Home » Public Forums » GMCnet » Readings on Isolator (Isolator)
| Readings on Isolator [message #166525] |
Mon, 16 April 2012 18:26  |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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I have been having starting problems with my 76 Palm Beach.
On occasions it starts up immediately but other times I have to crank and crank and than give it an extra boost to get it to fire over.
I took readings with the engine running on the isolator the top post was at 13.1, middle post 14.0, and bottom post 13.2. With the engine off top post 12.2, middle post slowly drained down from 12volts to .5volts, bottom post at 10.7. I checked battery voltage and it was at 12.1. Would these voltage reading be an indication of a bad isolator, bad alternator, bad battery or combination of all three?
Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166528 is a reply to message #166525] |
Mon, 16 April 2012 18:44  |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
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Senior Member |
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My guess:
Isolator most likely good.
I'd guess that your alternator needs to be checked.
Voltage at the middle post should probably be around
14.6 - 15.0 or so with the current state of your
batteries.
Engine off status:
Top post at 12.2 says your engine battery is PROBABLY
in pretty poor shape. It should stay close to 13.2 when
alternator is no longer charging it. Take it out and
have an auto parts store check it. My guess is that
it has gotten to the end of its life.
Center post dropping to .5 volts probably okay. That's
where alternator voltage is applied and with engine
off that may just be some leakage from somewhere.
Bottom post is your house battery and it should be
quite close to 13.2. Get a replacement, now!
NOTE: If the batteries have removable caps on the cells,
ensure that their electrolyte level is brought up to
the ring about 3/4" below the top of the battery. Then
run a charge cycle once again.
If you get the same results, it's time for new batteries.
Remember that my advice can be worth what you paid for it!
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~~ k2gkk @ hotmail dot com ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ex-Palm Beach, 76 ~ ~ ~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
_______________
*[ ]....[][ ][]\
*--OO---[]---O-*
> To: gmclist@temp.gmcnet.org
> From: hartsgmc@gmail.com
> Date: Mon, 16 Apr 2012 18:26:14 -0500
> Subject: [GMCnet] Readings on Isolator
>
>
>
> I have been having starting problems with my 76 Palm Beach.
> On occasions it starts up immediately but other times I have to crank and crank and than give it an extra boost to get it to fire over.
> I took readings with the engine running on the isolator the top post was at 13.1, middle post 14.0, and bottom post 13.2. With the engine off top post 12.2, middle post slowly drained down from 12volts to .5volts, bottom post at 10.7. I checked battery voltage and it was at 12.1. Would these voltage reading be an indication of a bad isolator, bad alternator, bad battery or combination of all three?
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
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| Re: Readings on Isolator [message #166534 is a reply to message #166525] |
Mon, 16 April 2012 19:53 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Get your charging problems fixed first before you start trying to fix the other problems. (I believe you probably have more than one problem going on.)
The alternator system has a sense line that monitors the voltage basically at the engine battery (it really is connected under the dash). The alternator raises it's output to make up for any losses in the path between it and the battery. The alternator tries to maintain approximately 14.0 volts at the battery. voltage drops between the isolator and the sense line vary depending on current flow. The drop occur in the normal cabling, the fusible link and the isolator. The isolator itself drops about .7 volts all the time.
In a normal running coach the isolator center terminal should be 14.7 volts or a little higher. The readings at the upper and lower terminals should be 14.0 volts or a little higher.
With the readings you are getting it is obvious that the alternator voltage is not high enough to charge the batteries. So any readings you are now seeing on the batteries (both house and engine) or the upper and lower isolator terminals do not mean much since we do not know the current state of charge on the batteries.
I suggest that you probably have a slipping (loose) alternator belt or a bad regulator in the alternator.
After you get that fixed and have driven the coach for an couple of hours to recharge all of the batteries, then we can start looking to see if you also have a cabling or battery issue.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Readings on Isolator [message #166536 is a reply to message #166530] |
Mon, 16 April 2012 19:52 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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Thanks for the help, I did clean up all connects to battery, isolator, and
ground wire. I just tried to take a voltage reading on the coach battery
and I must have a broken terminal as I am only getting .5 volts from it
now, two hours ago when I did my first readings it was at 10.7. Looks like
a case for two new batteries.
