Experiments like these are great learning experiences and if we can all watch and learn from you at the same time, it’s nothing you could ever call a failure.
Looking forward to your next experiement.

Steve.

Please excuse the repetition… but it sounds like the conditions of your experiment were very similar to the conditions under which I was able to successfully able to charge my cellphone using a folding solar panel:
- Late March / Early April in Japan (overcast, rainy, not much direct sunlight).
- Charged a Nokia N95 8GB battery in ~1-2 hours (I’m assuming similar capacity to the iPhone’s)
- Setup: Sunlinq 12W folding panel –> car adapter charger –> N95 (no auxiliary external battery).

The setup was surprisingly good at charging small devices (smaller than laptop) in northern latitudes w/o much direct sunlight. The panel is lightweight, and can often be had for ~$150 on EBay. Just in case you want a halfway compromise between a full-sized glass panel and the tiny portable panel you started the experiment with…

Tx,
Sam

It can be done on a small scale in an affordable manner…if you approach it as a fun hobby. I have been running my office with the solar power for about a year (charging cell phones, bluetooth headsets, running radio, printers, notebook computer, etc). Total cost? I invested $78 in the stuff…and have saved $10 to $15 a month off our electric bill. So, I am ahead. I do have the unfair advantage of living in San Diego….where the sun shines strong nearly every day.

How did I do it for $78? I have a motley collection of panels that total not much over 100 watts. I got each of them for free…or near free. My best is a 20 year old monocrystal 45 watt panel I found at a garage sale….and talked the guy down to $10 (burned out diode was easily replaced). I have five old car batteries that were being thrown away by their owners….properly cleaned up they have worked great for over a year now.

I stay up on the technology and am excited about all the advancement in panel technology of the last year or two…. Though my efforts have been nearly free so far, I would be willing to buy a proper 3KW system to take my home entirely off grid. Hopefully ever improving cost per watt panel technology and increased tax incentives in the New Year will allow it in the next few years.

As far as the car goes, I have a cigar/accessory socket wired directly to the battery. So my iphone charges whether the motor is running or not. And as far as i’m aware it makes no impact on fuel consumption when recharging the battery in the car. I’ve done this for about five years now and also had no adverse effects on the battery in the car.

Gordon

A typical 5×3-foot residential 200W module costs $1100, and only converts 20%-30% of the sunlight it receives. Insanely advanced panels such as those used on the Mars Lander would top out at 40% efficiency at best, and cost more than you want to know.

Assuming your house consumes a measly 2kW hours during the daytime, you would need 10 of those residential modules costing you around $12k for the panels alone. That does not take into account installation costs, associated hardware, government rebates and the fact that you still need a power source at night. Assuming a 25 year module lifespan, that $12k breaks down to $40/month. With power rates going between 7 and 30 cents these days, that same $40 could buy you between 150 to 600 kW hours of “dirty” electricity each month.

You would need to invest in a substantially larger 20kW-50kW solar array, spread that cost over 25 years and generate more power in the daytime than you use to see any real impact. If at all, your real savings would only begin after the first 5 years at best, or 25 years at worst.

Bottom line – solar power is up to 10 times the price per kw hour, and until their efficiency improves and panel prices drop, dirty electricity will remain “dirt cheap”.

I’m all for solar power, but unless someone gives me a couple thousand bucks and a house with a huge south facing roof slope below the 34th parallel, it’s simply more trouble than it’s worth.

In any case I’d be surprised if the amount of carbon saved by solar charging an iPhone ever exceeded the amount of carbon expended making the $90 solar charger… one complete re-charge is roughly a 1/4 pound of coal burned.

Do not know if that would be enough juice to keep an iPhone charged though.