Diagram Error

[Ken H.]

The just-published GMC Vintage RVing magazine has an article proposing the
modification of the GMC's alternator to a One-Wire configuration. That
article, on page 17, has an unfortunate error which could cause
undercharged house batteries. While the proposal to convert the
alternator to One-Wire operation has some merit, it suffers from one major
flaw: A One-Wire alternator CANNOT compensate for the inherent 0.7 VDC
voltage drop across the isolator diodes. That means that there will
inevitably be less than optimal charge voltage applied to the house
battery, allowing it to charge VERY slowly -- if at all.

There will be a follow-up article published in the magazine, but in the
meantime, this site offers a pretty good explanation of battery charge
requirements: https://www.powerstream.com/SLA.htm

If you DO convert to a One-Wire alternator, install a Combiner at the same
time -- that will eliminate the 0.7 VDC diode voltage drop and the
consequent problems.

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

 

[john r. lebetski]

I had pointed this same thing out to Mr. Jim B on a FB page but seemed to fall on deaf ears. He had posted a video touting the 1 wire.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Matt Colie]

I can tell you first hand that One-Wire is a looser.

During one excursion, we lost the regulator in Baton Rouge. I found a friendly shop and he replaced it for me, but the regulator he put in did not
recognize the voltage sense wire. We never had starting trouble, but it was warm. We did have a distinct loss of house bank capacity. I replaced
that regulator when we got home.

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

 

[Ken B]

I will second Matt's conclusion. If you want weak headlight and slow battery charging go to a one wire set up. Inn a one wire operation there is
nothing to make up for other voltage losses that we talk about in the system. One of then is through the fusible link and when the Heater fan is
running.

It is a real looser in higher current applications.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[Ken H.]

As expected, a lot of you immediately recognized the absurdity of the
proposition. But I was/am afraid a lot of newbies won't have that
expertise and some will fall into the trap. Thus my announcement and
expectation of a refuting article in the next issue of "our" magazine. My
quandary now is how deeply to go into the subject of battery charging,
isolators, etc.

Ken H.

On Sat, Sep 14, 2019 at 1:31 PM Ken Burton via Gmclist <

> I will second Matt's conclusion. If you want weak headlight and slow
> battery charging go to a one wire set up. Inn a one wire operation there is
> nothing to make up for other voltage losses that we talk about in the
> system. One of then is through the fusible link and when the Heater fan is
> running.
>
> It is a real looser in higher current applications.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
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>

 

[Irish Rogue]

Ken H:
Regards the upcoming article refuting the error - keep it straight forward and simple for the Newbies and is non mechanic types!
Thanx for all you do for this unique community!
Mike/The Corvair a holic

Sent from my iPhone

>
> As expected, a lot of you immediately recognized the absurdity of the
> proposition. But I was/am afraid a lot of newbies won't have that
> expertise and some will fall into the trap. Thus my announcement and
> expectation of a refuting article in the next issue of "our" magazine. My
> quandary now is how deeply to go into the subject of battery charging,
> isolators, etc.
>
> Ken H.
>
> On Sat, Sep 14, 2019 at 1:31 PM Ken Burton via Gmclist <

>
>> I will second Matt's conclusion. If you want weak headlight and slow
>> battery charging go to a one wire set up. Inn a one wire operation there is
>> nothing to make up for other voltage losses that we talk about in the
>> system. One of then is through the fusible link and when the Heater fan is
>> running.
>>
>> It is a real looser in higher current applications.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> _______________________________________________
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> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[Bruce Hart]

I was tempted to try the one wire alternator with the problem I faced with
my own alternator.

While searching for info on replacing the voltage regulator I ran across
this article on "One Wire vs Three"

http://www.madelectrical.com/electricaltech/onewire-threewire3.shtml

I nixed the idea but I had ordered the self energizing voltage relays
before I found the article

Another disadvantage of the one wire is they aren't a common stock item at
you local car parts store.

On Sat, Sep 14, 2019 at 4:17 PM Mike Kelley via Gmclist <

> Ken H:
> Regards the upcoming article refuting the error - keep it straight forward
> and simple for the Newbies and is non mechanic types!
> Thanx for all you do for this unique community!
> Mike/The Corvair a holic
>
> Sent from my iPhone
>
> > On Sep 14, 2019, at 5:08 PM, Ken Henderson via Gmclist <

> >
> > As expected, a lot of you immediately recognized the absurdity of the
> > proposition. But I was/am afraid a lot of newbies won't have that
> > expertise and some will fall into the trap. Thus my announcement and
> > expectation of a refuting article in the next issue of "our" magazine.
> My
> > quandary now is how deeply to go into the subject of battery charging,
> > isolators, etc.
> >
> > Ken H.
> >
> > On Sat, Sep 14, 2019 at 1:31 PM Ken Burton via Gmclist <

> >
> >> I will second Matt's conclusion. If you want weak headlight and slow
> >> battery charging go to a one wire set up. Inn a one wire operation
> there is
> >> nothing to make up for other voltage losses that we talk about in the
> >> system. One of then is through the fusible link and when the Heater
> fan is
> >> running.
> >>
> >> It is a real looser in higher current applications.
> >> --
> >> Ken Burton - N9KB
> >> 76 Palm Beach
> >> Hebron, Indiana
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class

 

[gmcnet1]

Bruce, that article from madelectrical.com is excellent, and you shared it just as I'm finishing some rework around my isolator. Thank you!
--
Christo Darsch
GMC Nor'easters
1977 Eleganza II - "Komet"
3.50 Power Drive, Disc Brakes, Alcoas
Weymouth, MA

 

[Matt Colie]

Where was this?

We don't seem to get Vintage Rving any more or the roster or the parts book.
Are these still printed?

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

 

[Ken H.]

Yes, very much so. You need to contact Kim!

Ken H.

On Sun, Sep 15, 2019 at 5:21 PM Matt Colie via Gmclist <

> Where was this?
>
> We don't seem to get Vintage Rving any more or the roster or the parts
> book.
> Are these still printed?
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>