Aerogenerator questions

[wedgeantilles]

Aerogenerator questions

You may not have noticed, but the forum software allows you to format superscripts and subscripts (using the X² and X₂ buttons). So you can write " w² " if you want to.

Dear Inetdog,

Many thanks, let's try it:

W²

I like to learn as much as I can.

Another thing, sorry for asking this in a thread, but if I want to rate all the comments and answers given by you and the rest, as perfectⁿ where n is far more bigger than one, how do I do it?

See you!

[ChrisOlson]

Let's give it a try Chris, and will also try to understand how you have estimated a Cp=0,37. Wish I was able to speak with persons like you everyday, just for a few minutes.

I estimated the Cp at .37. That would be average efficiency for a rotor of the type they use (from what I saw in the photos in the PDF).

Another crazy idea I have: if we connect a NO relay contact between positive and negative, just in case one day we have to give the aerogenerator a big brake

Yes, a small NO relay will work fine for stopping your small turbine. I would say a 40 amp would be adequate to handle the inrush when you initially short it without welding the contacts in the relay, even in the strongest wind.

On the regulator, I see no reason at all to bother with one if you are charging a decent sized battery (200ah or larger). The turbine simply cannot produce enough power to ever make it reach absorb voltage so it will basically float charge it (in really strong wind). That being said, a place where the wind blows at 10-12 m/s average is a VERY windy place. I know of only a couple places on earth where it is that windy on a consistent basis, and neither are suitable for human habitation because they are near the poles of the planet. At the more normal average wind speeds on a good wind site of 5-6 m/s I don't think your turbine will produce even 1 amp.
--
Chris

[inetdog]

Dear Inetdog,

Many thanks, let's try it:

W²

I like to learn as much as I can.

Another thing, sorry for asking this in a thread, but if I want to rate all the comments and answers given by you and the rest, as perfectⁿ where n is far more bigger than one, how do I do it?

See you!

The forum software does not have a mechanism for rating posts in threads. You can reply with a "thumbs up" smiley if you want. But members do not get any additional privileges, status or credibility based on any built-in karma or rating system. I am not sure if this is a conscious choice of the owner or just a limitation of the software used.

But you can increase the usefulness ranking of the whole thread if you want to alert other members to look at it first if when shows up in a search result.

Look at the "Rate this thread" link at the top of each thread.

[wedgeantilles]

I estimated the Cp at .37. That would be average efficiency for a rotor of the type they use (from what I saw in the photos in the PDF).



Yes, a small NO relay will work fine for stopping your small turbine. I would say a 40 amp would be adequate to handle the inrush when you initially short it without welding the contacts in the relay, even in the strongest wind.

On the regulator, I see no reason at all to bother with one if you are charging a decent sized battery (200ah or larger). The turbine simply cannot produce enough power to ever make it reach absorb voltage so it will basically float charge it (in really strong wind). That being said, a place where the wind blows at 10-12 m/s average is a VERY windy place. I know of only a couple places on earth where it is that windy on a consistent basis, and neither are suitable for human habitation because they are near the poles of the planet. At the more normal average wind speeds on a good wind site of 5-6 m/s I don't think your turbine will produce even 1 amp.
--
Chris

Dear Chris,

Crystal clear, thanks for your comments, will do as you say. And thanks for the info on the contact rating.

All the best,

[ChrisOlson]

Crystal clear, thanks for your comments, will do as you say. And thanks for the info on the contact rating.

I think your turbine will be a lot of fun for you. But I don't know how much energy it will produce for an off-grid system. It is designed to be used on a yacht where when the boat is under way the wind will trickle charge the house batteries in the yacht. We have a 58 foot yacht moored at a marina on Lake Superior and it used to have one of those little turbines on it (except a different brand) but we took it off because it never worked very good. We put 1.5 kW of solar panels on our yacht instead, on top of the pilot house.

