Galaxy S27 Ultra May Finally Get a Battery Boost, Rumor Says

It’s only been a few weeks since the Galaxy S26 series came out, and early leaks about the Galaxy S27 Ultra are already starting to surface. One of them comes from Schrödinger, who claims Samsung may finally break the 5,000mAh battery ceiling with the Galaxy S27 Ultra, most likely.

Samsung may finally break 5,000mAh limit and use silicon-carbon batteries soon

In a blog post, a tipster who goes by Schrödinger says Samsung is targeting next year to finally get silicon-carbon batteries working. If true, that would mark a quantum leap, to say the least. On the sidelines of Unpacked in February, Samsung confirmed it’s working on silicon-carbon batteries.

The company’s EVP, Jeong Seung Moon, told select media that those silicon-carbon batteries have to meet strict internal testing requirements before they can be adopted. Needless to say, Samsung doesn’t have much choice but to be careful after what happened with the Galaxy Note 7 years ago. Since then, the company’s been rather conservative with battery capacities.

The latest Galaxy S26 Ultra comes with a 5,000mAh battery, and so do the Galaxy S25 Ultra, Galaxy S24 Ultra, Galaxy S23 Ultra, Galaxy S22 Ultra, Galaxy S21 Ultra, and even the Galaxy S20 Ultra. That’s seven generations with the same battery capacity, and if the new rumor turns out to be true, we may finally see Samsung break that 5,000mAh ceiling.

Apparently, Samsung is testing high-capacity batteries in some devices

The rumor in question claims (and reiterates) Samsung is testing 12,000mAh, 18,000mAh, and 20,000mAh batteries in real devices. Internal documents, according to the tipster, suggest the tested units reportedly failed after about 960 charge cycles, which is below Samsung’s 1,500-cycle target. So that’s the main bottleneck.

It further adds that, “Samsung’s engineers are actively reworking the separator layers, stacking architecture, and battery management firmware to get there.” Lastly, the tipster concludes that if the new battery tech sees the light of day, it could arrive with the Galaxy S27 Ultra. We’ll stay hopeful, but it’s still too early not to take it with a grain of salt.