Hey everyone... Long time since I have posted anything here, but I noticed the fan running far more than normal here. Now the outside temp was fairly warm, but the most recent day I noticed it, the temps were only around 80-85 degrees out. I usually don't run the AC in my car unless it is terribly hot out - so when I hear a fan running it stands out to me. It is very obvious that it is coming from the rear seat vent area. The temps here have taken a dip (highs tomorrow are only about 70-75F), so I will keep an ear out for it to continue. Is this something to be concerned about? It is a 2010 Prius IV with about 32k miles... Thanks!
The HV battery fan uses the cabin air to cool the battery. If you do not use the AC and the cabin temp is warm or hot, the battery fan has trouble cooling the battery. You need to keep the cabin cool to keep the battery cool. Also, if you do a lot of start/stop driving this will "heat pump" the battery. I monitor my HV battery fan with ScanGaugeII and in 80-85 temps with start/stop driving my battery fan runs a lot. I do not think this is anything to be concerned with as the car does a good job of taking care of the HV battery.
This may be a sign it's time to clean the ventilation ports for the battery fan. They may be restricted by "stuff" causing the fan to run harder/longer.
