I have a 40 amp version of a SSR you are considering above. I simulated charging a 12v car battery with a turbine using a variable power supply. It does just what I hoped for. It looks like a SSR, heat sink, and a linear taper potentiometer would be all you need to field test. This along with the series resistor(s) you are experimenting with should fix all your issues. You might even be able to remove the resistor and gain some efficiency. My power supply is limited to 30 volts so there is a little uncertainty about what 60 volts does to it. I think the SSR will turn on fast enough resulting in battery charging which will instantly drop the turbine voltage to near the battery voltage. Wont know until you try it. Might need to stick a 20 volt Zener diode in there somewhere. What will make the SSR fail is disconnecting the battery from the circuit while the turbine is running. The potentiometer I was using is 250K ohms. It is too sensitive. I think the best value will be in the 10-20 thousand ohm range.The SSR looks interseting but I know the turbine will put out more than 60v. something like this maybe better? 250VDC at 40 amps? I know its a bit overkill, but since this imported stuff has a high failure rate, staying away from full scale operation might make it last longer?
What would I trigger the relay with? I could parallel the turbine feed, but that would kick it in too low (3v?) The minimum voltage doesnt seem to be adjustable. I could use a solar panel (I have some 100w panels around) that would kick in around 20v or so, but only during the day.
An old school centrifugal rev limiter would work well, very steampunk.