Waterwheel

[PettyVTX]

Hey guys! I am in the process of putting together a waterwheel micro hydro generator to power my man cave/shack. It consists of a full size refrigerator, a 42" LCD tv, small stereo, ceiling fan, small well pump, 10 gal hot water heater. I probably won't be able to run all this off the hydro, but can split it with power I already have. My waterwheel if 4 foot wooden wheel with an 18" pulley that turns 36RPM, running 24/7 thanks to a steel dam which is about 3 foot high built by a previous landowner to flood a wetland. Only problem is man cave is 500 feet away, so I am assuming I have to run an AC PMA.
I have 18 AGM 40AH batteries that were given to me that are in perfect shape.
What do guys think? What do I need to finish this job as far as controller, inverter and dump?
Is this doable?

thanks
Ted

[dbcollen]

you would get much more power if you lowered the wheel, turned it around and fed the water over the top of it. you are using it like an impulse turbine, instead of using the weight of the water and gravity to turn the wheel.

[Flux]

Yes absolutely, the over shot wheel is far more efficient.

Flux

[PettyVTX]

I wish I could I tied that setup first but I only have a foot below the waterwheel then granite. the breastshot is my only option but I do have a constant 4" of water coming out of a 6" pipe its hard to stop the wheel lots of torque. I live in Georgia so it never freezes and it the stream feeds a river on the backside of my property. This was going to be a yard wheel to start but ended up here. I think if I was going to start again I would built a smaller wheel to do a overshot. but for now im stuck with a 4' wheel and a 3' Dam not much head there.

[thirteen]

Could you go farther down stream with an extension on your pipe to get an over head flow on the water wheel. 13

[Bruce S]

Bunch more information needed.
Are you planning on building the PMA? or do you have something like a ECM motor or? that you plan on trying to use.
500 feet away is a haul for low voltage DC ! What size wire do you already have?
What are the loads in watts; you'll want to have on the system?
Generally there are two routes you can go for the batteries and inverter
1.) PMA, batteries and inverter close to the source. Let the inverter bring voltage up to 120/220 Vac , use extension cords , BUT still 500 feet!!
2.) Build / buy PMA that runs at high voltage wild AC, rectify it at the cave down to voltage for inverter, then run loads listed.
Both have their (+ n -)
Wire size is going to be important that's for sure.

[Flux]

Not easy to give much help without knowing the system volts and the power available from the wheel, have you tried a rope brake with spring balance to find out what power you are likely to get, it won't be a lot so the transmission loss may not be as serious as for a higher power source.

For long cable runs,high voltage ac is better, 3 phase is better but may not be worth the extra cable for a small set up. I wouldn't rule out a high voltage 3 phase alternator rectified at the wheel and a dc/dc converter to get the volts down for the battery. Best of both worlds to some extent. At the power level you are likely to get , running dc to a buck converter type solar controller may be better and cheaper than messing with transformers. 150v input solar controllers are readily available. I don't think I would want much higher voltage for hydro without serious consideration of maintaining insulation integrity in a wet area.

Flux

[PettyVTX]

I really just need to keep the refrigerator running. The man cave is only used on Saturday for poker and adult beverages. the ceiling fan and light is about all that is used 1 night a week so I can let the battery bank charge all week at a trickle with the only thing running is the frige. I was thinking a  PMA / 24 VOLT AC 3 PHASE Wind Turbine Permanent Magnet Alternator Generator PC with a 100 AMP 1600V VOLT THREE PHASE BRIDGE RECTIFIER DIODE WIND TURBINE GENERATOR DC and a
Battery Dump Controller SOLAR Controller Wind Regulator, Fused of coarse with a POWER INVERTER 12V DC to 120v AC 3000/6000 WATTS. Do you think this is over kill. I was going to run 3 phase to the cave then convert. I would hate to try to convert at the wheel due to the possibility of theft. I don't know what a rope spring test is could you explain. Like I said im new at this.
Thanks
Ted

[PettyVTX]

Could you go farther down stream with an extension on your pipe to get an over head flow on the water wheel. 13

No I looked into that the creek runs flat and lots of rock bottom so I cant dig it out.

[PettyVTX]

Im looking at another way to run the wire. I think I can cut the length in half if I run it a different way. I have some 240v 4 wire in aluminum conduit I can make the run but its thru the woods and I cant bury it.

[Flux]

Take a piece of rope, tie a spring balance to one end, take the rope over your pulley and anchor the other end of the spring balance to something below the pulley. Add a weight to the free end of the rope and this will cause it to drag the pulley. Find a weight that drops the wheel speed to half its free running speed. Read the spring balance and deduct the weight from the reading.

