Alternator connections

[Avocet]

Not really a "car" question this, but I have an 8 horse Honda engine doing nothing and I live out in the sticks with a poor electricity supply. I thought I'd build myself a generator by having the Honda engine driving a big car alternator, charging a car battery, and connecting the lot to a 2kW inverter. I've just become the proud owner of a 180 Amp alternator off a Passat, (2005-2010) but don't know what all the connections are. There's a great big stud on the back, which is obviously the heavy wire to the battery, and there's a small 2-pin connector socket that accepts an oval plug which would be on the engine loom of the car. Any thoughts as to how I could find out what to conenct to which pin? (and, indeed, where I might snaffle the matching male connector plug)! Would the alternator body need to be earthed to the battery negative?

The alternator is a Valeo 021 903 026L

 

[Belle427]

Any markings near the terminals?

 

[Stivino]

HTH.
http://tinyurl.com/o3mz8tz

 

[mfarrow]

This appears to be your alternator. L is the indication and DFM is used by the ECU to monitor the field.

Further reading: http://www.st.com/web/en/resource/technical/document/datasheet/CD00046504.pdf

 

[Mursal]

Yes, as above L to the bulb and the other side of the bulb to + battery
earth the alternator body

 

[Avocet]

Fantastic! Thanks chaps! I also noticed it has a one -way clutch built into the pulley, so it can only transmit drive in one direction. I'm curious as to why that is? Apparently, it's quite common in modern cars...

 

[Peter.N.]

I'm afraid a car battery won't last long if its deep cycled, the plates fall to bits, you really need a proper deep cycle battery, a used heavy lorry battery would be better than a car one. There are quite a few used deep cycle ones on ebay that have been used as standby batteries, although they are not all that cheap now. The AGM type are the best.

Peter

 

[Burnerman]

Fantastic! Thanks chaps! I also noticed it has a one -way clutch built into the pulley, so it can only transmit drive in one direction. I'm curious as to why that is? Apparently, it's quite common in modern cars...

Its a free wheeling pulley, Mr.A - which only drives when the battery needs charging, and disengages when there's no demand......saves fuel, apparently!
Good luck with your project, but please be aware that the 2kW envisaged will likely end up somewhat less than that.
What are you intending to power, in the event of outage?
John

 

[Mursal]

I do like a UTube
https://www.youtube.com/watch?v=4EXYP1CmL9Q

 

[Peter.N.]

Interesting that, I wondered what they were for.

Peter

 

[Dave54]

Amazing comparison that!

 

[Burnerman]

All new to me, that one....impressed!
I've never noticed excessive belt / tensioner movement before though, certainly not to the degree on the first clip.
John

 

[Dave54]

All new to me, that one....impressed!
I've never noticed excessive belt / tensioner movement before though, certainly not to the degree on the first clip.
John

No, I thought that I've never seen one flapping around like that either. At least that I've noticed. Perhaps the ones I've seen have all been fitted with free-wheeling pulleys!
Can't see the belt lasting as long as normal like that although they will take a large amount of abuse.

 

[Burnerman]

Presumably once the battery is charged up and the alternator output is minimal, the belt thrashing will reduce anyway.....?
I must say, I've never looked at the alternator pulley with any interest anyway, unless it was to change it - and those must have all been solid.
John

 

[Dave54]

http://www.decouplerpulley.com/basics.cfm

Explains it some more. Sounds to me as if the problem is caused more by belt "give" on heavy alternator load than the alternator itself? As you say John it would ease as the load went off I'd assume. And no I can't say that I've ever examined one. Apart from anything else they're 'orrible things to get at on most of the modern cars I've seen.