Introduction: DIY Hydrogen Generator

Picture of DIY Hydrogen Generator

This Instructable shows, how to build an easy DIY hydrogen generator.

Materials needed for this project:
- Empty container with lid
- Cables
- Pencil
- Luster terminals
- Hot glue gun
- DC Power Supply
- Drill
- Funnel
- Balloon

Step 1: Build the Anode

Picture of Build the Anode

For the anode, you need an old pencil, a knife, a luster terminal, cables and a hot glue gun.

Take the pencil and strip it with a knife, until you have the lead. Put the lead into the luster terminal and tighten the screw. (Don't screw the terminal too tight, as that will break the lead)

Strip the ends of a cable and put the ends into the other side of the luster terminal.

Seal the terminal and cable with hot glue. Make sure everything is watertight. The only part which mustn't be covered in hot glue, is the lead.

As you can see I used two pieces of lead and put them into two terminals. I connected the two terminals to the same cable. This increases the lead surface, and gives us a higher production quantity.

Step 2: Build the Cathode

Picture of Build the Cathode

For the cathode, you need a cable and a cable stripper.

Strip 10-20cm of the cable and roll it around a pencil. This piece of copper, is the finished cathode.

You can also attach a piece of copper metal to the cathode to increase the surface.

Step 3: Build the Cap of the Container

Picture of Build the Cap of the Container

For this step, you will need the lid of your container, the funnel, a drill, your anode, your cathode and the hot glue gun.

Drill a hole into the lid of your container, the hole should be big enough, for the end of the funnel.
After you drilled the hole, insert the end of the funnel and attach it with hot glue. (Be careful, that the hot glue isn't too hot! If it is too hot it will melt through the funnel and your container.)

After the glue is cold, glue the cathode on the inside of the funnel and the anode on the outside.

Know that you attached the electrodes, drill a small hole into the lid and put the cables through. Seal everything with hot glue.

Step 4: Hack the Power Supply

Picture of Hack the Power Supply

Before hacking the power supply, please make sure it isn't plugged in!

Hacking a power supply is easy. You only have to connect the green cable with a black cable (ground). Make sure not to solder the two, because in case of a short circuit you have to disconnect the two cables and reconnect them in order to reset the fuse in the power supply (It's a good idea to put in a switch).

The power supply will start running, as soon as the green cable is connected to the ground. Now you have a DC power supply!

To use the power supply, strip a blue cable (-12V) and a yellow cable (+12V). Put the stripped cables into a luster terminal.

Step 5: The Final Setup

Picture of The Final Setup

Now that everything is finished, you only need to fill the container with tap water (you should also add a bit of salt) and place the lid on top.

Attach the cables to the power supply and turn the power supply on. (You should see small bubbles rising from the electrodes now)

The last step is to put a balloon on top of the funnel, to catch the hydrogen gas.


NEVER attach the hydrogen generator to a normal power outlet.
!ONLY use low voltage currents!

Hydrogen is highly FLAMMABLE make sure you don't burn the gas uncontrolled or in closed buildings. Also make sure, to keep a safe distance when burning the gas.

Step 7: Educational Part

Picture of Educational Part

If you are not only interested in building a hydrogen generator, but also in the chemical background, please read this part of the instructable.

Electrolysis is an endothermic reaction. This means, the reaction is only running if you add energy to the system. This is achieved with our DC-Power supply. The power supply pulls the electrons out of the anode and pushes them to the cathode.

The electrons are from the water molecules. The power supply forces the water molecules (HHO) to split into a positive loaded hydrogen Ion (H+) and a negative loaded hydroxide ion (OH-).

Due to electromagnetic forces the positiv loaded hydrogen ions are pulled towards the cathode, and the hydroxide ions are pulled towards the anode.

As the cathode offers electrons to the hydrogen ions, the hydrogen ions become hydrogen gas (HH).

Because the anode pulls electrons, it takes the electrons of the hydroxide ions and the hydroxide ions become hydrogen ions, as well as oxygen gas (OO). The hydrogen ions travel to the cathode afterwards.