These batteries were purchased by the PO last October the brand is Super
Start? Made in Mexico. Cross reference that to O'Reilly auto parts
On Mon, Apr 16, 2012 at 5:50 PM, Bruce Hislop <bruce@perthcomm.com> wrote:
>
>
> Bottom post on mine is connected to the battery, so the battery should
> read the same voltage. Somewhere between the isolator and the battery you
> have a bad connection.
>
> Trace the wiring from the isolator to the battery and find where you are
> losing ~2V.
>
> I'm not sure why you have a higher voltage on the isolator terminal as its
> only source of power is the battery once the engine is off. Check your
> readings again and trace down this voltage difference.
>
> I suspect a bad connection somewhere from the isolator towards the engine
> battery. This would prevent that battery from getting a ful charge.
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 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
> _______________________________________________
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--
Bruce Hart
1976 Palm Beach
Milliken, Co
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166537 is a reply to message #166534] |
Mon, 16 April 2012 19:56 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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Thanks Ken, I did tighten the alternator belt but my readings didn't change.
On Mon, Apr 16, 2012 at 6:53 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Get your charging problems fixed first before you start trying to fix the
> other problems. (I believe you probably have more than one problem going
> on.)
>
> The alternator system has a sense line that monitors the voltage basically
> at the engine battery (it really is connected under the dash). The
> alternator raises it's output to make up for any losses in the path between
> it and the battery. The alternator tries to maintain approximately 14.0
> volts at the battery. voltage drops between the isolator and the sense
> line vary depending on current flow. The drop occur in the normal cabling,
> the fusible link and the isolator. The isolator itself drops about .7
> volts all the time.
>
> In a normal running coach the isolator center terminal should be 14.7
> volts or a little higher. The readings at the upper and lower terminals
> should be 14.0 volts or a little higher.
>
> With the readings you are getting it is obvious that the alternator
> voltage is not high enough to charge the batteries. So any readings you
> are now seeing on the batteries (both house and engine) or the upper and
> lower isolator terminals do not mean much since we do not know the current
> state of charge on the batteries.
>
> I suggest that you probably have a slipping (loose) alternator belt or a
> bad regulator in the alternator.
>
> After you get that fixed and have driven the coach for an couple of hours
> to recharge all of the batteries, then we can start looking to see if you
> also have a cabling or battery issue.
>
>
> Ken B.
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166538 is a reply to message #166537] |
Mon, 16 April 2012 19:59 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
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Can a parts store determine if the voltage regulator is working ok? The
house battery is shot, this I know and I have the engine battery on charge.
So tomorrow I will recheck my readings.
On Mon, Apr 16, 2012 at 6:56 PM, Bruce Hart <hartsgmc@gmail.com> wrote:
> Thanks Ken, I did tighten the alternator belt but my readings didn't
> change.
>
>
> On Mon, Apr 16, 2012 at 6:53 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>>
>>
>> Get your charging problems fixed first before you start trying to fix the
>> other problems. (I believe you probably have more than one problem going
>> on.)
>>
>> The alternator system has a sense line that monitors the voltage
>> basically at the engine battery (it really is connected under the dash).
>> The alternator raises it's output to make up for any losses in the path
>> between it and the battery. The alternator tries to maintain approximately
>> 14.0 volts at the battery. voltage drops between the isolator and the
>> sense line vary depending on current flow. The drop occur in the normal
>> cabling, the fusible link and the isolator. The isolator itself drops
>> about .7 volts all the time.
>>
>> In a normal running coach the isolator center terminal should be 14.7
>> volts or a little higher. The readings at the upper and lower terminals
>> should be 14.0 volts or a little higher.
>>
>> With the readings you are getting it is obvious that the alternator
>> voltage is not high enough to charge the batteries. So any readings you
>> are now seeing on the batteries (both house and engine) or the upper and
>> lower isolator terminals do not mean much since we do not know the current
>> state of charge on the batteries.
>>
>> I suggest that you probably have a slipping (loose) alternator belt or a
>> bad regulator in the alternator.
>>
>> After you get that fixed and have driven the coach for an couple of hours
>> to recharge all of the batteries, then we can start looking to see if you
>> also have a cabling or battery issue.
>>
>>
>> Ken B.
>>
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
>
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166540 is a reply to message #166525] |
Mon, 16 April 2012 20:03 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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Senior Member |
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try this, it is a good idea any way
http://www.gmcmhphotos.com/photos/showgallery.php?cat=5493
gene
On Mon, Apr 16, 2012 at 4:26 PM, Bruce Hart <hartsgmc@gmail.com> wrote:
>
>
> I have been having starting problems with my 76 Palm Beach.
