When the power goes out, modern life is thrown into disarray. But thanks to a new Kickstarter project you may not have to worry about your smartphone dying before the electricity comes back on. The Candle Charger is described as an "indoor power plant for smartphones," providing USB charging capabilities with just a candle and five ounces of water.

We've seen outdoor chargers based around camping stoves and boiling water before, but the Candle Charger breaks new ground by using very little heat, coming in a very compact shape and being suitable for indoor as well as outdoor use. It's being developed by the same people who previously gave us the FlameStower, a larger device that works with any open flame.

A special Stower candle sits under a small bath of water and the difference in temperature generates the electricity (though the device can also be used to sterilize water). One candle canister is reported good for six hours of USB charging at a steady 2.5 W (500 mA at 5V), which is the equivalent output of most laptop USB ports, and is roughly enough power to charge two iPhones from one candle. Cameras, torches and other small devices can be recharged through the Candle Charger, too.

At the heart of the contraption is a thermoelectric module (or Peltier cooler). The semiconductor device converts the temperature gradient (the heat of the candle against the coolness of the water) into electricity. A smart circuit is then used to match the output against the requirements of whatever device is being charged. The inventors recommend changing the water every 30 minutes to keep the temperature gradient in place, but this can be shortened to every 10 minutes to create a greater average power output.

Solar chargers are obviously of no use at night, while hand crank-powered devices often produce a minimal amount of power. With the Candle Charger, the makers say that a reliable, constant and usable flow of electricity is generated without any special setup, as long as there's a candle in the home.

Most of the charger is built from aluminum, and while it was designed for inside use, you could just as easily take it away for a camping trip as well.

The Candle Charger is currently on Kickstarter, with a single device currently listed at a pledge level of US$65. If all goes to plan, shipping is scheduled for December. The final retail price is expected to be $99.

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