Home-brewed wind generators

[CapnK]

I have heard of 2 homemade wind generators that sound like intriguing ideas. Both sound as if they could be made to convert into log/tow generators also.

The first I heard of was from a friend who was living on his Morgan OI4 in Key West. He had a neighbor who had made a wind generator from a Volkswagen Bug generator and a prop (I don't know where he got that, or what kind it was). He'd hoisted the generator up into his foretriangle. Couldn't be used sailing, but *might* be convertible to towing...

The other I heard about was made from a lawn tractor starter motor, and the prop was a rotor for a remote-control helicopters. I think this too could be convertible to a towed rig. It would be lighter than the above, more able to be mounted back in the cockpit area and made to swivel like a commercially-made version.

OK, they'd have drawbacks compared to a commercially marketed model, sure. Things like overspeed protection (which would be important), prop brakes, etc... BUT - would the money you'd save by building instead of purchasing justify their use? I think that it might, plus there's the fact that my own small boat energy budget doesn't need as much juice from a wind generator as do the much larger boats which usually sport them whirring away on the stern. I could use a smaller simpler model, and work around some of the "drawbacks".

Currently, I generate all power into the house bank via a 50W solar panel mounted flat  on the lazarette hatch. If I could make a small wind/tow generator that could produce the same amount of juice (or more) than my current panel, I'd never have a worry, energy wise.

Anyone ever played with this idea, or seen it implemented? It is something I'd like to pursue later this coming year, maybe early summer when we get our version of "the Trades" (summer seabreezes :)).

[Captain Smollett]

Kurt,

My only concern with using a converted auto alternator or generator is making sure you have the correct voltage regulation.  Automobile regulators are usually two-stage and use difference voltage steps than optimimum for deep cycle batts.  Deep cycle batts need a three stage regulator.   And the voltages at each stage are different than those for auto batts.

If you are using a generator and external regulator so you can supply the proper regulator, then no problem, mon.  But, if you happen to use an alternator with integral regulator, it won't be good for deep cycle batts.

Also, as a secondary consideration, the auto units are probably not marinized.  If this has longevity issues is anybody's guess.

If you did want to go this route, and you had trouble fitting certain parts (spinner for a towed set, for example) there's probably no reason you could not buy components from Ampair or other vendor.

I recommed getting a Ferris catalog; they have a wide variety of components and ready-systems for independent, off grid power solutions.

[CapnK]

I've wondered if one of the smart regulators for solar panels would workto regulate charge. I think it would, so long as the voltage input to it was kept within design parameters.

The old-school VW Bugs were very much KISS-principle cars, they didn't have an alternator - just a plain old 12V generator, so it seems as if they'd be great for experimenting with...

[Captain Smollett]

I've wondered if one of the smart regulators for solar panels would workto regulate charge. I think it would, so long as the voltage input to it was kept within design parameters.

From the Ferris catalog I have, for their 30 A Multi Source Regulator with Divert:

This ... potects your Gel, Wet or AGM batteries from overcharging! IT works well iwth ALL renewable source of power, including WIND, WATER and SOLAR chargers.  The MSR features a fully adjustable voltage set point and easy to read LED status lights.  The integrated divert function allows you to use excess power that would otherwise be wasted

So, that one at least would be useable for any charge source.  The limiting factor, I think, would be if the regulator that comes with your solar panel is usable at the level of currents provided by your wind'water generator.

My guess is that your solar regulator is 5 A, or maybe 10 A, right?

The Ferris Waterpower 200 (similar in design to the Ampair 100) delivers 12 amps at 6 kts of boatspeed, and just under 20 A at 8 kts.  A 10 A regulator would not be suitable for that.

Ferris Power Products

[CapnK]

Not sure what the regulator on my panel is, currently. ;) (har har)

Looked at the Ferris products - they look nice, and intelligently designed. Did the math, the 200 Generator with the Rigging-Suspended conversion kit (to make it a wind gen), and that same Regulator you mention above, comes out to $1497 not incl. shipping.

That's a lot of wiggle room for some home-brewing. :)

I wonder if there is anything in the electronics of a trolling motor which prevents it from sending current back upstream? I'd imagine that there is, but it could probably be cicumvented. It'd be awesome to just poke one down through my outboard well, and have it send current back up to my battery when underway. :D

[Captain Smollett]

Not sure what the regulator on my panel is, currently. ;) (har har)

Looked at the Ferris products - they look nice, and intelligently designed. Did the math, the 200 Generator with the Rigging-Suspended conversion kit (to make it a wind gen), and that same Regulator you mention above, comes out to $1497 not incl. shipping.

