Small wind turbine

[tazmann]

Hello all
I have always been kinda interested in wind turbines so when I ran across one on amazon for about $140 I could not resist. 24 volt 400 watt rated , anyway tested on bench with drill running it the AC part was good 60-65 volts on all 3 legs but the dc charging side was low, 3-1/2 amps with the drill maxed out not sure if the amp gauge was reading right ether, old school mechanical with shunt built on . needless to say I ordered a inline digital. The wife was watching the battery bank voltage and it was climbing pretty fast so I'm thinking it was a lot more than 3-1/2 amps. Anyway it is up on 10 foot pole temporary running and it does work, only getting 6-7 mile an hour winds so it's just trickle charging . If it works out ok I might make a portable stand with couple couple solar panels, couple batteries, wind gen on top

 

[Forbisher]

There is no power at 7mph.
Maybe a 30 foot tower if you actually get decent wind at your location.
A long but good read for wind enthusiasts.

The Truth About Small Wind Turbines – Solacity Inc.

Installing a small wind turbine? Get the information you need for an informed decision: The good and the bad, just the literal truth to help you choose.

www.solacity.com

Small Wind Turbine Site Selection – Solacity

Wind turbines work better when properly located! This article explains how to site a wind turbine; clearance from obstacle, turbulence, and tower height

www.solacity.com

 

[Ampster]

I still am fascinated with wind turbines. They need to have a good controller because they will self distruct if they do not always have a load or a way to brake their own rotation. They are much more complicated than solar panels.

 

[tazmann]

Plan is to complement the solar system on the motor home so it has to be portable and simple to setup, winds here at house are light and fickle on average so wind is not a good option. I am using the controller that came with it, has built in brake control and it is supposed to come on at 29 volts. If that actually works I should be ok. I tried to test that part yesterday turned on two solar panels and managed to get 65 watts with the sun far to the west and all the smoke in the sky and the wind turbine I would guesstimate 10 watts , battery bank hit 26.4 volts wind died and sun went down

 

[tazmann]

I can think of one really good way to spin a turbine mounted to a motor home!

Driving down the road

 

[tazmann]

Just an FYI for lighter winds. Bought an inline watt, amp, and volt meter plus a handheld wind meter. Prop will start spinning at about 5 MPH and then keep spinning down to about 3 MPH, at 5-1/2 MPH prop is sinning fast and the wind feels good but getting 0 output. At about 6 MPH it will start charging at .02 amps, .5 watts. Weather was saying 8 MPH but it was running 4-6 and about the best I got for short burst was 6.4 MPH and hit .2 amps, 5 watts. Looked it up online and that is about the norm 6-1/2 MPH to start producing power

 

[Forbisher]

6 mph wind is no power.
Need 15mph.
You must not have read the article.

The Truth About Small Wind Turbines – Solacity Inc.

Installing a small wind turbine? Get the information you need for an informed decision: The good and the bad, just the literal truth to help you choose.

www.solacity.com

 

[Forbisher]

Weather was saying 8 MPH but it was running 4-6 and about the best I got for short burst was 6.4 MPH and hit .2 amps, 5 watts. Looked it up online and that is about the norm 6-1/2 MPH to start producing power

From the article:
3 foot diameter turbine can make 160 watts rated power at 25 mph winds

I often see people post questions on forums, where they are looking for a wind turbine “with a low cut-in wind speed”. Depending on whom you ask, the cut-in wind speed is either the wind speed where the turbine starts turning, or the wind speed where it starts to produce some power. For most wind turbines it is around 2.5 – 3.5 m/s (5.5 – 8 mph), and it is an utterly meaningless parameter.

There is no energy in the wind at those wind speeds, nothing to harvest for the turbine. While it may make you feel good to see your expensive yard toy spin, it is not doing anything meaningful in a breeze like that:

To give you some idea, a wind turbine with a diameter of 6 meters (pretty large as small wind turbines go) can realistically produce just 120 Watt at 3.5 m/s wind speed. That same turbine would be rated at 6 kW (or more, see the next section), so energy production at cut-in really is just a drop in the bucket.
What is more, due to the way grid-tie inverters work, you are about as likely to be loosing energy around cut-in wind speed to keep the inverter powered, as you are in making any energy, resulting in a net-loss of electricity production.

 

[tazmann]

6 mph wind is no power.
Need 15mph.
You must not have read the article.

