When adventuring in the great outdoors, there’s nothing better than to completely disconnect from the digital world–unless, for business or family reasons, you really need to get in touch with someone. Luckily, a few innovators from Palo Alto made the FlameStower , a collapsable USB charger that generates energy by sticking one end in the fire .

Compared to green outdoor device chargers like rechargeable batteries or solar units, burning butane just to charge your USB devices sounds wasteful. But the FlameStower is built to charge under any significant heat, from campfire to home stove, so your phone can charge while you’re boiling water for your delicious dehydrated dinner or instant coffee. You can charge under a fire at any time of day (whereas solar chargers are useless at night) and carrying around extra batteries adds weight quickly compared the the FlameStower’s skimpy 7-ounce frame.





The charging tech is simple: Stick the blade into a fire (it won’t get damaged–think of the bottom of a frying pan) and the heat contrasts with cool water poured into the collapsible cup on the top of the device. The temperature difference is enough to drive the thermoelectric generator: Like a high/low pressure system, as the thermal energy increases the voltage on the “fire” side, power naturally flows to the lower-voltage “water” side and then out the USB port. As long as the blade sits in a fire of around 400 degrees Fahrenheit/200 degrees Celsius, the device will generate electricity.

The FlameStower doesn’t charge particularly fast (half the speed of a wall charger, about the same as plugging it into a computer), but the FlameStower team estimates that for every minute of charge you’ll get three minutes of talking time. Unlike other general device USB chargers, the FlameStower was designed with smartphones in mind, so it won’t brick your phone due to faulty wiring or a voltage/amperage mismatch.

The FlameStower has already surpassed its $15,000 goal–clearly, other techie outdoors folk are excited for the device. You can get your own for the $70 early-bird price while they last, but even the $80 standard price is more affordable than the fancier solar chargers.