Solar vest juices up cellphones on the go

Boda Boda operators will soon wear solar vests on their rides that harnesses the power of the sun to keep cellphones recharged. Boda Boda operators is not a mobile carrier, but bicycle riders that ferry passengers from main roads to villages which are well off the beaten track in Western Kenya. Their solar vests ought to pick up juice from the sun for up to 12 hours daily on an average. With all the pedaling done, why not use that to power a dynamo as well which could further aid cellphone charging times?