Power Banks for Phones: Picking One That Actually Lasts
Last verified: August 2026
A power bank is a pocket battery that recharges your phone anywhere. The big number on the box is confusing, and it's not the whole story. Here's how to pick one that truly lasts.
Understanding Power Banks
A power bank is a rechargeable battery you charge up at home and carry with you; when your phone runs low, you plug the phone into the bank. It's the simplest form of backup power and invaluable in an outage, a car, or a long day out.
The headline number is mAh (milliamp-hours) — the battery's size. Bigger means more charges, but there's a catch: you only get about 60 to 70 percent of that rating to your phone (some is lost in the transfer). So a 10,000 mAh bank realistically gives most phones about one to one-and-a-half full charges; a 20,000 mAh bank, roughly two to three.
For everyday carry, a 10,000 mAh bank is light and pocketable. For travel, outages, or charging a couple of phones, 20,000 mAh is the sweet spot. Beyond that they get heavy — that's where a power station makes more sense.
When to skip the DIY and just call: You want help choosing the right size and cables · You bought one and it barely charges your phone · You want a small kit ready for outages and travel.
Common Questions
1 What size should I buy?
- Everyday pocket carry: 10,000 mAh (about one full phone charge, sometimes a bit more).
- Travel and outages: 20,000 mAh (about two to three charges, or top up two phones).
- Charging tablets or many devices for days: consider a small power station instead.
- Remember you get roughly 60–70% of the printed mAh to your device.
2 How do I match it to my phone?
- Check your phone's plug: newer iPhones and most Android phones use USB-C; older iPhones use Lightning.
- Buy a bank with the right output ports, and keep the correct cable with it.
- For faster charging, look for a bank that supports your phone's fast-charging wattage.
3 How do I keep it ready for an outage?
- Charge it fully and top it up every couple of months so it's never dead when you need it.
- Keep the right cable taped or clipped to it.
- Store a couple around the house — one by the bed, one in the car.
- Recharge it right after you use it.
4 Are cheap power banks safe?
- Stick to reputable brands (Anker, Belkin, and similar) — very cheap no-name banks can be unsafe or wildly overstate their capacity.
- Look for safety certifications on the box.
- Don't leave any battery charging on a bed or couch, and stop using one that gets hot or swells.
5 Can a power bank charge other things?
- Yes — it can charge phones, tablets, e-readers, earbuds, a smartwatch, and even top up some medical wearables.
- It won't run wall-plug appliances; that needs a power station.
- A big bank with a laptop-capable USB-C port can also give a laptop some extra time.
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