Larger the blade diameter, bigger the danger circle that needs to be kept clear. Bigger the circle that needs to be kept clear, the fewer the boats that can use one...
wind generator experience in 10 knots or less
- Thread starter Paul Cossman
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Ross stated it, I'll reiterate.
A wind gen converts the POWER (watts) from the wind into Electrical energy. At below 10 kts. there simply isnt much power for a wind gen with normal sized blades to covert to electrical energy. Watts are watts and no matter if they are from wind or from electrical energy. The POWER from a wind gen comes at well above 10 kts (and then mostly from gusts above 15kts.) If you see a wind gen 'turning' at below 10 kts, you can bet your bippy that the output is in the range of 'nil'. Check out the output curves for any windgen that youre interested and do a careful comparison of the wattage output at less than 10kts ..... nil. You need POWER to make POWER; nothing in life is free.
If you need to augment your power at less than 10 kts, then a wind gen is not what you want; as you then need a solar panel array or a genset.
A wind gen converts the POWER (watts) from the wind into Electrical energy. At below 10 kts. there simply isnt much power for a wind gen with normal sized blades to covert to electrical energy. Watts are watts and no matter if they are from wind or from electrical energy. The POWER from a wind gen comes at well above 10 kts (and then mostly from gusts above 15kts.) If you see a wind gen 'turning' at below 10 kts, you can bet your bippy that the output is in the range of 'nil'. Check out the output curves for any windgen that youre interested and do a careful comparison of the wattage output at less than 10kts ..... nil. You need POWER to make POWER; nothing in life is free.
If you need to augment your power at less than 10 kts, then a wind gen is not what you want; as you then need a solar panel array or a genset.
one Horse power equals 550 foot pounds of work per second. Air weighs about .076 pounds per cubic foot. Therefore you must move no less than 7300 cubic feet of air past the blades of you wind turbine and extract the energy from that moving air every second.
One horse power is 760 watts electrical. From there you can do the math.
One horse power is 760 watts electrical. From there you can do the math.
Charge data at last...
Sorry this took so long.
In looking over my data from last summer, I have the following measurements for my Air-X wind generator. I have my wind gen connected through my Link 20 monitor on the second channel. This lets me observe in real time the charging current and I can also display the total AH contributed by the generator over a time period.
Since the initial interest was for winds under 10mph, my data shows that on two days out of three, the output was ZERO. The third day I observed a total of 2.6AH generated. Very poor, nearly worthless output for sure.
For winds that averaged 15-18mph, I have three days of data: 25.4AH, 45.2AH, and 15.6AH for a 24 hour period. The variable data is due to the length of time the wind was blowing and I was not able to record this data.
One of my goals and the reason I installed the wind generator is to top off my batteries when I am away from the boat. I am on a mooring so shore power is not an option. For the periods below I observed the following:
4 days - 97AH
6 days - 55AH
3 days - 13AH
16 days - 94AH
Obviously the wind blew at various speeds in my harbor during those time periods.
Hope this data will be of some use.
Sorry this took so long.
In looking over my data from last summer, I have the following measurements for my Air-X wind generator. I have my wind gen connected through my Link 20 monitor on the second channel. This lets me observe in real time the charging current and I can also display the total AH contributed by the generator over a time period.
Since the initial interest was for winds under 10mph, my data shows that on two days out of three, the output was ZERO. The third day I observed a total of 2.6AH generated. Very poor, nearly worthless output for sure.
For winds that averaged 15-18mph, I have three days of data: 25.4AH, 45.2AH, and 15.6AH for a 24 hour period. The variable data is due to the length of time the wind was blowing and I was not able to record this data.
One of my goals and the reason I installed the wind generator is to top off my batteries when I am away from the boat. I am on a mooring so shore power is not an option. For the periods below I observed the following:
4 days - 97AH
6 days - 55AH
3 days - 13AH
16 days - 94AH
Obviously the wind blew at various speeds in my harbor during those time periods.
Hope this data will be of some use.
Re: Charge data at last...
Rich, Thanks a bunch for the info. Helpful, and much appreciated.
Paul.
Rich, Thanks a bunch for the info. Helpful, and much appreciated.
Paul.
Hyperbole
Paul
No hyperbole intended.
I want to retire early. You retire by income not age. If I can provide a product for a community and retire then that is in line with my goals.
