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Water Wheel Advice in Portugal!

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I am about to start building a water wheel for my property here in central Portugal.

We already have a small 24V solar system and this is more than enough in the summer - but as we are in a valley we get limited sun and are looking for an additional power source to top our batteries up through the winter!.

We have an underground stream that exits a wall into a ditch and I think this is an ideal place to build a water wheel. (I have made a rough sketch of what this could look like!)

The height of this stream is around 1.5m and the water wheel would be around 1.5m in diameter. The stream produces between 20-40 l/s.

My main question is about what kind of wheel to build. And then what kind of alternator and gearing system would be best for efficiency.

I'm guessing a 400-600W PMA would be a good option and I hoped someone on here had some advice as to where I could get a good one!

Thanks and all advice is very welcome!

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Location: Massachusetts, Zone:6/7, AHS:4, Rainfall:48in even Soil:SandyLoam pH6 Flat
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To get the 1.5m of head your water-wheel/turbine needs to be flush to the ground not 1.5meter above the ground.

I would get a 400W-600W unit and expect 250W in actual production due losses.

A direct shaft sounds like the way to go.
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Location: latitude 47 N.W. montana zone 6A
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Hi Kai;  Welcome to Permies!

Looks like a good spring you have to work with.
A permanent magnet alt. is the only final way to go.  
Overshot wheel is going to gain you the most power.
Do you think your trough can catch all the water ? You need as much water weight as possible to spinup your PMA.

As far as what size PMA you can use ... well  I think I would build my trough and then try a free standard automobile alt.(temp remove one from a vehicle)  See just how much power you can make with it.
PMA's are not cheap.  Buy one to large and your water will not be able to spin it up.
Buy one to small and your stuck with less power than you could have gotten.
Experiment.  Build your trough. Give it as much slope as you can.
What made you decide to use a 1.5 M wheel ?  You may need to change the size.

Try the other alternator first and see what happens... Hydro's are great! I have had mine over 20 years. But they don't always make the amount of power a person hopes for...
It takes a lot of inertia to spin an alternator that is making power.  Then as your battery voltage rises your hydro has to work harder to push the electricity into your battery. So higher voltage less
amperage output.

EDIT) Kai' I added this post to the Iberia forum. Maybe someone in your area has a similar setup, or might just be interested in what you are trying to accomplish!
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ciao    questa   puo essere una buona soluzione    da collegare   sulla circonfernza      della  tua ruota ; motore da overboard  500 watt
ne ho disponibili  alcuni pezzi    
sono brushless trifase     alta efficienza  
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Location: Toronto, Ontario
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Welcome, Kai.

I was thinking that you might want to see if it is possible to build a stone and mortar or ferrocrete tank there where the water is gathering, and see if you could use it to raise the head you're working with. That would mean not only more retained water for use in other capacities, but also greater energy generation potential with the increased drop.

You could essentially end up with a giant fountain whose main outflow is diverted to your water wheel. Imagine such a tank, tall as two grown adults, with the facade of The Green Man, and the effect it would have on the landscape!

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Would the gravitational vortex turbine  be suitable or an alternative, its more flow rate of water based than head hight of water---wish i had a stream to experiment on
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