Stus-List Rewiring Universal starter/glow plug/alternator

Josh Muckley muckleyj at
Fri Feb 17 10:42:34 EST 2017

The water heater has a ~6 gallon capacity.  If you attempt to freeze
protect it then you would need to flush out the water with glycol and
probably end up using 3 or 4 gallons in the process.  Glycol isn't cheap
and considering that you can eliminate the risk of freezing simply by
draining, glycol in the water heater is a waste of money.

The ACR allows changing of a second bank once the first bank gets up to
near full charge.  A multi-stage regulator is what controls the alternator
output voltage to provide fast, efficient charging which also promotes
longer battery life.


On Feb 17, 2017 10:27 AM, "David Knecht via CnC-List" <cnc-list at>

Hi Josh- My plan at present is to not do quick and dirty.  I plan to
eliminate the ammeter circuit, remove the internal alternator regulation (I
have that conversion kit already), and then run the alternator directly to
the batteries.  I am still unclear on the functionality of the multi-stage
voltage regulators vs. ACR’s.  I would have to put in a voltage regulator
of some sort if I remove the internal regulation, but I am not sure whether
one also needs an ACR.  Dave

PS- no one has answered my question about the rationale for draining the
water heater.

Dr. David Knecht
Professor , Department of Molecular and Cell Biology
University of Connecticut
91 N. Eagleville Rd.
Storrs, CT 06269-3125

> On Feb 17, 2017, at 7:36 AM, Josh Muckley via CnC-List <
cnc-list at> wrote:
> David,
> It sounds like you got the "quick and dirty" answers you were looking
for.  If you are going to be using an external regulator then the quick and
dirty method shouldn't be used.  As Fred said, a dedicated large gauge wire
from the alternator straight to the house battery bank.  You'll program
your regulator to match your house battery chemistry.
> The solenoid I would use for the glow plugs looks like the one in the
link below.   They're cheap starter solenoids.  $10 or $20 is a good
ballpark cost.
> Rewiring your panel and eliminating the orange wire will render your
ammeter useless.  If you'd like, the safe way to add an ammeter is by
installing a shunt ON THE NEGATIVE BATTERY terminal.  The shunt has a
linear voltage drop (millivolts) to current ratio so with the shunt
attached to the negative battery terminal and all of the ground paths
attached to the shunt, a voltage reading (0-100mV) across the shunt will be
proportional to the current (0-100amps).  An inadvertent contact with the
shunt or signal wire will represent only millivolts more than ground so a
fault would not be hazardous.  Since the signal voltage is so low a very
long run of signal wire could be used to power your ammeter.  A new ammeter
would need to be selected such that it matches the shunt in order to read
properly.  Placing the shunt on the ground terminal also ensures that total
charging and discharging currents can be measured.
> The original "orange" wire was designed for a low current alternator on a
tractor or skid loader application.  Once the engine was started the charge
current would quickly drop as the engine charged the battery to its full
capacity.  A 30amp alternator might only see 30amps for a few seconds after
start.  The orange wire carried the full supply of alternator power from
the engine to the control panel ammeter and then to the battery.  30 amps
momentarily on a short run of 10 gauge wire isn't a big deal in a tractor
but on a boat with the panel and batteries significantly further from the
engine and often in opposite directions of one another its a more
significant concern.  Add to that the fact that owners regularly upgrade
their alternator to 3 or 4 times the normal output and you have a recipe
for disaster.
> Josh Muckley
> S/V Sea Hawk
> 1989 C&C 37+
> Solomons, MD
> On Feb 12, 2017 11:45 AM, "David Knecht via CnC-List" <
cnc-list at> wrote:
> Siting here watching lots of snow come down makes my thoughts turn to
boat maintenance and I have been reading the very useful Mainecruising site.
> First question- Engine panel, alternator wiring and charge control
> I have a Universal diesel on my boat and the infamous trailer connectors
described here:
wiring_harness_upgrade&page=1. I also have the panel pictured in this
article with ammeter and tachometer.  I have already replaced one of the
trailer connectors (partially melted) by directly splicing all the wires to
their mates with butt connectors and will do the other in the spring.   I
have read the article a number of times now and am reasonably sure I should
also do the starter circuit upgrade as he recommends, but some of the
details are fuzzy to me.  I have a hard time understanding the whole thing
if I can’t look at a wiring diagram.   Has anyone created a wiring diagram
for the starter/alternator/switches/glow plugs/panel on these Universals?
> More specifically- his first recommendation is the quick and dirty fix:
Simply jump the alternator output to the starter post and disconnect the
orange wire. With this jumper the alternator output bypasses the 20+/- feet
of teeny tiny 10GA wire and uses the large gauge starter wire to make its
way back to the battery switch and then to the battery banks.
> I presume this eliminates the ammeter completely (no big loss in my book
as I never look at it).   I am fuzzy on the reason this is important since
the alternator does not drive the starter, so without a circuit diagram I
am having trouble seeing what this accomplishes.
> Also- If I go for more than the quick and dirty- I think I have two
options.  First would be running the alternator to the house bank and an
ACR to the starter battery.  Second would be a charge controller (Balmar
614) between the alternator and the battery banks.  Am I right that it is
one or the other?  What I read from the same site makes me think the charge
controller is the much better option since I have AGM batteries and he
discusses extensively the problems of Motorola alternators, temperature
compensation and charge control
> Also, If I add a glow plug solenoid as he discusses, is this the right
solenoid to use:
> Second unrelated question:
> In his section on winterizing water systems he says: Water heaters are
always drained and by-passed you do not run pink through them!
> I have done this both ways, but I can’t see why it is so much better to
bypass and drain.  I found it a real PITA to bypass the water heater so
have been doing it the easy way of emptying the water tanks and then
running propylene glycol through until red comes out both hot and cold
lines.  Maybe if I plumbed it to make bypass easier, I might do it that
way, but I can’t see why it matters other than using more antifreeze.
> Thanks- Dave
> Aries
> 1990 C&C 34+
> New London, CT
> <pastedGraphic.tiff>
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> All Contributions are greatly appreciated!


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