PMA's are by their nature unregulated, the higher the rpm, the more volage produced. Our PMA's are designed for a 12 volt system. It will take twice the wind to get the same results for a 24 volt system. I do not know what you consider moderate wind but here is some data:
Our Lite Breeze Kit will produce 6 amps in a 12 mph wind with a 12 volt system. So with a 24 volt system you will need 24 mph wind to get 6 amps.
The amount of amps an alternator can produce depends on the wire size of its stator. The stator wire in our DC-540 is very fine, which makes it capable of producing 12 volts at a very low rpm. The drawback is that is limited in the amount of amps it can produce (15). A car alternator has large wire in its stator so it can produce more amps. But it requires high rpm, typically 2,000-3,000. A wind turbine cannot reach this rpm.