Nokia finds that solar power needs some sun

FINNISH PHONE FIRM Nokia has completed an experiment as to whether the sun can be used to power a mobile phone, and found that it really can't.

The firm found that in some instances, like where there is a lot of sun, solar charging does have some small benefits, but that in other regions where there is less sun it is less effective.

Nokia's experiment looked to see whether it was possible to use the sun as an alternative to electricity in areas where the electricity supply is uncertain.

Five prototype handsets with a solar panel where the back cover would normally be were built and taken to five places. Two went to the Arctic Circle, one to southern Sweden, one in Kenya, and one to a boat sailing in the Baltic Sea. The results were mixed, but perhaps obviously favoured Kenya, which is known for its sunny weather.

"The tests showed that charging a mobile phone by simply using a solar charging panel on the back cover is possible but challenging," wrote Nokia in a blog post.

"When carefully positioned, the prototype phones were able, at best, to harvest enough energy to keep the phone on standby mode but with a very restricted amount of talk time. This means there's still some way to go before a workable and care-free solution is achieved."

The biggest challenge according to Nokia is the limited size of the phone's back cover, which limits the amount of charge that can be delivered to the battery. It's possible that a phone shaped like a stingray could solve this, but it would be entirely impractical. Another impracticality comes from the need to weatherproof the back of the phone.

"The greatest amount of charge was generated in Kenya, as there was no shortage of sunlight and the phone tester, Amos, who works as a security guard, was often stationary," added the firm as it painted a rather bleak picture of the experiment.

"On the Arctic Circle, by contrast, the amount of sunlight depends very much on the time of year. But even during the light summer months, the sun's angle is relatively low, which means a lot of shadows. If the user is frequently on the move, the phone will receive a fairly low charge."

Results were better when the phone was carried about the person's body, specifically in a holder hung around their neck, however Nokia concedes that this is not the "most stylish or convenient arrangement", adding that "another solution is needed".

We suggest a kipper necktie, with the battery built into the kipper part of the tie. This might be inflexible and rather unattractive, but it would help with the removal of egg yolk or other foodstuffs, which should wipe cleanly off the solar panel. µ