I love the idea of wind power but you have to control the beastie - it always has to have some load. If the batteries are fully charged they reject any applied current so its the same as running with wires disconnected. Run away turbine discs can/will damage themselves.
I always thought a treadle - saddle held down by driving the trailer wheel onto it would be a great base for a wind generator but you still need guy wires.
400W @ 28 mph is your peak POWER. If you see 5% of that on average you may be lucky... Air-X turbines use flutter of the plastic turbine blades to keep from over-speeding, they are very noisy turbines. In gusts or stiff winds when it flirts with the self-protection speed control it sounds like a chain-saw missing a muffler in an alley.
There are better (not easier) turbines - the neodymium rare earth magnets now have such brute force anyone can take a light trailer hub, some steel plate, copper wire and some cedar lumber and make a good wind generator.
This would be a good unit to copy or scale to fit your project.
Forcefield - Otherpower - Wondermagnet Online Store
Note the lower power rating - the Air-X units are groomed to be irresistible marketing wise, not engineering wise...
Here would be a good place to use the search with Air-X as search term...