Introduction: DIY Solar Phone Charger ($5 Battery Free - UPDATED!)

Picture of DIY Solar Phone Charger ($5 Battery Free - UPDATED!)

Here's a real quick and easy tutorial on making a "Portable Solar Phone Charger", it only took me 5 minutes to make one! It's powered by PURE solar energy. The device is designed to fit right into your pocket, it also comes with a built-in stand! Works with apple devices (tested on iPod Touch and Quadcore Android Phone)

How Does It Work?
Solar powered chargers and powerbanks are pretty common these days. These devices usually have battery reservoirs inside them, to cut it short they are not 100% solar powered so as being eco-friendly. These products are gimmicks, they defeat the purpose of being 100% green and eco-friendly. My DIY tutorial will teach you how to make a "100% PURE Solar Phone Charger". Feel free to be independent from the power grid :D

My Review: (Pure Solar vs. Solar+Battery) 

  100% Pure Solar: (Pros)                           100% Pure Solar: (Cons)
   - 100% eco-friendly                                     - Can only charge devices during day
   - No need for charging internal bat.             - May Not Work with TABLETS (High Amp. Devices)
   - Independent From The Power Grid          - Ideal for outdoor use (where sunlight is present)
Solar Power Bank (w/battery): (Pros)            Solar Power Bank (w/battery): (Cons)
   - Can charge high power devices anywhere    - Conatains Lion Batteries (limited lifespan 1-2 years)
   - Doesn't need sunlight (internal battery)         - Not Completely Eco-friendly
                                                                             - Takes a long time to charge internal battery

Step 1: Tools & Materials

Picture of Tools & Materials

The links below are just alternatives since the stores where I bought my parts where just available localy in the Philippines. When converted into PHP to USD the price of my spendings would become $5! It's real cheap. The solar panel only cost me $3.

Materials: (Click on the link to see where to buy)
- 6V Mini Solar Panel
- 5V Step-Up/ Inverter USB Charger Circuit ($3
- Your Smartphone (for testing)
- Your Phone's Charger Cable (Interchangable)
- Flexible and Foldable Plastic Card (for stand)

- Hot Glue Gun
- 30W Soldering Iron
- Leatherman Multitool

Step 2: Choosing Your Charger Module (UPDATED!)

Picture of Choosing Your Charger Module (UPDATED!)

Step 3:

Picture of

The USB charger circuit came from a cheap old iPod USB charger. The main chip is similar to the well known MAXIM inverter chip. The circuit is a step-up/ step-down regulator, meaning when the power supply is underpowered it tends to boost the voltage but when the power supply is overpowered it limits the output voltage. It's ideal for solar powered purposes.

1st.) Dissemble a 12V High Power USB Charger.
2nd.) Cut the wires, short enough to be mounted on the solar panel.
3rd.) Solder the charger circuit to the solar panel (Adding a switch is optional).
4th.) Use a hot glue gun to mount the charger to the solar panel.
5th.) Be sure that the USB port is not protruding and the circuit should not touch any other leads on the panel.

Step 4: Adding the Foldable Stand (optional)

Picture of Adding the Foldable Stand (optional)

I recycled an old gaming prepaid card and bent it with a ruler. I also hot glued it to the right side of the solar panel.

Step 5: You're Done!

Picture of You're Done!

Now enjoy being completely independent from the power grid. I forgot to tell you that I have an interchangeable USB charger cable for Apple 30 pin, Micro USB, Mini USB, Samsung, Motorola, and Nokia, you can find one in your local dollar store. 

You can now carry your own personal solar powered charger anywhere. It's also a perfect survival kit since sunlight never runs out :)))) Have fun! :D


tasosi1 (author)2017-09-02

A 6V solar panel gets around 300mA output in summer when the sun is
bright. Using a step up converter you may get a 5V constant dc current
but best case scenario the current will be converted to around
600-650mA. Meaning that this set up will not work as most modern
androids require at least >700mA to start charging

correction:sun will run out lol

kamhagh (author)2016-08-19

Wouldn't it be annoying if you're in a cae and the sun keeps blocking it? A capacitor is not big enough and battery makes things complicated!aybe i could use 4 bulky ones :D in parallel

Joardey (author)2016-07-23

Guys i am realy interested what you think about this its a device to wire youre phone for free.... you think this is possible???

pictsidhe. (author)2016-07-07

ACAS, please remove or fix this instructable before someone fries their phone.
I'm not sure why you thought to use a step UP USB circuit, but it really isn't a good idea.
Scenario 1, the phone takes charge.
Unless a 10W panel is used, the phone is likely to use all the current it can suck from the circuit, the solar voltage will be loaded down by the step up regulator, probably to between 1 and 2 volts. Solar cells are effectively constant current devices, so instead of putting out ~4V and say 200mA, it will only give 1 or 2 volts at 200mA. That's wasting 3/4 to 1/2 of the directly connected power.
Scenario 2, the phone isnt trying to charge.
This is potentially dangerous for your phone, with no load on the charger output, the voltage WILL RISE TO THE OPEN CIRCUIT SOLAR VOLTAGE. A step up regulator does not have circuitry capable of reducing voltage. I measured my $1 6V 1W panel at 7V yesterday, not enough to damage the old phone I was playing with, but it refused to charge until I shaded the cell to bring the voltage down. If someone used a 12v panel with your instructable, the phone could see over 20V! I'd only test that on a phone I was about to throw away...

