Fan noise

[Spat]

Hi

Hope someone can help. When my engine is running on my Lexus 300H there is a fan noise which seems to be coming from the back seat. The fans are all off and also the radio so cannot be the speakers. Is it to keep the car cool in the hot weather or some kind of problem. Any help will be much appreciated. 

[sorcerer]

It's to cool the traction Battery. On my car there are vents under the seats that MUST NOT be blocked, I'm assuming your car is the same, so don't put shopping bags or coats on the floor in front of them..

EDIT:

Just found a photo and I'm assuming that this is one of the traction Battery fan vents on yours:

 

[Britprius]

In the hot weather it is advisable to run the AC with the windows shut. This helps keep the traction Battery cool as it gets it's air supply through that vent from the cabin.

The cooler the Battery the slower the fan runs as it is self regulating. Also keeping the Battery cool is good for it's longevity. 

John.

[Ben01]

2 hours ago, Britprius said:

In the hot weather it is advisable to run the AC with the windows shut

I think it is common sense and advisable in any car?

It is not a first time, hybrids' design suprised me (like feed the cooling of Battery from the cabin 🤨 for me it is like feed the beetle's air cooled engine from the cabin, why not), I feel old now.