How fast does HHO burn? The flash rate is more than 3,500 feet per
second. That is faster than a speeding bullet; Superman speed. I have
witnessed flashbacks several times; most of them were intentional
experiments. Intentional or not, they happen faster than we can react. You
will not witness a flash traveling through your cells tubes. What you will
see - is a quick flash (if you have clear tubes). It happens in the blink of
How do we stop a flashback? Safety is no accident. Think about that. It
means we have to plan for the unexpected; plan for the inevitable. In our
case, we have to take some precautions.
Make sure all hose connections are not leaking. Hydrogen will take the
least path of resistance. It is a very tiny molecule. It can escape
through some metals.
Make sure all of your hose connections can be pulled loose by hand.
That sounds strange, but it is a very good safety tip. If there is a
buildup of HHO gas inside the tube and it gets ignited, the force will
exit via the path of least resistance. With a little luck, you will blow a
Minimize the air space inside your HHO Generator. The more room you
have for gases to collect in, the greater an explosion will be. We call
that area - head space. In most cells, it changes while the cell is
operating. As my Tube cell uses water, the head space increases as the
water level drops. In Dry Cells, the head space increases while the cell
is operating, and decreases when the cell is turned off.
Minimize the air space inside a Bubbler - if you have one. Do not rely
on a Bubbler to stop a flashback. That is not its purpose. It is designed
to eliminate foam from entering your engine. Foam that consists of gasses
entrapped by anything dissolved in your water; including your electrolyte.
You don't believe me? What is a bubble? How do you make one. If you still
insist that the electrolyte in the water never gets depleted - think
again. It gets carried out of the cell via the water skin/membrane around
Do not light/ignite HHO bubbles in your cell or in your bubbler. You
are taking a big risk. I have witnessed flashbacks traveling from bubble
to bubble through a Bubbler, and continuing on to the Generator. I have
seen glass containers disintegrate - even though they were protected by
bronze wool flashback arrestors, one way check valves, and bubblers;
What is the best Flashback Arrestor? If you know, please tell me!
Cigarette Filters have worked better than anything I have tried. But they
are filters. They eventually get clogged up with your electrolyte. If you
are using Baking Soda, Potassium Hydroxide (KOH), Sodium Hydroxide (NaOH),
or any other dissolved solid you put in the water, you can expect them to
turn back to solids when they dry out. If you use Cigarette Filters,
replace them if they show burn marks; replace them if they are restricting
gas flow. Please do not use bronze wool arrestors. They are not reliable.
Bronze wool gets corroded really quick - by the electrolyte. Corrosion
will stop up the hoses; stop up your arrestor; stop up your one way check
valves. That will cause you to blow a hose - or a bubbler - or even blow
Make sure the Hydrogen Generator can only produce HHO gases while the
engine is running. I installed my generator so that it would only operate
when the ignition switch was turned on. Believe me when I tell you - "That
was not enough". One day I left the ignition on while I was testing the
cell. I walked away for 20 minutes and came back. Realizing what I had
done, I activated the starter to see if my battery held a charge. KA-BOOM.
It took an hour to get the motor to start again. I was very lucky it did
not do engine damage. I know of a trucker that stalled his diesel motor -
and left the ignition on for 5 minutes. When he started the motor back up
- KA-BOOM; bent the motors valves. It had to be towed; it would not start
again. I know of a lady that buckled the hood on her car. She turned the
radio on while waiting for a friend to come out of a store. The ignition
switch was on accessories; the HHO Generator kept producing gas. It goes
to show you that no matter how smart you are, you still have stupid
Do yourself a favor, install another level of safety, provide an
additional step in powering up the hydrogen generator. I did this by
installing a vacuum switch. I use it to provide ignition power to my
relay. When I turn on the ignition, it puts 12vdc on my vacuum switch.
When the engine starts, its vacuum activates my vacuum switch - which
sends that 12vdc to the Power Relay that operates my generator. The engine
must be running for the cell to operate.
Glass Containers. Who in their right mind would build an HHO Generator
out of glass? Probably a person that could not find a different container.
If your glass jar explodes, I hope you are wearing goggles that will keep
the glass and the electrolytes out of your eyes. Just for the record, both
Potassium and Sodium Hydroxides dissolve aluminum; imagine what that would
do to your eyes. One of the most successful HHO companies on the web uses
glass jars for containers. If you have one, tell me about any mishaps. I
would like to know.
