If you have sufficient water to supply your maximum demand at any time then it would be crazy to include batteries. The only need for batteries is to average the power if it is sufficient to meet peak demand.
The ideal scheme is to use a turbine with a governor to hold speed reasonably constant and to use an AVR to hold volts constant.
For small schemes this is a tall order unless you are skilled in designing turbine speed regulators.
The more common scheme for small hydro is to load the turbine constantly to something above your peak power demand into some form of dump load ( ideal heating in winter). You use a controller that shares your load with the dump such that the turbine load stays constant. This regulates the speed and voltage as neither the turbine or alternator see the change in load. The scheme often uses induction generators as they are cheaper than alternators and their problems of regulation of voltage with load are not a problem here.
Your initial cost for turbine, alternator and installation may be higher than for a battery system but you will not be burdened by the cost of batteries for eternity.
Flux