Why do we use pencil lead as the anode?:
We use pencil lead as anodes, because metals (except for platinum) are oxidised due to electrochemical reactions in the container. That means if you use an iron anode it would basically rust away while you produce hydrogen. The same thing happens when you use copper. The copper turns into copper oxide. This slows down your hydrogen production and gives the water a bad colour.


arvevans (author)2015-04-07

Remember that when Hydrogen collects it is lighter than air and when it burns it always burns upward instead of laterally as is the case with heavier combustibles. This makes it safer and easier to control than might be the case with gasoline, propane, etc. There are many nay-sayers who are afraid and against the use of Hydrogen, but it is actually safer than other combustibles and as mentioned by others it can be generated by solar power, making it the least expensive fuel that is available now and in the future.

Light_Lab (author)arvevans2015-04-07

Right on arvevans, but after witnessing 4 cars blow up with various gaseous fuels I still don't feel safe in a car with a high pressure gas cylinder in the boot/trunk. Hyundai have just opened the first hydrogen refueling station in Australia. I really hope that efficient safe ways of carrying the gas in cars follows soon.

Azide (author)Light_Lab2017-01-12

Honestly I'd think that they'd have a good few safety measures in place.

(Possibly- when a leak [minor or major] is detected, a secondary cylinder of a non-flammable, non toxic gas could also be released...)

Make it BIG (author)Light_Lab2015-04-08

Just think about how many gasoline filled cars cought fire. And how many people died in them due to the fires. I don't think that gas is unsafer than gasoline.

Light_Lab (author)Make it BIG2015-04-18

Seems like I have unintentionally stirred up hornets nest of dogma here so I am obliged to apologize but I can't leave without attempting to clarify.
My daughter and I were in a petrol/gasoline van that caught fire from a leaking fuel line, we had plenty of time to get out. Same story with one of my friends and his family. Lost the vehicles though, they just burned out, no explosions, it may well have been less destructive with gas fuel. I suggest you check the stats about car fires.
BUT fuel fires are not really the main consideration of my work, we are trying to reduce the gas pressure of the stored fuel. I concede I am probably over cautious (nervous) when considering the immense
potential energy in a gas cylinder but I have seen some memorable
explosions. Nevertheless I have to assure readers that a lot less LPG accidents have happened now stronger regulation is controlling gas conversions. I try to keep that in my mind when I am in a taxi.

Light_Lab (author)Make it BIG2015-04-08

Check the stats and numerous TV shows like the Mythbusters: Gasoline/petrol cars seldom catch fire and almost never explode, that is a movie myth. The stats on gas powered cars are less defined but from personal experience: An LPG fuel tank in a car near my house exploded in the middle of the night a few years ago. The trunk/boot lid landed in the middle of the street. The cause of the explosion was never explained. I admit that since LPG conversion was regulated and restricted backyard conversions less incidents have occurred.
What many people don't realize is that typical hydrogen tanks have much greater pressure than other gases. I have worked in research labs most of my life and I have seen the damage done when a compressed gas cylinder had a burst regulator; the damage done when a gas cylinder exploded a manifold; the damage done by a pressurized fire extinguisher when it malfunctioned. I consider all pressurized gas storage systems as a potential hazard, particularly hydrogen fuel tanks zapping along the road at 100MPH.
I am not alone on this, I have worked on research projects funded by car manufacturers to develop metal hydride and high surface area molecular sieves etc to permit carrying hydrogen at lower pressures to reduce weight and reduce explosion hazards. I am now retired and I have no idea how/if the safety of hydrogen storage in cars has been improved; I hope so. I do know that the car manufacturers do not mention this issue when promoting hydrogen fueled cars.

Make it BIG (author)Light_Lab2015-04-09

I never meant, that gasoline cars explode. What I wanted to say was, that if a LPG or CNG tank explodes in the back of your car (because that is where they place them), you are probably safer in the drivers seat, then you are if the whole car catches fire, due to a gasoline leak.

