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| [GMCnet] Combiner & Isolator [message #80822] |
Sat, 17 April 2010 07:45  |
bill schurman
Messages: 97
Registered: February 2004
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I installed a combiner several years ago and I am very happy with it. Then some time back I saw that some folks use both the combiner and the OEM isolater. I kept the photos as to how to make the connections. however, I'm not sure what the purpose is in doing that. I saved the isolater and I could reinstall it back with the combiner, however I just do not know why I would want to that ? It will be a slow weekend and Spring is FINALLY here (well, sort of). So, now is the time for a little project.
Bill Schurman
1978 Palm Beach TZE168V100258
Steamboat Springs, CO
at the base of "Rabbit Ears Pass"
With a 7% grade
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| Re: [GMCnet] Combiner & Isolator [message #80824 is a reply to message #80822] |
Sat, 17 April 2010 07:59  |
Steven Ferguson
Messages: 3447
Registered: May 2006
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Bill,
Probably because it's there and if nothing else, where could you find
a better connection board?
On Sat, Apr 17, 2010 at 5:45 AM, bill schurman <tubby123@aemail4u.com> wrote:
> I installed a combiner several years ago and I am very happy with it. Then some time back I saw that some folks use both the combiner and the OEM isolater. I kept the photos as to how to make the connections. however, I'm not sure what the purpose is in doing that. I saved the isolater and I could reinstall it back with the combiner, however I just do not know why I would want to that ? It will be a slow weekend and Spring is FINALLY here (well, sort of). So, now is the time for a little project.
>
> Bill Schurman
> 1978 Palm Beach TZE168V100258
> Steamboat Springs, CO
> at the base of "Rabbit Ears Pass"
> With a 7% grade
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: [GMCnet] Combiner & Isolator [message #80838 is a reply to message #80824] |
Sat, 17 April 2010 10:26 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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Steve is just right, if you are running with a combiner, you are good to
go.
some GMCers use functions that need the diode isolation, so it is easy (10
min) to attach the combiner to the isolator and get the best of both worlds.
good-to-go
gene
On Sat, Apr 17, 2010 at 5:59 AM, Steven Ferguson <botiemad11@gmail.com>wrote:
> Bill,
> Probably because it's there and if nothing else, where could you find
> a better connection board?
>
> On Sat, Apr 17, 2010 at 5:45 AM, bill schurman <tubby123@aemail4u.com>
> wrote:
> > I installed a combiner several years ago and I am very happy with it.
> Then some time back I saw that some folks use both the combiner and the OEM
> isolater. I kept the photos as to how to make the connections. however, I'm
> not sure what the purpose is in doing that. I saved the isolater and I could
> reinstall it back with the combiner, however I just do not know why I would
> want to that ? It will be a slow weekend and Spring is FINALLY here (well,
> sort of). So, now is the time for a little project.
> >
> > Bill Schurman
> > 1978 Palm Beach TZE168V100258
> > Steamboat Springs, CO
> > at the base of "Rabbit Ears Pass"
> > With a 7% grade
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
>
>
>
> --
> Steve Ferguson
> '76 EII
> Sierra Vista, AZ
> Urethane bushing source
> www.bdub.net/ferguson/
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Combiner & Isolator [message #80842 is a reply to message #80822] |
Sat, 17 April 2010 11:31 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
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Gene,
Care to elaborate on the specific functions that require the diode isolator?
I'll be installing 2 combiners and was wondering if there was any REAL benefit to keeping my 35 year old isolator.
Les Burt
Sent from my iPhone
On 2010-04-17, at 11:26 AM, "Mr.erf ERFisher" <mr.erfisher@gmail.com> wrote:
Steve is just right, if you are running with a combiner, you are good to
go.
some GMCers use functions that need the diode isolation, so it is easy (10
min) to attach the combiner to the isolator and get the best of both worlds.
good-to-go
gene
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Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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| Re: [GMCnet] Combiner & Isolator [message #80844 is a reply to message #80842] |
Sat, 17 April 2010 11:45 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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The biggest feature is the higher speed blower for the heater and A/C. The isolator provides .7 volts higher voltage to the blower motor. Also some people use the isolator to provide power to the electric fuel pump ONLY when the engine is running.
Both of these go away when a combiner is installed. There are a few other uses.
Since you have already spent your money, eliminated these features, and are happy with it, why bother changing it again?
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Combiner & Isolator [message #80855 is a reply to message #80838] |
Sat, 17 April 2010 14:39 |
jayrabe
Messages: 509
Registered: June 2009
Location: Portland, OR
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Well, 10 minutes is optimistic. It took me an hour and a half. But then, like all projects, most of the time is spent finding tools, repairing tools, finding hardware, running to the Ace for just the right screws, drilling the mounting, another trip to the Ace for hardware I'd forgotten, etc. Still, all in all a very straightforward and easy install.
:-)
J
76 PB
Portland, OR
> Date: Sat, 17 Apr 2010 08:26:10 -0700
> From: mr.erfisher@gmail.com
> To: gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] Combiner & Isolator
>
> Steve is just right, if you are running with a combiner, you are good to
> go.
