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A solar-powered charging station activated by texts

Posting in Energy

Up to 650 million cellphone users are off-grid, having to trek miles to the nearest charging station and pay a large fraction of their earnings.

London-based Buffalo Grid has developed a portable charging station, which they recently trialed in Uganda. It’s also the cheapest method found so far. New Scientist reports.

In Uganda, charging a cellphone at station powered by diesel generators or solar panels can cost 500 Ugandan shillings (about $0.20). "In rural economies, about 50 percent of the money spent on mobile phones is actually spent on charging them," says Buffalo Grid's Damon Millar. "That is some of the most expensive electricity in the world."

Their system consists of a 60-watt solar panel that charges a battery, which can be brought to a village on the back of a bicycle (pictured).

The innovation lies in how the stored power is released to charge a phone. A customer sends a text message, which in Uganda costs 110 shillings, to the device. Once it receives the message, an LED above a socket on the battery lights up, indicating that it is ready to charge a phone.

A fully charged unit can last for three days, has up to 10 charging points, and charges up to 50 phones a day. Each text message allows a phone to be charged for 1.5 hours.

To bring the cost down further, Buffalo Grid hopes cellphone network operators would subsidize the power, or even make it free. "When you bring power to phones that don't have any, people will use them more," says Buffalo Grid's Daniel Becerra. "Instead of paying for the charge, people will spend more on airtime."

Cellphone use is rapidly rising in parts of Africa and Asia. For instance, farmers use cellphones to get updated pricing information to help them manage crop sales. In Kenya, people without access to banking services exchange money using their phones. Buffalo Grid plans to do trials in Sierra Leone, where coffee traders are gearing up to pay farmers using cellphones.

[Via New Scientist]

Image: Buffalo Grid

— By on March 12, 2013, 4:33 AM PST

Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure