| Isolator question [message #301936] |
Thu, 09 June 2016 22:35  |
trapper
Messages: 52
Registered: April 2015
Location: Saskatchewan, Canada
Karma: 0
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I have my coach plugged into shore power and was poking around under the hood and found that my isolator is HOT. Really hot. Is that normal? Time for a replacement?
75 Glenbrook
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| Re: Isolator question [message #301937 is a reply to message #301936] |
Thu, 09 June 2016 22:47  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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What you have there is NOT a GM isolator. That said I would get out my meter and read the voltages at all three connection point where the isolator is wired. If it is operating normally I would expect no voltage on one connection (the one in the picture wired to both diodes). I would expect to see converter voltage on the second connection of around 13.8 volts and I would expect to see engine battery voltage of around 12.6 on the 3rd connection.
If that is not what you are getting, record what you have and come back here with the results.
The isolator should not be getting hot if the engine (alternator) is not running.
Ken B.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Isolator question [message #301938 is a reply to message #301937] |
Thu, 09 June 2016 23:30 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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It looks like it's under sized for sure. That's a heat sink and it probably won't last long, especially if it's running over temp now.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] Isolator question [message #301939 is a reply to message #301938] |
Thu, 09 June 2016 23:33 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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On Thu, Jun 9, 2016 at 9:30 PM, Hal StClair
wrote:
> It looks like it's under sized for sure. That's a heat sink and it
> probably won't last long, especially if it's running over temp now.
> Hal
> --
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
> 1974 Eagle Bus 45',w/slideout
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Isolator question [message #301940 is a reply to message #301939] |
Thu, 09 June 2016 23:38 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Could be that the battery for the living area is being drained so whatever
the hum box is putting out is being used up.
Check and make sure all 12 volt accessories are off.
On Thu, Jun 9, 2016 at 9:33 PM, Jim Kanomata wrote:
>
>
> On Thu, Jun 9, 2016 at 9:30 PM, Hal StClair
> wrote:
>
>> It looks like it's under sized for sure. That's a heat sink and it
>> probably won't last long, especially if it's running over temp now.
>> Hal
>> --
>> 1977 Royale 101348,
>>
>> 1977 Royale 101586, Diesel powered,
>>
>> 1974 Eagle Bus 45',w/slideout
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Isolator question [message #301942 is a reply to message #301940] |
Fri, 10 June 2016 00:17 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Heat means something has developed resistance instead of straight conductance or non-conductance. Label the wires with tape, remove and disconnect the isolator, check the diodes to make sure they only conduct one way, and clean all connections in the process. There should be NO heat from the isolator when the alternator is not charging. You are going to find one of those diodes (the "house" battery side)has shorted and a bad diode in the alternator or a low resistance in the chassis battery drawing current from your house charger through whatever resistance is left in the isolator diode, causing the heat.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: Isolator question [message #301950 is a reply to message #301936] |
Fri, 10 June 2016 08:11 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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One look at the rust on the right hand diode, and away it goes.
--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
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| Re: Isolator question [message #301964 is a reply to message #301955] |
Fri, 10 June 2016 12:05 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Took a few looks at the photo to understand that isolator. Finally figured it out, I think! What we can easily see on the visible side are the ends of the two diodes that do the isolation, with the other ends under the heat sink. The two red wires on the right and left side are connected to the battery terminals.
This looks very undersized for the application. I would replace it with a 100 amp or better isolator. OEM was just an 80 amp unit. Cheap enough to do so. You could also move over to a combiner to do the same mission. Purpose is to charge the batteries without allowing one battery to drain the other.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
[Updated on: Fri, 10 June 2016 12:05] Report message to a moderator |
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| Re: Isolator question [message #301965 is a reply to message #301936] |
Fri, 10 June 2016 12:38 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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One of the diodes is probably shorted to the heat sink.
I would disconnect that thing before it starts a fire.
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: [GMCnet] Isolator question [message #301966 is a reply to message #301964] |
Fri, 10 June 2016 12:54 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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I would replace that homemade unit ASAP.
You could go with 100 to 140 amp replacement unit.
or
http://tinyurl.com/jyaa2z7
There are many available, do a search on Ebay for battery isolator.
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
> On Jun 10, 2016, at 1:05 PM, Thomas Phipps wrote:
>
> Took a few looks at the photo to understand that isolator. Finally figured it out, I think! What we can easily see on the visible side are the ends
> of the two diodes that do the isolation, with the other ends under the heat sink. The two red wires on the right and left side are connected to the
> battery terminals.
> This looks very undersized for the application. I would replace it with a 100 amp or better isolated. OEM was just an 80 amp unit. Cheap enough to
> do so. You could also move over to a combiner to do the same mission. Purpose is to charge the batteries without allowing one battery to drain the
> other.
> Tom, MS II
> --
> 1975 GMC Avion
> KA4CSG
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: Isolator question [message #301970 is a reply to message #301936] |
Fri, 10 June 2016 15:35 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
Karma: 5
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Johnny,
I think the anode on that Ebay item is in the wrong direction.
" STUD IS THE ANODE"
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: Isolator question [message #301984 is a reply to message #301936] |
Fri, 10 June 2016 18:41 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Remove that thing and put it on the bench as a demonstrator tool on how to meter good and bad diodes. If it ruined your house battery you'rr in for way more cost, and heat usually has fire in the future
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Isolator question [message #302046 is a reply to message #301936] |
Sun, 12 June 2016 10:42 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Bill - The polarity within the diode doesn't matter, as long as the cathodes are paired and driven by the alternator, and each anode goes to a seperate battery.
--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
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