The Galaxy S23 series brings a lot of subtle improvements, but a charging power upgrade isn't one of them. The Galaxy S23 continues to feature a maximum of 25W fast charging, while the Galaxy S23+ and the Galaxy S23 Ultra support 45W fast charging (similar to their predecessors). However, the Galaxy S23 Ultra still charges slightly faster than the Galaxy S22 Ultra.
GSMArena tested the charging speeds of the Galaxy S23, Galaxy S23+, and Galaxy S23 Ultra. They found that the Galaxy S23 Ultra charges up to 68% in just 30 minutes with a 45W fast charger. In comparison, the Galaxy S22 Ultra charged up to 61% in 30 minutes. That's a small improvement, but it is an improvement nonetheless. It isn't far off from the Xiaomi 12S Ultra, which charged 4% more than the Galaxy S23 Ultra despite featuring 67W fast charging.
Galaxy S23 Ultra's faster charging speed could be due to an improved cooling solution
The Galaxy S23 Ultra charges fully in 59 minutes when using a 45W USB PD 3.0 charger with PPS (Programmable Power Supply). That figure is similar to the Galaxy S22 Ultra using the same charger. And it is just 9 minutes slower than the Xiaomi 12S Ultra. Phones in the same segment from Apple and Google take much more time to charge fully.
This minor improvement in charging speed in the first 30 minutes could be due to Samsung's improved cooling solution. Charging speeds also depend on the device's temperature. Since the Galaxy S23 Ultra has a much bigger heat dissipation solution, it can cool down more efficiently, leading to slightly faster charging speeds. However, despite having a similar cooling solution, the Galaxy S23 and the Galaxy S23+ don't show any improvement in charging speeds.
