How to choose a power bank.
More capacity isn't always a better fit. Here's how to compare portable chargers without getting lost in the numbers.
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1. Start with how you actually use it
For a short commute, a compact charger may matter more than carrying the largest battery available. For travel or multiple devices, compare the capacity, weight and charging outputs together. Don't judge a product by milliamp-hours alone.
2. Capacity isn't the same as energy delivered
Battery capacity is often advertised in milliamp-hours (mAh), but devices use different internal voltages and energy is lost when converting and charging. Watt-hours (Wh) can make batteries easier to compare when voltage is known. Real-world charging performance also varies with devices and conditions.
3. Read the input and output specifications
Look for the rated output in watts and check which devices and protocols it supports. A USB-C connector alone does not guarantee the same charging speed on every product. If you plan to charge more than one device, check whether the total available output changes when multiple ports are used.
4. Check compatibility, quality and practical details
Consider cable requirements, device compatibility, physical size, certifications where applicable and the manufacturer's safety information. For air travel, consult the airline and relevant authorities before packing any battery product; restrictions vary by route and battery characteristics.
5. A comparison checklist
- What devices will I charge?
- What output power and protocols do those devices support?
- Is the weight reasonable for my use?
- Are the technical details and seller information verifiable?
- Are any transport limitations relevant to my destination?
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