To do this properly (and cheaper!):
6v panel
5.1V zener diode of at least the wattage of the solar panel.
USB charging cable. Cut off a charger or cut the supply end off a standard one.
The zener is connected ACROSS the panel, the striped end to positive.
The USB cable is red to panel positive, black to panel negative. If using a cable cut from a wall charger, you're probably done! If there are green and white wires in the cable, connect them together but to nothing else. Insulate them.

Test that in bright sun and not connected to a phone, the panel voltage is about 5.1V. Up to 5.5V is within USB specs.

If it all looks good, plug in to your phone and watch it charge! I use the 'Ampere' app to check charging current.

This is for androids. Apple stuff needs the green and white wires to have set voltages, a wall charger may have that circuitry in the phone plug end, though.

mike.wanthal (author)pictsidhe.2016-07-11

Just have a question. I am working with my kids on a summer project to build one of these. Obviously I don't want to kill anyone's $400 phone in the process.

You state "USB charging cable. Cut-off a charger or cut off the supply end of one". I'm not clear on what you're referring to. Are you implying to just take a USB to Lightning cable and cut the USB end off? I have a USB extender that I would like to use so I can charge either and apple or android device. I assume that will work too.

Based on you comment, the whole USB 5V step-up piece is not required. Correct?

pictsidhe. (author)2016-07-07

Actually, Apples will probably charge at a max of 100mA or 500mA, so worth trying on small panels. I don't know anyone with an Apple to check this, though.

jaimeS32 (author)2016-01-22

I have tried with a 6V 720mA solar pannel and a DC-DC Converter Step Up Boost Module 2-5V to 5V 500mA (the one of the first image on step 2) and the battery keeps going low.

I am a bit desesperated...What do you think the mistake could be?

Thank you all!!!

der0keks. (author)jaimeS322016-07-05

Try 2-3A instead of 0.5. >2A is needed for a tablet.

AmalD4 (author)2016-06-16

Does it need diode??

Builders Shed (author)AmalD42016-06-24

You don't need a diode if you got the charging circuit from a car charger.. it already has a diode.. when you don't have a car charger just buy a 5v step up charging module and a 1N914 diode :D

AmalD4 (author)Builders Shed2016-06-24

Thanx (y)

FrancescoL25 (author)2016-06-19

I don't understand if the step up inverter/charging module is strictly necessary since I've read that all modern phones have a built in charging controller circuit and they are able to manage the ma/h and voltage. So is it true that I could connect a solar panel to the phone straight away? I just ordered a 5v, 4W module.

EmanthaC (author)2016-05-16

Wow really handy thankies :). The link for the - 5V Step-Up/ Inverter USB Charger Circuit ($3 is none existent. http not found . Very cool still :)

JassemU (author)2015-10-01

Hi sir, great tutorial. This is a great help. Btw, you mentioned that you bought them locally, where have you bought your step up boost module usb charger here in philippines?

EdwinLopez930 (author)JassemU2016-04-07

well I guess He was referring to GIZMO near DLSU(TAFT)

GooEvent (author)2016-02-15

if you have problems with charging, check your charger or phone specification about required minimum amps, typically iPhone will require 5V / 1A, an iPad 5V / 2A for correct charging.
The 5W, 10W and 12W chargers are all capable of charging an iPhone. All three chargers have the same voltage output (5V), The difference comes with the amp output (1A, 2A and 2.4A)
So when designing your solar powered charger, you have to be aware of the required voltage (5V) and amps (1-2A) incl. watts (5-10W)...

JanR31 (author)2015-12-02

i want to disassemble my old solar power bank(btw the solar panel is 0.7w, the input is at DC 5w 500ma and out put is DC 5.5w 500ma Capacity 2600mah) i want to upgrade it cus its ports are ancient (its a mini usb B it think ONLY) and i dont a charger for it and i cant buy it anywhere so can i use the 0.7w solar panel instead of a 6v solar?

and im also a noob at this so pardon me...

TheNotoriousHoppington (author)2014-03-06

I did a very, very simple version of this, by simply gluing a Powerbank to the back of a 4.5 V solar panel. The output from the solar panel goes into the Powerbank, and then when I want to charge something, I unplug the panel from the Powerbank, and plug my device in. However, I feel it's not charging properly, and also, I want to find a way to put a display of the power output on it. Any suggestions?

