Value in incorporating solar panels in a mobile phone?

[nemo]

Originally Posted by ecomodded

I think its a good idea, it can keep a phone ready for use if sits turned off most of the time.

Enough to keep up with standby losses would be great.

Tablets have a lot more real estate.

[UltArc]

Heat's a factor I considered, but I have never had the X or the G overheat.

I imagine the exterior could get hot if in direct sunlight for a while. I see the issues in it, I still think it would be of value to incorporate small panels. Between the minimal cost, and over the life of the phone (for people who don't upgrade every six months), it would be worthwhile.

James, I like the numbers. I know there are some people here who know them. It's not hard to research it, but KNOWING what it means in real life takes more than an internet search- so thank you, sir.

[Cobb]

Ive had a few solar cases and battery packs. Its my experience they need direct sun light from an untinted plate glass window to charge. I imagine one can build the solar panel to be worth while in office lights or sun light thats been filtered through a triple pane, bullet proof, etc office window it could at least negate standby if not maintain the current power draw.

[UltArc]

My garbage junk from China for $17 dollars ( I complained about the lies in capacity, and they refunded me $11, so now it's $6) seems to always be drawing power. Although I leave it in my car, when I had it inside it still seemed to be charging whenever it was remotely near a window.

Guys, keep in mind I don't mean for this to be the only way it charges, or for it to be a huge breakthrough to revolutionize the phone industry. I just think this would be a good use of resources. Not great, but we could bring some power back to the phone while just being out. I'd much rather have this then a heart rate monitor. I have fingers and a pulse, I don't need that junk. Scanning my finger to unlock my phone? No thanks. I have a passcode, and GPS enabled and tracked incase it ever disappears. Not needed.

[2000mc]

Yea, it was silly of me to assume a solar charger with a claimed 30000mah capacity would be some large external device, and instead of just saying, "why not a case?" To just throw out a link, and assume it was about something you wanted to try have yourself, in addition to what oems could try.
To actually address the question though, I think for most users the space taken by a solar charger would be better spent on a slightly larger battery

[jamesqf]

My point wasn't so much that solar on phones would be useless, as that there isn't enough energy in ambient indoor lighting to really charge much of anything. Most people don't appreciate the fact that the eye has a very nonlinear response to light: indoor lighting may appear about the same as sunlight to you, but in reality the sunlight is maybe 100 times as intense. Lux - Wikipedia, the free encyclopedia

Now if you're out camping, say, and leave your phone out in the sun, then solar would be useful. But how many people do that? Most keep their phone in a pocket or purse most of the time, and even if left on a table or desk indoors, the charging would be miniscule. Much more cost-effective to have separate solar chargers (which could charge/run any USB-powered device) for those who need such things.

[Cobb]

+! I have solar panels and toys in my window. Its creepy at times how the solar toys can slow or even stop when it still appears sunny out. Ive also had situations right before sunset where they perk back to life. I dont see anything different, but Ive assumed its a different wave length or something.

Hell, Ive spent a few hours laying under my solar array with a vom just taking readings and notes. Same thing, the poly crystal cells behaved one way while the monocrystals behaved another.

If you want to use ambient light to extend the run time of your phone you need to measure the light and design the solar array after it.

Originally Posted by jamesqf

Most people don't appreciate the fact that the eye has a very nonlinear response to light: indoor lighting may appear about the same as sunlight to you, but in reality the sunlight is maybe 100 times as intense.

[redpoint5]

Originally Posted by jamesqf

My point wasn't so much that solar on phones would be useless, as that there isn't enough energy in ambient indoor lighting to really charge much of anything. Most people don't appreciate the fact that the eye has a very nonlinear response to light: indoor lighting may appear about the same as sunlight to you, but in reality the sunlight is maybe 100 times as intense. Lux - Wikipedia, the free encyclopedia

Now if you're out camping, say, and leave your phone out in the sun, then solar would be useful. But how many people do that? Most keep their phone in a pocket or purse most of the time, and even if left on a table or desk indoors, the charging would be miniscule. Much more cost-effective to have separate solar chargers (which could charge/run any USB-powered device) for those who need such things.

Yes, exactly. Hence, useless.

Using solar indoors is only worthwhile for calculators that need minuscule amounts of power to run.

A solar panel covering the entire back side of a smart phone and "charged" indoors all day might give it 10 seconds of extra run time. There is no way you could even approach maintaining charge on a phone that is on, but idle.

Here's the math for my office:

30 fluorescent x 28 watt bulbs = 1008 watt
40ft x 36ft = 1440 sq/ft room
1008w / 1440 sq/ft = 0.7w per square foot
Fluorescent energy to light efficiency is 11% at the high end
0.7w/sq/ft x 0.11 light efficiency factor = 0.077 watts of light per square foot
Solar efficiency is 30% at the high end
0.077 w/sq/ft x 0.3 solar efficiency factor = 0.0231 watts of power per square foot of solar panel
iPhone back side area = 0.087 sq/ft
0.087 sq/ft x 0.0231 w/sq/ft = 0.002 watts total solar power

If I turned all the lights on in my office and the back side of my iPhone was entirely covered with the most efficient solar cells available, I would be lucky to get 0.002 watts of power.

My iPhone has a 5.3 watt/hr battery. Lets generously say that at full charge, it can sit 48 hours before the battery is dead.

5.3 Wh / 48 = 0.11 Wh consumed per hour.

0.002 watts of solar power divided by 0.11 watts demanded by phone = 1.8% of the total power used by my phone on, but sitting idle.

Maybe your office is brighter than mine.

[Cobb]

And that's assuming the phone or tablet is face down. Most of my coworkers have it face up.

I guess laying the charger/case face down on your dash board or window sill if you happen to have a window seat?

Now an office I use to work in we had to keep the blinds below the pelvis for fear of snipers.