Can somebody explain to me why you cannot use electrolysis to run a car just off the battery?

Question

I know you need a power source for the electolysis to happen but why cant you. Is it because the alternater isnt charging the battery orr somthing else, or what ?????

Answer 1

If I understand what you're attempting to ask, you want to know if a car engine can run on the hydrogen directly generated by electrolysis, provided by electricity from the car's battery. The answer is that with proper piping, fittings and carburation, you could in theory, run the engine. BUT (and there's always a but) the amount of water you would have to carry around would weigh too much and take up too much space. I'm talking about at least several thousand gallons to provide enough hydrogen to give the car any range at all. And you'd need a storage tank for enough hydrogen to provide a buffer supply (much like the bag on a set of bagpipes).

Any competent mechanic could design such a system, but why bother?... It's not practical.

Answer 2

Even with electrolysis, the battery is constantly being "drained" while you drive.  The car uses more power than the electrolysis can refill into the battery.  It needs help.  The alternator gives it the help it needs.

Answer 3

Basically, you'd be trying to defy the laws of thermodynamics.  In layman's terms, the laws of thermodynamics can be summed up as follows:

1) You can't win.

2) You can't break even.

3) You can't get out of the game.

You can't create more energy by driving your car -- you can only use energy.  There's no way you can use a car engine to move the vehicle and simultaneously generate enough current to electrolyze enough water to form enough hydrogen to power the vehicle.  What they are claiming is yet another perpetual motion machine -- and they can't work.  So what you're doing is burning gasoline to make hydrogen -- not a particularly good trade-off, because gasoline is much more energy dense than hydrogen gas.

Answer 4

The answer is that you cannot get energy from nowhere. But what does this mean in practice with reference to the example that you have given. I want you th think along these lines.

Your car is running on pure petrol mixed with air, and you get a certain petrol consumption, litres/ 100km or miles per gallon.

Now somebody tells you that if you inject a mixture of hydrogen and oxygen into the car's fuel intake system, because this mixture will burn to give power, you have to use less petrol. Your car will be more eficient and use less fuel. This is probably very true and it makes scientific sense.

The problem is - where do you get the hydrogen and oxygen from? That is easy your adviser tells you - you just set up an electrolysis system that electrolyses water (which is free) using the electric energy in the car's battery. This will produce the hydrogen and oxygen required. Sounds too good to be true!!

Now think about what will happen. Your electrolysis system starts to work, the two gases come off from the electrolysis cell and are used as fuel in the engine. You can release the pressure on the accelerator pedal because youneed less petrol. What a saving!! I am not an electrical engineer, but let us assume that to make sufficient gas to make a noticable effect on the operation of the car, you need to use 5kW of power in the electrolysis cell. This power comes from the battery. Very shortly after starting, the battery starts to discharge, becoming electrically exhausted. Now you have an alternator in the car which is run from the car's engine to recharge the battery. The alternator has to replace the 5kW that the electrolytic cell is consuming, on a contiuous basis, to keep the battery fully charged. This is 5kW that the alternator was not required to supply before the electrolytic cell was introduced. Having to supply this power, the alternator needs to be driven harder by the car engine, so the alternator is acting like an elecric brake on the engine. In order to keep the car at the desired speed and performance, you have to feed more fuel into the engine. You have to put baqck the pressure on the accelerator pedal, using more fuel.The problem is magnified because machines are not very efficient, and for the alternator to supply the battery with the 5kW of power, it may have to draw 7kW from the car engine, which really destroys any benefits you got from the water hydrolysis. So as you see you are only going around in power cicles, and unfortunately, the more complexity you dd the more inefficient things become due to the inherent inefficiency of machinery.

Answer 5

Quite simply...electrolysis consumes more energy then it produces...

you might as well just run an electric motor straight off the battery without another energy loss in between

This is for the classical electrolysis learned in chemistry...

Answer 6

If I'm understanding your question correctly, there are two answers to it.  First, unless the car is a hybrid, it doesn't have an electric motor, but only a gasoline engine.  "Engines" and "motors" work differently -- an engine turns by creating little explosions and pushing pistons up and down, while a motor turns by turning magnets on and off.  Electricity alone won't run an engine, because it runs by the gasoline exploding in the cylinders.  The second problem is that even if the car used an electric motor, it would take a lot more power than one battery to do the job.  That's why hybrid cars have a bunch of batteries hidden in the trunk or behind the back seat.  One by itself just isn't enough.