The main thing is that a small turbine that size is not a real high energy producer, so I would not expect a lot from it.
--
Chris

[inetdog]

It is designed to be used on a yacht where when the boat is under way the wind will trickle charge the house batteries in the yacht.

Yep, the average relative wind for a boat under way will be a lot higher than for a moored boat.
Even on a sailboat.

[Naptown]

Yep, the average relative wind for a boat under way will be a lot higher than for a moored boat.
Even on a sailboat.

Depends on the direction a sailboat is going in relation to the wind

[inetdog]

Depends on the direction a sailboat is going in relation to the wind

On the average, a sailboat is unlikely to be running directly downwind all the time.

[ChrisOlson]

On the average, a sailboat is unlikely to be running directly downwind all the time.

That's right. For anybody that has done much sailing, you got some serious wind in your hair most of the time. Those small marine wind turbines are extremely popular on sailboats to charge house batteries because the small Yanmar propulsion engine and onboard generator are usually too small to charge the batteries.

Even on our yacht where we have twin Cat 3406 diesels, the alternators on the propulsion engines only charge the house bank at 28.8 volts. The solar or shore charger can absorb them at 31.9V, which is required for proper absorption charging. So the propulsion engine's alternators can only be used to maintain them when underway, never charge them.
--
Chris

[SunEagle]

On the average, a sailboat is unlikely to be running directly downwind all the time.

Wouldn't the wind turbine keep changing directions. It could face into the wind pushing the boat or into the wind coming over the bow of the boat depending on which wind was blowing harder or does it even work like that?

[Naptown]

That's right. For anybody that has done much sailing, you got some serious wind in your hair most of the time. Those small marine wind turbines are extremely popular on sailboats to charge house batteries because the small Yanmar propulsion engine and onboard generator are usually too small to charge the batteries.

Even on our yacht where we have twin Cat 3406 diesels, the alternators on the propulsion engines only charge the house bank at 28.8 volts. The solar or shore charger can absorb them at 31.9V, which is required for proper absorption charging. So the propulsion engine's alternators can only be used to maintain them when underway, never charge them.
--
Chris

That was not my experience in 25+ years of sailing with small diesels.
But I also modified the pulleys on the alternator and replaced with high output alternators so I could charge at lower Rpm's

[ChrisOlson]

That was not my experience in 25+ years of sailing with small diesels.
But I also modified the pulleys on the alternator and replaced with high output alternators so I could charge at lower Rpm's

Even so you're lucky to get 500 watts of charging power. Depending on the size of the boat, if you have four 4D's onboard that are half sacked you're usually looking at 12 hours to charge them up with any setup I've seen on a sailboat. That's why the little turbines are so popular. They help maintain the battery if you're going to be at sea for a couple weeks so when you do have to run the Yanmar to charge them up it doesn't take as long.

With motor yachts it's different because you have a couple 600+ hp marine diesels down in the engine room that can easily power dual 135A 24V alternators, and they're running all the while you are under way. Although I still see a few motor yachts with those little turbines - mostly Ampair 300's.
--
Chris

[Naptown]

Never had need for that much battery

2 group 31's was sufficient for a week long cruise.

[ChrisOlson]

Never had need for that much battery

2 group 31's was sufficient for a week long cruise.

Yep - it depends on how big the boat is and how much electrical equipment you have. Most of the live-aboard sailboats in our marina have 600-800ah 12V house banks. The ones that have wind turbines use the wind coming off the main sail to drive the turbine.
--
Chris

[inetdog]

Wouldn't the wind turbine keep changing directions. It could face into the wind pushing the boat or into the wind coming over the bow of the boat depending on which wind was blowing harder or does it even work like that?

It would indeed face in whatever direction it needs to. But if the boat is running downwind the relative wind from behind will be slower than the actual wind speed relative to the earth.
And if a boat it tacking crosswind, the wind over the sail (and to some extent over the bow) can be much larger than the wind speed.