Battery Cooling Fan Constantly Runs Every Highway Trip - Normal?

it doesn't sound right, but i don't have an answer for you on a newer car like yours. could anything have clogged it? animal fur, children, etc.? i never hear mine. (but that doesn't mean it's not running.)

 

could be that the fan is defective and running normally but making noise so you think it's on more. usually, they are very quiet.

 

unfortunately, there is no way to know what the fan is doing unless you have a scangauge. hopefully, someone else with more knowledge will chime in here. i thought it was based on battery temp alone, so running your a/c on high should slow it down or stop it. still it sounds as if something is caught in it (baseball card) or a bad bearing perhaps.

 

I never hear my fan running on my 2011. I've done winter driving, summer heat (99F with A/C set on 77F), creeping through freeway congestion, long uphills to the Blue Ridge, and 75 mph freeway cruising. Never any fan noise.

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Are you sure it's the battery fan? Next time you hear it, try immediately slowing way down to 10 mph if possible. The fan should still run for a while if it's a battery heat problem. If you don't hear the fan noise, maybe it's a drive train noise or something.

At fast highway speeds, I don't think the battery is drained and refilled much more than at normal speeds. And that would be what would heat the battery up.

 

This does sound like abnormal behavior. If the fan is running that much then 1) the cooling fan is clogged or defective, 2) one of the temperature sensors in the battery compartment is reporting bogus information, 3) there is a problem with the battery pack or other component that is causing the battery to heat up. This is not a condition that I would allow to persist for long. I suggest having the dealer check it out

 

Have someone else drive your car and you can sit in the back. Maybe it is wind noise getting in? Or maybe it is the battery. I'm sure you can be postive if you ride in the back. If it is the battery fan you may need to stop by a dealer and explain it to them.

 

My 2010 has a fan so quiet I have yet to hear it. The BtT temp stays about 10 degrees over ambient so the fan must be working. Fan sounds defective or the temp switch that controls it or something is stuck in the squirrel cage...

 

You must keep the cabin as cool as possible both sitting and driving. Heat soak is hard on the Hybrid battery not to mention all the electronics in the cabin.

Tint
Window shade
Crack Windows at the top
park in shade

Keep cabin cool while driving AC on in recirc. If your sweating so is the Hybrid battery.

Having said that if you already do all that if it was me I would spend the $125 fee at the dealer for a Techstream diag.
They hook a laptop with TStream Toyota Software to the OBDII port and take the car for a ride and check Hybrid battery voltages on all the packs and charging rates and also can tell you why the fan is on. They can immed. tell you if the Hybrid battery has an issue. Also if there is an issue its free instead of the not sure please check diag fee.

Better to find out at the dealer than be stranded somewhere is my thought.

Please check out Lusciousgarage.com for more info.

 

You are about a 4 hour drive from Steve at AutoBeYours.com (Plug In Hybrid Electric Vehicle PHEV). Take your Prius to him and he will diagnose and fix it for a reasonable price.

JeffD

 

Is the drivers side rear window down half an inch causing wind noise? It's sometimes easy to press the wrong window switch when you're driving and at lower speeds you don't notice the wind noise.

 

The battery fan turns on when the battery temps get above 95F. If you are not using the AC in 85 weather then it can definitely be running but at a slow speed. When mine was at a speed mode of 4 out of 6 my wife could not hear it and she can hear a pin drop.

The fan does not change speed with car speed. If it sounds like it is running faster at higher car speeds that sounds like wind noise and not battery fan to me.

 

it does sound like normal operation. as you cool the interior, the hybrid battery cools and needs less speed of it's own fan or none at all. but as far as the sound goes, you would have to listen to another one to know if it's louder than average although, i suspect it is.

 

2011 owner, live in Cincinnati.

I hear my fan a lot. Not constantly, and not every highway trip, but I hear it on average once per trip. Car has a dark exterior and is never garaged. At work I crack the windows during the day, but the rest of the time when it's parked the windows are up.

I have the Torque app on Android and I monitor battery intake temperature. It's crazy, the intake temp. takes a long time to decline even with the A/C on. On a hot day (outside temps at 90F, for example) if the car was parked in the sun with the windows up, even if I have the A/C on at a comfortable temperature (Auto - 78F) for 30 minutes, that intake temperature will still be hovering around 90-95F after 30 minutes, with the fan spinning.

I've not taken the time to consider if there is anything wrong with my vehicle either, but for now I'm not worried about it. We've only put 3,000 miles on it since purchased. We do have a dog that rides along regularly, and a seat cover that can cover the vent if not careful - but I check regularly to make sure it's not obstructed.

 

FWIW - I've never heard my battery fan on my 2010 IV.