This is just the main dirrefence between gasses and liquid fuels. Liquid fuels burn long. This gives you a chance to escape. But if you can't escape (due to deformation of the car etc.) you are pretty sure dead.
Gasses explode in a short periode of time with much energy, but they won't burn for a long time, as all the energy is in the explosion. If the explosion is in the back of the car, you have chances to survive.

What I want to say is: Fuel always has a high "energy density" and if this is set free uncontrollable it is dangerous, no matter if it's a gas or a liquid. You have to be lucky to survive a crash with both. The only thing we can do is try to make it safer.

Light_Lab (author)Make it BIG2015-04-18

Yep...I have been in the center of a few gas explosions and all I got was singed eyebrows. Nevertheless I once had cause to investigate a terrible fatality where kids were playing with matches in the back of a van that had been fitting with LPG by an uncertified fitter. It does depend a lot on the conditions of enclosure and gas/air ratios. Overall I agree I would rather be in a gas fire than a liquid fuel fire.

arvevans (author)Light_Lab2015-04-09

Why is it that whenever anybody posts anything with the word HYDROGEN in it all the nay-sayers come out of the woodwork to hijack the original thread or article and convert it to be about running cars (or NOT) on browns gas. This is not what this Instructable is all about. Hijacking the Instructable of someone who is learning, or trying to educate others is rude, inconsiderate, and only shows a lack of knowledge about the subject at hand.

Light_Lab (author)arvevans2015-04-17

You brought up the issue of fuel first and I only sought to extend your bald statement about safety from my research experience working to develop safe efficient ways of transporting hydrogen. Incidentally research funded by car manufacturers concerned with the safety issue. If my efforts to inform and educate is considered rude and inconsiderate then I apologize.

Brooksdiy (author)Light_Lab2015-04-08

Light_Lab ...Your witnessing 4 cars blowing up makes the case for "hydrogen on demand" systems for use with internal combustion engines. Adding hydrogen or "Browns Gas" into an engines vacuum system from a device that has created it by splitting water only when the engine is running replaces the need to carry a tank around and maintaining a need for a centralized system of supply for hydrogen. I do realize though that Brown's gas is the mix of hydrogen and oxygen from water and, that the scenario I presented is one where the Browns gas is an addition to an engine that runs on liquid petrol fuel, either gasoline or diesel but it is possible to have an engine run entirely on Browns gas on demand and propelling a car about 200miles from a quart of water.

A very promising situation yielding a weeks worth of local driving with under one gallon of water.

kyle.kepley (author)arvevans2015-10-21

Indeed, hydrogen phobia is very frustrating because if you go try and buy hydrogen at a gas supplier they are very paranoid about selling it and it's like pulling teeth to get them to sell you some. Yet propane and acetylene are no problem! I think it should be mandatory that all outdoor advertising balloons be required to use hydrogen because helium is just too valuable to waste on frivolous applications like that, and when the helium is gone it's GONE, there's no making more.

leon.bed.3 (author)kyle.kepley2016-05-30

Yeah, its not like a lot is going to happen even IF the balloon catches fire.

Its not a good idea to use in blimps though, because you are actually risking peoples lives if that catches fire.

Hydrogen is also much cheaper, so the ballons would be potentially cheaper.

oo0oOo0oo (author)2016-04-16

This looks really nice but is the pressure enough to inflate a balloon?

StevenD6 (author)oo0oOo0oo2016-05-07

if you build it properly than yes it is if u want the baloon to float then you need to have a seperate funnel. have the negative side ( hydrogen) bubble through another container with distilled water so the pressure can build up but be careful of static diacharge hydrogen is explosive.

BrandonW55 (author)2016-02-07

Thank you for sharing this. I have looked all over the net and all I keep finding is HHO generators. On a side note, any idea how long the electrods will last in hours? Or how long the gas will keep for, in say a 20 oz plastic bottel? (May consider takeing down all the nonrelavant info.)

