Power banks

Buying guide

Capacity (mAh) is only half the answer – output power more often decides whether a power bank will do the job. For a phone, 18–30 W is quite enough; for a laptop you need 60 W and above, and definitely with Power Delivery. Bear in mind that the stated capacity is the battery's internal capacity, and conversion losses mean less actually reaches your device. When flying, it must go in your hand luggage, and airlines set capacity limits – check before you travel.