According to the company, the SmartLantern's battery should hold its charge for about a year. If you want to store the device in your emergency-preparedness kit, you'll need to remember to give it a boost of power from time to time using the included USB charger.
At a mere 7.5 ounces in weight, and just 4 by 2.5 by 2.5 inches in size, the SmartLantern is perfect for camping, where you can use its built-in metal loop to hang it from a branch or inside your tent, and just as easily stow it away in your pocket when you're on the go (the company helpfully provides a carrying bag). In my tests, the SmartLantern performed very well, providing plenty of power and illumination.
Eton BoostTurbine 2000
Eton's $70 BoostTurbine 2000 (3.5. of 5 rating) combines a 2000-mAh battery with a hand crank in a package that weighs less than four ounces and is just 5 by 2.2 by 1 inches in size. The battery provides enough power to fully charge a typical smartphone once, and can itself be recharged via USB or — as you might guess — that hand crank. (Eton also sells the $90 BoostTurbine 4000, which offers 4000 mAh of reserve power and can recharge tablets, a feat that escapes the model I tested.)
According to the company, the hand crank generates power at a 2:1 ratio. One minute of turning, at two turns per second, generates enough battery power for a thirty-second phone call, which should do in many emergencies. A set of LED lights on the bottom of the BoostTurbine gives you an idea of how much charge remains in the battery.
The BoostTurbine performs reasonably well when kept charged via USB. When the aforementioned power outage hit, the battery promptly recharged my iPhone, and even provided plenty of power for a USB-powered radio. Hand cranking, however, is another matter: The device is small, and its shape is blocky with a slick finish, which makes holding it in one hand while turning the surprisingly stiff turbine with the other a little too much of a challenge, particularly if you have big hands.
Still, this gadget makes for a good emergency-preparedness companion (particularly if you can remember to keep it charged), with a compact body that looks good and is available in four different colors.
On the other hand, Eton's $70 FRX3 (4.5 of 5 rating) ranks near the top of the devices I tested. A true emergency-preparedness tool, it combines half a dozen or so functions in a compact package (6.9 by 5.8 by 2.6 inches, 1.3 pounds) that you can take with you anywhere. Plus, it's both lightweight and rugged, making it perfect for a camping trip.
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