Get off the grid a little with this mini hydropower dam

Power your electronics for free with this DIY miniature hydropower dam.
Christopher McFadden

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Want to make your own electricity at home for free? Have a penchant for dams? Then this little project might be right up your street.

Follow this simple guide to find out how.

diy mini dam complete
Source: Great Inventions/YouTube

As you can imagine, you'll need some tools and materials before you get started.

Materials and gear needed

With all your gear in hand, it is time to get on with this great little build.

Step 1: Make the hydropower generator

The first step is to take your old motor and disassemble it to isolate the main rotor and magnetic disk. Mark out a series of equally spaced points around the circumference of the magnet, and sink some holes through it as shown in the video.

diy mini dam drill magnet
Source: Great Inventions/YouTube

With that done, glue into place some more small neodymium magnets into the drilled holes and then reassemble the motor as required.

Next, take your old uPVC pipe end caps, and drill a hole through its very center and one either side of it.

diy hydro dam lids
Source: Great Inventions/YouTube

With that done, take a length of uPVC piping to the same diameter as the caps. Dissect the pipe into a series of equally-sized rings, and cut the pipe into pieces as required.

Cut the rings into two pieces and attach these to the modified end caps to make a series of curved blades.

diy mini dam blades
Source: Great Inventions/YouTube

Rinse and repeat to make a second water wheel, and then secure both of them to the rotor of the motor-come-generator. Weld the motor to a length of metal rod ready for mounting on the dam structure later.

Step 2: Make the dam's weir

With that done, mock up a mold for the main dam weir using bricks, shuttering, and cling film. Then mix up your cement as required. 

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Use the bricks to form a ramp structure, and add channels to the inclined surface using more bricks. 

diy dam weir
Source: Great Inventions/YouTube

Once ready, skim the entire structure using more cement as needed. With that done, rig up a frame and sluice gate for the dam as required.

You will also need a mechanism to raise and lower the gate by hand. This will probably require you to do a little welding. Install the gate to the top of the weir as shown in the video.

diy mini hydro dam gate
Source: Great Inventions/YouTube

Step 3: Make the main dam

Next, choose a suitable site for your dam to be constructed and begin to break ground. Mark out the position of the main reservoir and retaining walls, and excavate the ground as needed.

With that done, line the reservoir with cement, compact, and level out the cement as needed. Next, take your weir structure, and cement it into place at the mouth of the reservoir as needed.

diy mini dam retaining walls
Source: Great Inventions/YouTube

With that done, take some more bricks and build up the retaining wall/levee of the reservoir as needed. Once the structure is complete, skim the brickwork with cement as required.

With the main dam structure now complete, you can install your hydropower generator at the top of the weir in front of the main sluice gates.

Affix to the main weir structure as needed.

diy mini dam install generator
Source: Great Inventions/YouTube

With that done, wire the motor-come-generator to an AC/DC convertor and, in turn, to an electrical socket outlet. Place the outlet somewhere on the dam structure way from the main watercourse - for obvious reasons.

With all the main elements now complete, you can flood the main reservoir in preparation for using the dam for real. Once done, open the floodgates, plug in some small electrical appliances to the socket and watch your hard work pay off!

If you enjoyed this project, you might enjoy some other low-tech gizmos. How about, for example, making another outdoor mini-dam hydro-generator?

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