For on-the-go cellphone recharging: 1. Panels for Goal Zero's Switch… (Kirk McKoy / Los Angeles…)
Superstorms that slammed the East Coast prompted many Southern Californians to take a hard look at their own emergency preparedness plans, including how to keep cellphones charged when the power goes out. With a flurry of battery-boosting devices landing on the market, I tested eight of the latest and most novel designs on a recent ski trip to Colorado, reasoning that besides a storm, earthquake or blackout, the last place you'd want to be stranded with a dead cellphone is on a cold chair lift, separated from your party when it's time for après Bloody Marys.
Most of these devices are charged via a USB cable, which you can plug into your laptop or wall outlet adapter, but I also tested products powered by sunlight or motion. I evaluated each on my iPhone 4S, which has a battery life of about five hours with regular usage when I'm out and about. I measured how much each product boosted my battery and assessed its convenience and efficiency. Your results may vary depending on your phone model, your operating system or how often you check Facebook.
In the end, the attractive Mophie Juice Air Pack earned a permanent place in my purse for on-the-go charging. I'd keep one of Goal Zero's solar chargers around for an emergency backup — pre-charged, of course, in case disaster strikes in the middle of the night (or on a cloudy day). And some might get a kick out of the motion-powered nPeg Power, which will help keep you in shape for when the zombies attack. Here's a rundown of all eight models that were tested.
When I landed at Denver International Airport, my battery was at 1%, so I plugged in the Plug Battery Charger by Molla Space ($26, mollaspace.com). The device looks like an oversized white plug — get it? — and fits directly into the 30-pin connector of my iPhone. After 30 minutes, I was back to 20%, the point at which recharging seemed to stall. I worried that the Plug might get bumped off the phone while they were connected in my purse, so I had to hold them together the entire time. The product worked fine, but a 20% battery boost isn't much: After 30 minutes of answering emails and using Google Maps, I had drained the power again.
The eFreesia (efreesia.com) — Get it? It frees ya! — comes in two models, the eFreesia Bar ($29.99) and the eFreesia Mini ($22.99), which have Minimalist designs that echo Apple products. As we drove up into the mountains, I plugged in. The Mini quickly recharged the battery 20%, and the Bar gave me a hefty 85%. Indicator lights let you know how much power the device has left. The only thing I didn't like about the Bar: One cord connects the power pack to the wall outlet, but a different cord connects the power pack to the phone. When I went to charge the phone a second time, I realized I'd left one of the cords on my desk at home.
Staring up at the bright Colorado sky, I remembered the Goal Zero Switch 8 Solar Recharging Kit ($119.99, goalzero.com) in my bag. Its solar panels are about the size of an open novel, small enough to leave in a sunny window for an afternoon. (You can also charge via USB port.) The solar panels connect to a slim cylindrical battery pack, which can be detached and used as a portable power station. It boosted my dead phone to 63%. If I'd wanted to, I could have brought the solar panels along for additional charging. The same company makes the Goal Zero Guide 10 Plus Adventure Kit ($159.99), which includes rechargeable AA batteries. Do I need an entire phone-charging backpack so I can watch Hulu while I'm on the bus? Probably not. But both make sense in a place like L.A., which has 300 days of energy raining from the sky.
For other alternative power options, I had to do some work. The Eton BoostTurbine2000 ($59.99, etoncorp.com) is slightly thicker than an iPhone and has a hand-crank that folds out of one side. Plug your phone in with a USB cable, turn the crank and you generate power. It seems poetically simple, but the manufacturer acknowledges that one minute of cranking generates only enough power for one minute of talk time or a few texts. That translates to 2% to 3% on my phone's battery life — not much. When I went to crank the BoostTurbine, I found it awkward to hold and annoyingly loud. My hand cramped so badly after two minutes that I couldn't imagine why I'd need a phone so badly to endure the pain — which might explain why the BoostTurbine also can be charged from a computer.