It’s Not Easy Being Green: the Solar iPhone Experiment


solio-classic-in-windowEarlier this month I took up another one of my wacky challenges. I took one for the team and decided to try and keep my iPhone off the grid. I wanted to see if I could run it strictly off solar power for 30 days and not use the AC adapter. Sure, it’s a very small token movement to use renewable energy and it’s not going to save me any money. I have no misconceptions there, especially after spending $99 on a solar charger with an integrated battery.

Since I was in the Valley of the Sun this past weekend, now is a good time for an update on the experience. Oh boy, has it been an experience.

So I’ve learned quite a bit in the past few weeks. Actually, some of this I already knew, but the experiment strongly reinforced a bunch:

  • Never start a solar experiment in the Northern Hemisphere at the start of the winter season.
  • Small solar panels = small amount of charge.
  • Small solar panels without a sunny day = no amount of charge.
  • The term “direct sunlight” actually means direct sunlight.
  • Three consecutive cloudy days is a killer. Four and you might as well run around outside screaming “the end is near!”
  • The Earth apparently rotates. As in around the Sun. (You can look it up, if you don’t believe me.)

OK, so I’m being a little facetious here, but that’s because the experiment has been an exercise in futility for the most part. Actually, the challenge hasn’t failed because the of the Sun; it’s a viable energy source that provides around 1.3 kilowatts per square meter. Yup, I learned that too along my sometimes illuminating journey. No, the challenge has essentially failed because of the approach that I took.

Let me start my explanation with a comment about the Solio Classic hybrid charger that I purchased. Unless you live in an equatorial area of the planet, this device isn’t meant to perform the hefty duties I asked of it. The Solio does work by capturing and storing solar energy in its 1650 mAh battery. But it can also store energy it pulls via the AC adapter, which gives it the hybrid name. Solio says it “provides an emergency power source when away from power outlets” so it’s better suited for just such a purpose and not the one I tried to use it for. Put another way: the product didn’t fail per se; I set it up to fail.

Before bed each night, I set up the Solio in my office window by using the included suction cup. I figured that it would be grabbing power from sunrise until lunch, since the Sun is positioned there during those hours. Not exactly. I noticed that the Solio’s red charging light wouldn’t come on for the first hour after dawn. There just didn’t seem to be enough light or light with enough intensity during that hour.

I also realized that having the Solio on the window wasn’t optimal after mid-morning. No problem because the Solio has a hole right in the middle of it: simply stick a pencil in there to prop it up and direct it at the Sun. That certainly worked well enough, but I found the charging light to be on for 20 to 30 minutes at a time. Apparently, Jean Bernard Léon Foucault was correct in that the Earth rotates around the Sun, a fact that was omitted in the Solio manual. OK, I’m joking about the manual bit, but I’m not joking about how often I had to reposition the Solio to ensure it was charging. By lunchtime, it was back to the suction cup on a window, only this time, the window was on the western side of my house. As a sidenote to cat-owners: be sure you wet that suction cup really good. The Solio can fall in a delayed action later in the day, thereby causing your cats to use up one of their nine lives.

Long story short: the device works but you may need to work harder to make sure it works. Follow?

Now about this thing we call “winter”. It greatly reduces the sunlight a solar system can use. I think it’s just a cruel trick of nature but some scientist types believe it has to do with the Earth’s axis. Regardless of the reason, it’s not conducive to efficient solar power of the photo-voltaic kind. The Solio needs a good 8 to 10 hours of solid sunlight for a full charge and winter likely doubles that, depending on your latitude and independent of your attitude. I know this because I kept offering positive reinforcement to the Solio. It didn’t help the Solio or me.

All this talk of the Sun reminds of things that get in the way: clouds. I found that with the small solar panels, even the faintest wisp of cloud vapor could extinguish the red charging light. I’m sure there was some charge generated, but it was likely so minuscule that it didn’t register on the LED.

So the experiment was generally a failure, but in hindsight it was likely doomed by my expectations and poor planning. Does this mean that I’ve given up? Not at all, but I’ll need to reassess my approach. I actually still haven’t plugged my iPhone into its AC adapter. On days I was out and about, I placed my iPhone in a Kensington car charger I use in my 2005 Toyota Highlander Hybrid. That’s certainly not the answer I’m looking for, but it helps decrease my electric grid consumption. Yes, the Hybrid puts pollution in the air (although it’s rated a SULEV) and requires gasoline to run; I’m not forgetting that by any means and I’m not suggesting that it’s a “better” solution. It isn’t.

What might be a better solution is a good hard look at my solar energy collection method. I already have a portable 20 Amp hour battery that I purchased to store energy. One of our jkOTR readers, Bob, wrote me several times during the challenge to help me learn more about solar. He pointed out that my portable battery solution can be charged by a solar panel of up to 30W. A little searching on the web shows that a panel like that can be had for around $175 new, less on eBay. I have looked at solar panels that unroll but they’re far more costly on a per Watt basis.

The benefit of a larger solar panel would be that far more solar energy can be captured and stored by my Xantrex battery solution. I could charge a much bigger battery in less time and I could use it to power far more devices for longer thanks to the integrated dual three-prong AC outlets. Unfortunately, the battery doesn’t offer enough juice to run my MacBook on a full-time basis. Unless I did the numbers wrong using the Xantrex online calculation tool, I’ll only be able to run my notebook for about 1.5 hours on stored solar power with this battery.

So what’s to become of my Solio Classic charger? I’ll still be using it, but not relying on it for the sole power of my iPhone. I can leave it in a window for several days without a thought and grab it for portable power on the go. When fully charged, it does fill up the tank on my iPhone and it still has a little juice to spare.

As I mentioned before, these experiments are about the journey and not the destination. I’m still looking to arrive at the same destination, but I’m glad the journey continues. It offers me the opportunity to learn even more.


J. Boedo

I am a bit confused about your report. Did you actually put this thing inside the window? Outside? If you put it inside, then the window’s glass is probably absorbing a large amount of the energy in the sunlight. Most of the UV, the most energetic part of the light is probably gone. If it is a double pane window, then part of the infrared will be gone as well.

Steve 'Chippy' Paine

Well done on the Solar experiment.

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.


Sam Trychin

Kevin —

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…


Kevin C. Tofel

All good commentary, thanks! I’d consider a windmill if our area had more breeze. Even if it did, I don’t think our homeowners association would allow it.

Brian Goodwin

Thanks for helping raise interest in Solar.

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.

Gordon Cahill

Well done Kevin. Sure it wasn’t all roses and as you can see, alternative energy still has a long way to go. But it also shows that in time, with some effort, we can clean our selves up. We’re going to have to as, regardless of the environmental arguments, eventually we’re just going to run out of coal and oil.

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.



The problem with photovoltaic panels today is that they are extremely expensive, while being terribly inefficient.

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.


Kevin, the start of winter is actually a good time to start a solar experiment. Dec 21, the official start of winter is also the shortest day in the year. As winter progresses the days actually get longer… not shorter as you stated.

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.


Regarding the title of this blog post: I wonder if buying a product like this is ever going to be “green” enough to overcome the overall environmental impact that producing and shipping it to the retailer/consumer has.


I have been using the Power Monkey to power my blackberry here in NJ and yes… direct sunlight is best, but the panels have seemed fine enough to grab enough power from the rays to keep the battery unit half charged (enough for 1.5 Blackberry charges).

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


Well I’m sorry about the failure (you made it pretty clear that you wanted this to work. But I’m glad your trying it again. Better luck next time.

I have a question though, has this experiment changed the way you think about solar energy?

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