Taking the iPhone off the power grid.

iphonesolarKevin Tofel, an eco-friendly blogger at the excellent mobile-focused website JKOnTheRun has bought himself a solar-powered battery-pack and plans to run his iPhone for as long as he can without connecting it to the mains power.

The charger is a Solio Classic with a 6wh capacity cell. The iPhone has a 5wh cell.

At first glance it seems like too much of a challenge. Looking at the solar cell area and comparing it to my own 25W panel which measures about 1m squared tells me that this device is going to have a tiny sun-capture capability. Looking at the FAQ on the device gives a few clues:

It takes 8-10 hours to fully charge a Solio from the sun. With peak charging times between 10am and 2pm, it takes a minimum of 2 days to fully charge a Solio.

8-10 hours for a 6Wh battery is under 1W of solar capture, under ideal conditions.

It’s winter in Philadelphia right now so I guess we’re looking at an average 60% sun-power through the peak hours which means it will take about 3 average days to charge the solar unit. Taking into account that about 20% power will be lost on cross-charging I’d estimate that Kevin is going to struggle to get a full charge every three days.


2.5G Smartphones like the first-gen iPhone that Kevin has, can easily take 2W of power when driven hard. So if Kevin isn’t careful. he’s going to be out of power in the first day but it looks like he’s done his research and is well on top of the challenge…

The strategies…let me go two days without charging my iPhone however, and that gives me two days to capture sunlight with the Solio. I guess if we have a three-day rainstorm, I’m out of luck.

The interesting part of the experiment will be to see what type of usage Kevin gets out of the device. Will it be voice only? Will he be able to use regular email polling as he’s planning. Will he use it as a mobile internet device or just as a voice phone?

It’s clear that this isn’t the best way to save energy given that the $75 Euro initial costs that could power an iPhone non-stop for about 40 years (*1) but these sort of experiments, this sort of publicity and the resulting discussion is exactly what’s needed to stimulate development and improvement of consumer solar solutions.

I don’t get many readers on this blog but from the responses I’ve had over the last year or so I know that many of the readers here will have already thought about this. Perhaps you’ve already done it? If so, what devices did you use and how did it / does it work out for you?

Track Kevin’s progress at JKOnTheRun.

(*1) Assuming the iPone takes a (very high) average drain of 1W, $75 would buy something in the order of 500kwh of household power. With an AC adaptor efficiency of 80%, the $75 over 45 years of iPhone usage.

  • Bob

    Good for Kevin!!!!
    I have my whole home powered by Solar so I know what he’ll have to go through on cloudy days. I’m writing this on my Mac Book running off an inverter along with everything else. You can see my Solar Home website at http://www.coppermountainmesa.com/solar1.html

    PS it might be good to try two batteries; be charging one as you use the other.


  • Claudia

    I use the PowerMonkey/SolarMonkey combo myself, and it works great. There’s even a more powerful version that can be used for equipment that needs more than 5V, like laptops — the SolarGorilla/PowerGorilla.

  • Documentally

    I was excited to get a solar case but soon disappointed. I ended up taking a freeloader and a powermonkey into the wilds of Scotland to test for a week and found the Powermonkey worked pretty well with mainly web use and a few calls.


    Cheers for a great blog.

  • Chippy

    Keving wrote up his conclusions here.
    He learnt a lot and and thank goodness people like this write their experiences down so that we can all learn.


  • Bryan

    I’ve been playing a game at urgentevoke.com and one of my missions is to find a cheaper and more environmentally friendly way to power an everyday appliance. Since my iPhone is about the most everyday appliance I have I would love a solution that worked with it. The statement “It’s clear that this isn’t the best way to save energy given that the $75 Euro initial costs that could power an iPhone non-stop for about 40 years” I think this option is out. Does anyone have any cheap DIY ideas that would get me the current I need without the grid?