That's a lot of wiggle room for some home-brewing. :)

Well, I think you could use your home-brew ex-volks generator, rig your own tow line and adapt an old prop or something as the spinner.  Buy a regulator for $200, and you are in.

I wonder if there is anything in the electronics of a trolling motor which prevents it from sending current back upstream? I'd imagine that there is, but it could probably be cicumvented. It'd be awesome to just poke one down through my outboard well, and have it send current back up to my battery when underway. :D

Um, I'm guessing that if it DID output voltage, it would not be high enough to charge.  You run a 12 V motor actually at something like 13.25 V or so, right?  But, the first charge stage is well over 14V (for some batts the first stage is over 17 Volts!).

What it might work good for is directly running 12 V appliances.

The other point is if you wanted to use your existing regulator with a towed gen, put a shunt/diverter in at just below the rated current of your regulator and be done with it.  Or, if you wanted to, go to Bomb Shack, er, I mean Radio Shack, but components and build your own regulator.  I'd guess that the time you spend doing this, after engineering and all, would make that $200 for the Ferris model seem worthwhile.

(HUGE DISCLAIMER:  For me to be pushing a store bought item over home grown DIY version is very rare.  Heck, I'm into designing and cutting my own sails to save money; but, your batts and their longevity are important to your safe passage, I'm assuming, so maybe paying for the proper engineering in a regulator is one of those rare instances that the $$ is well spent.  You could always look for a used one, too  :)  )

[captedteach]

VW generators have an external regulator (its under the rear seat on the drivers side if you go to a junk yard to get stuff)  The shaft runs all the way thru the unit as the drive belt is on one end and the cooling fan for the engine on the other.  NOW they do have to be polarized before they will work but I'm not about to try to remember that process -  Get a Haynes ot Clymer manual for that.  I'm not sure how much prop you would need to spin it but I do know they will stand 16,000 rpm for a while (I raced a VW for a while and we spun the heck out of the engine)

A friend of mine was going to build a generator for alternative power at his house  I can see if he ever got past the I'm gonna do this stage and sourced any parts

[Jack Tar]

Volks genorators will work. The generate at very low speed. The Alternator might work but its regulator system is self contained unlike the Gen. Marinized is easy. plastic spray coat everything you can. The bearings are sealed so no problem there. What the heck if you want to tinker its only a few bucks to pick one up and have it tested at Pep Boys. Alternators are not self exciting and need power to make power. The old D C Generators have a permanent magnet and need no external power to work. Thats why you can push start an old VW but not a new one with an Alternator. 

[starcrest]

these generators  are actually called servo motors.the one I had one starcrest was actually a computor drive motor.it also needed to have a diode put in line to prevent current from  going from the battery to the generator.plus this is a set up I devised myself.it was completely gimballed and the propellor was from a 30 foot inboard motorboat,a no bullshit prop.when generating current it would spin at 180 rpm,(I counted howmany times the tail end of the knot would hit my hand in 10 seconds)and when the load was disconnected from the battery it would run wild.in order to pull the prop in I had to wear gloves...the nylon rope would form large hockles that could tear the skin on my hand.I  would disconnect the rope from the generator and in a hand over hand motion I pulled the prop in and let the free end of the rope unwind in the water untill I had the prop shaft in my hand and the rope trailing behind the boat.the prop itself was on a 4 foot long aluminum shaft and there was 25 feet of line.during some conditions the prop would jump out of the water and back spin itself...quite a sight.

[Captain Smollett]

"They" make a recovery device that slides down the rope to stop the prop...kinda like a funnel.  I'm thinking a funnel would work.

[Fortis]

Hi. This is my first post here. Nice site!

I can actually contribute somthing here as we recently went through the excercise of trying to DIY a wind/prop tow generator and the original idea was to use off the shelf alternator parts,
My wife decided to run the numbers for it as part of her university maths project  in alternative energy sources.

The very very brief summary is as follows.

The very best marine alternators are about 30% efficient. The ones that come standard on an automobile are about 15% efficient. The reason for this is that they do not need to be better, and by the manufacturer's POV, they need to be as cheap per unit as possible.

So why such a low efficiency?

Well, for starters, Magnets. Commercial alternators use electro magnets that eat about 30-50% of the charge in order to "work".They also use a very narrow winding which means that a lot of the magents area of effect is missed.

The reason they can be like this is that alternators are hooked up to huge monsterous things called engines....And they have power to spare, so wasting it is acceptable.

If you are ever in sailing conditions that reproduce the sort of torque and rpm on your wind/tow alternator/generator that a gas or diesel engine gives off through its pulley...check the liferaft and radio the people on land that you love them. It is possible that  ABM AMRO1 in the Volvo race could pull along a tow prop driving an alternator at somthing like the revs and torque of a Suzuki Micra...maybe. Almost.

