u/Impressive-Cap233 — reddlx

Hi everyone, I’m working on a school project involving a micro-hydro turbine designed for intermediate wastewater flow in condominium piping.

My goal is to generate at least 5V to prove the prototype's viability. However, I’m struggling to find the right generator for a low-RPM environment. Here is what I’ve tried so far:

9V DC Motor (8000 RPM rated): The turbine spins it easily, but it only produces 0.2V. It seems the RPM from the water flow is far too low for this motor.
Stepper Motor (Nema 17 / 17HS4401): The "cogging torque" (magnetic resistance) is too high. My turbine cannot overcome the resistance to start spinning.

Current Setup:

Water Source: Testing is currently done using a kitchen sink tap.
Target: Stable 5V output at low RPM.

Does anyone have recommendations for a small, low-torque, high-efficiency generator? I am also considering using a DC-DC Step Up Converter if I can get the voltage up to at least 1-2V. BTW the voltage generated is used to charge two 18650 lithium ion battery if possible.