Cuktech 15 Ultra Charging Test: A 20,000mAh Power Bank Built for Serious Speed
The Cuktech 15 Ultra is not an ordinary 20,000mAh power bank. In testing, it showed exactly why it stands out among high-capacity portable chargers: this device can refill at remarkable speed, especially when its high-performance mode is activated.
With Beast Mode enabled, the Cuktech 15 Ultra immediately pushed charging power beyond 150W. The results were impressive from the very beginning. After just over three minutes, the battery had already recovered 10 percent. In under 10 minutes, it reached 30 percent, making it extremely useful for anyone who needs a quick top-up before leaving home, heading to work, or traveling.
The pace remained strong up to the 70 percent mark, which was reached in less than 23 minutes. After that point, the charging speed dropped noticeably. At around 90 percent, the power bank was still charging at just under 80W, which is still fast by typical power bank standards. The slowdown appears to be linked to the device switching to single-port charging after reaching 70 percent.
In total, the Cuktech 15 Ultra charged from 0 to 100 percent in 44 minutes and 30 seconds during the test. For a 20,000mAh power bank, that is an excellent result and makes it one of the more practical choices for users who want fast turnaround times.
This kind of charging performance is especially useful when the power bank is completely empty and needs to be ready again in a short amount of time. If you only have a few minutes, Beast Mode can restore a meaningful amount of battery very quickly. That makes the Cuktech 15 Ultra a strong option for frequent travelers, laptop users, gamers, photographers, and anyone who relies on high-power USB-C charging throughout the day.
However, there is one important thing to keep in mind. Charging at this level can generate some heat, and while the power bank only warmed slightly during the test, repeated high-speed charging may not be ideal for long-term battery health. Only extended use over time can confirm how much impact Beast Mode has on durability. For everyday charging, it may be smarter to use the standard mode most of the time and save Beast Mode for situations where speed really matters.
The good news is that normal charging is still very fast. Using the USB-C1 port with a sufficiently powerful charger, the Cuktech 15 Ultra accepted around 130W in testing. In this mode, it reached 70 percent in about 27 minutes, only around four minutes slower than Beast Mode. A full charge from 0 to 100 percent still took well under an hour, which remains highly impressive for a power bank of this size.
That makes Beast Mode exciting, but not always necessary. The standard charging mode already delivers more than enough speed for most users, while likely being gentler on the battery over time.
Overall, the Cuktech 15 Ultra proves itself as a powerful and fast-charging 20,000mAh power bank. Its ability to recharge in under an hour, even outside its maximum-performance mode, makes it a compelling choice for users who need dependable portable power without long waiting times. Beast Mode is the headline feature, but the real strength of this power bank is that it remains extremely fast even when used in its normal charging mode.
