Building your own thermoelectric phone charger

Turning waste heat into electricity seems to be a popular trend these days. Although we’re not quite as good at harnessing heat the way we do sunlight or wind, thermoelectronics is a promising field and provides yet another opportunity to go off grid without sacrificing the gadgets we love.

We’ve featured several heat-powered chargers in the past, like the Power Pot and theVoto, but if you’re more of a hands on type, you might like to build your own. A project on Instructables provides a step by step guide to creating a gadget that will turn waste heat into juice for your favorite gadget.

Image via David Johansson/Instructables

Like most innovators, David Johansson came up with the idea for this design to solve a personal problem. “I sometimes do several days of hiking/backpacking in the wild and I always bring a smartphone with GPS and maybe other electronics,” Johansson explains. “They need electricity and I have used spare batteries and solar chargers to keep them running. The sun in Sweden is not very reliable.”


In addition to electronics, the one thing he always brought on a hiking trip is fire in some form, usually an alcohol or gas burner. So Johansson decided to craft a thermoelectric charger that would allow his cooking stove to do double duty as a charger.

Building on his past experience creating the Thermoelectric-Fan-Driven-by-a-Candle, Johansson put together a functional yet portable thermoelectric charger that utilizes a 40x40mm TEG to produce 5.9W (4.2V/1.4A) at 180ºC difference. The prototype is crude, but charges his iPhone using a camping flame, which was the ultimate goal. He encourages others to replicate the project and add improvements of their own!

Beth Buczynski, EarthTechling