From this force you have measured ( balance reading - weight) and the radius of the pulley you have the torque the wheel can sustain at maximum power point.

HP can be calculated from 2 x pi x N x T/33,000  Where pi is 3.142, n is the speed in revs/minute and T is the torque you measured. To get watts multiply hp by 746.

I don't know how much solar you have but I don't think the water wheel is going to produce a lot. Yes it will add up in the battery all week but I suspect having to run a fridge is the killer. Even with an efficient battery boat fridge you will need a continuous 20w to keep it running, using a mains fridge via an inverter you will need over 60w.

Halving the cable run will help. I don't see why a little rectifier in a box is more likely to be stolen than the wheel or alternator. I could see that leaving batteries and inverter at the wheel end could be a problem.

I think you are thinking way beyond what this system can produce, Even a charge controller may not be needed unless you have lots of solar. I think for efficiency you are forced to use the dc efficient fridge so the inverter need not be very big for lighting and if you choose 12v the new LED MR16 lights are probably all you need. If the solar has its controller you won't need any controller for the hydro it won't supply the fridge and battery self discharge.

Flux

[PettyVTX]

Leaving a rectifier at the wheel wouldn't be a problem I just thought that I needed to run 3 wire AC to the end of the wire run then convert with a rectifier to get more current with smaller wire. I also have seen on the internet a PMA 6 to 1 ratio that would turn my 250 RPMS to 1500 Rpms. If my wheel wouldn't get bogged down. I have a spring balance I bought years ago I need to try to dig it out and try to calculate the HP before I buy a PMA.

[PettyVTX]

Well I finally got everything working. I used a E-Bay Pma 12V 3 phase, built a dump load system, my pma puts out 22V after 500FT. rectified in the man cave, 18 40AH AGM sealed batteries. My dump cuts in at 14.3V and cuts off at 12.5 and is dumped into a small hot water heater. Everything (lights, Radio ,blender) is working with a small 400W inverter. My only problem is it takes my batteries forever to charge back to dump load again fast at first slower toward the end. I guess im only getting a trickle amp charge im going to put a shunt in my system to see how many amps im using and putting in. I picked up a RYOBI watt meter at home depot marked down so I can measure my watt usage. But it looks like to recover faster im going to have to add a couple of 245W solar panels. Any other ideas?

[Mary B]

If the alternator is a converted car one that is your problem and where I would start. Replace it with something real.

[joestue]

Well I finally got everything working. I used a E-Bay Pma 12V 3 phase, built a dump load system, my pma puts out 22V after 500FT. rectified in the man cave, 18 40AH AGM sealed batteries. My dump cuts in at 14.3V and cuts off at 12.5 and is dumped into a small hot water heater.

well fix the dump load cutting off at 12.5, change that to 13.5.
also you're losing i'm guessing 2 volts in those diodes.
if you have some scrap computer power supplies, they have a 30 amp Schottky diode in them. you will need 6 of them. some power supplies have two of them, this will save you at least one volt, maybe 1.4 volts, should save you 5% or more power.

gearing up the alternator further is also an option but i suggest you measure its efficiency first before doing that.

[tanner0441]

Hi

If you can't lower the wheel can you build a dam to hold the water back? Your not holding the water back to gain pressure your just holding it back for depth. Looking at your wheel you are only getting a few degrees of thrust and your buckets are spaced fairly far apart.

Brian

[Flux]

Difficult to comment without knowing the power you are getting in relation to what is available. Measure head ( which you seem to know),flow and you can estimate what is available.

Rather than using the wattmeter to measure your load, use it to measure what you are generating. If you are getting 40% of the available of power into your battery  you are doing fine and not much more can be done but if you are way down in efficiency then you have a chance.

I suspect it may be a good idea to measure the wheel power out before the electrical stage to see where improvement is possible.

Just looking at the pictures the waterwheel may not be very efficient, no information to have any ideal of the electrical figures but 50% or better electrical should not be difficult, if you are way down on that you have room for improvement but at a cost.

Flux

[PettyVTX]

Yeah the waterwheel was going to be a yard ornament with a solar power pump in a small plastic pond. Yes the PMA is a converted alt. I just wanted to see if I could use the small metal dam that was already available to me. Here is some video and the make shift gearing I did as you can see in the background I have a beaver problem. I have to clean up every morning after them. They are relentless. Cant get the video to load to big I will try later.

[XeonPony]

Ya there is your biggest issue those alts are useles imo, even at higher speeds. Get a real perpose made generator head.