Batteries only die on you when you need them the most. It seems like there's an abundance of wall outlets and chargers when your battery is full, but when you want everyone on Facebook to see your Spice-Rubbed Game Hen with Rhubarb-Date Chutney, they're nowhere to be found.
Fortunately, there’s no shortage of alternative charging gadgets on the market. These devices use solar power, hand cranks, power cells, and even the wind to charge your mobile devices and cameras. While most of them are not very practical for routine charging, they serve an important function for emergency situations, like when you want to snap the perfect shot of your friend Philip staring pensively over a glistening Vermont sunset.
You could devote an entire website to alternative charging gadgets, but we decided to take the easy route and quickly test two of the cheapest alternative charging products on the market. Since neither of these products requires utility power, they could be seen as "green" alternative chargers—if they were more practical, that is.
Innovative Digital Hand-Crank
Hand-powered generators are nothing new—the technology is about as old as the photograph. It's one of the simplest, most straightforward ways to generate electricity, so it makes sense that it's been adapted to charge phone batteries. But after using the Innovative Digital Hand-Crank, we'll give it an A for effort, but a D for performance.
I tried the hand-crank on two different phones (a Galaxy Nexus and an iPhone) and did a number of tests. While each device recognized the charger, neither of them registered any change in battery life. In fact, after five minutes of strenuous cranking on the Android device, I noticed a 1 percent decline in the battery’s life. Over three separate attempts to charge an iPhone 5 with five minutes of cranking, I did not notice any increase in battery life. I even tried bringing my phone back to life after a complete battery drain. Nada. In fact, the iPhone 5 even delivered a prompt stating it was not compatible with this charging device, even though the charging icon appeared and the instructions clearly stated it works with the iPhone. (Several user reviews also suggest that it doesn't actually work with the iPhone.)
The Innovative Digital Hand-Crank is extremely cheap at about $12, but it's not even worth that little. With an average user rating of less than 2 out of 5 stars on Amazon.com, it looks like most owners don't find it useful either.
ReVIVE Series Solar ReStore
The ReStore solar charger was much more effective than the crank charger, and far less tiring. We did a few simple tests and found that direct sunlight on a cloudless day in Somerville, MA, was able to charge 5 percent of an iPhone 5 battery in a mere 10 minutes. That’s comparable to the speed of a standard plug-in charge (though charging the entire battery takes significantly longer).
Our only beef with the ReStore is the lack of a clip accessory, which we imagine would be helpful given the kinds of environments where a solar charger would be needed (hiking, outdoor events, travel).
Also, it's worth noting that the ReStore device works like a battery pack. It charges itself though the solar panel, or with a standard AC adaptor (included). Once it has started to fill its own battery, it can then share that energy with your phone, camera, or other gadget that supports USB charging. Most of the time, this doesn't present a problem—but you'd be wise to charge the ReStore whenever you can, to make sure you don't end up in the dark or away from an outlet. It’s important to think of the ReStore as more of a backup battery than just a solar charger.
You also have to remember to turn the device on and off before and after use, as it will not automatically charge once hooked up to a device. That being said, this thing costs less than $30, so we can forgive a few of its interface quirks. Even if you're not an outdoorsman, this thing could come in handy during a prolonged power outage, making it well worth the price.
While the ReStore costs more than twice as much as the Innovative Digital Hand-Crank, the former is clearly a better value. However, it's important to point out that neither of these devices are viable sources of "alternative" energy for your phone. Yes, the ReStore does serve as a backup battery, but it'd a stretch to rely entirely on sunlight to charge both it and your phone, camera, or tablet. And the Innovative Digital Hand-Crank is only as useful as forearm exerciser. The bottom line is, the ReStore may be handy, but it's not going to revolutionize the market. For that, we'll have to wait for those nifty graphene supercapacitors.