Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-04-2012, 03:07   #1
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Car Alternator as Wind Generator?

stupid question time but i've been pondering this for some time - why not set a car alternator up as a wind generator? Would it run too slow to be effective? too vulnerable to the exposed environment? wish there was a smiley with a dunce hat for this question... there ya go...
__________________

__________________
charliehows is offline   Reply With Quote
Old 11-04-2012, 03:24   #2
Registered User
 
anjou's Avatar

Join Date: Apr 2009
Location: Malvernshire, on the sunny side of the hill.
Boat: 50' steel canal and river cruiser
Posts: 1,905
Re: car alternator as wind generator???

Unless you have a complex variable pitch prop, speed control is the issue.

If you have shorter blades with a shallow pitch, you wont get much power from it, ie, you cant load it enough to generate much current.
if you have longer blades with a correspondingly greater pitch, you need more wind to turn it and the tips so super sonic and are noisy

There are other reasons which I cant recall right now
Its a complex thing to get right.
__________________

__________________
www.amy-artimis.blogspot.com
anjou is offline   Reply With Quote
Old 11-04-2012, 03:34   #3
mrm
Registered User

Join Date: Feb 2011
Location: Poland, EU
Boat: crew on Bavaria 38 Cruiser
Posts: 651
Re: car alternator as wind generator???

Quote:
Originally Posted by charliehows View Post
why not set a car alternator up as a wind generator? Would it run too slow to be effective? too vulnerable to the exposed environment?
Basically you answered your question.
Exposure to environment can be dealt with quite easily, the other problem is more difficult. Alternators are designed to operate full power at approx. 10.000 RPM - no way to drive the shaft directly from a propeller - some sort of transmission is required.
__________________
mrm is offline   Reply With Quote
Old 11-04-2012, 03:39   #4
Registered User
 
kellyp08's Avatar

Join Date: Jul 2008
Location: Northeast Harbor, Maine
Boat: Sou'wester 50 yawl
Posts: 131
Images: 10
Re: car alternator as wind generator???

For what it's worth, I don't think that your question is stupid. Car alternators are cheap, anything associated with a boat is not. I wonder whether the RPMs would be adequate (but I guess that could be regulated by having a very large pulley on the axle of the rotor and small pulley on the shaft of the alternator). Then there's the issue of exposure of non-marine spec equipment (the alternator) to wind and waves. Here one could fashion a water-tight fiberglass housing (with West system and fiberglass cloth) to surround the alternator. Nigel Calder has a nice section in his great book, "This Old Boat", on how to create fiberglass housings.

I hope you put such a system together. If it works - please let us know! I, for one, am just pee'ing in my pants to find out. (But not eager enough to do the work myself!)
__________________
kellyp08 is offline   Reply With Quote
Old 11-04-2012, 03:55   #5
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: car alternator as wind generator???

I think my car idles at about 700-900rpm and it spends a lot of time sitting in traffic - batt. seems to stay pretty well charged - cant see why 10000 rpm is needed. on the boat i putt along at 1200 rpm although the alt. is still charging at 700 when idling (needs a blip to 1200 to start it though) and the ratio wouldnt take it much more than twice that. Seems to me once the things are going above a minimum speed they're working ( my understanding is thats the basic difference between a generator and an alternator - the alt produces more at lower speeds). the charge rate shouldnt be a problem - if its producing anything at all multiply that by 24 hrs a day and you gotta be getting something. Give me time, im stupid enough to try it.
__________________
charliehows is offline   Reply With Quote
Old 11-04-2012, 04:04   #6
mrm
Registered User

Join Date: Feb 2011
Location: Poland, EU
Boat: crew on Bavaria 38 Cruiser
Posts: 651
Re: car alternator as wind generator???

Quote:
Originally Posted by charliehows View Post
I think my car idles at about 700-900rpm and it spends a lot of time sitting in traffic - batt. seems to stay pretty well charged - cant see why 10000 rpm is needed.
Charlie, I wrote that 10000rpm is a typical point for full power.
A typical turn on/cut in speed for car alternators is in the 1300-1500rpm range. Once alternator cuts in, it will produce some power. For details on how much, google an alternator performance curve - for example from Bosch.
__________________
mrm is offline   Reply With Quote
Old 11-04-2012, 04:17   #7
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: car alternator as wind generator???

Quote:
Originally Posted by mrm View Post
Charlie, I wrote that 10000rpm is a typical point for full power.
A typical turn on/cut in speed for car alternators is in the 1300-1500rpm range. Once alternator cuts in, it will produce some power. For details on how much, google an alternator performance curve - for example from Bosch.
ok, with ya there.
__________________
charliehows is offline   Reply With Quote
Old 11-04-2012, 04:22   #8
Registered User
 
anjou's Avatar

Join Date: Apr 2009
Location: Malvernshire, on the sunny side of the hill.
Boat: 50' steel canal and river cruiser
Posts: 1,905
Re: car alternator as wind generator???

