I was watching some videos on Youtube and the following popped up as a commercial.
I did a search on Thingiverse to see if anyone has created a model and low and behold, I found this.
I ordered motors:
Waiting on some step up converters:
With a slight twist of the motor, a LED gets extremely bright, more to follow as I build this and test it out.
The best version of off-grid micro-hydro I’ve seen on YouTubes is where someone uses the pump on a discarded washing machine to create 12VDC to charge a bank of batteries. I would have to search for it 
–Konrad, WA4OSH
You may be a little disappointed with it’s performance as a water turbine. I have a water turbine but I need to gear it up (or belt it up) to about 600 rpm to get the generator functioning. This high speed can not be achieved in the water stream due to cavitation and other resistances… and a word of caution… the critters that contact with the moving parts don’t fare too well.
Using it as a water turbine is not possible where I live, but using it as a wind turbine is.
this product may be useful for users trying to use 18650 batteries as a UPS.
I doesn’t plug directly into the dreamcatcher (no gpio and not the same I2C)
but the idea is what I was looking for since it does the “pass thru” charging.
Many of the battery power supplies can only either charge the backup battery or
provide output at the "out’ usb. but not both.