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Nokia: the Sun Can't Charge Your Phone
itwbennett writes "Nokia's research into solar-powered cell phones ended with a (barely audible) thud. Under the best of conditions researchers were able 'to harvest enough energy to keep the phone on standby mode but with a very restricted amount of talk time,' Nokia wrote in a blog post on Tuesday. Not surprisingly, the prototype phone, which had a solar panel on the back cover, performed better in Kenya than in other testing locations, like southern Sweden and the Arctic Circle."
You can get 0.5W panels about the size of a smart phone for $2.00. considering they only have a ~5w/hr battery it should be possible to get an 80% charge in 10 hours. The problem being that solar power drops significantly when not in direct sunlight, partially covered, through glass, not perpendicular... etc.
Over 3.5 years for me (by the numbers in that link) - my phone does a discharge/charge cycle once a day basically.
It's hardly suspiciously low.
My phone has a battery in it with 3.7V and 1300mah. My old high school memories tell me that P=IV, so 1300mah*3.7V = 4.8Wh. My electricity bill says that the distribution charge is $0.0654531250/kWh and the energy charge is $0.113187500/kWh (more expensive than the original calc used, and by lord how many decimal places do they want to use...)
So one charge would cost if that was the price of abstract electricity:
(0.0654531250+0.113187500)/1000*4.8 = $0.00086
So $1 gets me 1166 charges, at once a day that's 3 years (Wh are likely higher due to the voltage actually being higher when fully charged, but we have enough slop over 3 years to cover that).
The charging efficiency while not 100% is high enough that it is more than covered by the fact my phone doesn't actually get to 0 charge each day - it tends to have 25% or so left.