Plastic Containers. Listen, temperatures can get hot enough to boil
water in your container. Regular PVC is going to weaken with the heat. It
will get soft and loose its shape. That is not good. I have seen
electrodes get so hot they melt the PVC around them. If you are going to
use PVC, use CPVC; the grade for hot water pipes. There are some good
grades of plastic that will stand up to the heat.
Stainless Steel Containers. One can not make a better, more reliable
container than by using stainless steel; but it is expensive, harder to
find, and usually requires some welding. I built mine out of 304
stainless. It has very low magnetism, withstands flashbacks, and freezing.
I can tell you that 316L would be a better choice because it is least
likely to corrode.
Where is the best place to install an HHO Generator? The best place
will not necessarily be the safest place.
Let's start by saying "Never put it inside the passenger
compartment". Remember the balloon - KA-BOOM? Do you think you can
drive with broken ear drums, flying shrapnel, and electrolyte eating
away at your skin?. If you do, a lawyer will eat you alive in
today's court systems. If you happen to be using Sodium Hydroxide
for an electrolyte, the fumes from the vapor will take your breath
away and possibly burn your lungs. Why take that chance? Believe it
or not, there is a seller on ebay that makes a generator out of a
plastic tool box. It contains all hookups. He recommends putting it
behind the seat. In his videos, the thing is not even secured to the
How about the Trunk compartment? The infamous Bob Boyce has his cell
in the trunk. It is safer there, than inside the cab. You will need
heavier gauge wiring because of the longer wire runs. The battery is on
the other end of the vehicle. You will also need a longer output hose
going from the cell to the engine; the engine is on the other end of the
vehicle. If you rout the hoses through the passenger compartment, there is
an increased risk to the passengers. If you rout the hoses underneath the
car, there is an increased risk caused by road debris; ice, sticks, rocks,
metal tailpipes, mufflers, litter, etc.. It would be a good idea to run
the tube through pvc conduit.
Most installations use the Engine compartment; there are many good
reasons. The hho gas is close to the motor. The wiring is close to the
battery. The environment is air cooled. The generator is out of sight and
out of mind. In the summer time, the cell will heat up quicker; but is air
cooled. In the winter months it will be shielded from the elements, yet
warmed by the motor. Needless to say, if a flashback occurs, you and your
passengers are better protected.
I installed my generator outside of the vehicle; on the bumper. At the
time, I did not have room in the engine compartment and did not have a
trunk. As it turned out, it was a very convenient location. It is air
cooled. I have easy access to it. I can see the hose come off if I have a
flashback. It is a great place for demonstrating and advertising the cell
operation. I have not had any problems with vandals; it is amusing how
people react when they see the word "hydrogen" on a stainless steel tube
:) Is it dangerous to have a cell in front of the bumper? Not at all.
How safe is it to have a hydrogen generator if my vehicle is involved in
an accident? Actually, it is safer than gasoline. Gasoline is a liquid; as a
liquid, it will not burn. If gasoline leaks out, it evaporates and falls to
the ground - where it accumulates as fumes; this can be very dangerous.
If the generator/cell container gets ruptured, the hydrogen will
instantly escape upwards. It is 14 times lighter than air. It will not
hang around like gasoline does. If for some reason the hydrogen is
entrapped in the engine compartment, consider the fact that it will be
diluted considerably with the existing air. It will not be the same
explosive mixture being produced in your cell.
If the generator/cell does not rupture, but continues to operate, is
there a danger? Ok, let's say all of our safety switches and sensors
failed, and for some unknown reason the cell continued to produce hydrogen
gas; what could happen? Most likely, a build up of pressure will blow a
hose off the cell. If not, the hydrogen is going to leak out - one way or
another. As long as the motor is running, the hydrogen will continue to be
consumed. If the motor stops, one or two cylinders in the motor will fill
with the hydrogen, but the additional hydrogen being manufactured will
escape through the exhaust valves of the other cylinders. In this case,
you would not want to restart the motor. It could cause a small internal
explosion that could damage the engine. I would disconnect the coil wire
or the spark plug wires and crank the engine over a few times first. That
would fill the cylinders with fresh air. But what if the vehicle is on
fire? In that case, worry about the gasoline; you have many gallons on
board. The hydrogen is not stored, it is being made on demand - in small
LZ 129 Hindenburg disaster, two thirds of the passengers and crew
survived. The skin of the Hindenburg may have contributed to the actual
blaze. Of the 62 passengers, 27 died. Of the 27 dead, 25 jumped to their
deaths from the stricken airship in panic. The other 2 that died did so due
to the fire spreading to the diesel powered engines. The hydrogen combustion
itself was above, and mostly away from the gondola.