The batteries of Galaxy S27 Ultra And Galaxy S27 Pro they appeared in the database of Safety Korea, the South Korean certification body that in recent years has become a recurring source of previews about Samsung devices. The published shots do not allow you to read the capacity printed on the casing, but the identification codes leave little doubt about the models to which they belong.
The acronyms EB-BS957CBY and EB-BS958DBY in fact they correspond to the model numbers SM-S957 and SM-S958, attributable to the S27 Pro and S27 Ultra respectively. Both cells are produced by Zhuhai CosMX Powera Chinese company that already supplies other components to Samsung.
The capabilities, although not visible in the photos, were already known from previous leaks: a first indiscretion dates back to July, then confirmed by the Chinese 3C certification in September. For S27 Ultra we are talking about a nominal capacity of 5,534 mAhwhich should result in a typical stated capacity of 5,700 mAh. For S27 Pro the nominal value is 5,087 mAhwith a typical capacity estimated around 5,200 mAh.
Samsung abandons the 5,000 mAh after years of inaction
Should the figures be confirmed at launch, S27 Ultra it would mount a 700 mAh higher battery (+14%) compared to the typical 5,000 mAh of the Galaxy S26 Ultra. Even the Pro model, despite its more compact dimensions, would exceed the current Ultra by 200 mAh (+4%), a detail that alone tells how much Samsung has decided to correct course on a parameter that has remained unchanged for several generations.
Samsung has in fact maintained the 5,000 mAh threshold on Ultra models for years, despite pressure from Chinese competition. According to rumors circulated in the past, the company even tested a 7,000 mAh prototype, which was then discarded so as not to give up the space needed to house the S Pen.
On the charging front, both smartphones are certified for a maximum power of 60W via cablethe same value already seen on the Galaxy S26 Ultra. No leap forward, therefore, on this front, while other Chinese manufacturers have already well exceeded the 100W threshold.
The presentation date of the S27 series has not yet been announced. Some recent rumors suggest that Samsung may return to the usual January or February window, after this year’s advance. However, it should be remembered that these are pre-production units, and Samsung has not confirmed the final specifications of the two smartphones in any way.
