I guess it's time to be surprised, as the tiny $7.50 hydro plant is still cranking out power. Most days I have to shut it down by mid morning as the batteries are fully charged from the previous night's consumption.
Since this leaves me with a surplus of power, I have run the extension cords across the yard a couple of days to the 24 volt grid-tied system and run it during the daylight hours. The plant puts out .45 amperes at 26.7 volts nominal, about 13 watts. This makes me think about an automatic change-over that switches the hydro plant to the 24 volt system when the 12 volt system comes up full. I still have the custom designed and built charge control that I used to use to divert excess PV power into the RV refrigerator, it was designed to run an external relay and operate on hysteresis so the relay doesn't chatter. Just the thing to integrate the two systems to charge from one source.
Went up to the spring today and there's a load of water coming off the hill that I can't capture or use. A larger penstock pipe is a must, as is a more industrial pelton and alternator.