On Sat, 25 Jun 2016 21:14:41 -0700 (PDT), wrote:

You are mistaken. I come from a car family and know. There were many with the
mechanical regulators that had alternators.
(...)
It was in the 1980s that internal regulators came out, and I didn't like them.
I liked taking off the cover and loosening the spring to give a hotter charge.

I never saw any alternators with mechanical regulators, so I'll take
your word for it that they existed. I also didn't have any luck using
Google to find alternators with mechanical regulators.

I still think you're off on the date of introduction for internal
regulators. The one's I saw were based on ceramic substrate hybrids
such as this one from Delco:
http://store.alternatorparts.com/ProductImages/d10se6-1.jpg
I couldn't find a photo of the insides of a hybrid voltage regulator.
It's a ceramic substrate, with screened and fired resistors on the
substrate, conductive paths, and components attached with reflowed
solder. It's much like a modern SMD PCB, but using a ceramic
substrate instead of G10/FR4 board.

Prior to these hybrids, regulators were external for a multitude of
reasons. They were to big to fit inside. They didn't handle the heat
very well. Unsecured component leads would vibrate and eventually
break. Threshold adjustments were necessary with different alternator
to battery wiring schemes and grounding derangements. Etc. Mounting
the regulator externally allows for a lower temperature location,
potting, and adjusting. When hybrids arrived, they solved all of
these problems. They were small enough to fit inside, the parts were
nailed down to the PCB, and they handled the heat MUCH better.
Internal was also much cheaper.

You know, an alternator uses a separate set of top diodes in the three phase
bridge to regulate. They do not WANT to perfectly regulate the voltage. Even
the old externally regulated ones were like that. They wanted the current
charging the battery slightly soft.

However, the various manufacturers did not want customers to be
playing with regulator adjustments. One mistake, and all the black
boxes will go up in smoke. So, the regulator had to be an integral
part of the alternator, and designed for the specific wiring and
ground derangement of the vehicle. Variations in positive lead
resistance was cured by adding a sense wire to the battery. Variations
in ground resistance were reduced by adding a heavy grounding cable to
the frame, so that it wouldn't rely on the electrical resistance of
the frame. However, they also couldn't compensate for variation in
charging required by different size batteries. In other words, the
regulator had to be designed for a specific vehicle and was NOT
universal.

Over the years, the situation improved, slightly. The problem was
that vehicle manufacturers wanted to take advantage of improvements in
charging technology, such as 3 stage charging, AC de-sulfidation, SoC
(state of charge) monitoring, etc. However, with the regulator
located inside the alternator, and the battery at the end of a rather
long extension cord (wire harness), such things were not going to work
well. So, todays alternator is largely the same as what you saw in
the 1980's. They're all a single bulk stage charging system, with no
ability to do 3 stage charging (bulk, absorption, float). It could be
done if manufacturers would go back to an external regulator, but
that's unlikely.

Things are very different in the marine electronics biz. There's no
such thing as a "standard installation" in marine electrical and
electronic wiring. So, the charging system has to be sufficiently
versatile, flexible, and adjustable to handle just about anything. For
example, you can get an alternator that offers a bolt on "internal"
regulator of sorts, but which can also be remote mounted, and is
adjustable:
http://www.pbase.com/mainecruising/alternator_conversion
Exotic systems, such as those required by having two engines are
accommodated by combiners and charge controllers. For example:
http://www.starmarinedepot.com/balmar-centerfield-ii-cfii-12%2F24/pzz35761.html
Notice the external regulators and 24V system. I believe that there
are 3 stage charge controllers available, but I couldn't find any with
Google.

Now, back to the soft charge you mentioned. That is intentional as
you not. However, it's a side effect of the isolation diode installed
in series with the common point of the 3 rectifier diodes. It's only
purpose is to prevent the battery from discharging through the stator
windings when the engine isn't running. The problem is that the
manufacturers originally used the cheapest power diodes that they
could find, which had a rather high forward voltage drop. The result
was like putting a resistor in series with the battery, which
eventually resulted in a rather soft knee on the charge curve. This
allowed for larger variations in frame ground resistance, which was
deemed a good thing, so it became a permanent feature.

Incidentally, much of my experience with automotive electrical systems
came from installing tube type mobile radios in commercial and public
safety vehicles in the 1960's and 1970's. The radios were big, heavy,
ugly, drew about 5 Amps in receive, and sucked 20-60(?) amps in
transmit.
http://www.radiomuseum.org/r/motorola_fmtru_80d.html
(The photo is really a 160D and is missing the Carter "SuperMotor"
motor-generator). Anyway, replacing the alternator and regulator with
something much bigger was standard practice in new mobile radio
installs. For a short time, I also worked for a Ford dealer while
attending college and did automotive electric. Both of these required
that I learn something about automotive electrical systems. Later, I
ended up designing marine radios, which exposed me to marine
electrical systems.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558