A power bank is a water tank you carry around. Capacity is how much water the tank holds, and Wh is the honest measure because mAh ignores pressure. Output watts are how wide the tap opens: a phone needs a narrow tap, a laptop a wide one. Port count is how many taps share the flow. Recharge input is how fast you can refill the tank. Some water always spills on the way out, so your device gets less than the label.
The stored energy in watt-hours (Wh). This is the most honest capacity figure because it accounts for voltage.
When it matters: Compare power banks by Wh, not mAh. Airlines also set limits in Wh: up to 100 Wh is allowed in carry-on without approval.
Capacity in milliamp-hours (mAh), measured at the internal cell voltage, usually 3.6 or 3.7 V.
When it matters: Trap: a 10,000 mAh bank does not deliver 10,000 mAh to your phone. Voltage conversion and heat losses mean a noticeably smaller amount reaches the device.
The battery type inside: lithium-ion, lithium-polymer, or LiFePO4 (lithium iron phosphate).
When it matters: LiFePO4 lasts many more charge cycles and is more heat tolerant, but it is heavier for the same energy. Lithium-ion and polymer are lighter and common.
Skip it if: Skip it for everyday phone power banks.
The most power the bank can deliver across all ports at once, in watts.
When it matters: Phones charge fast at 20 to 45 W. Laptops often need 60 to 100 W or more. Trap: the total may be split across ports, so one port can be much lower.
The most power one port can deliver on its own, in watts.
When it matters: This decides whether a laptop charges at full speed. Check it is at least close to your laptop's charger wattage.
The power available per port when every port is in use.
When it matters: Plugging in a second device often cuts the first port's speed sharply. Matters if you charge a laptop and phone together.
Skip it if you charge one device at a time.
How many devices can charge at once, and which connectors they use.
When it matters: USB-C handles fast charging for phones and laptops. USB-A suits older cables and small gadgets and usually charges slower.
A charging cable attached to the power bank.
When it matters: One less thing to forget. If it breaks, the whole bank may be harder to use. Check its connector matches your devices.
Skip it if you always carry cables.
A wall-style power socket on the bank, for devices that need a standard plug.
When it matters: Useful for devices without USB-C charging. AC conversion wastes energy and adds size and weight.
Skip it if all your devices charge over USB.
USB PD (Power Delivery) is the main fast charging standard for USB-C. Version 3.1 supports higher laptop power than 3.0.
When it matters: Most phones, tablets and laptops fast charge over USB PD. A bank without it charges modern devices slowly.
PPS (Programmable Power Supply) is part of USB PD that adjusts voltage in small steps during charging.
When it matters: Needed for top charging speed on many Samsung phones and some others. Without PPS, those phones charge more slowly.
Skip it if your phone does not use PPS.
Brand-specific fast charging systems, such as Qualcomm Quick Charge or a phone maker's own standard.
When it matters: Some phones only reach top speed with their brand's charging system. Most modern phones also accept USB PD at good speed.
Skip it if your phone uses USB PD.
How fast the bank refills from the wall, in watts, and the rated time to full.
When it matters: Large banks take hours to refill on slow input. Rated times need a wall charger that matches the input wattage, which may not be included.
Whether the bank can charge your devices while it is plugged in and refilling.
When it matters: Lets you charge the bank and phone from one wall outlet overnight. Some banks pause output briefly when power is connected.
Skip it if you charge the bank separately.
A built-in solar panel for recharging.
When it matters: Built-in panels are small and refill very slowly, often taking days. Treat it as an emergency trickle, not a main source.
Skip it if: Skip it for normal daily use.
Charges phones without a cable, using a standard like Qi or Qi2.
When it matters: Wireless charging is slower and wastes more energy than a cable. Qi2 adds magnets for alignment and faster charging on supported phones.
Skip it if you always charge by cable.
Magnets that hold the bank to the back of a phone.
When it matters: Convenient on MagSafe and Qi2 phones. Thick cases can weaken the hold and slow charging.
Skip it if your phone has no magnetic ring.
A screen or LEDs showing charge level, and on some models the power flowing in and out.
When it matters: An exact percentage beats four LEDs. A watt readout shows whether a device is fast charging.
Skip it if LED dots are enough for you.
A fold-out stand that props up your phone while it charges.
When it matters: Handy for videos on a plane or desk.
Skip it if you do not watch video while charging.
Whether the bank is within common airline carry-on rules, usually 100 Wh or less.
When it matters: Power banks must go in carry-on, never checked bags. Banks between 100 and 160 Wh need airline approval. Some airlines add extra rules, so check before flying.
The bank's weight and dimensions.
When it matters: Weight tracks capacity closely. A bank big enough for laptops is heavy for a pocket. Pick the smallest capacity that covers your real use.
The IP (ingress protection) rating shows dust and water resistance, such as IP67.
When it matters: Useful for hiking and camping. The first digit is dust, the second is water.
Skip it if: Skip it for indoor use.