Antbal0 (author)BrandonW552016-04-29

this is an hho

bjrmeno (author)2015-12-18

I have a question. Where does the oxygen go? From what I understand, the anode produces one gas and the cathode produces the other. Most electrolysis systems I have seen, have a vent over both and the O2 comes out one and H2 the other.

Am I confused, or would this unit not produce a balloon full of both gases?

Please let me know if you have an explanation. I really want to make a low pressure H2 generator and this seems simple enough to suit my needs.

Also, mythbusters mentioned that tap water and regulat table salt could produce chlorine gas which is also bad news and heavy.


awabo (author)bjrmeno2016-04-08

the anode produces oxygen gas and the cathode produces hydrogen gas and in this case they all end up in the balloon so you have a hydrogen-oxygen mixture in the balloon.

Also if you use salt it will produces chlorine gas but you can replace the it with baking soda and the chlorine will be gone!!

awabo (author)awabo2016-04-08

one thing if you're using salt or baking soda there will be sodium hydroxide which then can be neutralized by adding vinagar to it

rasel88 (author)2016-03-30

Well done good job i also make high power cell which run my motorbike

Goober 2 (author)2015-10-24

Most HHO units call for stainless steel in some manner or fashion. could the stainless steel be replaced for a similar effect?

PysselPappan (author)Goober 22016-01-30

Don't use stainess steel! The Chromium in the steel will produce very toxic chromates that are illegal to put in household drains, or in the ground. AND they are toxic. Very. Don't do it.

bergpa (author)2015-12-06

would a 12 volt battery work as the dc power supply?

Make it BIG (author)bergpa2015-12-18

Yes it would.

Make it BIG (author)2015-04-06

I think Instructables is not a childrens platform. I also think that anyone being able to find and build this project, is old and responsible enough to know the risks of hydrogen gas.
I'm totally aware of hydrogen being flammable (but nevertheless I added it in the WARNINGS section).
I also think, that there are much more dangerous projects on instructables, for example things where you have to deal with high voltages.

As instructables is a makers platform and not a platform for small children to have fun and mess around, it is not irresponsible to post such a project. (In my opinion)
So I also see no reason to take this instructable down. Nevertheless I see your concerns but I think you are a bit overreacting. (climbing trees is also dangerous as you could fall, you can kill yourself with a knife etc.)

rgaines (author)Make it BIG2015-04-06

There's a lot of myths about hydrogen. Hydrogen is very unstable, so unstable hydrogen doesn't stay H2 for very long. However, its point of combustion is so low, it takes a lot more hydrogen than gasoline to run a car! In fact, water separates all the time and recombines. Ever notice the tiny bubbles in a bottle of water which has been sitting for awhile? If you were to release that hydrogen directly into the air, it would combust at room temperature with the oxygen in the air and turn to water, probably before it even hit the ceiling! Many teenager with interest in science have played with electrolysis. I even did and it never once did it flared up on me. You must collect an entire balloon full of hydrogen and then take a match to it. Sadly, most of it won't burst into flames, but there will be a quick burst. Do EVER dare fill a balloon with natural gas and take a match to it as you may find yourself in the ER!

Hydrogen is a renewable fuel we can use, but of all the fuels it's the least powerful. There would be no interest in it, if it weren't for the fact is so plentiful and when it's spent it goes back into water, which then can be separated again and again. Dispel the images of the Hindenburg. Most of that wasn't hydrogen, but the gun power like substance used in the finishing of the outside. The Zeppelins were very hard to bring down in WW1. The Hindenburg was sabotaged. Hydrogen is around you and IN you. Even plants us electrolysis in the process of photosynthesis making sugar from carbon dioxide and water!

The biggest danger in electrolysis is electric shock, which is why this experiment using 12 Volts though you could be by with 38VDC (must by DC as AC would produce both gasses at each terminal).

