AutoMac "Voltage" Regulators

[Stu Jackson]

In the recent Batteries thread, Ray asked a question about AutoMacs.

See: http://c34.infopop.cc/eve/ubb.x?a=tpc&s=329609511&f=829605811&m=936606927

As far as I know, they do not make them anymore.  See below.  Sorry about the formatting but I just cut and pasted from my word processor and these little windows don't do a WYSIWYG.

I wrote this in June 2002 to a C36 member who had asked questions about wiring harnesses and AutoMacs, two very separate subjects.

The wiring harness and the Auto-mac are two separate and mutually exclusive things.
The wiring harness upgrade is a necessity, because of two things: the long run of wiring
from the batteries to the engine panel in the cockpit ammeter wastes a lot of energy
going there and back again through the small wiring. Second, the plugs on the old
harness are a disaster waiting to happen - they wick in moisture, corrode and generally
screw up your boat. The new harness replaces the old plugs with terminal strips, a
much cleaner wire connection. It also replaces the ammeter with a voltmeter, so the
power goes directly to the starter, not all the way back to the engine cockpit control
panel and back again. I strongly urge you to do this ASAP.

The Automac is a completely different function and has absolutely nothing to do with
the wiring harness. On boats of our "distinguished vintage" :) the alternator is a 55 amp Motorola, with an internal regulator. Simplistically, and without getting into a long discussion of battery charging, this means it just puts out a small amount of charge most of the time. At anchor, it would take many hours to recharge your batteries. You
may recall seeing new "Smart Regulators" in the boat store or in catalogs. What these
external regulators do, again simplistically, is tell the alternator to put out as much
charge as they can based on the battery's ability to accept a charge. The Motorola
internal regulator doesn't have a clue as to what the battery condition is.

What the Automac does is "fool" the alternator to put out more amps by interrupting
what is called the field wire, which is the sensing wire of the alternator. This is what the
smart regulators do, albeit with more sophisticated computer algorithms to enhance the
charging process. The Automac does the same thing manually that the newer smart
regulators do automatically. Of course, you need to know a bit about batteries and
charging before you use it to avoid damaging your batteries. With an Automac, you can
significantly reduce the amount of time needed to charge your batteries, say at anchor.

Many of the Catalina dealers installed the Automac during this period. I don't think that
Catalina did it at the factory, although I don't know this for a fact. It doesn't appear as an option on the 1985 C34 price list on the C34 website under the History section.

You can put an Automac on your boat without changing the wiring harness. You can
change the wiring harness without installing an Automac or a newer smart regulator.
The wiring harness solidifies the wiring between the engine panel and the starter, and is
used to get your engine started. The Automac is a manual regulator for charging your
batteries from the alternator after the engine is running.

In a real world situation, you have two choices. Leave your old stock alternator on the
boat and see if you can find an Automac. I doubt if they are still for sale, however a
company called Spa Creek used to make them, and they were taken over by Weems &
Plath. You might try a web search on Google under Weems & Plath and see if they're
still for sale. They're easy to wire and install.

One of the reasons they don't make them anymore is because of the new smart regulators. Accordingly, you also have the choice of buying a new alternator with a smart regulator, like Balmar. Given the age of your boat and the alternator, this may be the way to go for you. I don't believe it is worth it to put a new smart regulator on your old alternator.

I have the M25 21 HP engine, with the old alternator and the Automac. In lieu of
swapping out this rig when we bought the boat 4 years ago, I installed a Freedom 15
combination inverter/charger, took out the old Ferro resonant charger (which you should
also do immediately - separate subject, those old chargers will kill your batteries), and I
will upgrade the alternator when boat bucks allow. The new charger keeps the batteries
in good condition. We haven't done any extended cruising, so the old alternator and
Automac still works fine for us. The age of the alternator is beginning to bother me, so
it's high on my projects list.

A few cautions. Limit the size of your new alternator to no more than 75 to 90 amps.
The reason is the power of your motor, and more importantly the all important main
bearings. These are behind the main pulley on the engine, but deeper inside. Any extra
unnecessary sideways torque could mess these bearings up big time. Many folks have
put 120 amp alternators on their 21 HP Universal engines and had big problems, with
pulley belts and the like. In this case, bigger isn't better.

Stu

PS

They also used to make TWO different models, one for up to 55 amps and another for larger alternators, but that was limited to about 90 amps as I recall.  I'd have to look it up in my old West Marine products catalogs, if anyone is interested.

PPS

They are also described in Calder's Boatowner's Manual.  Some fo the mdoels, mine included, had an automatic over-voltage cutout, which was adjustable.

PPPS

And, last but not least, it wouldn't b me without a reference to a FIND on Automacs:

http://c34.infopop.cc/eve/ubb.x?a=search&s=329609511&reqWords=Automac

[Jack Swords]

Lewco Electric Co., 456 Newport Blvd, Newport Beach, Ca (714) 548-8383 makes a version of the AutoMac, but instead of a wirewound rheostat, it uses solid state components.  Our Cat 30 has used one for years on the stock alternator (Lewco will also rebuild and beef up that alternator).  In use, it requires you pay attention to not overcharging batteries.  For us, on the hook in the Sea of Cortez, it works great. Just dial in the desired current while the motor is running.

[Monty]

Please note that in this thread the correct number to Lewco Electric in Newport Beach Ca is 949-548-8383. I suppose the area code changed at some time.