# which car alternator to get?



## tater1337 (Apr 22, 2010)

I'd like to pick up a car alternator for energy experimentation, but would like to get the most generic, cheapest one I can find...If I go to a car salvage place, which model cars should I look for? if I decide to buy new, which alternator should I be looking for?

yes, I know it would be better for me to just wind my own axial generator, and yes, a permanent magnet one would be more logical. I would like to see what a car alternator would do for comparison. I plan on using a op-amp for a window comparator for running the field coil. if you don't know what that is or how it works, then trust me, I have a better idea then you do.


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## Harry Chickpea (Dec 19, 2008)

You don't say how much wattage you want to get out of it, running speed, or whether it will feed a battery bank or you are going to change voltage.

Do a web search for "Neon John." I think you'll find his experiments and views useful.


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## tater1337 (Apr 22, 2010)

well I could be silly and say 1kw, 300 RPM and that i'd wire it straight to an inverter and feed it to the house 

not silly? well it depends, most likely a small battery bank(smaller the better), if it works well, i'd tie the bank into an inverter(small to begin with) take any excess and use dump loads to heat the basement(maybe raise the temp up .001 degrees)

I just shaped and weight matched some PVC pipe blades, and would like something to hang them on. I can either put it up on a 30' ham radio antenna tower, or build a 80' watermill tower that I plan on doing anyway, then upgrade to a decent windplant.

if all that fails, I could get a gas engine and use it for low voltage backup. the main thing is to get a run-of-the-mill alternator and not pay extra because it only fits 3 different models of cars, or some other attribute that makes it more expensive that some other alternator. something cheap, so if it doesn't work out, I won't be at a major loss. something common, so when I burn it out I can go to the scrapyard and pick up another one and have it fit without remaking mounting holes


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## Fire-Man (Apr 30, 2005)

tater1337 said:


> I plan on using a op-amp for a window comparator for running the field coil. if you don't know what that is or how it works, then trust me, I have a better idea then you do.


Hey Tater. I wanted to welcome you, but first---Why the Smart attitude? There is alot of "Smart" guys on here that could give you some good advice if you be nice.

Some of these Guys are So Smart they eat Op-amps for lunch with Their "Taters".


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## vicker (Jul 11, 2003)

An early 70s type from a GM. Look for three wire connections. The extra wire is to adjust the field.


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## tater1337 (Apr 22, 2010)

sorry, didn't want to be snarky, but it seems every time someone talks about using a car alternator for an alternative energy project, 100's of posts sprout saying "don't do it! it's a waste of time! you know nothing about power generation!"

then I have to reply and explain how to use a window comparator to regulate the field coil to (hopefully) get max wattage for existing wind loads.

Yeah, I've been thinking about things like this for about 20(?) years and been researching in earnest for the past 10 years or so. that's a lot of "it can't be done" posts to reply to.

Especially when i can't get a good suggestion for a starting point, namely a car alternator.


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## tater1337 (Apr 22, 2010)

vicker said:


> An early 70s type from a GM. Look for three wire connections. The extra wire is to adjust the field.


70's alternators are getting harder and harder to get. yes i need one with the field tap. I was wondering what the more recent makes models were a good idea to look for.


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## Fire-Man (Apr 30, 2005)

tater1337 said:


> Yeah, I've been thinking about things like this for about 20(?) years and been researching in earnest for the past 10 years or so. that's a lot of "it can't be done" posts to reply to.


Have you figured out how to make a car alternator put out a higher voltage at a lower RPM?


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## artificer (Feb 26, 2007)

I was going to add to the "don't do it" group when I saw your post on hanging pvc pipe blades on it. No/minimal thrust bearings, too low of speed, too much drag...

However, as a generator, they make a lot of sense. Take a look at the microcogen site. They have a forum just for automotive alternaltors. One person found running a Leece Neville 110-555 alternator set up for 12v at 24volts ended up being just as/more efficient than a diesel driven generator head and battery charger.

As for "1kw, 300 RPM and that i'd wire it straight to an inverter and feed it to the house", its not silly at all. Some of the people on the site mentioned run Lister(oids) as an engine. They typically run at 650rpm, and some are being run much slower to see if fuel economy improves. 1,000 watts? Less than 50 amps from a 160 amp alternator? no problem. Straight to an inverter isn't the best idea, but just add a battery, and you're good to go.

The microcogen forum even has someone that has designed and built an alternator and engine controller. If you want to get your soldering iron hot, he has the PCBs designed, and the arduino program written. The system is in use on his boat.

For the cheapest, most available alternator, take a look at the 10SI. Not a good choice for high loads, but useable for smaller systems and experimenting. Yet another project on the microcogen site...

Good luck on your project.

Michael


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## PorkChopsMmm (Aug 16, 2010)

Second the 10SI recommendation. You can find them on many vehicles and new/remanufactured they are about $35 from a local auto parts place.


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## tater1337 (Apr 22, 2010)

arent' the SI's self regulated? I an looking for one with an external regulator.

I'll probably pick on up anyway, they look like a fun thing to tinker with


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## PorkChopsMmm (Aug 16, 2010)

You are correct, they are IR.


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## Harry Chickpea (Dec 19, 2008)

I've seen the photos of PVC blades. Guess they are OK for playing around with, but I don't think I would want to be around one that isn't properly braked to stop it in higher winds. I've got PVC electrical conduit kicking around, and I've found that it likes to shatter into nice sharp bits when stressed. I can imagine a blade failure being pretty dangerous.


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## Jim-mi (May 15, 2002)

PVC **blades** will spectacularly self destruct long before reaching the RPM's necessary to get any amount of out put from a "car" alternator............

Lots of liability insurance will not help...... 
Once the investigators find out where those lethal shards of PVC came from.......


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## artificer (Feb 26, 2007)

tater1337 said:


> arent' the SI's self regulated? I an looking for one with an external regulator.
> 
> I'll probably pick on up anyway, they look like a fun thing to tinker with


The SI means "system integrated", or built in everything. You can hack the alternator, and make external connections for the field windings. Here's some photos of the alternator.

Michael


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## Jim Bunton (Mar 16, 2004)

Right up front I will say I don't know much about alternators, but if it was me I would decide what features I was looking for and find a knowledgeable parts guy to ask what you are asking hear. Cheapest readily available alternator that meets you specs. This work good for me when I needed a solenoid to repurpose.

Jim


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## Ky-Jeeper (Sep 5, 2010)

DIY blades here.

http://otherpower.com/


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