Portable cell phone battery chargers have saved my bacon more than once while traveling. From overtaxing my iPhone taking vacation pictures to relying on Google Maps to get me where I’m going in a car without an aux port, there are times that low battery warning would trigger a major anxiety attack were I out and about without a power brick capable of refilling my phone’s tank at least once. But I’ve also made a habit of keeping one of them fully charged in a desk drawer at home, and you should too.
There’s a lot going on in America right now. It’s summer, a time when higher temps and increased air conditioner use trigger brownouts when energy supply can’t keep up with demand. We’re also three days into what looks to be a record-breaking hurricane season; I probably don’t need to tell you what storms can do to cut off juice to your home. Factor in the remote possibility power will be disrupted in some way by the ongoing nationwide protests over police brutality alongside a host of other more mundane causes (from fallen tree branches to an overzealous contractor) and there are more than enough reasons to keep a charger at the ready even when you aren’t out and about.
Chargers come in all sizes and capacities, from tiny cylinders that will recharge your smartphone once or twice to heavy bricks that will do so eight times or more. Because you’re going to be keeping this one at home rather than lugging it around in your purse, pocket or backpack, I say go big; who knows how long your electricity will be out, and you don’t want to be left without the power to keep in touch with emergency services, call friends and, perhaps most importantly, stream Netflix when your entire block has gone dark.
You have a wide range of options, prices and features to consider. Do you want something super basic that will get you through an unexpected brownout, or something that will serve if your power is out for a whole day? Wirecutter recommends looking for a USB-C charger rated for at least 15-watt charging; for micro-USB and USB-A, 8 watts or more should be the target. These wattages will ensure your device will charge as quickly and efficiently as possible. In terms of capacity, you’ll want to calculate how many times you’ll be able to use a power bank to charge your device. An iPhone 11, for example, has a battery capacity of 3,050 mAh or so, so a charger with a 10,000 mAh capacity should theoretically give you around three full charges, but in reality, it will probably be closer to two, depending on how closely your power bank’s performance matches up to its advertised specs. (You can figure out your device’s battery capacity with a quick Google.) The price will vary based on the brand, power capacity and weight. Since I’m recommending leaving this one at home, I’d say bigger is better.
If you truly want to be prepared for an emergency, consider getting a power bank capable of charging your laptop as well. These devices will have a regular AC outlet built in, which means you can actually use them to charge anything with a plug that runs on up to about 60 watts.
Updated to clarify language and correct errors in the section describing how many times you can expect to be able to charge your phone based on its capacity relative to that of your power bank.