra layer of separation to the claimed five sources.

Nonetheless, @PandaFlashPro seems pretty sure. When it was pointed out that the 5,500mAh cell might be an early prototype, the leaker suggested the actual final capacity might be even lower: “Even [if] it’s not complete 5500mAh it’s like 5396mAh.”

It’s worth noting that 5,500mAh still represents a 10% gain on the 5,000mAh battery in the Samsung Galaxy S25 Ultra, which should be celebrated. With the energy-efficient Qualcomm Snapdragon 8 Elite for Galaxy chipset, it lasted an impressive 17 hours and 14 minutes in our battery test. While that’s a hair behind the iPhone 16 Pro Max at 17:35 and even more adrift of the OnePlus 13 at 19:45, it still leaves the Pixel 9 Pro XL (12:54) in the dust.

An extra 500mAh battery combined with the usual generational improvements in efficiency could make it the phone to beat for power users in 2026 — especially if Samsung ups the charging speeds from 45W.

As you might expect, it’s quite early in the cycle for a full picture of the Samsung Galaxy S26 to have formed, but there are a couple of early rumors to keep tabs on. The Ultra model has been tipped to feature a massive 324-megapixel main camera, and there’s talk of Samsung abandoning the hole-punch camera (though there’s some argument over whether that’s likely). For the non-Ultra versions, it looks like Samsung’s Exynos chipset may make a return in some territories, after missing out on the S25 series due to poor yields.