Old laptop batteries still have sufficient life in them to power homes in slums, researchers have said.
An IBM study analysed a sample of discarded batteries and found 70% had enough power to keep an LED light on more than four hours every day for 1 year.
Using discarded batteries is cheaper than existing power options, and also helps deal with the mounting e-waste problem, said by researchers.
In the Indian city of Bangalore this year, this concept was trialled.
The adapted power packs are expected to prove popular with street vendors, who are not on the electric grid, as well as poor families living in slums.
The research result, which comes from IBM’s team, will be discussed at a conference in San Jose, California, according to Technology Review from the Massachusetts Institute of Technology.

Cheap :
A device that uses lithium-ion cells from the old batteries to power low-energy DC devices, such as a light created by the IBM team. They called it an UrJar.
The researchers are aiming to help the approximately 400 million people in India who are off grid, and use other sources to get power.
The UrJar uses lithium-ion cells from the old batteries to power low-energy DC devices .
Options like solar power are greatly more expensive and logistically more unwieldy at the moment.
Researchers estimate the price per unit at just 600 rupees (about £7), if it is made in sufficiently large volume.
UrJar has the potential to channel e-waste towards the alleviation of energy poverty, thus simultaneously providing a sustainable solution for both problems.
Team said that, Reaction from the trial was positive. Among the improvements suggested by users was a call for rat-resistant wires.

Urgent :
The major problem is E-waste, particularly in the developing world, where the majority of the West’s unwanted technology ends up.
Research result of IBM’s said In the US 142,000 computers are thrown away daily – around 50 million a year.
India’s difficult circumstance is particularly urgent. Not only does the country receives a lot of e-waste from many other countries, but with a booming, according to one estimate IT market is also generating huge amounts of its own – around 32 tonnes a day.
Computer Aid, a UK-based charity that redistributes undesirable old technology, accept the initiative.
Keith Sonnet, its chief executive said “We think that this is an excellent initiative as it is in line with our practice of reusing and refurbishing rather than recycling”.
“Refurbishing has surely a more positive impact on the environment and we should encourage more companies to adopt this practice.”