Anyone else have a high pitched noise while braking? I've heard it since I got my 09' but since it's going in for some HVAC flapper noises I thought I'd ask...anoyone else hear a high pitched while when you touch the brake pedal?

 

No noises from my '09 brakes or anything else. Never had one problem going on 25,000 miles knock on wood. The most FE FEH I've driven with a LMPG of 52.2mpg and growing fast. The OEM tank gauge is at 66mpg today with 550 miles, so it looks like a 61mpg tank for the first time if I can hold on to it.

GaryG

 

My 07 gets a noise as decribed most likely the inverter, like a high power SCR

 

My 2008 MMH has always had an extremely high pitched whine on braking. Usually not too noticable with the AC on or in the winter, but noticable with the windows down. THe transmission can also cause a high pitched noise in the radio when at idle. If I shift to neutral, the noise goes away.

 

My 2010 Toyota Prius exhibits a high-pitched tone most noticeable when braking, but also apparent whenever the electric motor is active. Not a bothersome noise, but troublesome, nonetheless, given the newness of the technology, with regard to potential problems ongoing in a vehicle we hope to have for a decade or thereabouts. We have about 17000 miles on the vehicle, which averages 49.6 MPG.

 

If it is the same noise I am thinking of, it is most likely the generator kicking in to put power back into the battery via regen. It is interesting; some people cannot hear it because of the high pitch. On my 2008 FEH, I will hear it even at highway speeds when the vehicle is slowing down. My father-in-law kept asking if there was an emergency vehicle somewhere every time it happened. It does sort of sound like a far-away siren.

Think of it as the sound of MPG going into the battery...

 

I've read some scattered reports on the frequencies
used in the Prius and FEH systems. And just listening
to my 06 FEH it sounds to be around 400Hz. This is a
pretty common AC frequency in industrial/military
systems. Way back when I was working on Navy systems
power was distributed using 3-phase 400Hz. Transformers
can be small and efficient at that frequency. If you
apply 400Hz AC to a motor your gonna get some whine.
From what I understand the FEH MG1 & MG2 motors are
permanent magnet DC motors. Believe it or not very
similar to the motor used in a 3.5in floppy disk drive.

 

When I was in the USAF they used 400 Hz for our power systems, and my headset carried the tone. Come to think of it, I hear the sound only in my right ear (I always wore my earpiece in the left ear, so I think I am deaf to that particular frequency on the left side), so you may well be right.

 

FWIW from what little I found they move the frequency around some
as the regen process occurs and/or the ICE recharges the HV battery.
When you first start your FEH you hear one frequency and that moves
around some as the battery charges up. I'd say it 400Hz +-50Hz.
The frequency will fall as the battery gets up to desired charge.