Why Your Battery Life is Terrible, in One Handy Chart

The seemingly intractable problem of how to increase the energy density of batteries means that researchers have begun in earnest to think about abandoning them altogether. In other words: How can we harvest energy from sources outside of our devices, whether it’s powering our smart phones with ambient light, or running large-scale deployments of wireless sensor networks on vibrations and the movement of our bodies.

The average human expends between 100 and 200 watts of power when exercising vigorously, but your iPhone can only accept up to 2.5 watts when charging. Somewhere, somehow, there’s got to be an inexpensive and reliable way to connect these two realities.

via Introduction to Vibration Energy Harvesting (pdf)