What should I look for in a portable power bank?
Capacity and Power
Capacity is measured in milliamp-hours (mAh). A 10,000 mAh bank typically charges a phone 2–3 times, while 20,000 mAh can do 4–6 times. Higher capacity means more weight and bulk.
Output power matters more than capacity for charging speed. Look for at least 18W USB-C Power Delivery (PD) for phones, and 30W or more for tablets or small laptops. Some banks support QuickCharge or other fast standards.
- 10,000 mAh: good for a day trip, pocketable
- 20,000 mAh: great for weekends, charges multiple devices
- Check if the bank can charge and be charged simultaneously (pass-through)
- Look for USB-C PD and maybe USB-A for older cables
Ports, Size, and Safety
Ports should match your devices. USB-C is becoming universal, but many still have USB-A. Some banks have built-in cables or wireless charging pads, which add convenience but can be slower.
Size and weight matter if you'll carry it daily. A 10,000 mAh bank is usually around 6–8 oz, while 20,000 mAh can be 12–16 oz. Safety certifications like UL, CE, or RoHS indicate the bank has passed basic safety tests.
- Built-in cables save space but may break sooner
- Wireless charging is convenient but slower and less efficient
- Avoid no-name brands with no safety marks
- Check airline limits: most allow up to 100Wh (about 27,000 mAh) in carry-on
Common mistakes
- Assuming higher mAh always means better; a high-capacity bank with low output may charge slowly.
- Ignoring output wattage and buying a bank that can't fast-charge your phone.
- Overlooking safety certifications; cheap banks can overheat or fail.
