The results are in from Nokia's solar charging experiment, and it doesn't look good for those hoping to charge up their cellphones from sun rays in future. The Finnish handset maker has been using prototype solar panels for the past six months, across a variety of countries, to test the viability of sun driven cellphone charging. Nokia's tests involved a customized C1-02 device (dumbphone), and five participants with different lifestyles and local weather conditions.

A device situated in Kenya, near to the equator line in Africa, harvested the best charge results thanks to weather conditions, and the fact the tester works as a security guard who was often stationary throughout the day. Results at that location showed that 20 hours talk time, or 41 days of standby, could be achieved during 59 days based on an average charge of 12 hours a day. Nokia says the tests demonstrate that solar charging is possible for cellphones, but that it's a "challenging" process that would take days to charge a smartphone battery whilst it was switched off. We'll need to hang onto our chargers for a little while yet sadly, the research has clearly proven solar energy charging isn't ready just yet.