Mini Hydro Generator - Economy parts

[Mike8500]

Hey Guys,

Just signed up to this board.  I have a fascination of generating a small amount of power 25-30W for personal use.

My plan is to build a Micro Hydro Generator with common parts.

The Creek i intend to tap, has plenty of flow, but low head.  THere is no significant drop, just a steady ~10:1 run.  I cannot block the water completely as it is a fish bearing stream.

I have a good working GM alternator which I intend to use if possible, for simplicity reasons, if I can get enough power from the creek.

After researching these setups on the net, I intend to make something like a water box, far upstream to cather approx 10GPM of water, then pipe it downstream approx 50ft to the generator.  

I intend on using a water wheel of sorts, possibly multiple as I don't have any pumps to use for turbines.

Now I realize that the alternator is going to need to spin at least 900RPM to put out >12V.

This would mean a 1ft water wheel in a creek with a water speed of 2ft/s would need a 23.5:1 gear ratio to spin the alterator to 900RPM.

Non this particular alternator can consume up to 5hp wihtout problem.  

I am fearing a loss of efficiency through the pully/belt reductions.

Would it make sense to use 2 wheels right after eachother to catch more flow, or one wheel with bigger scoops?

How does one determine the most efficient wheel desgin/size needed to produce a certain amount of power.

This alternator is capable of putting out 50+ amps but i only need 2 or more to trickle charge a 12V car battery too run a stereo, possibly an inverter for 11 devices.

I can throttle the current that excites the fiel of the alternator to reduce current output and lower the power needed to turn the wheel.

The reason I want to use the GM alternator is that it is already recitified and regulated.

Is turning an alternator with a wheel/low head setup possible??

Thanks for your input.

[Gog]

Hi mike , I think you alternator may eat up all the power your little wheel might produce.

I have a little 4 ft x 14 inche breast shot wheel (water feeds in at axle height , two ft drop)

It has a crude bicycle chain drive to a 25" bicycle wheel with a permanent magnet washing machine motor

friction driven off the tyre but that will soon be changed.

With a relatively full 12" x 6" feed flume it puts out 25-30 watts

Or I should say did untill we received 6" of rain in 7 hours and the creek went from 6" deep to 5 ft.

The wheel now needs some repairs after being tied to a tree to stop it being swept away

A learning experience

I'll supply better flow/power figures when I get it all put back together

Cheers

[hiker]

check out--otherpower.com--

then go to the bottom of the page and click on-hydro-

may be of some help.........

[willib]

i would love to see some pics of that setup , even during the rebuilding process would be great !

[Nando]

Mike:

You are going too fast and at the same time guessing

Car alternators are not good for you, inefficient and will take most of your energy to just feed the field rotor.

Stop the idea of using gearing for the generator.

Now, go to the stream and from the upper part where you can place the intake to the lower part where you can place the turbine measure the head or slope, do not guess or estimate -- do it, to have for sure what you have -- then measure the water volume ( total ) in gallon/sec or liter/sec of what ever you want.

Supply the info, then we can tell you what can be done, practically.

10 gpm = 0.63 liter/sec will produce 3 to 3.8 watts for each meter of head ( 3.3 feet).

So, we will be waiting for your data.

Nando