In Africa, more and more people have access to cell phones and they're becoming increasingly reliant on them. Farmers use them to check prices at local markets and people far from a bank can use them to exchange money. While cell phones are becoming easier and cheaper to come by, for people in rural areas where the electrical grid is unreliable or non-existent, keeping them charged has become a major burden.
New Scientist reports, "The lack of access to grid power means that people have to trek for kilometres to a nearby town to find a charging station, powered by diesel generators or solar panels. More importantly, it's not cheap. In Uganda, charging a cellphone can cost 500 Ugandan shillings, or about $0.20. That's a huge burden for those who earn less than a dollar a day, especially when you have to charge the phone two or three times a week. Rural areas need stronger signals from cellphones because there are fewer cellphone towers nearby, a further drain on power."
In Uganda, new gadget is being tested that could be the solution to the problem: a solar-powered charging station that is activated by text message. One text gives users 1.5 hours of charge time and the only cost is the fee associated with sending the message.
The device and organization behind it is called Buffalo Grid. The charging station, which travels to villages strapped to the back of a bicycle, is charged by a 60-watt solar panel using a technique called maximum point power tracking (MPPT). MPPT works by changing the resistance of the circuits depending on available sunlight and temperature to ensure a maximum power output at any given time.
A fully charged Buffalo Grid can last for three to four days and can charge 30 to 50 phones a day from 10 charging ports. When a text message is sent to the device, an LED lights up indicating it's ready to charge. Sometimes more than one text's worth is needed to fully charge a cell phone, but at 110 shillings each in Uganda, that's still a fraction of the price that people are spending now.
Buffalo Grid hopes to partner with cell phone carriers to make charging even cheaper, who could benefit from people having greater access to cell phone charging.
"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."
For now, Buffalo Grid is planning on expanding their trial to Sierra Leone at the request of coffee traders who will soon start paying farmers for crops using cell phones. In this case, having a fully charged cell phone could affect how quickly a farmer receives payment.