Went for a mostly highway drive today and the IPU fan ran continuously during the highway portion of the trip. Seemed rather loud at times. The car was in the garage overnight where the temperature was about 30 degrees F. I was maintaining a constant speed of 60 mph and using little if any assist. The climate control was set at 72 degrees. I didn't observe any strange hybrid battery behavior or recals. This is the first time I've noticed the fan running for a long period of time during my one month ownership of the car. The only thing that I can think of that might be significant is that I did a 12 volt battery maintenance charge with my Battery Tender and removed the charger just before the drive.

Is this normal fan behavior?

 

It's been too long for me to remember. 30 is cold, and charging is inhibited. It's conceivable that it might try to heat the battery by drawing in cabin air.

 

That's definitely possible. What seems strange is that I've driven the car in much colder temperatures and didn't notice that the fan was running. Everything else with the IMA seems normal. Because I have the rear seat removed from the car temporarily, I was able to check the IPU cover for any hot spots with the palm of my hand. The area around the warning and disposal stickers was warm. The other areas were cold to the touch.

Hopefully it isn't anything to worry about.

 

Inverter, converter, MCM, BCM and A/C controller are all on the passenger side of the IPU. The inverter/converter will definitely get warm.

 

Thank you for the information and quick reply. I've also noticed that the IPU fan sometimes turns on immediately after starting the car. I guess what I'm trying to say is that the fan behavior seems somewhat random from what I've observed. I've only owned the car for a month and driven about 2000 miles. Still getting to know the quirks of the legendary HCH2.