>
> some GMCers use functions that need the diode isolation, so it is easy (10
> min) to attach the combiner to the isolator and get the best of both worlds.
>
>
> good-to-go
>
> gene
>
>
> On Sat, Apr 17, 2010 at 5:59 AM, Steven Ferguson <botiemad11@gmail.com>wrote:
>
> > Bill,
> > Probably because it's there and if nothing else, where could you find
> > a better connection board?
> >
> > On Sat, Apr 17, 2010 at 5:45 AM, bill schurman <tubby123@aemail4u.com>
> > wrote:
> > > I installed a combiner several years ago and I am very happy with it.
> > Then some time back I saw that some folks use both the combiner and the OEM
> > isolater. I kept the photos as to how to make the connections. however, I'm
> > not sure what the purpose is in doing that. I saved the isolater and I could
> > reinstall it back with the combiner, however I just do not know why I would
> > want to that ? It will be a slow weekend and Spring is FINALLY here (well,
> > sort of). So, now is the time for a little project.
> > >
> > > Bill Schurman
> > > 1978 Palm Beach TZE168V100258
> > > Steamboat Springs, CO
> > > at the base of "Rabbit Ears Pass"
> > > With a 7% grade
> > > _______________________________________________
> > > GMCnet mailing list
> > > List Information and Subscription Options:
> > > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> > >
> >
> >
> >
> > --
> > Steve Ferguson
> > '76 EII
> > Sierra Vista, AZ
> > Urethane bushing source
> > www.bdub.net/ferguson/
> > _______________________________________________
> > GMCnet mailing list
> > List Information and Subscription Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
>
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Combiner & Isolator [message #80864 is a reply to message #80822] |
Sat, 17 April 2010 17:55 |
bill schurman
Messages: 97
Registered: February 2004
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However, do I not need the isolator to power the hi switch? Or can it be powered in a different way from the alternator? (I have had the combiner [only] installed for several years without any problem, however the hi switch does not work on my ' 78 coach)
Bill Schurman
1978 Palm Beach TZE168V100258
Steamboat Springs, CO
at the base of "Rabbit Ears Pass"
With a 7% grade
--- rwdenney@gmail.com wrote:
From: Richard Denney <rwdenney@gmail.com>
To: "gmclist@temp.gmcnet.org" <gmclist@temp.gmcnet.org>
Subject: Re: [GMCnet] Combiner & Isolator
Date: Sat, 17 Apr 2010 18:46:55 -0400
On Saturday, April 17, 2010, bill schurman <tubby123@aemail4u.com> wrote:
> ... I saved the isolater and I could reinstall it back with the combiner, however I just do not know why I would want to that ?
Bill, using a combiner with the isolator has only one advantage: it
prevents electricity from reaching back along the alternator wire, so
that the wire only has power when the engine is actually turning. That
lets you use that wire to power a fuel pump, for instance. I don't do
that and haven't missed the isolator. It also makes it much easier to
install a combiner the first time, and much easier to explain to
people how to do it.
Rick "working fine without an isolator" Denney
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| Re: [GMCnet] Combiner & Isolator [message #80879 is a reply to message #80856] |
Sat, 17 April 2010 21:17 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| bill schurman wrote on Sat, 17 April 2010 15:34 |
My question is: in my ' 78 coach w/o an isolator that I cannot install the hi speed switch function? Correct ? Also, does the red wire come directly from the alternator to the "side" (or middle) terminal on the isolator ??
Bill Schurman
1978 Palm Beach TZE168V100258
Steamboat Springs, CO
at the base of "Rabbit Ears Pass"
With a 7% grade
|
How do you have a 1978 PB and not have an isolator. As far as I know they all came with one and two battery systems.
I was answering specifically the other poster's question. That poster removed his isolator. If you remove the isolator the alternator output runs .7 volts lower. That was my point. The high speed position on the blower motor gets it's power direct from the alternator. After an isolator replacement with a combiner, the alternator still powers the high speed position of the blower motor so you still have the high speed position operational but it is slightly slower.
Gene Fisher has been pushing an alternate idea of adding a combiner on top of the isolator. If you went wit that arrangement you would not loose the isolator isolation function and the additional .7 volts.
Originally the combiner proponents were pushing combiners to charge the engine battery from the converter when parked. I never saw much need for that since there is nothing to drain the engine battery when it is parked, so why charge it? I feel over charging an already charged engine battery just shortens it's life.
Gene's proposal to install a combiner on top of an isolator gives the same results as the first group but it also keeps the advantages of the isolator. If one of them (isolator or combiner) were to fail the other will cover for some (not all) of the failures. It is kind of like running two wires to a headlight in case one of them were to fail. It works, but my position is "why bother?". I would like to know one of them fails and fix the failure.