> On occasions it starts up immediately but other times I have to crank and
> crank and than give it an extra boost to get it to fire over.
> I took readings with the engine running on the isolator the top post was
> at 13.1, middle post 14.0, and bottom post 13.2. With the engine off top
> post 12.2, middle post slowly drained down from 12volts to .5volts, bottom
> post at 10.7. I checked battery voltage and it was at 12.1. Would these
> voltage reading be an indication of a bad isolator, bad alternator, bad
> battery or combination of all three?
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List 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] Readings on Isolator [message #166545 is a reply to message #166540] |
Mon, 16 April 2012 20:41 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
|
|
Gene, you must be a mind reader, I was looking for that information but
couldn't put my finger on where I had seen it before.
I will rewire my starter tomorrow.
On Mon, Apr 16, 2012 at 7:03 PM, gene Fisher <mr.erfisher@gmail.com> wrote:
> try this, it is a good idea any way
>
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=5493
>
> gene
>
>
>
> On Mon, Apr 16, 2012 at 4:26 PM, Bruce Hart <hartsgmc@gmail.com> wrote:
>
> >
> >
> > I have been having starting problems with my 76 Palm Beach.
> > On occasions it starts up immediately but other times I have to crank and
> > crank and than give it an extra boost to get it to fire over.
> > I took readings with the engine running on the isolator the top post was
> > at 13.1, middle post 14.0, and bottom post 13.2. With the engine off top
> > post 12.2, middle post slowly drained down from 12volts to .5volts,
> bottom
> > post at 10.7. I checked battery voltage and it was at 12.1. Would these
> > voltage reading be an indication of a bad isolator, bad alternator, bad
> > battery or combination of all three?
> > --
> > Bruce Hart
> > 1976 Palm Beach
> > Milliken, Co
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List 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
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166547 is a reply to message #166538] |
Mon, 16 April 2012 20:52 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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|
| Bruce Hart wrote on Mon, 16 April 2012 19:59 |
Can a parts store determine if the voltage regulator is working ok? The
house battery is shot, this I know and I have the engine battery on charge.
So tomorrow I will recheck my readings.
|
Yes, but first humor me and disconnect the house battery (either cable) and re-check your readings at the isolator.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Readings on Isolator [message #166550 is a reply to message #166547] |
Mon, 16 April 2012 21:10 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
|
|
Ken, I will check that in the morning.
The terminal on the house battery (side post) most have been damaged and
when I removed it from the generator compartment I must have finished it
off as it doesn't register any volts now.
On Mon, Apr 16, 2012 at 7:52 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Bruce Hart wrote on Mon, 16 April 2012 19:59
> > Can a parts store determine if the voltage regulator is working ok? The
> > house battery is shot, this I know and I have the engine battery on
> charge.
> > So tomorrow I will recheck my readings.
>
> Yes, but first humor me and disconnect the house battery (either cable)
> and re-check your readings at the isolator.
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Readings on Isolator [message #166556 is a reply to message #166550] |
Mon, 16 April 2012 21:48 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| Bruce Hart wrote on Mon, 16 April 2012 21:10 |
Ken, I will check that in the morning.
The terminal on the house battery (side post) most have been damaged and
when I removed it from the generator compartment I must have finished it
off as it doesn't register any volts now.
On Mon, Apr 16, 2012 at 7:52 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Bruce Hart wrote on Mon, 16 April 2012 19:59
> > Can a parts store determine if the voltage regulator is working ok? The
> > house battery is shot, this I know and I have the engine battery on
> charge.
> > So tomorrow I will recheck my readings.
>
> Yes, but first humor me and disconnect the house battery (either cable)
> and re-check your readings at the isolator.
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
Bruce Hart
1976 Palm Beach
Milliken, Co
|
I do not think this is happening but I just wanted to make sure that a bad battery on the house side was not dragging down the alternator. I would feel real bad if you went through all of the effort to change the alternator or regulator only to find the problem was a bad battery on the house side. That is why I asked you to disconnect it and read the voltages again with the engine running.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Readings on Isolator [message #166559 is a reply to message #166525] |
Mon, 16 April 2012 21:57 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
| Bruce Hart wrote on Mon, 16 April 2012 17:26 |
I have been having starting problems with my 76 Palm Beach.