So the answer becomes using a "real" generator. This means genuine rare earth magnets, a broader coil (this means that instead of being the size of a standard alternator, it is about the diameter of a standard bucket) that collects more of the magnetic field, a regulator that does not automatically shut out low revs (cars idle at around 900revs, most units cut out anything less then 600) and improved bearings for reduced friction.

Now you are at about 85-90% efficiency, including at low revs, and do not need a lot of torque to turn the unit. All good...but you have spent a fair bit of money.

So what happens to all that lovely wasted effort that does not turn into electricity to gladen the cockles of your AGM?
Yep...heat. Now alternators form cars have a lovely notion of how to deal with this...they have great big holes cut in them and catch the passing breeze of both the car's rapid passage along the kinds of uncluttered roads only found in car commercials and the radiator cooling fan. Mostly fine, and it is not like it needs to be all that efficient.

Commercial tow and wind units are built more or less sealed, with cute little heat dispersal fins that radiate the heat out...but those fins actually are pretty carefully designed to take heat form critical areas inside the casing and make the whole thing work within its tempreture parameters. Of course, if it is over 100degrees F and in direct sunlight....it is going to be working outside of its temp range and be producing less power...but that's life.

Now you CAN just shove a commercial alternator into a waterproof can you make for it...and even try for some cooling fins...but it is going to further reduce its usefull output...and salty moisty goodness getting in there is not going to improve things.

So what, give up? NO!

Because an ideal home made generator is possible, it just looks really different to what you had in mind. It is basically a disk, imagine a breifcase, only round and about the same thickness. That si what your ideal generator will look like, and at that point it is practical and efficent and can be water proofed (it is so efficient that waste heat is greatly reduced as an issue, and cooling is simplified because of the increased speed around the rim of the much broader winding plate (which also becomes your flywheel and a good place to attach a brake...oh yes, a brake is a good idea for a wind generator, unless you enjoy that kind of gladitorial combat with six spinning blades).

So then we went looking to find if anyone was building gens along these lines...and wouldn't you know it, they were.

http://www.otherpower.com/

Check around their wind turbine pages and get the pics of their winding plates and stuff. They build on a much bigger scale then what works for boats...but they have got the efficiency thing down, and it can be scaled down nicely.

Some of the other stuff on their page is pretty out there, though the wind anemometer made from a bicycle speedometer is either a work of madness or genius!

So what else can I drop into this that might be of help?
More blades is better. Lots of shorter blades is quieter and more efficient then two or three big long blades for wind gens.
Mounting higher up is better as there is more wind the higher above water level you get.

Do not expect too much from your wind generator....The sheltered anchorage you want for yourself at night is going to be the same place that blocks all wind to the wind turbine. Anchoring in an exposed 30 knots of breeze to feed your batteries seems a bit of a waste in terms of comfort and enjoyment (Trying to run the aft-rail charcoal grill in 30 knots is a special way to make friends with the boat owners downwind).

The added advantage of the broad disk type generator is that you get rid of the drag of one of the bearings(the whole thing runs on one), which is nice)

I think I have more or less emptied my brain on the subject for a bit. I am going to go back to parusing the posts.


Alex.

[Captain Smollett]

Good info, Alex.  Have you tried the unit?  Does it work well on board?

[Captain Smollett]

Oh yeah, and welcome to the board.   :)

[Fortis]

Sorry, at this point it is a pruely a maths model...
Fortis is currently ona  cardle in our driveway with its transom backed up to my workshop doors...and it is going to get worse before it gets better.

Total strip out and rebuild. Some major hull modifications...All the fun and games of ending up with a 26foot pocket bluewater cruiser.

Actually building the generator is going to be a next year project.

All of my sailing lately has been on other people's boats...also all of my maintenance work and upgrades, but that gets to change soon.

Alex.

[Pixie Dust]

Welcome to the board!  Great to have new input and new ideas. 

[Captain Smollett]

Total strip out and rebuild. Some major hull modifications...All the fun and games of ending up with a 26foot pocket bluewater cruiser.

Sounds like you found the right forum. :)

What kind of boat is she?  Care to post some more info over in the SB/LD Cruisers Forum?

[krissteyn]

From my own experience  :o

when deciding on a prop configuration - confirm at what revs the tip of the blade exceeds the speed of sound  ::)

When this occurs - the prop can "explode" with little shards shooting into un-expected places and probably going right thru what it hits  :(

Also remember that any imbalance is exponentially a problem with increased speed and vibration kills the thing and increases noise.

Good post

keep spinning...

kris