You’re in the middle of nowhere, your phone rings but your battery is dying… Here is a rescue charger to build for less than 5€ !
Our mobile mates are everyday more powerful, and also more power hungry. It has become hard to end a day without charging them, which is pretty annoying especially if you are in the country side, in a festival or on a trip.
Here’s a 5€ trick that allows to fully charge your smartphone one or two times (says Mosquito Xing, the autor of this tutorial) using a single 9V standard battery and a cigarette lighter adapter. Low tech, cheap and rather simple.
Here’s a video tutorial (in French) :
Here you can try two other similar tutorials, including one in English: