Picture of Water Powered Calculator (Original)
This Instructable will show you how to make a very simple water powered calculator.
I built this because there was a time that we forget to buy a supply of AAA, AA, C, D and LR44
battery so I built this. It solve my problems so it might do the same for you too. Check out for more projects by: angelo10.

This is the original version by: angelo10

Please give the credits to me not for your selves. I saw people getting my pictures and telling  others that they made it. Please don't get all the credits!

Proud to be Filipino (pinoy) like Manny Pacquiao.

Step 1: Meterials You Will Need

Picture of Meterials You Will Need
You will need:
- A Calculator
- Carbon Rod/ Copper Rod
- A 1x1 Inch Aluminum Foil
- A Small Cylindrical Container
- Two 3 Inch Wire
- Multi Purpose Pliers
- Glue Gun

shalo3 years ago
aside from batteries where can you find those cooper rods? pls help im so desperate :( and im from the philippines as well so if you a pls tell me:)
ASCAS (author)  shalo3 years ago
It's hard to find one, probably in construction hardwares, they usually call it copper tubing. I made another design of the water battery by only using copper wire and nails. My new version is more efficient, more powerful and uses mor common materials.
Nice job man! I am just starting to explore electronics at 15 years old, and you are an inspiration for me to keep with it!
ASCAS (author)  austinbro2173 years ago
Thanks! But what ever you do, never give up, specially when you fail. Use your failures as your guide and try and try again, later on you will succeed.
dagob3 years ago
What an interesting instructable! Thanks for sharing!
I think you should explaing why it works (scientifically)
this is marvelous project...!!
bt u cn do better with carbon n zinc rod using general acids.. :) wel done
aschmois4 years ago
Great tutorial, my first try I had water leaking from everywhere and only a mere .3-.5 volts. Vinegar is NOT the best solution. I have tried and what seems to work best is Lemon Juice and Salt. (water and salt is still better than vinegar). The picture has two batteries in series which add up to a good 1.5 volts. However, for some reason I cannot get a light to turn on. My guess is that voltage reading stabilizes with a circuit, but the bulb cannot stabilize. Might also be the amperage not being high enough.
ASCAS (author)  aschmois4 years ago
Nice job. I recommend you to clean each carbon rod carefully, there's a lot of manganese sticked on it. Second both metals should not touch. Third if none of this work make 2 more of this in parallel
ASCAS (author)  aschmois4 years ago
Yeah (:D) try adding a joule thief powering a LED bulb. It should work.
jmcdermott4 years ago
silly matrix, inside duh
chaitanyak5 years ago
most innovative - yet simple thing i found today! Good job!
Dipankar5 years ago
How long does the battery work? Good Idea. Keep it up.
I think we have a good kid here. Now if he'll take after you.
Yeh! He's a bright kid. Hope he does well in life.
artworker5 years ago
Innovative. Nicely done! It's sad that teachers don't encourage these projects in school! Every student should know these tricks. 5*
ista rita11 months ago

Its amazing!
anyway, can I use copper nail instead of copper rod?

Yeah. It's copper anyway.
mohd hashir2 months ago
SanjayK11 year ago

can you say where did you get the carbon rod? I made it with a graphite(pencil lead)but it doesn't work

I think you can get some out of c or d cell batteries.
ista rita11 months ago

Its amazing!
anyway, can I use copper nail instead of copper rod?

I luv it!

You gave me an excellent idea to be used at the science fair project.

But will you allow me to use it?

mlee wei1 year ago

wow lol so nice but how many volts is dat

Himers1 year ago

How long does the battery last and how many volts does it generate?

ASCAS (author)  Himers1 year ago

2 weeks, as long as you keep it wet.

Can i use insulated copper wire instead of bare copper wire?
Can i use battery calculator instead of solar powered?
ASCAS (author)  franceserikey1 year ago

Yup! there's no difference I suppose.

Can you pls send me a video on how to do the water powered calculator
ASCAS (author)  franceserikey1 year ago

Just replace the LEDs with a calculator :)

lteodoro1 year ago

What kind of wire is used for the Water Powered Calculator?

ASCAS (author)  lteodoro1 year ago

Bare Copper Wire :)

ABC2XYZ1 year ago
How many volts does it produces?Is it enough to light up LED.
ASCAS (author)  ABC2XYZ1 year ago

My new version produces 0.6v - 0.9v and yeah it produces enough energy to power an LED, with the help of an inverter circuit of course (joule thief). In fact I was able to make a flashlight out of it.

Click Me: Water Powered Flashlight

Okay will someone please tell me why it looks like there is cotton in there, and tell me when i put it in there, since i believe there is some in there when do i put it in, and do i need to replace it every time i need to recharge it, because when i made mine i did not use cotton i only followed the instructions and it is not working for me. Neither the aluminium foil or the carbon rod are touching each other, the negative wire is touching the salt water. Will someone please tell me what i did wrong. Also i am going to be charging a home made capacitor, but ,beside the point, it is not having any output. Please help

ASCAS (author)  xMontyPythonx1 year ago

The tissue paper became mushy because of its long exposure to water. A lot of people got this to work. Have you tried checking your battery's polarities? Try to connect a volt meter, check if the battery has an output.

i did not use cotton do i need to?

ASCAS (author)  xMontyPythonx1 year ago

No, I used tissue paper but you can use any type of porous material.

Why don't you answer my q's
ASCAS (author)  xMontyPythonx1 year ago

Sorry, it's exam week. I forgot to check my ible inbox for such a long time. After all, my studies are my priority :D

yimn1 year ago
Under what topic is this project related to? Thank you
ASCAS (author)  yimn1 year ago
Chemistry under Redox reaction :D
yimn ASCAS1 year ago
Thank you sir! Uhm Do you have any idea on how i can relate this project to the topic electricity in physics??
noingwhat4 years ago
How much voltage and current do you get out of something like this?
And if you were to make it bigger or smaller, would that affect the voltage or current?
not the size but the surface area would make the difference
uy pilipino din ako
I was wondering if it would work when i fill it with urine i said that because i know that
urine has salt and water.
ASCAS (author)  crazy lazy man2 years ago
Probably, but that's grows and very unhygienic.
ToXiCATOM2 years ago
It is so easy opening SONY Alkaline batteries.
ASCAS (author)  ToXiCATOM2 years ago
Nope. Please don't attempt to open any type of alkaline batteries. They get messy, unlike the regular ones.
Hey, I am from the Philippines as well. Are you still selling the water powered calculators? How soon can I buy it from you if they're available?

Hoping for your favorable response soon.
Thank you.
ASCAS (author)  bankaitenshi2 years ago
I can't ship them because I don't know how. It's not worth it to buy one from me, specially when you came from a far place. That's why I posted this guide when I was 10.

But if you are still curious of the price, It costs for around P200.00
CuSO43 years ago
Should you avoid touching the wires? Should you make a casing for them?
ASCAS (author)  CuSO43 years ago
Please be specific.
Javin0073 years ago
Things I have learned since reading this instructable:

1.) Energizer alkaline batteries do not have carbon rods.  The batteries are filled with an inside "sludge" of zinc powder and potassium hydroxide, inside of a paper tube with a black carbon and manganese dioxide "sludge" on the outside.

2.) Said black carbon sludge will stain a white porcelain sink.

