Solar Powered Cellphone A True Hack

The polished quality of this hack isn’t quite there, but we love the ingenuity and exploration exhibited. [Paulie1982] shows us how to make an old cellphone work with the rays of the sun.

You can see above that he’s added photovoltaic solar cells to the back case of what looks like an old smart phone. He grabbed the cells from two inexpensive solar landscaping lights and inserted them by cutting holes in the case and using black silicone sealant to glue them in place. Each can pump out about 3V and together they get above the 5V threshold that he needs to do some charging. See the build process in the video after the break.

From what we’ve seen there’s zero consideration of current in this hack and that’s what makes us skeptical. Still, we love the idea of trickle charging and we’d love to see some speculation in the comments about how to improve upon this. Surely the additional hardware necessary for proper regulation, etc. could be fit in a custom case cover like the one used for this inductive charger hack.


34 thoughts on “Solar Powered Cellphone A True Hack

  1. I love this concept. 2 questions though.

    I know cell phones take 5v, but he’s got 6v in the sun. So I’m assuming that this is safe?

    Secondly, is it doable to take 4 of these and put them on a separate box? I know this isn’t AS portable, but does it offer a quicker charge since it’s more voltage?

  2. I think leaving your phone in direct sunlight might overheat the phone, not to mention the heat generated while charging.
    My phone shuts off if it gets too hot.
    Maybe if you shut the phone off first then charged it in the sun it would be ok.

  3. I’d rather see cheap lion batteries like those from a power tool used on a bigger cell (or cells combined into a panel) to charge the phone more “normally” ie – usefully; faster than it drains.

  4. I prefer the mintyboost coupled with an Ikea Sunnan solar battery pack. The two appear to be made for each other…then you can also charge anything with a USB charger.

    Nice thing about that is that the battery pack can be in the sun all day while you have your phone in your pocket.

  5. interesting coincidence; i was just experimenting with garden lighting solar cells.

    the glass ones were producing 3v at 40 mA… enough to run an ipod shuffle at best.

    the plastic cells are much better. the ones i have appear to be composites of off-cuts of silicon solar cells wired together. if i recall, they were outputting 3v at about 100mA.

  6. as stated by others, this thing has two drawbacks that make it useless
    -it sits in the sun gettting really hot which will probably kill the battery more in he long term
    -it charges too slowly to be useful for anything

    my choice would be to use a panel that coul charge something like the minty boost, but without being stuck on it and being required to leave the batteries in the sun.

    Some people seem to have poor understanding of facts…. Like i remeber the guy who thought it would be a good idea to put solar cells on cilindrical AA batteries and leav them out for a charge in the sun…

  7. Current pocket-sized solar cells are not efficient enough to be useful for anything but the most constantly-sitting-in-the-sun / able-to-run-on-a-few-electrons applications (which garden lights are an excellent example, and cell phones are an excellent counter-example of). Unless you go on long hikes and need some sort of independent charging source – no matter how weak – solar cell won’t do much for you.

  8. @Life2Death

    I’ve just built something of that caliber.
    I used recycled 18650 li-ion cells pulled from old laptop batteries (2 in parallel, 2600mAH per cell) with a standard mintyboostkit. The cells are in a snap in holder, so I can charge a set and use a set. I also just received a solar cell in the mail today which I plan on adding to the device to trickle charge the pack.

  9. the phone is a samsung gt something or other its a cheap touch screen phone and its not very smart, it doent produce much heat when used so all in all make a good candidate for glueing a solar pannel to the back. but no regulation on a li ion battery he must hate that phone as much as i did when i had it

  10. RIM (Blackberry fame) already produce a commercial solar charging case for some of their models. It would have been better to make a case like that rather than stick bits to your handset…

  11. hmm makes me think whether the hand driven generator from my LED camping light would have enough power to charge the phone.
    But most likely I’ll be bored or tired long before having charged my phone to any significant degree.

    I have one of these seperate solar cell packs with an internal battery. Leave it in the sun the whole day, and it can charge my phone once. I think this works better, since I like to have my phone with me.
    Works great when you are away from a convenient wall plug (I like to go sailing, the completely unpowered kind)

  12. It seems like a more workable solution would be to keep the solar charger separate and simply rotate multiple batteries through the phone as needed.

    However, there is always value in the journey one takes down these roads, so I hope everything works out ultimately.

  13. Neat hack. I like it because it’s permanently stuck to the phone and it’s just enough of a backup to get you going when you need it. I know if I were going to go hitchiking abroad again tomorrow, that’s exactly the sort of thing I would be doing today.

    To those suggesting the mintyboost kit, that’s fine in first world countries, but I bet you never tried getting genuine alkaline AAs in India for example. And having a solar panel out all day is fine if you are lying on a beach, but normally if the sun is out, it’s hot so you want to be indoors.