The Truth About Small Wind Turbines – Solacity Inc.

Installing a small wind turbine? Get the information you need for an informed decision: The good and the bad, just the literal truth to help you choose.

www.solacity.com

Yep I did I just posted fyi of results of the cheap turbine so folks know what to expect out of them. Today wind is bumping around at 5 to 8 MPH at the 8 + MPH it is charging 1/2 amp 12 watts at about 25.5 volts So not much but better than nothing

 

[snoobler]

Wind turbines and solar trackers seem to be on the poo poo list in this forum. Interesting.

The poo poo list exists for a reason. Wind is poor in most parts of the U.S, the industry is rife with misleading marketing, and getting a straight answer from an installer/seller is often a struggle. They will happily take more of your money for a 2kW 2m turbine over a 1000W 2m turbine knowing full well, a customer will never benefit from the difference - neither of which will ever produce anything near either rated number, and they will produce exactly the same amount of power for a given wind speed.

2-axis trackers improve yield by 30-40%. It's cheaper to buy 30-40% more panels than put panels on trackers. If you live in an area where you can't increase your array by 30-40%, then maybe a tracker is a good idea, but for the vast majority of installations, they're the wrong choice.

 

[boondox]

Wind turbines and solar trackers seem to be on the poo poo list in this forum. Interesting.

There reasons for that. In my case I have built both, good examples of each. I had a great time building them. Both times the juice wasn't worth the squeeze. Many others have had the same experience.

 

[snoobler]

the juice wasn't worth the squeeze.

Even with 22 years in OK, I never heard that.

Quoted for truth

 

[tazmann]

Wind turbines and solar trackers seem to be on the poo poo list in this forum. Interesting.

it is understandable, If you bought a wind turbine in my area with high hopes you would be disappointed. My brother lives about 20 miles from me in the hills all off grid, several trackers and arrays , battery house you name it anyway couple years back he put in a big wind turbine, set it up to catch the wind coming up through canyon. He was not a happy camper over that one, not sure what the story was on it but it was pissing him off just thinking about it so I didn't ask.

 

[GLC]

Check this guy out. He has several videos. He is to wind as Will is to Solar..

 

[snoobler]

Don't insult Will. Will follows a reasonably scientific process. Will approaches things with skepticism. John feels like a "proud papa".

That video is raw bullshit. First, he's estimating wind speeds based on what Weather Underground is reporting. I'm seeing NO anemometer.

I'm not seeing that he's verifying his claims with a second source. There is an absolute limit to the amount of kinetic energy in wind. It's impossible to pull more than that.

He's also at about 3700ft elevation, so he's already taking a hit due to lower air density.

AND he's using a cheap watt meter. I have half a dozen of them, and they're not consistent. 50-100% variation, and the same unit will have dramatically different errors at different currents. If he's verifying current with a respectable clamp meter, I'll buy its output, until then, I have no confidence that either his wind speed, his current or his power values are accurate.

Assuming that wind turbine is MORE efficient than the most efficient ones in the world, at the claimed 14mph the MAXIMUM POWER YOU CAN GET FROM WIND WITH A TURBINE THAT SIZE IS 95W.

If we assume that the wind turbine is nothing special and has a 30% efficiency, in order to get the 240W there's at least a 21mph wind.

This may seem like a nitpicky small thing, 7mph difference, but wind turbine power is proportional to the wind velocity squared, thus power drops off rapidly with decreased wind.

Using his WU wind graph, it looks like the next several days will be 5-7 mph.

He will be getting a whopping 9W for the next several days at 7mph wind speed assuming the turbine spins at all.

If you have sustained high speed winds, then wind is fantastic! Unfortunately, the vast majority of the country does not, and wind becomes a poor choice.

To clarify my position, I'm pro-wind. I plan to eventually install a wind turbine for about $2400 complete. It has a larger diameter and will be mounted on a free standing 24' tall pole. There are long periods where we have SUSTAINED winds in excess of 20 mph that die down at night, but I'm going to be happy with an average of 80-100W throughout the year. Some periods will be crazy high. Some will be zero.

 

[snoobler]

Though, he sounds a lot like the lead singer from The Beat Farmers:

 

[Hedges]

Wind turbines and solar trackers seem to be on the poo poo list in this forum. Interesting.

