So today my car was out in the sun for 4 hours. The outside temp was 41 degree Celsius. I opened the car and turned on the AC. Everything worked fine. Just out of curiosity i plugged in my obd2 and it read the battery temperature at 46 degree Celsius. I used torque and started the fan at speed 6 to bring the temp down My question is: At which temperature would the car ECU bring on the HV fan? Posted via the PriusChat mobile app.
I wouldn't be concerned at all. Not sure what the exact temp in which the fan should turn on is, but my 2010 sat outdoors in the Texas sun for a decade where we saw temps like that daily. The fan usually wasn't audible. 10 Texas summers and 2 Minnesota winters, my original battery is still holding up. If the battery temperature was only 46° C when the outdoor temp was 41°C, the cabin temp, after sitting in the sun that long, I guarantee was hotter than 46°C (I once left a digital thermometer in my car while it was parked in the sun, the thermometer overheated after an hour, car started up just like any other day). The car probably knows this and doesn't turn the fan on immediately so that it didn't suck air in that was warmer than the battery itself. I'm sure the fan was running at low speeds and once the cabin cooled, probably picked up speed.