Emergency situations such as Hurricane Sandy really bring it home: Just when you need your cell phone the most, it could run out of juice. A charging case or spare external battery can help extend your phone's battery life, but those devices eventually run out of power too. Enter emergency chargers that don't rely on working electricity, generators, or a car to recharge your phone.
We tested four products that can be used to charge any USB-compatible device to see how well they work. The Goal Zero Lighthouse 250 Lantern gathers power via a hand-cranked generator, as does the Eton BoostTurbine 4000. The myFC PowerTrekk relies on a disposable fuel cell to supply energy. All three include an internal battery that can be pre-charged for energy storage. The Goal Zero Nomad 7 Solar Panel uses (obviously) a solar panel, but does not come with an internal battery.
We used each of the emergency chargers to recharge an iPhone 5s and a Samsung Galaxy S 4, using the internal batteries in each and the device's power-generation capabilities.
Each tested device works, providing additional power for those times when power is out. And each has pros and cons, compared with the other models.
Check our review of four cases that charge your smart phone. And for more tips, read "How your electronics devices can help in emergencies."
The most versatile device we tested is the Goal Zero Lighthouse 250 Lantern ($80), which uses a hand-cranked generator that can work under any conditions—as long as your cranking arm holds out! Its internal battery is the largest of the tested devices, and it includes an integral USB charging cord. And unique among these four devices, the Lighthouse 250 also provides light: a dimmable white LED light, and a flashing red light that could be useful for emergency signaling on the road.
An Apple iPhone 5s has a battery capacity of 1440mAh, so the Lighthouse 250's 4400mAh charged battery should be able to fully charge the 5s about three times. When the charger's battery is depleted, an iPhone 5s's battery-life indicator will increase about 1 percent for every 5 minutes of hand-cranking you do.
This is not the most portable of chargers, though; it certainly won't slip easily into a back pocket or computer case. But if you're traveling by car or hiking, it provides a lot of value.
The Eton BoostTurbine 4000, also $80, has a large internal battery (4000mAH) and works with a hand crank, so it can be used to generate power under any condition. It also offers a handy battery-level indicator. But it's not as versatile as the Lighthouse 250, since it lacks LED lights. Also, its charging cable isn't integral, and is therefore loseable. And we found it harder to crank than the Lighthouse 250.
On the plus side, this charger can fold into a smallish rectangle, so it would be easier to carry than the Lighthouse 250.
The foldable Goal Zero Nomad 7 Solar Panel ($80) has no internal battery, so you can't charge it up before you use it, though you can string several panels together for more power.
The Nomad 7 is handy when the sun is shining, but it becomes less useful at night or on cloudy days. So its efficacy is limited in emergency situations.
About the same size as the Eton BoostTurbine 4000, the myFC PowerTrekk ($150) features an internal 1100-mAh battery. It works well, but it requires expendable fuel packs to work—so it's not as endlessly useful as the other devices we tested.
Each fuel cell costs around $4 and is claimed to provide 5-plus watt hours of power, enough to fully charge a standard smart phone, according to myFC. But you need to carry the fuel cells with you on trips—and they aren't cheap.
As emergency devices, all of these products provide a comforting level of backup power for your USB-compatible electronics in the event of a blackout. The Goal Zero Lighthouse 250 Lantern is the most versatile of the devices we tested, and would make a good addition to your emergency provisions. Just make sure that you practice with your selected device before a real emergency happens, so that you can be confident of how it is used. And if it has an internal battery, make sure to keep it charged.
—Carol Mangis and Bernie Deitrick