The Galaxy S27 Ultra battery is rumored to be big enough to match and even beat the iPhone 18 Pro Max, but capacity may not be the only upgrade. Samsung’s next flagship is expected to pack a larger cell than the Galaxy S26 Ultra, and a clever trick could also keep charging times in check.
Galaxy S27 Ultra Charging Speed: Rumored Upgrade via Clever Trick
The Galaxy S27 Ultra is rumored to finally move past the 5,000 mAh battery Samsung has used for years, with a much larger 5,700 mAh cell reportedly on the way. What wasn’t clear was how quickly that bigger battery would charge, but leaker @WalleGalaxy on X now says the Galaxy S27 Ultra charging speed will improve too.
The upgrade isn’t a higher wattage, as the phone may stay at 60W charging. Instead, it could hold peak charging speeds for longer at the start of the charging cycle. According to the leaker, that should shave a little time off the total charge, even with the larger battery.
Galaxy S27 Ultra Battery Upgrades: Bigger Cell, Better Charging
A faster-charging Galaxy S27 Ultra isn’t surprising, given how far Samsung has trailed leading Chinese brands in both charging speed and battery capacity. What’s more interesting is that the company may skip a higher wattage and instead adjust the charging curve to get similar results.
That change should be a clear step up from the Galaxy S26 Ultra’s fairly modest charging performance. Samsung’s current flagship supports Super Fast Charging 3.0 at up to 60W, which the company says can reach 75% in 30 minutes.
In his in-depth review of the Galaxy S26 Ultra, my colleague Victor measured 76% in 30 minutes, and a full charge took 49 minutes. That’s already faster than what he got in the iPhone 18 Pro Max charging test. Apple’s flagship reached 71% in 30 minutes, then slowed down considerably, needing 1 hour and 8 minutes to hit 100%.
Galaxy S27 Ultra Battery: Is Samsung Borrowing Apple’s Tech?
Apple has reportedly used metal-can battery tech in both iPhone 18 Pro models, a design it first patented in 2020 and used in the Apple Watch Series 5. That could explain the higher capacity compared to the iPhone 17 Pro, though the more efficient chipset also contributes to the better performance.
Chinese Android brands are still on a completely different level from both Apple and Samsung. They’re reportedly investigating how to combine metal-can tech with the silicon-carbon batteries they already use, which could lead to phones with over 10,000 mAh batteries. That would top even the Xiaomi 18 Pro Max and its 8,500 mAh battery.
The Galaxy S27 Ultra is rumored to get a 14% bigger battery than the Galaxy S26 Ultra, but people online remain unimpressed. Some Reddit users appreciate the upgrade, but most expected silicon-carbon batteries and much larger capacities to challenge the Chinese ultra flagships.
Battery Longevity vs. Size: Why Lifespan Matters Just as Much
A 10,000 mAh silicon-carbon battery sounds impressive, but I worry about how long it would stay at peak performance. I’d rather have a bit over a day of battery life and the same performance two or three years later. Samsung has long offered that, and I hope the Galaxy S27 Ultra keeps putting battery longevity ahead of raw capacity.
