I work at an electronics component retailer, much like the Radio Shack of lore (nothing premade, only parts). Now, we get mostly folks in who are there for business (lots of oilfield people), but from time to time, I am pleased to see an assortment of regular people who are interested in electronics. We get circuit-benders, robotics hobbyists, parents helping children build science projects.

Although these people tend to spend less than the professional types, I try to give them the best service I can for two reasons: they are a dying breed, one which I wish to encourage; and they tend to be less boring. However, of these tinkerers, there is one group that seems to have come from nowhere to the point where damn near every day we have someone in our store: the credulous water-car people. Don’t get me wrong, I don’t dislike them personally, and I hardly blame them for being conned into as attractive a scam as this, but it boils my blood to see such scientific illiteracy that something so clearly false, so obviously too-good-to-be-true spreading to so many people. Credulous media don’t help either. Not to mention the danger of messing around with hydrogen gas and fiddling with your car’s engine. So, rather than rehashing every single time why these people are going to at best find failure, and at worst seriously injure themselves, I’ve decided to write down WHY you can’t run a car on water.

  1. You cannot re-burn ash. Water is the ash of most combustion reactions. In a simple combustion reaction, all carbon in a compound is trapped in CO2. All the hydrogen is consumed to form water. So, if hydrogen->water produces energy, then water->hydrogen consumes an equal amount of energy. The only getting around this is if you come from some bizarro universe without thermodynamics. It’s the same reason a turd isn’t a delicious kielbasa.
  2. But Ben, my machine uses super-special pulsing to electrolyze water A big excuse these hucksters use is the idea that by oscillating the voltage applied to the electrodes the devices will somehow cause the water to resonate, and eventually break the H-O bond. Even if this was possible, you still can’t possibly do it for less than 459 kJ/mol. It doesn’t matter if you use heat, electricity, or tiny gremlins with tiny hammers, you can’t get less energy from breaking a chemical bond than you get from making it.
  3. Of course my car doesn’t run on water, it simply uses HHO to boost engine efficiency. Nonononono. This is the most infuriating claim of all, as it is on the surface plausible. Any amount of research into basic chemistry shows it to be clearly absurd, though. Internal combustion engines rely on the expansion of hot waste gas (carbon dioxide and WATER) to propel a cylinder. This pressure comes from two sources: Charles’ Law, and Avogadro’s Law. The first dictates that hotter gasses take up more room than cooler gasses, and the second states that more molecules of gas take up more volume, regardless of molecular mass. So, does hydrogen produce more pressure on combustion than octane? Well, the ideal gas law states that PV = nRT, so the change in pressure is proportional to the product of the changes in temperature and moles. One mole of hydrogen burning produces one mole of water vapour, so for hydrogen, the moles stay constant (n=1). The temperature is proportional to the energy released, and 1M of H2 produces 918 kJ of energy. Octane, on the other hand, produces 8 moles of CO2 and 9 moles of water vapour (n=17), and has a heat of combustion of 5430 kJ/mol. This means that one mole of combusting octane produces ~100 times greater pressure increase than one mole of hydrogen. Not only that, car engines have been finely tuned and engineered to provide an ideal mix of fuel to oxygen. Hydrogen burns in a molar ratio to oxygen of 2:1. Octane burns with a ratio of 1:17. This means by replacing some octane in the cylinder with hydrogen gas will result in a much leaner burn than optimal. Modern engines don’t just waste fuel by running too rich. They are carefully designed by teams of engineers who are much more talented than you, me, and the morons who came up with these ideas. You can’t just throw any fuel into an engine and expect it to run at optimal efficiency. Hydrogen is a TERRIBLE fuel for internal combustion.

Of course, none of this information is free, although $97 is not that much to pay for a pdf full of lies (couldn’t even spring for real paper?). Wouldn’t you trust a guy who’s last name is Freedom? Ironically, this has spawned a secondary-scam industry of people who fix HHO generators. This stuff is the very definition of too good to be true. I never discourage the people who want to build these, but for FSM’s sake: when it doesn’t work, accept the evidence. There is no free lunch.