The Walking Charger™ from Energy Harvesters LLC incorporates an innovative approach to collecting energy from human motion, using the pressure of the human footfall to drive a Faraday generator. This elegant design increases the power output, decreases the complexity, and improves reliability over existing designs.
Consumers are increasingly using mobile devices, and becoming dependent on them. The experience of being out of battery power when we are away from a wall plug has moved beyond inconvenience. We have come to expect access to our devices for communications, reminders, meeting details, and directions. The Walking Charger™ can recharge our mobile devices when we are away from convenient wall sockets, when the value of battery power is at its greatest.
The market is at the intersection of personal electronics and footwear. These markets each provide sizable opportunities. There are 285 million U.S. cellular subscribers and 2.4 Billion pairs of shoe sold domestically every year. In our estimation this market would support revenues of $360 Million annually in the domestic market. In addition, Energy Harvesters has received specific interest from the U.S. Armed forces, providing potential for an additional high penetration market.
The system consists of pair of flat fluid-filled cavities, one under the heel and one under the ball of the wearer’s foot, used to convert the force of a person’s foot fall to fluid pressure. This system is capable of harvesting pressures of up to 57 Newtons, which is used to drive a strong, rare earth magnet piston within a Faraday generator. The two cavities provide the force needed to drive the piston in alternate directions. For a 58 kg wearer, this system is able to convert about 570 mJoules of work into electricity. The electric output of the Faraday generator is rectified and conditioned to recharge batteries used to power mobile electronic devices.
We have an issued U.S. Patent, filed a U.S. provisional patent and an international patent application under the Patent Cooperation Treaty (PCT) and for patent rights in the European Union, Japan, and China.
The system uses easily manufacturable components and is simple to assemble.
In its first product inception the Walking Charger™ is a plug-and-play sole insert for footwear. Our power output for a pair of devices (one in each shoe) is anticipated to be 4 watts at normal walking pace, able to provide a full charge for a mobile phone battery (3.7 V, 1100 mAh) in about an hour. Following this market introduction, energy harvesters will sell production kits to specialty footwear manufacturers, targeting incorporation of energy harvesters into boots for military markets, outdoors occupations, and recreational users. Longer term, Energy Harvesters will pursue opportunities to license our technology to large footwear companies, leveraging the manufacturing scale and marketing reach of these companies to sell energy harvesters in mainstream markets.
The simplicity of our design has advantages of low cost, good manufacturability and reliability over previous designs, creating an affordable solution that will drive energy harvesting into mainstream markets.