Picture of Water Powered Flashlight
Batteries are too mainstream, let's make Water Powered ones! The DIY flashlight never runs out of batteries, water is all around us and will never run out. One of today's causes of pollution is the improper disposal of batteries containing heavy metals such as lead and mercury. The answer, using water as electrolyte!

Imagine, running wall clocks for 6-12 months with water, you'll never need to leave your house just to buy batteries and there's no need to recharge them. What could be more convenient than replenishing your batteries with tap water? :D

The flashlight runs 30mins continuously with tap water and 2 hours with saltwater. Not bad for a single celled prototype :D This thing also works well with calculators, clocks & radios Remember, adding a second cell triples the glow and lighting time! 

How Does It Work?
This is a type of battery called the "Galvanic Cell", having 2 different types of metals and is connected by a salt bridge. It works like your typical battery but uses water as its electrolyte. If you want to read more about how batteries work "click here" The output voltage is pretty faint and isn't enough to run a single LED. By the help our trusty "Joule Thief Circuit", the LEDs would glow even at low voltages.

Is It Really Powered By Water?
Well not really, the water serves as an electrolyte, a replacement for toxic chemicals used in regular batteries, which usually ends up in dumpsites. So why call it water powered? Of course no one would be interested in the title "Galvanic Flashlight" plus that's what easily pops up in people's minds. The Redox reaction takes place in this project.

Practical Uses:
1st.) If you got lost and stranded out in the woods, you can't rely on batteries, eventually they run out. A mini version would save stranded people in the woods. Just go to the nearest river and fill her up! Whala, you have light!
2nd.) School science experiment
3rd.) A fun and educational project for all ages!

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A Larger Scale Water Powered Project (a.k.a Galvanic Cell):
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knexpert170011 months ago
Would a 9011 transistor work instead of a 2N3904?
ASCAS (author)  knexpert170011 months ago
Yes it would! :D any general purpose NPNs would work just fine!
xhp2611 months ago
Impressionante !
xaviergoby11 months ago
Fantastic :D Love it! Great thinking!
icekid11 months ago
Oh dude thanks for this, voted too! We have an investigatory project for chem class. A project like this would do great. How about: "Testing the feasibility of galvanic batteries" (a.k.a "Water Powered") for the title?
ASCAS (author)  icekid11 months ago
That's a good title :)) Similar to our last year's IP title, about the feasibility of hydroponic planting.
rimar200011 months ago
Brilliant as always, Casimiro!
ASCAS (author)  rimar200011 months ago
Thanks sir rimar!

Excellent work! I've found that potassium or sodium hydroxide works very well as the electrolyte solution in aluminum oxidation. With potassium hydroxide and water producing about 0.75 volts at about 75 mA for at least a week using nickel as the positive electrode and a 1/2 inch dia. by 9 inch long aluminum rod. Quite a bit of hydrogen was produced in the process which could be ran to a fuel cell. Have you tried replacing the copper electrode with a carbon one? You may perhaps get more voltage and amperage as the copper tends to react too although much less than the aluminum Just something to think about.

JayvoneF26 days ago

Can someone tell me how to power a charger using water?

I have personally used the joule thief circuit (modified with no resistor and PNP transistor instead) in conjunction with a transistor (also PNP) wired as a diode to get up to 18 volts at around 2mA max on dead batteries(1 volt to 0.45 volts). I'm sure that a 5.4 volt regulator with a large electrolytic capacitor or small battery would hold enough to charge a phone or something similar. Adding more cells in series would also boost the voltage (a 12 volt battery is actually six 2.5 volt cells wired in series) and also increasing the plate surface area or connecting more of the cells in parallel would increase the amperage.

nheroi1 month ago

Oh and can I have the procedures please? My IP is due this friday, and I need to pass it. Pretty pleasE? Can you give it to me?

nam20022 months ago

could there be a material to use instead of copper and zinc which can be found at home... pls reply quickly i have a school project, so i am using this. awesome instrucable i must say. quickly!!!

Battlespeed3 months ago

Very neat.

As an aside, this bugs me whenever I see it: "Whala" or "walla" etc. The word is "voila" - a common French word - and I also don't know why so many people think the word starts with "w" because the "v" IS pronounced - as in VWALLAH.

xcien4 months ago

ACSAS, when you say toroidal core/bead , do you mean toroidal bead or just an ordinary bead.

ASCAS (author)  xcien4 months ago

A toroidal bead, not the ordinary bead.

xcien ASCAS4 months ago
Oh ok then... Thanks
CHAMP_134 months ago
I am having trouble wrapping the wire around the core for the joule thief circuit... I have tried 22 and 24 gauge coated wire, but It will only wrap through once. How would I be able to fix this?

Heyy I already made it and it works great..
Great work I must sayy
But I wanna do something with this concept on a larger scale..
Or something that works better and could be more efficiently used..
Any suggestions ?
I would appreciate that :)

ASCAS (author)  garvit sonawala5 months ago

AWESOME! I'm building a version 2.0 for the "Scientific Method Contest". This time I'm going to use a compact 10 cell galvanic setup. I'm thinking of using a 3W LED. If possible you could try to charge a phone with it.

love it!

DanTDM6 months ago

I want to disguise it as a Minecraft torch.

franceserikey7 months ago
It is not working. What's wrong?
This is a cool build! From checking out your other ibles, it seems that you like to make speakers and water powered things... Why not combine the two? The "Water Powered Speaker!" Could your water cells power a mini Bluetooth speaker? Tell me how you like this idea.

franceserikey7 months ago
Can I use copper wire instead of copper strip?
ASCAS (author)  franceserikey7 months ago


ngowon7 months ago

pls let have more information on how to purchase. thanks

ASCAS (author)  ngowon7 months ago

I have a second version, a much more stable one and 5x more efficient than the previous version. The new guide will include the to-buy-list.

twenrich8 months ago
Is it water proof?
ASCAS (author)  twenrich7 months ago

This version isn't completely waterproof but my second one (3-celled) is.

yonskiboy8 months ago

That is chool...

arghya98 months ago
great project! the making of joule thief circuit is awesome
yurin9 months ago

it's greats

Electrichound9 months ago
You've made an excellent project, but i don't understand what you mean by "make sure there's a thread on the other side". A clarification would be very useful.Thanks
ASCAS (author)  Electrichound9 months ago
Thanks! By thread I mean the pipe's screw.
Electrichound9 months ago
You've made an excellent project, but i don't understand what you mean by "make sure there's a thread on the other side". A clarification would be very useful.Thanks

makeshiftmech9 months ago
will this work with urine in a survival situation, and would it work with a carbon rod from another battery and copper tape.
ASCAS (author)  makeshiftmech9 months ago
LOL, that's a crazy yet a good question :) I think so, yeah! 2 urine cell's could power a flashlight and 3-5 urine cells could power a small 3V radio.

I didn't have a good experience with carbon rods. They give out weak electricity when given a watery electrolyte, they like the mushy types of electrolytes (like in batteries).
babadipapa9 months ago
I have been trying to do this for the past 5 years....please please please can you email me of where i can find a 3xLED torch, zinc strips, and copper strips? If I can replicate this it would mean the world to me.
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