I got into my car tonight and heard a very strange sound coming from the rear vent - I pulled out the manual and it must have been the fan cooling down the hybrid battery. It freaked me out! :Wth: Has anyone else had their vent fan come on? I had been running errands most of the day and it was 99 - 100 degrees most of the day. I had come home, parked (in the sun) and about 2 hours later went out to the car to go out, that's when it came on, but was cooler - in the 80's when I went out to drive it again. I guess it's not something to worry about as no lights, bells or whistles came on, but it still freaked me out.
I've been pondering having someone make careful recordings of the various sounds the Prius makes...that whine when you step on the brake to start the car, the pump for the thermos, the circuit for the battery, the fan for the battery, etc. It would be a pretty cool addition to the FAQs if someone has that capability. And you're right, it's nothing to worry about.
you sure it wasnt the hot water pump to the engine? it will run nearly all the time if you take a short trip in the car that isnt sufficient to warm up the engine. (i found that even in hot weather this happens in my car) this is normal operation according to the manual. the pump sound like a pump if you pop the hood, but it isnt as easily identified if say inside the car. as for sounds, i admit, i drive with music all the time, but when i first got my Prius, everyone commented on how quiet the car was even at freeway speeds. other than road noise, the engine was so quiet as to be eerie. i laugh when someone derides me when they think my brand new car that i touted so highly seems to stall at a stop light. i love the look on their face when the light turns green and i take off nice an smooth. i got my car the weather was very mild the first day i had it, i was driving around with my sister and nephew late at night so traffic was minimal, we had the windows open and at traffic lights you could hear a pin drop. they were impressed.
I don't think it was the hot water pump. This sounded my laptop when it gets hot and the fan kicks on. It was definitely coming from the vent. I just wish it had stayed on long enough for me to park and check it out close up. As per Murphy's Law, it stopped just as I had pulled over to check it out.
i havent noticed any noises like that but maybe the fan for the battery was on or something. you living in So. Ca might make your car do that and mine not. we have only had a few days in the 90's here. most of the days here are between 75-85º
when your driving the car, air is forced thru the vent and across the battery assy. If your using the car a lot and the battery is charging and discharging there is heat built up in it. All the cells packs have a thermistor in them to keep track of the internal temp. When you stopped the car what happens is that Latent heat builds up and when you started the car the temp in the battery was high enough to tell the computer to turn the fan on and remove it. Then when you start moving the car again the normal airflow thru the battery pack helps keep it cool. Once the car is moving the interior of the car is a positive pressure compared to the outside and that's where the airflow comes from. If you have the window open and it's 100 degrees out I could imagine the fan running a lot but with the windows closed and the a/c on recirc there is still enough outside air pumped into the car to have flow across the battery. In the frozen parts of the country the air is heated and forced across the battery.
See... my first reaction was, what rear vent?!, but it does sound like you're talking about that grillework next to the passenger-side door in the back seat. yep, that's the air intake for the main battery (the 200+Volt one, not the 12-volt one). it once dawned on me how smart these Prius engineers were: where can you find air that's almost never too hot, for cooling off a battery? well, take it from where the passengers are! if it's too hot out, they'll probably have the A/C on, and if the battery gets too cold in the winter, and its efficiency drops, just warm it up with some cabin air! neat! so, i think we agree: don't worry.... (be happy!) but here's a noise i found coming from under the hood of my Prius one day: a tiny peeping sound like "beeebeeebeeebeeebeee...." went on for several minutes! i finally tracked it down to the cap on the radiator expansion tank, and it stopped immediately when i loosened the cap. what puzzled me was that i thought that tank should not be pressurized at all! any suggestions on THAT one? thanks, gang!
I have heard it once. It sounded like a notebook computer's fan, but much louder, and it definitely came from the main battery's vent. You can't confuse this noise with anything else. My fan came first thing in the morning, so the battery was not hot; it was on for about 30 seconds.
Same thing happened today in our '06 Prius -- never heard that sound before, and we have both '06 and '02 Priuses. it was about 75 degrees out, the car was in the shade, and had been parked for a couple of hours. We had driven about 200 miles earlier in the day, so who knows. No idiot lights went on. Seems okay now. : Any clues?
