Folding turbine makes smartphone charging in the wild a breeze

Solar chargers are one means of keeping a smartphone charged when in remote locations, but they're dependant on hours of daylight and sunlight intensity. Portable turbines are an alternative and product designer Nils Ferber has created one he says is more portable and effective than any other.

The idea for the Micro Wind Turbine came about in March this year as a result of Ferber finding that his smartphone would routinely lose charge on long treks. He turned to a number of mountaineers, climbers, film-makers and expedition leaders for advice and found that solar chargers were the overwhelmingly popular solution, but that their sunlight dependency was considered a serious shortcoming.

His suggestion of a wind turbine is said to have been well received, but weight, pack-size and ease-of-use were flagged up as key factors that would affect uptake. Portable wind turbine device chargers, like the Trinity, do already exist, but Ferber says there are none of a similar scale that are commercially available, as well as adequately simple, portable and effective. As such, he went about creating one that would meet all these requirements as the graduation project for his Master's course of product design at the École cantonale d'art Lausanne (ECAL).

A series of digital and physical models were made to test stability, different folding mechanisms and performance in various wind conditions. Different generators were also tested, with voltage converters, a battery pack and a circuit board to manage incoming and outgoing loads all added to complete the required electronics.

All this came together in a prototype completed in June that weighs less than 1 kg (2.2 lb), which Ferber believes is 40 percent lighter that the closest competitor. Based on tension and compression, it is able to be erected in a matter of seconds by pulling on the telescopic shaft and securing it in place with guide ropes. Crucially, unlike a solar charger, it can operate both during the day and at night ... if there's a sufficient breeze.

The shape of the vertical axis rotor is said to be based on that of an optimized Savonius turbine, with a vertical, shaft-mounted cylinder design. This, says Ferber, allows the turbine sails to catch wind from all directions and allows it to work in a wide range of wind speeds, as well as in unsteady and gusty winds.

High output, even at low wind speeds, is said to be made possible by using a larger rotor than competitors and by mounting it directly on the generator shaft to minimize energy loss through both friction and mechanical transmission.

Power output obviously varies depending on wind-speed, but the turbine can reportedly produce a constant output of 5 watts if the wind is blowing at 18 km/h (11 mph). The energy harvested can either be used to charge devices directly via a USB output or can be stored in an integrated 24-Wh battery pack.

At the wind-speed given above, the generator is claimed to produce enough power to maintain the load of the battery pack while also charging a USB device.

Ferber says the simple design of the turbine means that it can be manufactured at a very low cost and that it could be easily adapted for varying scenarios or for communal use.

Partners are currently being sought to develop the concept further and to commercialize the turbine. The prototype is set to be exhibited at this year's Dubai Design Week from October 24.