“Where does it get the energy to do the electrolysis?”
Your battery and alternator. My friend thinks if we retrofit a stronger batter and alternator that we should be good to go.
The secret here is the “deep discharge” battery that is used to run the electrolysis device. That’s what produces the illusion of getting more energy from burning hydrogen that is required to separate water into its component elements.
Ultimately, this battery has to be recharged from an external energy source to keep the illusion of greater than 100% efficiency going.