Dont forget that alternators have a pulley to gear it up so the car engine speed isnt the armeture speed
__________________
www.amy-artimis.blogspot.com
anjou is offline   Reply With Quote
Old 11-04-2012, 05:07   #9
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: car alternator as wind generator???

yeah somewhere between 2 and 3 - 1 . How many rpms can you get out of a wind propeller of less than 1 metre dia. or span?
__________________
charliehows is offline   Reply With Quote
Old 11-04-2012, 05:19   #10
mrm
Registered User

Join Date: Feb 2011
Location: Poland, EU
Boat: crew on Bavaria 38 Cruiser
Posts: 651
Re: car alternator as wind generator???

Quote:
Originally Posted by charliehows View Post
How many rpms can you get out of a wind propeller of less than 1 metre dia. or span?
Assume wing tip speeds below 0.95 of speed of sound.
__________________
mrm is offline   Reply With Quote
Old 11-04-2012, 05:21   #11
Registered User
 
Reefmagnet's Avatar

Join Date: May 2008
Location: puɐןsuǝǝnb 'ʎɐʞɔɐɯ
Boat: Nantucket Island 33
Posts: 2,735
Re: car alternator as wind generator???

The direct dc drive motors from Fisher & Paykel washing machines make excellent alternators for wind generators. There's plenty of information about doing this on the 'net. The diameter of the standard motor, which is about frisbee size, would probably be a limiting factor. Pretty easy to get hold of too, as the electronics of these washers are cleverly designed to destroy the entire machine bar the motors in the event of the slightest component failure. I've squirreled a couple away in the shed for another time when I finally run out of other projects.
__________________
Reefmagnet is offline   Reply With Quote
Old 11-04-2012, 05:25   #12
Registered User
 
anjou's Avatar

Join Date: Apr 2009
Location: Malvernshire, on the sunny side of the hill.
Boat: 50' steel canal and river cruiser
Posts: 1,905
Re: car alternator as wind generator???

And those washing machine motors are 7 phase, so they start up in lighter winds and run more smoothly
__________________
www.amy-artimis.blogspot.com
anjou is offline   Reply With Quote
Old 11-04-2012, 05:34   #13
Registered User
 
cburger's Avatar

Join Date: May 2006
Location: Nyack, NY
Boat: Westsail 32
Posts: 1,547
Images: 1
Re: car alternator as wind generator???

Quote:
Originally Posted by charliehows View Post
stupid question time but i've been pondering this for some time - why not set a car alternator up as a wind generator? Would it run too slow to be effective? too vulnerable to the exposed environment? wish there was a smiley with a dunce hat for this question... there ya go...
Just built up a GM 10si alternator that was given to me for free. Unit is making 14.5 volts at 700rpm. During the search for parts for this project I came across rotors for automotive alternators that were marketed as being used for building wind generators. My instinct is there are people out there doing it, just start searching the internet. The question that I have is that after you procure all the required components and engineer the housing and other related issues that won't be available off the shelf and figure in all the hours of time required would you really save that much money over purchasing a true marine wind generator and end up with an inferior product.

That being said it certainly would be an interesting project to be involved with.
__________________
"All men are created equal, some are just more equal than others"
cburger is offline   Reply With Quote
Old 11-04-2012, 05:59   #14
Registered User

Join Date: Aug 2010
Location: sydney, australia
Boat: 38 roberts ketch
Posts: 1,021
Images: 3
Re: car alternator as wind generator???

what got me thinking about this again was the boat i saw with a fixed - ie non-swivelling wind gen on their mizzen mast - if the boat is at anchor or on a swing mooring the gen doesnt need to swivel - the boat lines up into the wind. The work is in building a robust blade and gearing system, the alts. are a chuckaway part from the junkyard, no housings, just run em til they bust. But you're right about the false economy of wasting time and energy.
__________________
charliehows is offline   Reply With Quote
Old 11-04-2012, 06:08   #15
Registered User
 
anjou's Avatar

Join Date: Apr 2009
Location: Malvernshire, on the sunny side of the hill.
Boat: 50' steel canal and river cruiser
Posts: 1,905
Re: car alternator as wind generator???

Have a read through this little lot, as I recall we discussed this topic here some time

Wind Turbines and associated systems
__________________

__________________
www.amy-artimis.blogspot.com
anjou is offline   Reply With Quote
Reply

Tags
alternator, generator, wind generator

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:35.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.