On occasions it starts up immediately but other times I have to crank and crank and than give it an extra boost to get it to fire over.
I took readings with the engine running on the isolator the top post was at 13.1, middle post 14.0, and bottom post 13.2. With the engine off top post 12.2, middle post slowly drained down from 12volts to .5volts, bottom post at 10.7. I checked battery voltage and it was at 12.1. Would these voltage reading be an indication of a bad isolator, bad alternator, bad battery or combination of all three?
|
A fully charged battery will gradually settle down to 12.6 volts. For all practical purposes you should not run a battery below 12.2 V or the life will be dramatically reduced. I would charge them all up using the engine alternator and then disconnect them. Check the voltages the next morning and they should all be around 12.6. If they are less, the batteries are bad. I wouldn't worry too much about the 14V on the middle post since it is within serviceable range especially if you have some semi bad batteries hooked up.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Readings on Isolator [message #166579 is a reply to message #166538] |
Tue, 17 April 2012 06:21 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
Yes, AutoZone at least has a tester for the alternator regulator combination. But you'll have to unmount the alternator and take it to them - the regulator is integral. If you do, be sure the AZ gerbil reads all the instructions on his tester. It spins the alternator up and loads it and measures performance.
--johnny
'76 23' transmode norris
'76 palm beach
From: Bruce Hart <hartsgmc@gmail.com>
To: gmclist@temp.gmcnet.org
Sent: Monday, April 16, 2012 8:59 PM
Subject: Re: [GMCnet] Readings on Isolator
Can a parts store determine if the voltage regulator is working ok? The
house battery is shot, this I know and I have the engine battery on charge.
So tomorrow I will recheck my readings.
On Mon, Apr 16, 2012 at 6:56 PM, Bruce Hart <hartsgmc@gmail.com> wrote:
> Thanks Ken, I did tighten the alternator belt but my readings didn't
> change.
>
>
> On Mon, Apr 16, 2012 at 6:53 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>>
>>
>> Get your charging problems fixed first before you start trying to fix the
>> other problems. (I believe you probably have more than one problem going
>> on.)
>>
>> The alternator system has a sense line that monitors the voltage
>> basically at the engine battery (it really is connected under the dash).
>> The alternator raises it's output to make up for any losses in the path
>> between it and the battery. The alternator tries to maintain approximately
>> 14.0 volts at the battery. voltage drops between the isolator and the
>> sense line vary depending on current flow. The drop occur in the normal
>> cabling, the fusible link and the isolator. The isolator itself drops
>> about .7 volts all the time.
>>
>> In a normal running coach the isolator center terminal should be 14.7
>> volts or a little higher. The readings at the upper and lower terminals
>> should be 14.0 volts or a little higher.
>>
>> With the readings you are getting it is obvious that the alternator
>> voltage is not high enough to charge the batteries. So any readings you
>> are now seeing on the batteries (both house and engine) or the upper and
>> lower isolator terminals do not mean much since we do not know the current
>> state of charge on the batteries.
>>
>> I suggest that you probably have a slipping (loose) alternator belt or a
>> bad regulator in the alternator.
>>
>> After you get that fixed and have driven the coach for an couple of hours
>> to recharge all of the batteries, then we can start looking to see if you
>> also have a cabling or battery issue.
>>
>>
>> Ken B.
>>
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
>
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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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
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| Re: [GMCnet] Readings on Isolator [message #166671 is a reply to message #166556] |
Tue, 17 April 2012 21:11 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
|
|
Ok, it's been a busy day today.
I charged my coach battery overnight and got the following results:
Engine running
T-12.6v
C-13.5v
B-12.9v
Engine off
T-12.2v
C-.2v
B-12.9v
My center reading has dropped .5 volts
Took coach battery to O'Reilly's and they bench tested and first got 8.2
volts. They put it on fast charge charger and got the battery up to 13.2
Ran engine with house battery disconnected
T-12.5
C-13.4
B-13.2
Ran engine with house battery connected
T-12.5
C-13.4
B-13.7
Engine off
T-12.2
C-0
B-13.7
None of these reads are making any sense to me!
What I am thinking is a new alternator might be in the near future.
On Mon, Apr 16, 2012 at 8:48 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Bruce Hart wrote on Mon, 16 April 2012 21:10
> > Ken, I will check that in the morning.
