When Will a Cell Phone Run on Solar Power?

When they take off all the extraneous cr4p and make it just a simple phone.
Del

well, you need about 4 watts to run a cell phone at full power, so in direct sunlight you need about 20 watts of sunlight at 20% conversion efficiency.

At about 1000 watts per square meter (~10 square feet), a small solar array of about

0.2 square feet effective would suffice. Keeping this array in the sun and at the right angle means that a one square foot array based on a stetson hat pattern coupled with a battery would work. Depending on the duty cycle, % solar light, etc., smaller arrays would suffice

4W seems a lot...
I wonder what the minimum power requirement is? A conventional phone doesn't have a display... soooo, if we just had a keypad, mic, speaker and the important bits.
Del

How easy is it to charge a cellphone using sunlight?

Dead easy, Plug your charger into a solar (fossil or realtime) powered source.

Chance of solar powered cell phone is remote because of solar cell efficiency ranging around 14 to 20% but I have seen MEMS based solid oxide fuel cell which will recharge battery and may replace the battery itself.

Apple is working on Solid oxide fuel cell which they intend to test out as beta for computer and if it is good for computer it will be very good for cell phone.

Lilliputian Systems is having MEMS based potable solid oxide fuel cell which will be in market in 2014 and will make cell phone to work 24/7