Technical standards confirm that relying on large capacity alone is not enough when choosing a power bank for laptops, as there are three basic numbers that must be taken into consideration to ensure effective performance, which are: capacity in milliampere-hours (mAh), actual power in watt-hours (Wh), and output capacity in watts (W).
For example, a 20,000 mAh power bank stores about 74 watt-hours of energy, but losses resulting from voltage conversion and charging operations may reduce the amount actually delivered to the device to only about 52 watt-hours.
In the same context, “output capacity” is a decisive factor in the selection process; A bank that has a huge capacity but with an output power that does not exceed 15 watts may be sufficient for charging smartphones, but it is completely unable to power a laptop that requires 65 watts or more. Hence, it is necessary to ensure support for USB-C Power Delivery technology and to carefully verify the capacity of the charging port itself.
In addition, the guidelines stressed the importance of choosing a USB-C cable that has the ability to withstand the required power, especially when using chargers with a capacity of about 100 watts.
As for storage capacities suitable for various uses, a capacity of 20,000 mAh is a practical option for daily use or emergency situations, while capacities of approximately 27,000 mAh, or the equivalent of 100 watt-hours, provide a larger power reserve.
