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World Changing Ideas

Your Old Cell-Phone Batteries Could Power Solar Lamps For 3 Years

Better than recycling that old phone battery, it can be put to good use helping deliver kerosene-free lighting to the poor.

Your Old Cell-Phone Batteries Could Power Solar Lamps For 3 Years

Photo: Flickr user PhotoPhoto33

Reuse is always better than recycling, because it uses way fewer resources. And if the reusable item is an environmentally filthy cell-phone battery, all the better. That's why researchers at the University of Seoul want to take the batteries from discarded cell phones and use them as storage for solar-powered LED lamps in rural areas.

Most cell phones are replaced every couple of years, but their lithium-ion batteries are good for five years of use, meaning that they go to the landfill (or recycling center) with three years life left in them. Study author Boucar Diouf wants to use these batteries to store solar energy for the one-third of the world’s population that doesn't have access to electricity. "Used mobile phone batteries associated with a solar panel and a light emitting diode lamp can be a good replacement for candles or kerosene lamps that generate pollution, are hazardous, and only give poor lighting," says Diouf in his newly-published paper.

Currently, the most-used kind of light is a kerosene lantern, which is dangerous, requires a lot of work to use compared to an electric light, and kicks out choking fumes. Electric can provide a better quality of light, which is safer and easier to use.

Flickr user m01229

Diouf also points out that all these people during lamps and candles add up to a rather large carbon footprint. His back-of-the-envelope calculation, taking a 30-cent candle in Senegal as his basic unit, comes out at 36,000 tons of CO2 per day. Using solar would cut these emissions to zero.

Diouf proposes a simple solar system, wiring a panel to an array of batteries and then a lamp. A single, standard cell-phone battery of 1,000 milliamp-hour capacity can power a one-watt LED for three hours. Swap in a half-watt bulb, which is enough to read by, and you get six hours. Diouf’s team has built a 12-volt system using three batteries, a five-watt lamp and a solar panel for less than $25. That’s enough to light a room for fiver hours a day, for three years, pretty much maintenance-free. The panel (and possibly the bulb) should outlast the batteries, and as the batteries were going to be trashed anyway, it’s an almost perfect solution.

The very hard part, the researchers agree, is putting in place an infrastructure that can take our used batteries and get them to where they need to be. But it could be worth it, for both the people who need the light and for everyone else who hopes the world can begin to reduce its carbon emissions.

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