3.) Fiance does not find any of this as fascinating as I do. 
lol....in the same boat with my mom on number 3!
ASCAS (author)  Javin0073 years ago
Its true. Any kind of alkaline batteries have the same components. Just use the cheap regular ones like Energizer.
Sweet project, I wonder if it will work with some lemons...
Ceejay103 years ago
HELLO, I'm from Philippines And I'm Interested to Buy a Calculator. Where can i order or s/t. ? Please.
ASCAS (author)  Ceejay103 years ago
I can probably ship it via mail (LBC). P150 for delivery and P200 for the water powered calculator, total of P350. My only problem is that how are you going to pay me?
Ceejay10 ASCAS3 years ago
Or Anything na pwede tayong makapagusap ng mabuti. hindi po kasi ako masaydong marunong dito.
Ceejay10 ASCAS3 years ago
Do you have Fb Account? Opo, Marunong ako. hahaha
ASCAS (author)  Ceejay103 years ago
Nagsasalita ka ba ng Pilipino?
Inducktion4 years ago
ooo, try gatorade! (lotsa electrolytes in thurr!) :D
yeah u r correct !!!
Krayzi99 yukthi3 years ago
lol! scientificaly, would this really work?
ASCAS (author)  Krayzi993 years ago
Krayzi993 years ago
hey, im Filipino too!
ASCAS (author)  Krayzi993 years ago
izdravkov3 years ago
This is a Triboelectric! See this site for more information about Triboelectric series: http://www.siliconfareast.com/tribo_series.htm
Ceejay103 years ago
HELLO, I'm from Philippines And I'm Interested to Buy a Calculator. Where can i order or s/t. ?
Xyver5 years ago
Thats actually really cool.... What's the chemistry behind it?
I would imagine that this is occurring because of the difference in electronegativity between the electrodes. That is, the aluminum/zinc has less of an attraction for its electrons than the carbon, and so they move through the circuit from the metal to the carbon rod. The ions in the water oxidize and reduce the carbon and metal electrodes, respectively, to maintain balance. Zinc works better because it is less electronegative than the aluminum. Try it with copper or nickel, those would probably work even better.
Hmm... that is an interesting idea, but I think its works the same way that regular batteries do just using salt water for the electrolyte. Since most water contains salts that is why this works with tap water. I don't think this would work with distilled water. Someone should try that? Basically the salts in the water react with the carbon and metal and produce electrons. That is why water
"Regular" batteries do work in this way, although I cannot say that all do. They generally contain strictly controlled types of ions, but it doesn't matter that much as long as the basic structure of the system is maintained. I'm sure you know that vinegar contains quite a few more ions than standard tap water, explaining its described success as an electrolyte.
Brawndo has what batteries crave!
joosh Javin0075 years ago
:) I love idiocracy. Batteries need water. Like from the toilet?
bbrown26 joosh3 years ago
I know you where being stupid but I saw you talked about toilets... So do you think urine would work??? It would give you brownie points for re-using waste...
Javin007 joosh5 years ago
Probably one of my favorite movies of all time, mostly because you can actually SEE everything they're talking about in action all around us. The general dumbing down of society, etc. That's why I spend so much time on instructables. I figure SOMEONE'S going to have to know how to do the basics here in a few years.
joosh Javin0075 years ago
I totally agree with you. I look around and I see the world going towards that. Well at least America is. I blame it on this narcissistic instant gratification entitlement everyone has. My generation seems to be the worst. Also I blame it on the internet, but some sites (like Instructables help).
Javin007 joosh5 years ago
I think they might have had it pegged in the movie. We're just breeding ourselves into stupidity. Just look at YouTube and think to yourself, "The vast majority of those people are breeding profusely." This could even be the CAUSE of the "narcissistic instant gratification entitlement" generation.
joosh Javin0075 years ago
Yeah you're right. I just love the interview at the beginning of the movie. Sadly its true. The stupid people have 10x as many kids. I'm not saying stupid people only have stupid kids, but its more likely. Another thing that I just thought of (because my dad was watching Glen Beck) is the media. The media is dumbing us down by just filling us with bullcrap (such as Glen Beck).
Tchnclfl joosh5 years ago
Distilled water is indeed nonconducting, so it wouldn't work (at least not well enough).
bloodgarm14 years ago
i tried doing this but mine is not working... :( i have one doubt.. is it absolutely necessary that aluminium and carbon shouldnt come in contact?? in my model they are touching.. i just tried it 5 min back..
ASCAS (author)  bloodgarm14 years ago
Yup thats the cause why it's not working. It shouldn't touch or else it wont work second you might want to add another water battery in series :)) I sell this in our country for $2
Do you get a lot of buyers of of this?
ASCAS (author)  Kante Tech3 years ago
Yes. I sold about 15 of this in 3 days, I stopped because, I don't need money.
skysaber894 years ago
What happens to the water? I mean, does it just disintegrate? Or is the salt used up? I dont want to waste the limited amount of water we have on Earth. This really is a big question I have, if anyone could answer this, please, be my guest.
ASCAS (author)  skysaber894 years ago
Actually the battery only dehydrates the water. It's still water bayt with less minerals. You can still replace those minerals in some ways. Its still renewable.
Thank you, i just didn't want to waste water, since, you know, we only have so much water on Earth.
I think you can use sea water for your water battery (Since sea-water has salt, it should even be better than fresh water)

