Rain Power Generator

Intro: Rain Power Generator

This is an educational project I made and published on YouTube. It shows how much rain power (watts) is available from a residential rooftop and the best way to harvest that energy. Most of the parts are 3D printed from a CAD model I made in Fusion 360 which is available for download on GrabCad (search for Quint BUILDs). I did some machining and welding but I've seen others get away with all 3D printed parts or substituting with wood if necessary.

YouTube video part 2 showing construction and testing with details on rectifier circuit:

YouTube part 1 using off-the-shelf DC generator (simpler but less efficient)

STEP 1: Fusion 360 CAD Model

This project pretty much requires access to a 3D printer. You don't need to be an expert at Fusion 360, but it's free to download and use and there are tutorials galore on everything you need to know to use it. I recommend starting with the rotor and seeing if you can get the magnets to fit in place to start.

STEP 2: Winding the Coils

You don't need a lathe for this, a hand drill will suffice. The fixture is included in the CAD model and is two identical parts that mesh together. The hole in the center fits a 1/4-20 bolt that would easily fit in any drill for spinning and winding the coils. I used 26 AWG magnet wire, winding until the width across the coil approached 33mm.

STEP 3: Install Coils in Stator

You'll have to 3D print the stator piece for this of course. Before removing the wires from the fixture you'll want to restrain it with zip ties or wire ties to keep the wires from separating. I applied a little glue where I could before removing the fixture but the ties proved sufficient by themselves. I used super glue or gorilla glue applied to the surfaces and added a little heat to speed up the drying process. Good old-fashioned Shoe Goo worked great to hold the coils in the stator.

STEP 4: Assemble the Generator

Here are all the parts laid out on the bench. The stator with coils installed, rotors with magnets installed (magnets were tight enough fit I pushed them in with no glue), housing front and back with bearings installed and 1/4" aluminum shaft. I turned the shaft on my lathe to make it fit in the bearings but have seen people do this with a drill and sandpaper. The bearings are 6mm inside and 19mm outside that pressed right into the housing parts by hand as printed. I hand-tapped the printed parts for fasteners to hold it all together.

STEP 5: Mount to Plate

There are a bunch of ways to mount the generator in front of a jet of water. I chose a piece of aluminum diamond plate I had lying around. You could use wood or plastic though the wood could easily swell with exposure to water (which it will get plenty of). I mounted the plate to my vertical pipe with stainless muffler clamps, but feel free to mount it anyway that works best for you and what you have access to.

STEP 6: Mount to Vertical Pipe

There are lots of details not covered here that are included in the multiple YouTube videos I published on this project. If I included everything here it would be an entire book. Watch the videos, look at the steps and see if this is something you want to try to tackle. At a minimum you can figure out how much power you'd be able to collect from your roof depending on area and how much height (head) you're able to take advantage of.

Good luck!

Quint

Comments

[kiervz_tdz123]

Hello, 👋, I'm planning to use this cad files and to print this 3d design on our nearest shop. May I ask the weights the 3d printed materials?(for budgeting purpose because our the nearest 3d printing shop has their price 12 per grams)

[fuzzyhypothesis]

I like the build, are the 3D printed parts available to download by any chance for others to try out?

[QuintBUILDs]

Yes, instructions for where to find the files are in the instructable. You'll have to figure out a shaft though. I recommend metal but other materials may work.

[SamyE2]

I can`t find the 3d files, can you please help me?

[bushido tittnl]

Hi, I am inspired by your project and want to replicate (possibly upscale) your generator. You say files are to be found here, but I was unable to locate them. Could you please be so kind to be more specific where to look for them. Thanks in advance!
PS: Great job on the YouTube video. Extremely beginner friendly and educational!

[QuintBUILDs]

Did you read the first paragraph of the instructable pointing to GrabCAD?

[bushido tittnl]

Thanks for the reply. I have to admit, I did not.
But I found your project (pure luck) at Thingiverse.
Below the link if someone is interested:
https://www.thingiverse.com/thing:4096897
Cheers (and keep up the good work you are doing!)

[pgs070947]

Nice project, nice explanations, nice video.

The turbine probably needs some improvements like enclosing it to make sure
that the water gets away cleanly.

The coils remind me of hard drive head coils, same shape, efficiently wound and
stuck together.

The spent water needs to be put to some use as well. I use rainwater for
everything apart from drinking.

As well as batteries and capacitors to store the generated electrical energy,
how about increasing the high level water storage?

One problem I get here is the rubbish that comes off concrete tiles - lichen,
moss and plenty of sand from the tiles. I filter this with a kitchen strainer
and a nylon jam strainer bag.

There's something satisfying in getting something for free, provided you ignore
the costs of collection etc.

What you are getting here is the potential and kinetic energy provided by the
Sun when it evaporates surface water to form clouds

[making is great]

Can you add the design you made?
This project seems like it would be fun to make, but I don't want to design it myself.

[AdrienR]

Nice artice!
Did you try different loads to see which one extracts the more power?

PS: if you add an iron plate (see my picture) to conduct the magnetic field on the rotor, you will have a much higher induced tension.

[QuintBUILDs]

interesting!!!

[jott_1]

Couldn't fine Build2learn at GrabCAD.

[QuintBUILDs]

Sorry, try looking for Quint BUILDs instead. That should work now!

[AdrienR]

Do not put your aluminium plate too close to the magnets otherwise a lot of foucault’s currents will run into the aluminium. But the distance seems ok :)

[marcm95]

Perhaps you should use existing device as bicycle generator, which is an alternator, the diodes could be Schottky type to reduce voltage drop........

[QuintBUILDs]

I'm considering using it for one of those gravity generators that use a crazy gear ratio to generate power while gradually lowering a weight. Thanks for suggesting the Schottky diodes, I heard about them from another maker and mentioned that's what I switched to in the video. One of those things I had no clue about prior to the project!

[JohnC430]

Excellent article. Very innovative way to describe rectification of a sine wave. Converting to a rotating magnet motor to make an alternator is also a great idea and then using LEDs for the diodes to show current flow is also a great idea. Thanks for sharing.
One thing I noticed is that the water is spraying on the siding of the house which may cause damage. I would turn it to it sprays away from the house.

[Chico da Rave]

The practical explanation you made in the video is something I never seen before!
Nice work!
Hey bro, I think you sould try a Tesla turbine here.

[nickcj]

Yep be interesting to see the difference in output!!

[hugbear]

An instructable that ACTUALLY instructs? Who'd've thought?! Crazy world we're living in...
Thanks for posting. I'll head on to YouTube now to check out your channel, seems worthwhile!