Why is Jim Bounds push the 1 wire??

[Matt Colie]

I just was over on FB (not recommended) and Jim Bounds was recommending the one wire alternator set up.

Before I closed the South Pointe Chandler, I tried this on three performance cruiser builds (read retired racing sloops). The systems could never get
get everything to full density and the owners were not impressed. It took some work to salvage the relations with those clients.

Does anybody know of a one-wire that is completely successful?

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

 

[john r. lebetski]

I think he just doesn’t get the advantage of remote sensing, more critical with an isolator. 1 wire seems like quick fix for a farm tractor or home
made hot rod for simplicity being the only reason I can see. .
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[RF_Burns]

JimB pushes the one-wire alternator as his solution to the Nichrome (resistor) portion of the alternator exciter wire getting hot and melting
insulation in the wiring harness.

Matt, you know that the ONLY time current flows in the alternator exciter wire is when the alternator is not operating or there is a fault. The GEN
light also comes ON during either of these conditions to alert the driver. So if the exciter wire has melted, there was a fault causing excess
current to flow in it.

I suspect many of these faults are due to a failure in the Isolator. In this case the chassis voltage starts to drop and the alternator tries to
compensate by raising the output voltage. The GEN light should turn ON to warn of this condition, however GM added a diode to cure the "Dim GEN"
light issue that occurred when there was high current draw in the motorhome application. This diode will prevent the GEN light from coming ON during
this failure. The APC cable will prevent the excess current draw in this failure mode, but also prevents the GEN light from coming ON. So the driver
continues on blissfully unaware that there is a problem.

One-wire alternators are a fixed voltage output device. They work well in applications where the current draw from the alternator is low and more or
less constant such as a fixed industrial/agricultural engine pumping water etc. They do not sense the voltage near the chassis battery, so they are
not able to compensate for voltage losses due to varying current demands and also the voltage drop across the Isolator and hence the batteries do not
get fully charged.

I suspect most owners with a one-wire alternator are unaware that their batteries are getting less than a full charge. As long as there is enough
charge in the engine battery to start it and enough charge in the house batteries to get through a night of dry camping. They might notice their dash
HVAC fan does not run as fast, especially on high, or that their headlights are not as bright, or that the headlights dim and fan slows with the
operation of the turn signals.

I had my alternator go south while on the way to have the transmission issue fixed. I asked them to replace the alternator at the same time (it was
12 years old so it had a good run) On the way home my DigiPanel was showing low voltage with an orange light on the voltage bar. It turned out the
alternator shop sent him a one-wire alternator as a replacement. I had asked for my old alternator back so I could repair it for a spare. After
fixing the old alternator and swapping it back into service, I opened the new alternator. Sure enough it was a one-wire regulator in it. I replaced
the regulator with a proper 3- wire 14.5V regulator and now it is my spare.

I bypassed my nichrome wire with a clearance light assembly and mounted it under the dash where I can see it. This lamp gives the extra exciter
current during startup and will also come ON to warn of a alternator failure (my 1977 has the dash GEN diode).

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[dave silva]

THis thread is a goldmine- I never understood any of this until now.

I was recently educating myself on bigger alternators, double pulley and whatnot and i had an idea-

What if you put a 30 amp charge controller between the alternator and the battery? Maybe a second one for the house batteries?

There are cheap ones on amazon, apparently they take whatever incoming voltage they get, like from a solar array, and output proper charging voltage
for a variety of battery types.

I'm thinking this device would not care if it got input voltage from an alternator.

The automobile charging system is designed to replenish the drain from car starting as quickly as possible but that's not good for the battery or the
belts and is not necessary on a vehicle that's always used for long trips.

--
Dave & Ellen Silva
Hertford, NC

76 Birchaven, 1-ton and other stuff

Currently planning the Great american Road Trip Summer 2021

It's gonna take a lot of Adderall to get this thing right.

 

[Keith V]

I would guess it the lesser of 2 evils. 1 wire may not fully charge but it's not going to melt the harness or start a fire either.
Personally I think it's a terrible idea. Do the job right.
________________________________
From: John R.Lebetski
Sent: Sunday, March 20, 2022 7:12 PM
To: gmclist
Subject: [GMCnet] Re: Why is Jim Bounds push the 1 wire??

I think he just doesn’t get the advantage of remote sensing, more critical with an isolator. 1 wire seems like quick fix for a farm tractor or home
made hot rod for simplicity being the only reason I can see. .
--
John Lebetski
Woodstock, IL
77 Eleganza II
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[Ken B]

I agree with John We have hashed this over many times over the years. There are just too many ways to protect the nichrome wire from burning .
Reducing the charge voltage to the entire system and reducing the charging capability of the coach does not seem like a good idea.

The only one wire alternator I have installed anywhere is on my John Deere diesel tractor to keep the battery charged and run an occasional light or
two.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[johnny]

Had one on the hotrod toad, worked fine. On the GMC however, it will only work correctly if you have a battery combiner across the isolator.
Otherwise you'll not get a full charge on either battery. If the nichrome wire bothers you, replace it with a 10 Ohm five or ten Watt resistor. This
will be slower to ramp up the alternator output which won't matter in this case.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell

 

[john r. lebetski]

Johnny that won’t work either. A combiner across the isolator parallels the outer 2 isolator terminals (Bat 1 and Bat2) but both still experience
the 0.7VDC diodes drop referenced to center alternator terminal.
You’d have to hard wire the chassis battery to the alternator, then add a combiner to the house side to get the 1 wire to have a chance at working
right. It still will not correct series voltage drop and still will not give you proper boosted high blower speed.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[johnny]

ACK! You're right. I should of looked at mine....

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell

 

[john r. lebetski]

Still best bet is remote sense alt with isolator and combiner. A 125A or bigger isolator should never fail as no moving parts. Relays go CLICK until
they don’t. If combiner fails you are just back to stock no worse.
--
John Lebetski
Woodstock, IL
77 Eleganza II