Power Banks

Power banks are ordered as staff and conference giveaways, as issued equipment for field teams, and as the thing that keeps a phone alive through a long outage. They are also the item most often bought on a number that does not mean what buyers think it means.

Capacity is quoted at the cell, and cells run at a lower voltage than the device being charged. Converting between the two costs real energy, so a nominal 20,000 mAh bank delivers roughly 12,000 to 14,000 mAh at the phone - about two and a half full charges, not five. Any bank claiming otherwise is quoting the cell figure and hoping.

Output decides what it can charge at all. A bank with a 10 W output will trickle a phone and will not charge a laptop, whatever its capacity. A laptop needs USB-C Power Delivery at a wattage matching its own charger, and this is the specification to check first if a laptop is the point.

Capacity also has a practical ceiling: airlines restrict what can be carried in a cabin, which matters for staff who travel.

Tell us what it has to charge and how many times, and we will specify from that rather than from a headline figure. Bulk orders can be branded.