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
Exactly what isolator is it?Do the research and call the manufactuer,or post the brand and model and someone here will.
It is pretty warm in engine compartment. but I would loosen off and retighten. Temps will be higher if not a good connection.
What is the capacity of the isolator? Is it overloaded?
Cole Hersee 48160 Battery Isolator 200 amp
I wonder what Cole Hersee would say about those temperatures?
May be normal. As my isolater aged it looked like it had been hot.
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.
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?
Yes, I used an IR heat gun
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.
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.
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
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.