Hydro Power

Discussions about Renewable Energy, including photovoltaics, wind, and small scale hydro.
Creating power for your home, off grid.
Emphasis on nuts-n-bolts, hands-on projects.

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Sharkey
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Post by Sharkey »

The hydro plant is back on line. I couldn't find a solvent-based cement that would fuse both the wheel and buckets. ABS plumbing cement reacted with the wheel, so I used it to "pot" the buckets into the lower wheel, filling all of the voids between the bucket mounting tabs and the wheel assembly. Before putting the top cover back on the assembly, I drizzled cement over the tops of the buckets, then pressed the cover into the layer, latching it into place.

The result is that the wheel and buckets are now one solid piece. Although the cement did not burn into the plastic of the buckets, it does adhere well to them, so they are unable to move.

Putting the plant back into operation, it makes full power (10 whole watts) and now runs much more quietly, with the sound of the water spray and a tiny background hum as the buckets rotate in and out of the stream.

Done for now, next time this needs attention, it will be the end of life for this project and time for a new plant.
Sharkey
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Post by Sharkey »

Running up to the three month mark, with a week off for rebuilding...

Yesterday, I decided to do something about all the tail water coming off the plant. I've been a bit concerned about it from the beginning, soaking the ground right next to the house on a hillside didn't seem real smart, and that ice buildup couldn't have been good either.

Spent a few minutes with a second plastic water jug and a razor knife, and made a slip-on bottom cover to catch the water and direct it into an old piece of gutter to carry the water away from the area.

Image

The gauge is reading a bit low these days, I have a leak somewhere in the pipe coming down from the spring. This afternoon, I went up to the spring to clean the screens, etc, and after removing the supply from the barrel, I watched the water level drop rapidly. Something is amiss with the pipe somewhere down the hill. If the next couple of days are rain-free, it looks like I'll be trudging up the ravine to see if I can find the problem.
Sharkey
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Post by Sharkey »

A year and counting. This little project is still paying off, as I'm using it once again to keep the batteries topped off as the light disappears towards winter. To be fair, it didn't get run much over the summer, but it still seems to be holding together.

No improvements since the last post, I haven't even had an opportunity to take it down to the lower garden and try it at higher pressure. I do think about trying to put together a "linear current booster", essentially a buck/boost converter so that I can find the optimal running voltage for the plant and then convert that (whatever it turns out to be) into a charging current for the batteries. I do know that the plant puts out more current at voltages above 12 (13.5 - 15 V), but less when connected to the 24 volt system, and even less when the 24 volt system is full (~28 V). Somewhere between those two potentials is a "sweet spot" where the voltage and current curves intersect to produce the maximum number of watts.

Now that I've written it down, it sounds like a lot of trouble for a device that will still produce less power than a couple of night lights can consume...
Stealth Camper
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Post by Stealth Camper »

Yeah, but it is still very cool!
Sharkey
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Post by Sharkey »

Today, I did something that I've wanted to do since the first day of this project, I took the hydro down to the lower garden and connected it to the water supply there. Being as the garden is about 40 feet lower in elevation, there was more pressure available. I was able to put the larger orifice nozzle on the plant and maintain about a 27 PSI running pressure.

The power output of the plant into a 12 volt battery was doubled with this increase in pressure and nozzle combination. I was able to put out a scorching 20 watts!

Of course, there are some drawbacks to this configuration. One problem is that I am about 200 feet away from the house, meaning that there's no easy way to get the power back to the batteries.. The other problem is that with the running pressure at 27 PSI at the plant, there was nearly zero pressure and no flow of water up at the house. Both of these problems are surmountable, I can string wire all up the hill to return the power, and some manner of servo-operated valve will need to be fitted to the plant so that it can be shut down automatically when water is drawn from the domestic supply. I just need to decide if it's a priority project or not. Having 480 watt-hours available is attractive, but that's less than 3¢ worth of electricity a day. Lots of other important project around the homestead waiting ahead of this in the line of to-do's.

For now, the plant is back on it's cider block humming along and making 10 watts of power to keep the lights on in the Housetruck. Maybe that's enough for now.
Sharkey
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Post by Sharkey »

Time for some unscheduled maintenance. Last week, I went out and turned on the plant at dusk in preparation for the evening's lighting. About nine o'clock, I noticed that the plant wasn't putting out any power, as indicated by the dedicated ammeter inside the Housetruck. "Great" I thought, "the spring has quit again, I'll have to trudge up the hill again tomorrow and get it put back into shape", and got on a coat to go out and switch the house and truck over to the backup water supply.

When I got outside, I could hear that the water was running full on at the plant, but it didn't sound quite "right". Looking at the plant revealed that although the water was blasting the pelton cups, they weren't rotating. I reached underneath the plant and gave them a twist. It was stiff, then started spinning of it's own accord. I just assumed that since the weather was below freezing, I just had some ice buildup somewhere that prevented the plant from starting up, and I just hadn't noticed.

This morning, I went out to shut the plant down when the batteries looked like they would get filled by the PV array, and found the plant stalled again. This time I know it was running, because I had checked for charge current when I got up. Obviously, something was binding inside the generator, and putting enough load on the shaft that the pelton had been unable to supply enough power to keep it turning. Time to investigate.

Just at dark tonight, I went out to turn the plant on, and decided it was the right time to find out what was going on. I removed the plant using the pipe unions, unplugged the electrical wiring, and took it into the garage. I was afraid that it would be a rusted-solid block of corrosion, but amazingly, it all came apart easily. I attribute this to all the lithium CV joint grease that I slathered on all the exposed surfaces, motor shaft, etc before I assembled it last time.

Inside the motor/generator, I found that the brushes were worn almost all the way down (no surprise), and that the motor case was well filled with carbon from the brushes. The front (shaft) end of the motor seemed to be very stiff in the sleeve bearing, so I completely disassembled the armature and end plates, cleaned everything up, and relubricated the bearings. I also chucked the armature up in the drill press and used some emery cloth to polish up the commutator.

Nothing to do about the worn brushes, they still had a few hours left on them, so I reassembled the motor, put it all back into the housing and reassembled the pelton runner, etc. After it was done, the motor shaft turned freely and had no sticky spots.

Putting it back online brought it up to full output, and it runs quieter than ever. Next time I go to the city, I'll have to stop by the motor shop and see if they have any brushes that can fit this motor, or something that can be modified to fit. If I can replace the brushes, I think I can get another year and a half out of this thing.
Wallfly
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Post by Wallfly »

Great little contraption - long may it spin!
But when it does finally clap out it will be interesting to see what replaces it. I suspect that you won't let that source go to waste for long.
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