Do the math.
When I put in PV 15 years ago, a consumer size tracker cost as many $$ per kWh/day additional power as adding PV panels.
Back then PV panels cost $4 to $5 per watt.
So trackers were cost parity as for as capital cost goes.
However, active trackers were expected to last 5 years, but PV panels were expected to last 25 years.
Today, PV panels cost me $0.35/watt, so I wouldn't eve consider that sort of tracker.

I just over-panel, but I do so with multiple orientations on a single MPPT input. Think of it as passive tracking. I get multiple orientations without moving parts.

 

[Hedges]

Another thing about wind power is that the efficient turbines rely on lift, which gets killed by turbulence, like having a bumpy ride in an airplane.

There was a study done, testing output power from many wind turbines. Wind speed was measured. Power output from the turbines was well below spec for the speed (forget if it was low by 33%, 50%, or 66%). Only non-turbulent wind would provide the lift needed by wind turbine airfoils to meet specs, and most locations had too much turbulence at the height of the towers.

If you build a drag device (an anemometer, or split 50 gallon drums on vertical shaft) and use that as a wind generator, it's output won't be impacted by turbulence. It'll be equally poor, with or without turbulence.

Home wind turbines are probably a good thing for select locations, and for off-grid homes during poor weather. If you get a week of clouds and storms, the wind turbine will be giving you power when PV isn't. You pay capital cost to have it there, but worth it.

 

[GLC]

Don't insult Will. Will follows a reasonably scientific process. Will approaches things with skepticism. John feels like a "proud papa".

That video is raw bullshit. First, he's estimating wind speeds based on what Weather Underground is reporting. I'm seeing NO anemometer.

I'm not seeing that he's verifying his claims with a second source. There is an absolute limit to the amount of kinetic energy in wind. It's impossible to pull more than that.

He's also at about 3700ft elevation, so he's already taking a hit due to lower air density.

AND he's using a cheap watt meter. I have half a dozen of them, and they're not consistent. 50-100% variation, and the same unit will have dramatically different errors at different currents. If he's verifying current with a respectable clamp meter, I'll buy its output, until then, I have no confidence that either his wind speed, his current or his power values are accurate.

Assuming that wind turbine is MORE efficient than the most efficient ones in the world, at the claimed 14mph the MAXIMUM POWER YOU CAN GET FROM WIND WITH A TURBINE THAT SIZE IS 95W.

If we assume that the wind turbine is nothing special and has a 30% efficiency, in order to get the 240W there's at least a 21mph wind.

This may seem like a nitpicky small thing, 7mph difference, but wind turbine power is proportional to the wind velocity squared, thus power drops off rapidly with decreased wind.

Using his WU wind graph, it looks like the next several days will be 5-7 mph.

He will be getting a whopping 9W for the next several days at 7mph wind speed assuming the turbine spins at all.

If you have sustained high speed winds, then wind is fantastic! Unfortunately, the vast majority of the country does not, and wind becomes a poor choice.

To clarify my position, I'm pro-wind. I plan to eventually install a wind turbine for about $2400 complete. It has a larger diameter and will be mounted on a free standing 24' tall pole. There are long periods where we have SUSTAINED winds in excess of 20 mph that die down at night, but I'm going to be happy with an average of 80-100W throughout the year. Some periods will be crazy high. Some will be zero.

I apologize snoobler, i did not mean a slam at Will at all. All i meant is i did not know anyone with more info than this guy that i had heard about. He definitely is not scientific at all but fun to watch and has had some decent luck with turbines.

 

[Hedges]

5 days of clouds=squat from pv. A wind turbine could save your ass if you're off grid. It will be thousands cheaper than 5 days worth of batteries. No math necessary.

Agreed, and that is what I said in a follow-on post.

Traditionally, 3 days worth of batteries was recommended for PV users. Wind is likely to tide you over, and hydro is either year-round or available during most times when storms last for days.

I'm on-grid, have 0.1 days worth of batteries. But I'm over-paneled as far as PV goes, could get by on 20% of full production. Batteries cost several times what PV costs, so that's how I balance things. The excess PV on net metering provides for electric heat in the winter, but I also have gas. During grid outages, I run A/C, laundry, anything I want direct from PV with the battery just supplying any kick needed to start motors. For instance, 2.5 kW A/C motor might have a starting surge above my 10 kW PV production.

Small portable generator, maybe 1 kW, would be ideal backup for a modest PV/battery system, and the price point is quite cheap.
If you've got wind, sure, a wind generator is good to install.