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HOT Isolator

Are these temperatures normal for the isloator while the engine is running?

Left and right terminals 175 degrees
Center terminal. 185 degrees

All charging functions seem to be working ok.  It is a new isloator as the old one had a spun center terminal. 

1997 U295
Terry and Cheryl Brown
1997 U295 36'
Build #5066
2006 Jeep TJ Rubicon
1993 BMW R100 GSPD

Re: HOT Isolator

Reply #1 –
Exactly what isolator is it?Do the research and call the manufactuer,or post the brand and model and someone here will.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: HOT Isolator

Reply #2 –
It is pretty warm in engine compartment. but I would loosen off and retighten. Temps will be higher if not a good connection.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: HOT Isolator

Reply #3 –
What is the capacity of the isolator? Is it overloaded?
John Duld
1995 U320C SE 40'

Re: HOT Isolator

Reply #4 –
Cole Hersee 48160 Battery Isolator  200 amp
Terry and Cheryl Brown
1997 U295 36'
Build #5066
2006 Jeep TJ Rubicon
1993 BMW R100 GSPD

Re: HOT Isolator

Reply #5 –
I wonder what Cole Hersee would say about those temperatures?
May be normal. As my isolater aged it looked like it had been hot.
John Duld
1995 U320C SE 40'

Re: HOT Isolator

Reply #6 –
Yup I would be visiting with Cole Hersee.  Tell them approximate amps their isolator is handling as well as temperature in the engine room where it is located.

FAR better than our guesses.

But 180 degrees, particularly with all the heat-dissipating fins means you are turning a LOT of alternator output into heat.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: HOT Isolator

Reply #7 –
Not sure where his is but mine is next to the safe under the floor,so probably a little cooler than the actual engine area,I assume
you were using a heat gun for your temperatures?
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: HOT Isolator

Reply #8 –
Yes, I used an IR heat gun
Terry and Cheryl Brown
1997 U295 36'
Build #5066
2006 Jeep TJ Rubicon
1993 BMW R100 GSPD

Re: HOT Isolator

Reply #9 –
Measure the current through the diode and the voltage across.  There should be a spec, if the drop is higher than spec for that current, there is a heat generating problem either in the diode or connection.

By the way, if the current is 100A and the diode drop is 0.7V, that diode is dissipating 70 Watts. Think of the heat from a 70W incandescent light bulb.  This could easily be normal. There is a reason for the heat sink fins.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer

Re: HOT Isolator

Reply #10 –
How far away is the ir gun from the bolt head.  With a beam of 10:1 you can not be more than 2.5" away from a .25" bolt.  I would use a contact thermometer in this instance.  You're probably measuring the heat sink temperature.
'87 40' Grand Villa 4000 SBID ORED
CAT 3208TA 300Hp driving MT647, PacBrake
Unkown watts Solar
'17 Conti's HSR2 10-22.5
Cove, Texas
Previous: '76 to '16,  5' 10", 0.1Hp, hauling 85lb BackPack shod on Keen Boots

Re: HOT Isolator

Reply #11 –
I think that the problem is fixed.  I removed , cleaned, reattached all connections to the isolator and relays.  The temp is now 165 degrees at the alternator terminal on the isloator.  I drove the coach for 30 minutes to get a true reading.
Thanks everyone for the help.
Terry
Terry and Cheryl Brown
1997 U295 36'
Build #5066
2006 Jeep TJ Rubicon
1993 BMW R100 GSPD
 

Re: HOT Isolator

Reply #12 –
On our coach if we deplete house battery bank, we run generator to let inverter/charger charge batteries.  We do not consider the engine alternator / isolator the best way to charge depleted house batteries.  It seems that the isolator's big job would be to replenish start bank from engine start, which would be minimal work.