    Most cellphones are fine with unregulated charging voltage. If you connect a Nokia to one of those hand cranked torches for example, you can feel the phone slowly modulating the current as you turn the crank.

  14. Considering this project, a better approach would be to create a custom (smart)phone carry case / bag, with some side cutout and there placed the solar cells.

    This way it might reduce some of the heating and also the system would be more robust.

    And, as an improvement, the cells could be detachable so that these could be placed directly in the sun (without the phone).

    Just don’t use too tight pockets or it may break the cells.

  15. Guarentee it will not work to run the phone but to trickle charge the phone. that solar cell is far far too small to deliver any amount of power.

    And why not do this to a case cover?

  16. Or get a phone with a small screen that works for one week without a recharge and carry a replacement battery that goes another week.
    If you’re in the wild for more than 2 weeks without power, you shouldn’t rely on improvised stuff.

  17. I built system with solar panels charging AA’s that charged cell phones. The project idea came from when I’m on the road working but I can’t really have my phone sitting away from me if its dead. I had beefier solar panels though. You could also use the solar panels that are thin and can conform to the shape of the case.

  18. My approach was to use a large camping-lantern pv cell (the lead-acid battery had long ago gone bad, and no replacement could be found). The cell is approx. 4″ x 8″, and already encased in a sturdy plastic frame.

    I directly wired the output voltage of the pv cell to the INPUT of the ac-adapter for a powered USB 1.0 hub. ( found at a garage sale, discarded, 50 cents.) 4 ports of +5v, because the inverter INSIDE the hub ensured that when the PV cell is putting out > +5v dc, it is limited to +5v. (excess is converted to heat – radiated at the rectifier’s heat-sink.)

    In practice, however, I mounted the cells on top of my backpack, my iPod in my pocket. 8-hours on pine-shaded trail yeilded a 50% battery charge for my nano. When I was hiking above the treeline, results were better.

    This solution did not work for an iPhone, because the phone b*tched about “unauthorized charging device attached”.

  19. @Niru iDevice charging authorization can often be spoofed by resistor dividers between +5 and GND delivering specific voltages on D- and D+. The amount of current an iDevice draws can vary with the voltage setting. We tried D- = 2.5 and D+ = 2.0 with 50k and 100k resistors and the iSink tried to take 500+mA. YMMV. Google: resistors unauthorized charging apple.
    But do not believe all the exact voltages you read about.

  20. i made something similar to this, but i had issues with it turning on the backlight when the phone detected it was charging, which used more power than i was getting from the panel. i also had issues with the phone not charging and giving a warning message if the voltage went above about 5.5v.

  21. Looks like a Samsung Tocco Lite – these get quite hot sometimes when in use, and they do shut off when they get too hot.

    Sunlight will also kill them. It killed mine!

  22. Here’s what I got. Currently I have 6 12 trickle chargers that are paralleled into a charge controller that feeds a standard 650 cold cranking amps (it doesn’t start a car, but does charge up to 14 volts). I have the charge controller mounted in an old (dumpster rescue) alarm enclosure. I mounted a 12 volt cigarette lighter socket on the side of the enclosure (due to spacing configuration). I can use that 12 volt socket to power anything 12 volts including using car chargers for phones. Now with the right size of a 12 volt trickle charger, one could use one of those, glue a enclosed 12 volt socket to the back of it (might help angle the solar panel more then just laying it flat, better charge you’ll get) and use standard car charger for you phone to charge the phone. Even make a mount for a phone under the trickle charger. phone is in the shade, and the solar panel soaks up the sun to charge. Just another idea, not saying it’s the best, but there are a hundred ways to do this kind of thing. Oh the batteries and solar panels and a day of using a car to charge the batteries quicker then those 6 (well 3 at the time) trickle chargers kept a 3 amp glow rod fired up to keep a propane oven running all day to have thanksgiving diner on thanksgiving (wife didn’t want to wait a day). 8 )

  23. my thiking is if solar cells used in scitific calculators works successfully.then why we can’t implement the same to work a cellphone battery for emergency purpose.this idea can be implemented using dual battery in the battery which is used like a normal battery in the cellphone.the other can be used to collect charges whenever the light falls on it.whenever the cellphone is switched off and on the secondary battery which store charges by light should be activated.hence the solar cell that used in calculator of dimensions 3.5cm length and 1 cm height can produce to activate a cell phone battery we need 3.7v .if we connect eight single solar cell in series means we will obtain 4v.hence it is enouge to activate a secondary battery

  24. Well said, but everyone needs to realise that adding Solar to their property is an asset that could increase the longer term valuation of their residence if / when they make a choice to sell. With the environment the way it is going we cannot overlook any product or service that offers totally free electricity at no cost to both the consumer and more significantly the world!

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