First, there’s no such thing as “100% efficiency” - so I am not saying the author doesn’t know what he’s talking about. I question the author’s remarks regarding certain things I’ve already laid out.
And no, you and several others have made the comment that “alternators don’t” do anything unless a load is demanded of them.
Technically... unless there is a “complete circuit” - which in very simple terms is a complete path for current flow, a resistance and a potential difference of electrons (that would be a battery or another voltage source) there is NO demand, therefore there is only “potential energy”.
This means that basically ANY generator that is turning (AC, DC doesn’t matter) has a set of coil windings that being moved in a stationary magnetic field, or a moving magnetic field around stationary coils) whether CONNECTED to a circuit or NOT is a “potential energy source”.
If there is a path - which in a running engine, there IS (at the very least to power the charging circuits for the battery) current flow. More current will flow as the load increases. (This means as the RESISTANCE DROPS more CURRENT flows - which means more electrons flow in the circuit.)
The fact is that generators/alternators in cars are capable of producing much more current in most cases than they actually produce.
In proper engineering you always over design a circuit... so if your circuit will use say, 1 Amp, you design the circuit to have devices that can handle roughly double that so you have little chance of overheating components etc.
(Using heavier wire than the minimum necessary is good practice. Using 2 watt resistors in a circuit instead of the 1 w resistors that are all you need is good practice. Putting in an alternator capable of handling EVERYTHING in the car plus extra items that might be added on - as in my case, radio systems and a different stereo system than came iwth the jeep... is GOOD practice)
This is exactly what I said in my post. An alternator has excess capacity, but not excess output.
Yes, the alternator usually has the capacity to produce more than the electrical system of the vehicle typically demands, but that's not excess output, it's excess capacity.
None of that makes the hyrogen electrolysis unit create a net gain in engine efficiency. It simply can't, unless there is some part of the process which is greater than 100% efficient.
And like the engine, if more power output is required, more power energy input is simultaneously required.
If you add electrical load to the alternator, you have to increase power input to the alternator. If the RPM’s are kept constant, the additional power required to match the increased force by the increased electromagnetic fields is supplied by additional torque. This requires additional fuel from the engine. All this additional load has the same inefficiencies of the engine, friction and the alternator so even more fuel energy is consumed than the electrical energy produced.