Not to discourage you, but I think if I were you, I'd stop and assess what you're trying to do and how best to do it. Maybe you've done this, but doing a bit of homework would save you a whole lot of frustration down the road. If you're loads are modest you can probably do what you want with a simple fixed voltage system (12 or 24V likely). Converters, and strategies to step down, or buck a DC voltage, are do-able but can introduce losses and unnecessary complexity. And, if you're dumping load, if it is not going to something dependably useful, it is just loss.
I started to watch the first video and left at the point where the author said, "...just want to let you know too about electricity...electricity vibrates people.." He goes on to explain that it loosens fasteners and terminals. While this might be true at the molecular level - and that's not my area of expertise - I think what is loosening his fasteners is the repetitive action of that large starter relay/solenoid.
Some for profit sites post rather ambitious projections for relatively small diameter turbines, and/or talk about unrealistically high usable winds. They also promote installing them on towers that are too short, or on rooftops. If you're not familiar with "Betz Limit" you might take a look here:https://www.ndsu.edu/pubweb/~klemen/Perfect_Turbine.htm
You might enjoy reading some of Hugh Piggott's books, or "The Dans" at Otherpower. There are a lot of products out there and a lot of them sound too good to be true with good reason.
You might also google what Hugh, Paul Gipe and others have to say about rooftop turbines and small turbines in urban areas.