Milliamp-hours describe the cell, watt-hours describe the flight
A power bank is sold in milliamp-hours, and that unit describes the cells inside rather than the energy that comes out. The cells sit at about 3,7 V, a phone charges at 5 V or more, and the conversion between them costs a fifth of the total or thereabouts: a 20 000 mAh bank holds roughly 74 Wh and delivers meaningfully less. The comparable figure is watt-hours, which is also what an airline reads — carriage limits are written in watt-hours, and this shelf is one where a specification has a legal consequence. Output power in watts, and the protocols behind it, decide what charges quickly: USB Power Delivery for laptops and modern phones, Quick Charge and its cousins for older devices, and a port that lists a protocol but not a wattage is telling half the story. Whether the total wattage is shared or per-port is the detail that decides whether two devices charge at full speed. Pass-through charging — using the bank while it charges — is either supported or explicitly not. Then recharge time, port count and type, and weight, which on this shelf is roughly proportional to the honest capacity. We compare capacity in mAh and Wh, output power and protocols, port sharing, pass-through, recharge time and stated carriage limits.
20 000 mAh · watt-hours not published · 22.5 W · PD 3.0 and QC 4.0 · port sharing not published · pass-through not stated · recharge time not published · carriage limits not stated
A 20 000 mAh power bank rated 22.5 W with PD 3.0 and QC 4.0, an LCD charge display, and a listing that names a different brand in its own second bullet.
Best for: A spare bank for a bag, where the price is the specification.
≈ €10
20 000 mAh · watt-hours not published · 45 W · protocols not named individually · two integrated cables, sharing not published · pass-through not stated · recharge time not published · 10.9 × 6.6 × 3.0 cm, 363 g
A 20 000 mAh power bank with two integrated USB-C cables at 45 W, published with its dimensions and weight, in a slim format for everyday carrying.
Best for: Two USB-C devices carried daily, where the cables should be part of the bank.
≈ £34 / €33
20 000 mAh · watt-hours not published · output power not published · protocols not named · two outputs, sharing not published · pass-through not stated · recharge time not published · carriage limits not stated
A 20 000 mAh power bank with USB-A, USB-C and micro-USB connections, charging two devices at once, from a maker with a long-established European presence.
Best for: Older equipment with micro-USB, where the charge rate is not the point.
≈ €18
20 000 mAh · watt-hours not published · 45 W · PD and QC · integrated cable plus ports, sharing not published · pass-through not stated · recharge time not published · carriage limits not stated
A 20 000 mAh power bank delivering up to 45 W over PD and QC with an integrated USB-C cable, built on a cell technology the maker calls TinyCell.
Best for: A phone and a small laptop, where 45 W is the difference between topping up and charging.
≈ £32 / €27
20 000 mAh · watt-hours not published · 22.5 W · fast charge protocols not named individually · three ports, sharing not published · pass-through not stated · recharge time not published · carriage limits not stated
A 20 000 mAh power bank with one USB-C and two USB-A ports, a mirrored LCD showing charge from 0 to 100 %, and protection against over-charge, over-voltage and over-current.
Best for: Charging three devices slowly from one bank in a bag.
≈ €13
20 000 mAh · watt-hours not published · 22.5 W QC3.0 and 20 W PD · four built-in cables, sharing not published · pass-through not stated · recharge time not published · 9.5 × 8.9 × 2.6 cm, 310 g · carriage limits not stated
A 20 000 mAh power bank with four integrated cables — USB-C, Lightning-compatible, USB-A and micro-USB — charging up to four devices without carrying anything else.
Best for: A bag where cables get lost and four devices need charging at once.
≈ €24
20 000 mAh · watt-hours not published · 45 W · PD · three devices in parallel, sharing not published · pass-through not stated · self-recharge in 4 hours at 45 W · carriage limits not stated
A 20 000 mAh power bank delivering 45 W with an integrated USB-C cable, and the only bank in this family to publish how long it takes to recharge itself.
Best for: Someone who recharges the bank overnight and wants it ready again by lunchtime.
≈ $35 / £24 / €27
20 000 mAh · watt-hours not published · 45 W · PD 3.0 and QC 4.0 · four ports, two of them bidirectional, sharing not published · pass-through not stated · recharge time not published · airline-approved, no figure given
A 20 000 mAh power bank at 45 W with two USB-A and two USB-C ports, both USB-C supporting input and output, charging four devices at once.
Best for: A household or a family trip where four devices need charging from one bank.
≈ $30 / £31 / €28
20 000 mAh · watt-hours not published · 87 W total, 65 W maximum on a single device · protocols not named · THREE devices at 87 W total with a 65 W per-device maximum — the only published sharing here · pass-through not stated · self-recharge in 1.5 hours with a 65 W supply · airline-approved, no figure given
A 20 000 mAh power bank delivering 87 W across three devices with up to 65 W to one of them, recharging itself in a stated 1.5 hours from a 65 W supply.
Best for: A laptop and two phones from one bank, where the split actually matters.
≈ $66 / £40 / €40
A price quoted in the text of a PowerVerdict page dates from the day that page was written; the live figure beside each product is fetched while you read and replaces it.