> > The terminal on the house battery (side post) most have been damaged and
> > when I removed it from the generator compartment I must have finished it
> > off as it doesn't register any volts now.
> >
> > On Mon, Apr 16, 2012 at 7:52 PM, Ken Burton <n9cv@comcast.net> wrote:
> >
> > >
> > >
> > > Bruce Hart wrote on Mon, 16 April 2012 19:59
> > > > Can a parts store determine if the voltage regulator is working ok?
> The
> > > > house battery is shot, this I know and I have the engine battery on
> > > charge.
> > > > So tomorrow I will recheck my readings.
> > >
> > > Yes, but first humor me and disconnect the house battery (either cable)
> > > and re-check your readings at the isolator.
> > >
> > > --
> > > Ken Burton - N9KB
> > > 76 Palm Beach
> > > Hebron, Indiana
> >
> >
> > Bruce Hart
> > 1976 Palm Beach
> > Milliken, Co
>
>
> I do not think this is happening but I just wanted to make sure that a bad
> battery on the house side was not dragging down the alternator. I would
> feel real bad if you went through all of the effort to change the
> alternator or regulator only to find the problem was a bad battery on the
> house side. That is why I asked you to disconnect it and read the voltages
> again with the engine running.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
|
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| Re: [GMCnet] Readings on Isolator [message #166678 is a reply to message #166671] |
Tue, 17 April 2012 22:34 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
| Bruce Hart wrote on Tue, 17 April 2012 20:11 |
Ok, it's been a busy day today.
I charged my coach battery overnight and got the following results:
Engine running
T-12.6v
C-13.5v
B-12.9v
Engine off
T-12.2v
C-.2v
B-12.9v
My center reading has dropped .5 volts
Took coach battery to O'Reilly's and they bench tested and first got 8.2
volts. They put it on fast charge charger and got the battery up to 13.2
Ran engine with house battery disconnected
T-12.5
C-13.4
B-13.2
Ran engine with house battery connected
T-12.5
C-13.4
B-13.7
Engine off
T-12.2
C-0
B-13.7
None of these reads are making any sense to me!
What I am thinking is a new alternator might be in the near future.
On Mon, Apr 16, 2012 at 8:48 PM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Bruce Hart wrote on Mon, 16 April 2012 21:10
> > Ken, I will check that in the morning.
> > The terminal on the house battery (side post) most have been damaged and
> > when I removed it from the generator compartment I must have finished it
> > off as it doesn't register any volts now.
> >
> > On Mon, Apr 16, 2012 at 7:52 PM, Ken Burton <n9cv@comcast.net> wrote:
> >
> > >
> > >
> > > Bruce Hart wrote on Mon, 16 April 2012 19:59
> > > > Can a parts store determine if the voltage regulator is working ok?
> The
> > > > house battery is shot, this I know and I have the engine battery on
> > > charge.
> > > > So tomorrow I will recheck my readings.
> > >
> > > Yes, but first humor me and disconnect the house battery (either cable)
> > > and re-check your readings at the isolator.
> > >
> > > --
> > > Ken Burton - N9KB
> > > 76 Palm Beach
> > > Hebron, Indiana
> >
> >
> > Bruce Hart
> > 1976 Palm Beach
> > Milliken, Co
>
>
> I do not think this is happening but I just wanted to make sure that a bad
> battery on the house side was not dragging down the alternator. I would
> feel real bad if you went through all of the effort to change the
> alternator or regulator only to find the problem was a bad battery on the
> house side. That is why I asked you to disconnect it and read the voltages
> again with the engine running.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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|
You need to let those batteries sit overnight before you can make any judgements. Even a crap battery can be brought up to charge and hold it for a short period. I'm suspecting whatever is hooked to the top is a marginal battery. Like I mentioned before, charge them up, disconnect them and check them in the next morning.
Bob de Kruyff
78 Eleganza
Chandler, AZ
|
|
|
|
|
|
| Re: [GMCnet] Readings on Isolator [message #166707 is a reply to message #166689] |
Wed, 18 April 2012 09:48 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
| Matt Colie wrote on Wed, 18 April 2012 04:59 |
| Bob de Kruyff wrote on Tue, 17 April 2012 23:34 |
You need to let those batteries sit overnight before you can make any judgements. Even a crap battery can be brought up to charge and hold it for a short period. I'm suspecting whatever is hooked to the top is a marginal battery. Like I mentioned before, charge them up, disconnect them and check them in the next morning.
|
Bruce,
I agree with Bob on this. I would suggest you not chase an alternator problem until you get the battery issue squared. Alternator output looks reasonable to me and the strange scatter in battery terminal voltages I can chalk to instrument issues. (Rounding error on some cheap meters can be surprising.)