So, no worries :D
hey ur not wastin water that water inside is abt 2ml and can last abt 1 month i think so ur not wastin water ur conservin energy...and if u really want u can put waster water
shalo3 years ago
aside from batteries where can you find those cooper rods? pls help im so desperate :(
Bruno1534 years ago
My water battery only generated about 0.5 volt.... the calculator will need about 1.5 volt.... I added salt and then was the same....
ASCAS (author)  Bruno1533 years ago
I had troubles with this thats why I connected another battery in series
If you are putting the "water battery" in place of the solar cell, it will be enough those tiny solar cells only put out .5 volts in bright sun. If you are using a calculator that has a battery also, hook it up to the solar cell connections, because the battery connectors run through a resistor. If you put the battery in parallel with the solar cell you can leave it in and then it will use the battery when there is no sun, and the solar cell when there is light, and use both when it is dim. Just make sure you don't hook it up in series.
eye8813 years ago
im doing this for my science fare in salem arkansas my teachers said i need 5 links that i got this info off of i put down lifehacker.com and instructables.com but i cant think of any other links.
eye881 eye8813 years ago
and i have limited time so reply fast anyone'
kquiambao3 years ago
How do you glue the foil? :)
Hey I have an idea! What if you wired the water battery and the solar panel in parallel so that there are two possible power sources for the battery? Oh, and add a switch for the water battery. When there is light, turn the water battery switch OFF to save energy and the calculator will be fed by the solar panel. Likewise, when it's dark enough to not have the benefit of solar power, let the water battery do its work! Totally green either way! Ah, and you might want to add an LED Joule thief circuit also powered by the water battery to light things up if you want to read the numbers in the dark.
That's what I thought!
yvarcot5 years ago
Is it non the top and take better pic's!! And write MORE information!!
i guess you forgot the magic WORD....
You might want to try some Borax and see how that works out. I'll have to try this sometime. I expect you would also do well to try recharging it too, although if you're using water obviously that's not in short demand. Just some ideas to play around with.
The battery is actually not powered by the water. The water and dissolved salts are merely the electrolyte. He's consuming his anode. The title of the post is misleading. It should say, aluminium foil powered battery.
That's a very astute observation! I realized this too when i started reading this "ible". I would think gatorade or powerade would work very well too, as each are chock full of electrolytes.
metalman555 years ago
where is the foil glued?
ASCAS (author)  metalman554 years ago
glue the other side of the foil to the container :D
Do i glue it outside or inside???
ASCAS (author) 4 years ago
Probably there's a flaw on the batterie that you made
alexw21504 years ago
Amazing, I'm going to put a large water battery into a rucksack and hook it up to some electronics on a halo helmet (http://www.instructables.com/id/Cardboard-Halo-3-Master-Chief-Helmet/) Thanks!
tats gr8!!!
but wer s t foil glued????? reply pls??
robot13984 years ago
can i power a 1.5v motor from this
MCzone4 years ago
how power full is this battery
can you use it for a flash light
1arrow245 years ago
The graphite from a pencil that's been carefully remove will serve as your carbon rod.
How about a 4mm carbon rod from a mechanical pencil? Since you can find those in art supplies stores for cheap it's way easier than removing one from a pencil.
I tried it before for electrolysis. It worked ehhh okay but it didn't last long. It got thinner and thinner after not very long. wood pencil graphite, broken and extracted for the rod, works better.
you became a inventor someday
are you a genius
i cant see a copper rod or carbon rod
wow...i'm so happy you're a Filipino!! T.T
you might want to mention that it's battery powered and not water powered .
ASCAS (author) 5 years ago
Yes it works with a LED flashlight you just need a joule theif circuit. I tried it and it worked!
n33r5 years ago
Does It Make Any Difference With More Carbon Rods ??? & Should Aluminium Foil Touch Carbon Rod Or Not Neccesary?? Btw Awesome Instructable Really Usefull For Daily Life & Helps Recycling old AA battery