Light_Lab (author)rgaines2015-04-07

Water does not spontaneously "separate all the time" the bubbles you see in a bottle of water is just air or carbon dioxide.
Hydrogen does not spontaneously "combust" in air or even pure oxygen at room temperature. It is merely highly flammable.
I have burnt many balloons full of methane and other natural gases they are typically less violent than hydrogen.
The "gun power like substance" on the outside of the Hindenburg was nothing more than an early form of aluminum paint and has been discounted as a significant contribution to the disaster:
Photosynthesis is not electrolysis.

bpark1000 (author)Light_Lab2015-04-08

Regarding the Hindenburg covering, it was not an insignificant part of the disaster. The part you are missing is that the covering also contained nitrocellulose, which is a strong oxidizer. When combined with aluminum powder, which is a fuel, you have in essence rocket fuel!

kyle.kepley (author)bpark10002015-10-21

Myth Busters already debunked that "rocket fuel" claim with a model covered with the exact same paint. To attribute the Hindenburg fireball to the fabric paint is like coating a nuclear bomb with lighter fluid and then saying the fluid was responsible for the scale of the nuclear explosion. It's just a ridiculous claim.

Light_Lab (author)bpark10002015-04-18

Perhaps you should check out the link I included. I cannot confirm if nitrocellulose was used in the paint but I have seen nitrocellulose burn and the photograph in the above link doesn't match what I have seen. Then again it doesn't look like any hydrogen fire I have seen either.

bpark1000 (author)Light_Lab2015-04-18

The Hindenburg was covered with cotton cloth painted with "dope". The "dope" consists of nitrocellulose dissolved in volatile solvents. When the solvents evaporate, the nitrocellulose shrinks, tensioning the fabric to withstand the wind loads. Powdered aluminum is added to the latter coats to protect the cloth and the dope from ultraviolet damage. This was standard practice on dirigibles and "rag and tube" aircraft.

kyle.kepley (author)rgaines2015-10-21

There's a lot of myths surrounding the Hindenburg too-- especially that idiotic one that blames the fabric doping for the explosion. It is indisputable that the giant fireball ripping through the Hindenburg can not be anything else than hydrogen mixed with oxygen burning as the gas cells rip open. The original explosion that started it all was also a mixture of hydrogen and oxygen along the top near the tail where a gas cell had been ripped open and spewing gas for a period of time. There is no evidence that points to sabotage either, that is just Hollywood BS. The inquiry found the most likely scenario was a tension wire snapped during a hard turn during the landing and slashed open a gas cell. Static electricity generated when the mooring lines hit the ground is the most likely cause of the spark that then set it off. Not that any of this justifies the hydrogen phobia that everyone seems to have. The Hindenburg was millions of cubic feet pre-mixed with oxygen, not even close to what would happen on the tiny scale of a rubber balloon.

mclabough (author)rgaines2015-09-02

This is a few paragraphs of mostly misinformation. So much wrong in it that my head started to spin. Best to forget what you just read and scroll down.

42etus (author)rgaines2015-04-08

"Hydrogen is a renewable fuel we can use, but of all the fuels it's the least powerful."

Probably why NASA used it as the fuel for the space shuttle launches

bpark1000 (author)42etus2015-04-18

The reason hydrogen is used for spacecraft is that it has the highest energy per pound. (Its energy per volume is low, but its density is also very low).

AJMansfield (author)rgaines2015-04-08

I frequently fill 15" balloons with propane and light them by hand with a blowtorch. It makes a great trick to show off at various things.
It is perfectly safe if you do it outside, away from overhead combustibles. Even though I am in fact inside the exploding fireball when I do this, it barely feels warm because it lasts such a short time. I do take protective measures of wearing safety goggles, close-toed boots, nonflammable natural fiber clothing, and fireproof leather gloves, but the hair on my bare arms doesn't even get singed.
The single biggest risk is having a fragment of hot latex balloon hit you, and you can mitigate even that by clamping a.pair of locking pliers around the balloon's stem to ensure the breaks occur at the top of the balloon, leaving the latex in a single piece.

tkddms225 (author)2015-08-23

I've been researching hydrogen generators lately, and many people have advised others not to use salt (because it can produce chlorine gas, which is, as you may already know, a very toxic chemical that you would not want to produce). Other than that, great project!