Hi,i was trying the same thing, is there any solution you found ?

yhdesai (author)2015-02-01

i used 7805 and my phone started discharging and it showed charging

your polarity may be reversed with the usb pinout

what? polarity reversed? are you kidding me?! :D .. its because the current flowing through it is enough to see that is "charges" but the actual consumption of the phone itself is much higher... so your phose lasts longer instead of really charging it up. I think it would help if you shut down your phone.. also is a good idea to connect it to a little power bank instead directly to the phone, because the sunshine isnt hundert percent of the time shining so it would lead to charging on charging off and so on and this isnt good for any battery.. so better destroy some power bank instead your internal battery

i reversed polarity then nothing happened
it didnt show charging nor it charged

iDefine (author)2015-10-18

that old as game that i used to play before CSGO lol Special Forces

SabariS1 (author)2015-10-04

so nice.I like it very much......

bwash70 made it! (author)2015-08-19

I put this together but although the power is getting to the USB booster it's not charging my phone. Any ideas?

bwash70 (author)bwash702015-08-19

Oh no, it's working. Just took 20 minutes for the charge to 'warm up'. No charging iPhone 5. Awesome.

IstvánG (author)2015-07-25

I have built the circuit, but the percentage of mobile battery - during charging - less and less. I do not know why? Everything works, the step-up / inverter LED lights, indicating that the cell is being charged.

brennervate (author)2015-03-30

So I'm using two 2.5 V 500mAh panels and a step up converter and I'm getting a reading of ~6V and ~1 a A across my board when in the sun but my iPhone isnt acknowledging it when plugged in. Any thoughts?

amir hosayns (author)brennervate2015-07-07

you should see information on your charger then if it was necessary use a regulator!!!

try new thing!!!

draxema (author)2015-04-21

isn't 120mA (from the panel you linked) too low to charges big devices like a phone?

Rand0mUser (author)2015-04-21

Hmm... a boost circuit? Surely a buck-boost would provide more power? It's certainly not a great ideas to feed a maximum of 6v over USB - many devices expect an almost perfect 5v from it.

BrownDogGadgets (author)2013-06-15

How are you able to use a 12V charging circuit with a 6V solar cell? That doesn't seem to make a lot of sense. Wouldn't it be easier to use a DC to DC boosting circuit instead?

ASCAS (author)BrownDogGadgets2013-06-17

If your'e familiar with the joule thief, the circuit almost acts just like it except there's a regulator feature.

BrownDogGadgets (author)ASCAS2015-03-06

I was under the impression that 12V car systems were step down regulators, whereas a Joule Thief is a step up converter. Thats why I'm confused.

All the car USB adaptors I've pulled apart have lacked the necessary circuitry to handle voltages lower than 12.

mueblesdejardin (author)2014-10-14

do you know if you of these parts could be bought online?

curiouser1 (author)2014-09-13

I am totally new to this stuff :) Can someone please tell me if it is meant to use the disassembled usb circuit or one of the things in the picture on this page? Or I am to somehow use both? Thanks so much for helping me to understand!! :)

playboysbend (author)2014-08-27

It doesn't work with my Iphone 4s and my ipod touch...

Mr_Rep (author)2014-08-25

My plan is to wire two in series to the guts of a ciragette lighter style car charger since it's got the 5v regulator USB connection. Will this work?

eagletz101 (author)2014-07-18

Please let me know where did you buy the items locally in the Philippines. I would like to know. Thank you.

Daniel Amaldas (author)2014-06-29

Hi, great instructable! question. does the voltage monitor screen turn off or does it constantly stay on? because I would like to just press it if I can and it appears for a few seconds and turns off, to conserve power.

jtagnepis (author)2014-05-19

Pre saan ka nakabili ng parts sa pinas sabihin more yung part cost tapos kung Satan more binili ex
Solar Panel P120 cdrking fairview

jtagnepis (author)2014-05-19

Pre saan ka nakabili ng parts sa pinas sabihin more yung part cost tapos kung Satan more binili ex
Solar Panel P120 cdrking fairview

pgrferrari (author)2014-05-05

Can i also use this solar panel?

cnelson17 (author)2014-04-29

How long does it take to reach full charge in optimal conditions? Will this also work for android phones? Does the step-up inverter boost charging time?

andrea biffi (author)2014-03-14

I didn't realize that my last solar projects were unconsciously inspired by your project of one year ago, indeed I had it in my favorites :-) but I didn't remember that! Well done, awesome project!

fbiletta (author)2014-03-02

No, I just soldered those two components with wires, as you did

fbiletta (author)2014-03-02

Hi, yesterday I connected tis solar panel ( with the first charging module of the step 2.. But it doesn't charge at all my iPod, but the strange things is that my Nokia lumia, when it's connected, show the charging icon on the battery as usual, but it doesn't charge a bit, even after 2 hours. What should I do??

ASCAS (author)fbiletta2014-03-02

Do you have the booster circuit installed?

About This Instructable




Bio: Hi I'm Angelo! I am a 18 y/o college sophomore taking my majors in BS-ECE at the DLSU. I use my course as ... More »
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