Prepared Society Forum banner
1 - 11 of 11 Posts

·
Semper I
Joined
·
28 Posts
Discussion Starter · #1 ·
How to Build a Windmill Using a Car Alternator | eHow.com

I have always wondered if this was possible so I did a search, turns out it can be done. I figured I wasnt the first to think this idea up. It might not be the most usefuly tool in your box but in an emergency senario it could be used to charge some dead batteries or maybe to get a jump on an only vehicel. Maybe just hook an alternator up to the chain and do a bit of pedal charging, you would get in some exersice as well as making a bit of electricity.
 

·
Registered
Joined
·
1,922 Posts
Some of my electrically savy sailing buddies have built wind generators from car altinaters to keep their batteries charged. ( I didn't get that creative gift.) You can also drag a taff rail log spinner in the water that is connected to an alternater and it will charge batteries also. The only problem with this is that big fish will think the spinner is a bait fish and attack it. Taff rail log spinners are old technology that were used by sailors to see how fast they were going.
 

·
Registered
Joined
·
171 Posts
How to Build a Windmill Using a Car Alternator | eHow.com

I have always wondered if this was possible so I did a search, turns out it can be done. I figured I wasnt the first to think this idea up. It might not be the most usefuly tool in your box but in an emergency senario it could be used to charge some dead batteries or maybe to get a jump on an only vehicel. Maybe just hook an alternator up to the chain and do a bit of pedal charging, you would get in some exersice as well as making a bit of electricity.
These generator are designed for high RPM. If Lance Armstrong had one hooked to his bike he couldn't power a toaster.
 

·
Jack of all trades?
Joined
·
8,397 Posts
The only way to make a car alternator work (direct drive) is to re-wind the stator with much smaller wire, so the voltage cut-in speed is reduced (lower RPM when it starts working). I tried once and failed - - it is NOT an easy job!!!

If you want to go through that much effort, it would be best to just start from new and build one of the Hugh Piggott designed "Axial Flux" wind generators - - which is worth your time and effort. A car alternaotr is not.
 

·
Registered
Joined
·
171 Posts
The only way to make a car alternator work (direct drive) is to re-wind the stator with much smaller wire, so the voltage cut-in speed is reduced (lower RPM when it starts working). I tried once and failed - - it is NOT an easy job!!!

If you want to go through that much effort, it would be best to just start from new and build one of the Hugh Piggott designed "Axial Flux" wind generators - - which is worth your time and effort. A car alternaotr is not.
Welcome aboard Linc Tex. :beercheer:
 

·
Jack of all trades?
Joined
·
8,397 Posts
Thanks, HELIXX!
 

·
Registered
Joined
·
48 Posts
Water or wind

I have a friend who has a cabin near ours and he has a water wheel. He used and old car generator ( before altenators ) He ran a 1 1/2" pipe to a home made water wheel (for cups?? he uses cut beer cans) and this is enough to charge his batteries and get a couple days worth of power. We they have a crowd he has to use his gen. If it is only his wife and himself they can go for about a week on batteries. And the system only takes a few days to fully charge his system. The water wheel is about 100' from his batteries. I don't know alot about his system but I hope this will help someone.
 

·
Jack of all trades?
Joined
·
8,397 Posts
I just read this ^... oh my goodness, how poorly that is written!!! That's the worst eHow in existence! I wonder if it would make ANY electricity at all! I think probably not.

This guy is using a 10 HP diesel to spin a car alternator, and is getting very little output. In his own comments, he expresses his disappointment in the very low efficiency numbers that car alternators have. Lots of work in, and very little power out.

 

·
Registered
Joined
·
171 Posts
I just read this ^... oh my goodness, how poorly that is written!!! That's the worst eHow in existence! I wonder if it would make ANY electricity at all! I think probably not.

This guy is using a 10 HP diesel to spin a car alternator, and is getting very little output. In his own comments, he expresses his disappointment in the very low efficiency numbers that car alternators have. Lots of work in, and very little power out.

YouTube - Homebrew Diesel DC Generator
OMG! Somebody get out and push! lol
 

·
Jack of all trades?
Joined
·
8,397 Posts
I still haven't given up on trying a few different alternators....

The newest Ford alternators are very efficient. There are wiring diagrams online for "simple" applications, like race cars and such that don't need computer inputs.

Watts (or amps) out also = corresponding Kw/HP in.
A 360 Amp alterntor just needs a much larger engine, to keep from stalling the engine out under load.

746 watts = 1 Hp

I think he might just be geared improperly. A 10 Hp diesel at rated power should put out 7,460 watts at 100% efficiency. That's 532 amps at 14 volts. (in a PERFECT world, which we are not in!)

Small air-cooled diesel engines are only about 25% efficent, so knock it down to around 125 amps for that same 10HP diesel engine setup. That is only if the alternator is 100% efficient, which it is not.

You'll lose a lot with that single V-belt (due to % slip and pulley friction - a serpentine would be better), so let's say 100 amps. Now we need to deduct losses in the alternator.

Now lets just say we can get 50% efficiency (should not be too hard) from the alternator. That's about 50 amps at 14 volts, but only if everything is working well, and on a cold day.

Kind of disappointing, huh?

He is getting 20 amps or so - and the engine is working pretty hard, but not smoking black. There is definitely room for improvement.

Now, using all this math - to run that 360 amp ambulance alternator at rated output, you'll need a 50 HP diesel engine or better. There is still no guarantee you'll get the full 360 amps out of it, though. Output goes down as it warms up.

Crazy how it all works out, Huh?
If I can get caught up on my "honey do" projects I can start playing with stuff like this again. Maybe I can put up a $50 prize to the person that can get the highest effciency (output in watts/ per fuel used)? That would stimulate folks experimenting and getting some real world results.
 
1 - 11 of 11 Posts
Top