HTH
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Combiner & Isolator [message #80880 is a reply to message #80864] |
Sat, 17 April 2010 21:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| bill schurman wrote on Sat, 17 April 2010 17:55 |
However, do I not need the isolator to power the hi switch? Or can it be powered in a different way from the alternator? (I have had the combiner [only] installed for several years without any problem, however the hi switch does not work on my ' 78 coach)
Bill Schurman
1978 Palm Beach TZE168V100258
Steamboat Springs, CO
at the base of "Rabbit Ears Pass"
With a 7% grade
|
When you installed the combiner where did you attach the wire that was on the isolator and went to the blower relay?
If it is attached to the combiner then you have a bad wire, a bad fuse, a bad blower relay, or a bad fan control switch.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Combiner & Isolator [message #80906 is a reply to message #80880] |
Sun, 18 April 2010 13:21 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
Karma: 0
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Ok, Now I understand the advantages of using an Isolator and a combiner
together. I do have a concern that relates to the longterm effects of
running electrical equipment direct from the alternator output BEFORE the
isolator diodes.
I'm curious to hear what the more knowledgeable techs have to say, so this
is directed towards you electrical gurus.
Here are a few of my thoughts so that you understand where I'm coming from.
- Older alternators such as those used on the GMC do not provide a clean DC
signal. The vehicles of the same era relied on the battery to help absorb
the fluxuations and "clean" the dirty alternator output.
- Placing a diode isolator between the battery and the Alternator output has
the effect of reducing the battery's ability to stabilize the alternator
output. The result is higher voltage fluxuations, and dirtier DC at the alt
output than at the battery. This is due to the resistance within the
isolator.
- I was frequently burning 100w halogen bulbs on my car(every 2-3 months)
with the wiring harness connected to the alternator output. I switched the
wire to the battery post and the bulbs survived near twice as long. I
compaired voltage under several conditions and never saw more than 0.2V
difference between the alt and the battery, so I have to assume that the
dirty alt output affected my lights.
So my concern is this:
Will the alternator output BEFORE the isolator diodes have any potential
negative effect on any devices powered from that output?
Has anyone put the alternator output on an occilloscope to see how clean it
actually is?
How about a comparison of the 12V output at the isolator as well as at the
battery?
I doubt that the heavier windings of a fan motor or a fuel pump would
suffer, but other more complex devices might not be so tolerant.
Thanks,
Les Burt
Montreal
1975 Eleganza II 26ft
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Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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| Re: [GMCnet] Combiner & Isolator [message #80911 is a reply to message #80906] |
Sun, 18 April 2010 13:55 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
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Les,
Your concern is justified; the battery DOES serve as a great big sinkhole
for noise of all sorts. Any delicate electronic equipment will probably do
best if connected directly to the battery. That's one reason most things
should NOT be connected to the alternator side of the isolator. But neither
the OEM HVAC fan nor the add-on fuel pump is delicate enough to be disturbed
by the noisy, unfiltered alternator output.
Ken H.
On Sun, Apr 18, 2010 at 2:21 PM, Les Burt <burtco99@yahoo.com> wrote:
> Ok, Now I understand the advantages of using an Isolator and a combiner
> together. I do have a concern that relates to the longterm effects of
> running electrical equipment direct from the alternator output BEFORE the
> isolator diodes.
>
> I'm curious to hear what the more knowledgeable techs have to say, so this
> is directed towards you electrical gurus.
>
> Here are a few of my thoughts so that you understand where I'm coming from.
>
> - Older alternators such as those used on the GMC do not provide a clean DC
> signal. The vehicles of the same era relied on the battery to help absorb
> the fluxuations and "clean" the dirty alternator output.
>
> - Placing a diode isolator between the battery and the Alternator output
> has
> the effect of reducing the battery's ability to stabilize the alternator
> output. The result is higher voltage fluxuations, and dirtier DC at the alt
> output than at the battery. This is due to the resistance within the
> isolator.
>
> - I was frequently burning 100w halogen bulbs on my car(every 2-3 months)
> with the wiring harness connected to the alternator output. I switched the
> wire to the battery post and the bulbs survived near twice as long. I
> compaired voltage under several conditions and never saw more than 0.2V
> difference between the alt and the battery, so I have to assume that the
> dirty alt output affected my lights.
>
> So my concern is this:
>
> Will the alternator output BEFORE the isolator diodes have any potential
> negative effect on any devices powered from that output?
>
> Has anyone put the alternator output on an occilloscope to see how clean it
> actually is?
> How about a comparison of the 12V output at the isolator as well as at the
> battery?
>
> I doubt that the heavier windings of a fan motor or a fuel pump would
> suffer, but other more complex devices might not be so tolerant.
>
> Thanks,
> Les Burt
> Montreal
> 1975 Eleganza II 26ft
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] Combiner & Isolator [message #80912 is a reply to message #80911] |
Sun, 18 April 2010 14:01 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
Karma: 0
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Ken,
I figured you would confirm my concerns.
I recall you mentioning that the newer CS130D alternator was much cleaner
than the old GM units. Have you done an oscilloscope comparison of the two
and how much of a difference was there? How bad are the older alternators?
Thanks,
Les Burt
Montreal
1975 Eleganza II 26ft
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Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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