The Penny Drops

[Huw Powell]

> > > >"Y'oughta get your alternator looked at," sez Tommy.  "Car
> > > >oughta run if you take the battery OUT once it starts."
> > >
> > > Wrong.
>
> I don't know the intricacies of the charging system, but why is this?

> I get that. But if I had clean power from the regulator, I can't see any
> reason why I would need a battery once it was putting out power. Just
> from a feeding power standpoint.

the key is your hope for "clean" power from the alternator.  it won't
be.  With an ole workhorse like my F250, it prolly doesn't matter much,
since there isn't a single transistor in the vehicle (AFAIK).  With
modern cars having more and more complex electronics, the problems of a
spiky electrical supply increase rapidly.

> Without the battery to stabilize everything the regulator will switch
> wildly and chaos will reign.  The system voltage will vary wildly.

Exactly.  I would expect an "unfiltered" (the battery is the filter)
alternator to oscillate back and forth between, say, 10 and 17 volts
fairly rapidly.  The only thing filtering or damping this oscillation
that I can think of are the coils themselves in the alternator.


--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/