fathant (author)2015-07-28

Any one can help with the lead? :c

AirbourneNation made it! (author)2015-05-09

Thanks, mate, for an easy instructable!

voblak (author)2015-04-12

Try 1000VA toroid where you wind secondary (centre taped) so you have about 5V/200A or even better is 10V/100A. Than use few power diodes in paralel. And you can produce some serious amounts of hydrogen. Also it helps if you put a few drops of HCl into water, so it has lower resistance.

gfetters (author)voblak2015-05-04

How fast will this produce hydrogen. I need about 100cf of hydrogen to for a balloon launch. I would like to produce it at the launch site if possible. If it takes more than an hour to produce this will probably not be viable for my problem.

Make it BIG (author)gfetters2015-05-05

It will DEFINITELY take longer than an hour to produce that amount.

I also think I have to break your dream of being able to produce that amount in that time as a DIY project. (And even transportable)

I did some research and all professional generators which produce such an amount of gas in an hour are as big as a cupboard.

Just as an example.

ashuki (author)2015-04-15

Warning should be in front of any tutorial in my opinion

NotI1 (author)2015-04-07



I can walk across the street to my local dollar store and pay $1.50 for a "POSSIBLE DANGEROUS EXPLOSIVE FIREBOMB"... I recommend that you try lighting one of these. I'm sure you'll find the results... anti-climactic.

Gordyh (author)NotI12015-04-07

That's because those balloon's are filled with Helium not Hydrogen.

MaskMarvl (author)Gordyh2015-04-13

Helium in non flammable.

NotI1 (author)MaskMarvl2015-04-13

See statement below for clarification.

NotI1 (author)Gordyh2015-04-07

My apologies. I wasn't very clear. To clarify, I meant that I could purchase supplies at very little cost to fabricate something much more dangerous than filling a party balloon with hydrogen.

Brooksdiy (author)NotI12015-04-08


To NotI1studleyleeEunixLaserByte I was making Hydrogen on demand generators from plans from one of those "gas for free" websites 7 years ago. For weeks before putting it in my '95 Ford Escort wagon with four cylinders, I would fill up at the local station till the gas poured out and then run it to almost empty. I did this for five tanks in a row and ran mixed highway/city driving the whole time and always got 26.2 mpg.(same number, 5 tankfuls in a row)

I finally finished and installed my "hydrogen on demand" generator, and drove 400 miles at an even 60 mph to an annual camping trip on the one tank I had filled till it poured out before leaving, and immediately filled up till it poured out when I arrived at my destination. I did the math. I got 52.4 mpg on the 400 mile run! That equates to a 50% increase mpg! Now, getting back to the dangers of ballons full of hydrogen gas (and kids) (and I don't know about you guys but I've noticed that ballons and kids have a magnetic like attraction correct me if I'm wrong about that)

When I got back, The owner of the gas station at home heard this story and didn't believe it was possible to get any significant improvement of mpg on a well tuned car and set out to prove both his brother and I wrong. He pulled out his lighter, went over to the top of the hydrogen generator while the engine was running, pulled out the small hose on top of the generator that feeds into the engine, and flicked his lighter near the top of the unit....................... Well after and extremely loud crack sound and the smoke cleared, blood was pouring from his leg and his face, and the whole top of the hydrogen generator was blown off !!! It was made from a high pressure inline water filter canister, about 1.5 liter sized and I'll never forget the tremendous power displayed at that moment. Keep in mind that the canister was mostly filled with water so the mix of hydrogen/oxygen gas created by the generator filled only the top 3 or 4 inches of the canister. This is my reference story and why I don't think it's a good idea to fill ballons with it.

My suggestion: Get the plans, put one in your car, tweek all the suggestions and don't casually make ballons full of this Browns gas (as they call it) because we just don't know how it may go wrong when you least expect it....Thanks for reading.... brooksdiy

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Bio: I am a german student and joined Instructables, because I like to build your projects and share mine with you.
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