ASCAS (author) 5 years ago
As long you are using carbon-zink or alkaline it is totaly safe. I might make a instructable for opening a battery properly. I opened it without breaking. lol
tomtortoise5 years ago
yo i found some battery and there was this white sticky stuff (don't say it) arount the carbon rod so wen i pulled it out the rod broke in half. is this a problem. also i got some on my hand so im wonderin if it will kill me.
ASCAS (author) 5 years ago
I just used some excess wire (gray) from another school project.
redlizard55 years ago
what wires did u use the reds or blacks
ASCAS (author) 5 years ago
  • About .5 amps
  • About 1.1 volts
  • Last about 3 days (tap water) and 2 weeks (vinegar)
  • Carbon-Zinc are common here. It should do nicely.
how long can it last??? and how many mA per hour it can give?
Pale_Flyer5 years ago
so, what kind of battery should we get the rod from?
carbon-zinc batteries should do nicely
Can you use the rods from an alkaline battery, though? Carbon-zinc batteries seem to be hard to find :\
Kasm279 Kasm2795 years ago
Whoops, nevermind. I should have read the other comments first >.>
smartrobot5 years ago
what Is the voltage output
Pale_Flyer5 years ago
try copper and zinc with an acid, like lemon juice or vinegar...
ASCAS (author) 5 years ago
Usually carbon rods are found in regular batteries but not alkaline. Be careful to open the regular battery it might cause itch.
ASCAS (author) 5 years ago
Leaving the end cap would be better because it is easier to glue and to connect the wire.
hurten5 years ago
Where did you find your carbon rod, and does it need to have an endcap on the rod like the one in the photo?
check inside a AA battery -- not the alkaline kind either.
Ok thanks.
ASCAS (author) 5 years ago
I have 10 carbon rods from regular AA batteries. You can replace the rods with copper tubes (small).
imakethings5 years ago
you could use lemon juice too!
ASCAS (author) 5 years ago
I have another version. Replace the aluminum with zinc and add 3 more. That would do the best result. It will last up to 3 weeks. And I am just 12 years old sorry I can monitor my instructable very well im Grade 6. My foucus are my studies.
mathman47 ASCAS5 years ago
You did a great job. Actually I think almost any conductive liquid would work. Vinegar works well because it is an acid. Just think of the sulfuric acid in your (well, Dad's) car battery. How did you decide to try this? Keep up the ideas. Ever think of taking up Amateur Radio as a hobby? Dennis, KC9PYD
dude3005 years ago
This battery could be easily a water powered torch using a joule thief circuit found at http://www.bigclive.com/joule.htm . This water battery could even charge up another battery using kubikop's idea shown in lidmotor's videos it may even be the worlds first water torch. This is depending on how much voltage is produced and how long it lasts because no one wants to have a water torch that lasts 5 seconds. 
Won't this eventually ruin the Ni-Mh cell if you take it to too low a voltage? Great idea though. Really like the boxing.
matstermind5 years ago
how many volts does the battery produce?
I am sure that this works. I tried it and it works! For those who are trying this use salt water.
samuraijack5 years ago
pretty cool project if you ask me.. and the instructable is very well put.. keep up the good work.
seanroberts5 years ago
The water is definitely not powering it. You have a simple battery with a poor replacement for a proper electrolyte .
Jester_boy25 years ago
This sounds like simple electrolysis, what happens when the rods break down a melt through the plastic? I would be careful about the chemicals once broken down.
ASCAS (author) 5 years ago
You can search in youtube "water calculator" it works but their version is open so the the water evaporates faster. If you think this is fake there is a logical explainaton that this works. I found the principles in a book "this works". This is for real :)
ASCAS (author) 5 years ago
Actually I disconnected the solar pannel. And my instructable version last for 1 week.
TSC5 years ago
Need more how to do with the wire!!!!! but nice!!!!!!!!
Persona5 years ago
I love the idea of making your own batteries, but I am wondering whether you disconnected the solar panel or not. How well would/ does it work without the solar panel?
profpat5 years ago
you must be very good in chemistry? good idea, beats buying rechargeable batteries....