Most of the units I've seen are small diameter prop types. The one that had a 6' prop did produce power (5-7 amps) at 5-10 knots wind speed. Since you can't increase the speed of the wind you are left with more blades and/or larger ones to increase your capture of wind energy.
Totally doable but is there a market?
Now if an enterprising old fart can fashion a larger prop for all those small diameter wind generators and up their output........
Paul
No hyperbole intended.
I want to retire early. You retire by income not age. If I can provide a product for a community and retire then that is in line with my goals.
Most of the units I've seen are small diameter prop types. The one that had a 6' prop did produce power (5-7 amps) at 5-10 knots wind speed. Since you can't increase the speed of the wind you are left with more blades and/or larger ones to increase your capture of wind energy.
Totally doable but is there a market?
Now if an enterprising old fart can fashion a larger prop for all those small diameter wind generators and up their output........
Bill, I would think there IS a market for a unit like that. My Fourwinds has a blade diameter of 60 inches--only 12 inches shy of your proposal. I would happily modify my unit to accommodate another 12 inches of blade diameter for an output like that. Unfortunately, the Fourwinds (permanent magnet 12VDC) unit requires much more wind to start moving and generate any power. It rarely moves w/less than 12 knots, and doesn't produce anything noteworthy in less than 14 knots.
And let me thank you also for your time and input on this issue. It's a big one to me. I've got a little 5 HP Kubota genset onboard, and I'll be installing some solar panels as well. But I'd sure like to put something productive on the top of my (already constructed) wind generator mast.
And let me thank the others who have weighed in as well. Ross, you also had some good input, but unfortunately I just don't have the time, energy, and money to re-engineer the ventilation spaces of my engine compartment (to limit the noise and heat). Other tasks are taking precedence . . . .
Paul.
And let me thank you also for your time and input on this issue. It's a big one to me. I've got a little 5 HP Kubota genset onboard, and I'll be installing some solar panels as well. But I'd sure like to put something productive on the top of my (already constructed) wind generator mast.
And let me thank the others who have weighed in as well. Ross, you also had some good input, but unfortunately I just don't have the time, energy, and money to re-engineer the ventilation spaces of my engine compartment (to limit the noise and heat). Other tasks are taking precedence . . . .
Paul.
Here is an idea:
If you were on the hook and had a stern anchor set tight so the bow was held off the wind. What would happen if you then raised your main (in light air of course) and directed the exhaust from the sail toward the gen?
Would this create a high pressure zone that would relieve itself off the windward leach creating an increase in air flow. I realize this approach is not very practical, but I wonder if it would work to help increase output?
If you were on the hook and had a stern anchor set tight so the bow was held off the wind. What would happen if you then raised your main (in light air of course) and directed the exhaust from the sail toward the gen?
Would this create a high pressure zone that would relieve itself off the windward leach creating an increase in air flow. I realize this approach is not very practical, but I wonder if it would work to help increase output?
Take a look at these options. one of these is a hybrid wind or water driven. http://www.onpassage.com/Alternative_Energy/Water_towed_generators.htm
Not sure why they don't design them that way other than expense.
I would love to be able to use the strong current I'm moored in to create power, but I don't think 2.5 knots is enough. It would nice to be able to combine wind and water on the same gen-set, but that's a difficult problem to solve at a reasonable price.
I would love to be able to use the strong current I'm moored in to create power, but I don't think 2.5 knots is enough. It would nice to be able to combine wind and water on the same gen-set, but that's a difficult problem to solve at a reasonable price.
Practical Sailor
I just got the May issue of Practical Sailor. They tested the Air Breeze wind generator and seem to think pretty highly of it. They say it shuts down when the battery is fully charged, and has very few moving parts, so it should be pretty reliable. They say it will generate power at wind speeds as low as 6 knots, although the amount at that speed is negligible. They say over a 24-hour period with winds ranging from 8-14 knots, the generator generated between 79 and 87 amp hours, for an average of 3.7 ah per hour. Sounds pretty good.
I just got the May issue of Practical Sailor. They tested the Air Breeze wind generator and seem to think pretty highly of it. They say it shuts down when the battery is fully charged, and has very few moving parts, so it should be pretty reliable. They say it will generate power at wind speeds as low as 6 knots, although the amount at that speed is negligible. They say over a 24-hour period with winds ranging from 8-14 knots, the generator generated between 79 and 87 amp hours, for an average of 3.7 ah per hour. Sounds pretty good.
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