| [GMCnet] Diagram Error [message #347803] |
Sat, 14 September 2019 06:58  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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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
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Diagram Error [message #347805 is a reply to message #347803] |
Sat, 14 September 2019 07:53  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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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
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| Re: [GMCnet] Diagram Error [message #347827 is a reply to message #347803] |
Sat, 14 September 2019 12:31 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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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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| Re: [GMCnet] Diagram Error [message #347838 is a reply to message #347827] |
Sat, 14 September 2019 17:08 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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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 <
gmclist@list.gmcnet.org> wrote:
> 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:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Diagram Error [message #347839 is a reply to message #347838] |
Sat, 14 September 2019 17:17 |
Mike Kelley
Messages: 467
Registered: February 2017
Karma: -2
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Senior Member |
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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 wrote:
>
> 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 gmclist@list.gmcnet.org> wrote:
>
>> 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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| Re: [GMCnet] Diagram Error [message #347850 is a reply to message #347839] |
Sat, 14 September 2019 22:13 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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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 <
gmclist@list.gmcnet.org> wrote:
> 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 gmclist@list.gmcnet.org> wrote:
>>
>> 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 > gmclist@list.gmcnet.org> wrote:
>>
>>> 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
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Diagram Error [message #347863 is a reply to message #347850] |
Sun, 15 September 2019 13:57 |
Christo
Messages: 109
Registered: April 2019
Location: Weymouth, MA
Karma: 0
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Senior Member |
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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 - "The Komet"
3.50 Power Drive, Disc Brakes, Alcoas
Weymouth, MA
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