WARNING!!! My method on cracking water for fuel can be a dangerous experiment if you are inexperienced or careless. High voltage along with explosive hydrogen gas can kill you and others in the immediate area. Extreme caution is advised.
My experiments with cracking water are not new as I have spent allot of time in this interesting area over the years. The problem as widely known is the high required amp usage to split the water into single hydrogen and oxygen components. I am just not convinced that the load placed on a car alternator to crack the water will justify the outcome for mileage improvements. Plus your literally guaranteed premature alternator failure on most stock units eventually. My experiments have led me to using high voltage and low amperage. The picture below is a capacitive discharger that I built and experiment with to crack water. I don't personally use a hydrogen generator on my car yet. But I am getting close to trying it using my low amp method. My capacitive discharger would be plugged into a inverter that is plugged in at the cigarette lighter socket in a car. The capacitive discharger hammers the electrolyte with unfiltered square wave DC pulses between the anodes and cathodes setting up high frequency vibrations and lots of bubbles. As of now I can create hydrogen for heating when needed to supply a small burner by using voltage supplied from solar panels into a inverter that runs the discharger unit. It is certainly not a overunity method, but I can stay warm if needed on low amperage. Go to this section for a capacitive discharger schematic design that could be adapted to a car for better gas mileage.
Making hydrogen picture