When you check them this morning, try to identify the top and bottom as house and chassis. We know which they were were it was born, but POs do lots of strange things sometimes.
Matt
|
While the numbers are screwy, I'm of the opposite opinion. Fix the alternator problem. We know it should be 14.7 or slightly higher. Until you get the charging voltage within the normal range you are not going to be able to check the voltage at the batteries because you do not know what their level of charge is.
Bob is correct in that you can not check the resting voltage of a lead acid battery right after taking it off of charge. They need to sit for a while to bleed off any "Surface Charge". One quick way to speed up this wait time on the engine battery is to turn on the head lights for a minute or so. Then turn them off and check the battery voltage. If you have a digital voltmeter. You can watch the surface charge bleeding off by watching the right hand most digit. If it is slowly dropping then the surface charge is not yet completely gone or you have something inside the coach draining the battery.
I may be confusing postings but if you were the one that moved the isolator lead direct to the battery, DO NOT DO THAT. The purpose of the alternator is to run electrical accessories on the engine. This includes things like the distributor. The battery is nothing more than an accessory and changing the wiring to run to the battery first lengthens the path for the rest of the accessories in the engine electrical system.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
| Re: [GMCnet] Readings on Isolator [message #169167 is a reply to message #166707] |
Thu, 10 May 2012 17:21 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
|
|
Thought I would update this post.
Took my alternator to NAPA and it tested good. I would put a full charge
on batteries and they would eventually trickle down to under 12 volts.
Bought new coach and starter batteries. Took a small trip to town for gas
and came home and measured the voltage across the isolator.
Coach running
Top (starter bat) 13.6 volts
center 14.5 volts
Bottom (house) 13.7 volts
Engine not running
Top 13.4 volts
Center .1 volts
Bottom 13.2 volts
I also installed a new converter.
Will try out the coach again next week camping with an electrical hook-up.
On Wed, Apr 18, 2012 at 8:48 AM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> Matt Colie wrote on Wed, 18 April 2012 04:59
> > Bob de Kruyff wrote on Tue, 17 April 2012 23:34
> > > You need to let those batteries sit overnight before you can make any
> judgements. Even a crap battery can be brought up to charge and hold it for
> a short period. I'm suspecting whatever is hooked to the top is a marginal
> battery. Like I mentioned before, charge them up, disconnect them and
> check them in the next morning.
> >
> > Bruce,
> >
> > I agree with Bob on this. I would suggest you not chase an alternator
> problem until you get the battery issue squared. Alternator output looks
> reasonable to me and the strange scatter in battery terminal voltages I can
> chalk to instrument issues. (Rounding error on some cheap meters can be
> surprising.)
> >
> > When you check them this morning, try to identify the top and bottom as
> house and chassis. We know which they were were it was born, but POs do
> lots of strange things sometimes.
> >
> > Matt
>
>
> While the numbers are screwy, I'm of the opposite opinion. Fix the
> alternator problem. We know it should be 14.7 or slightly higher. Until
> you get the charging voltage within the normal range you are not going to
> be able to check the voltage at the batteries because you do not know what
> their level of charge is.
>
> Bob is correct in that you can not check the resting voltage of a lead
> acid battery right after taking it off of charge. They need to sit for a
> while to bleed off any "Surface Charge". One quick way to speed up this
> wait time on the engine battery is to turn on the head lights for a minute
> or so. Then turn them off and check the battery voltage. If you have a
> digital voltmeter. You can watch the surface charge bleeding off by
> watching the right hand most digit. If it is slowly dropping then the
> surface charge is not yet completely gone or you have something inside the
> coach draining the battery.
>
> I may be confusing postings but if you were the one that moved the
> isolator lead direct to the battery, DO NOT DO THAT. The purpose of the
> alternator is to run electrical accessories on the engine. This includes
> things like the distributor. The battery is nothing more than an accessory
> and changing the wiring to run to the battery first lengthens the path for
> the rest of the accessories in the engine electrical system.
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
|
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