Speak EV - Electric Car Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1
So, after the demise of my old Ampera in a collision, I’ve looked at a couple of replacements (there’s not many to chose from!). I took the only one which appeals to me for a test drive and was loving it until I became aware of a very slight, very high pitched buzzing in my left ear (not tinnitus!) which became more audible if I turned my head to the left so that ear was facing the back where the battery is. Only did this while being driven, but the pitch didn’t change with speed. I’ve watched a couple of the wheel bearing vids on YouTube and it doesn’t sound anything like that; I would describe it as very much like those plug in gadgets you get which are meant to scare away mozzies and spiders.

It’s not atrocious, but it would bug me because I would be aware of it, and I know for a fact that my old Ampera didn’t have the same thing. Any advice or ideas?

:rolleyes:
 

·
Registered
Joined
·
2 Posts
Hi Dougmeister,

I have noticed a similar thing with mine as well. I supposed it was normal. I am a new owner :).

For me the high pitched happens only when I run out of battery and the ICE is on.
It is not unpleasant and sounds a bit like a high-current terminal box.
It is not happening all the time though, it comes and goes and might last max 2, 3 minutes.
I do not yet know the source of it and it doesn't seem to vary with engine load or speed.
My girlfriend cannot even hear it.

I am curious to see if others have it as well :p.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #3
Hi Dougmeister,

I have noticed a similar thing with mine as well. I supposed it was normal. I am a new owner :).

For me the high pitched happens only when I run out of battery and the ICE is on.
It is not unpleasant and sounds a bit like a high-current terminal box.
It is not happening all the time though, it comes and goes and might last max 2, 3 minutes.
I do not yet know the source of it and it doesn't seem to vary with engine load or speed.
My girlfriend cannot even hear it.

I am curious to see if others have it as well :p.
Hello matey,

Glad to hear I’m not the only one! Now you mention it, I didn’t notice it at the start of the test drive, but only after I went through all the driving modes including “Hold” which obviously employs the ICE. Seemed to be that’s when it started, though I noted that it persisted even when I came out of Hold and back onto the battery. Test drive was only for 10 mins or so, so can’t say whether it would have shut up of its own accord.

Interestingly as well, the guys at the dealership said they have never noticed it... but one of them admitted being mutt & jeff and they probably would have denied hearing anything if it sounded like a pneumatic drill anyway! :censored:
 

·
I'm not crazy, the attack has begun.
Joined
·
26,315 Posts
The DC-DC converter is located under the rear floor, on the driver's side. It can sound quite noisy if there are no other sounds around. Obviously, one might be a bit noiser than another, just natural variation. I would bet you could hear this. Maybe its fan bearings are getting worn, I believe it has a cooling fan which contributes the most noise.
 

·
Registered
Joined
·
330 Posts
Mine has a noise a bit like that from the rear under the boot floor, which I assumed was the converter, which Donald has confirmed. It's not really high-pitched though in mine. It runs all the time but I hardly notice it unless stopped and I think about it (with radio off and windows closed). The time I notice it the most is when I power off, then it occurrs to me I can hear the fans(?)wind down.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #6
Cheers guys, that offers me some reassurance, and it’s fair to say that I did have the radio off and windows closed. Maybe I was just lucky with my old Ampera before its demise...

Might have to revisit this one and take her for another spin, see if it happens again...
 

·
I'm not crazy, the attack has begun.
Joined
·
26,315 Posts
I would offer you the following 'measure'; you SHOULD [unfortunately] notice it when stationary with the ventilation off, but you should NOT hear it once you put the fan on and set off driving, it disappears as background noise along with all the other noise sources (primarily road noise).
 

·
Registered
Joined
·
2,752 Posts
Sounds like the DC/DC convertor, yes. It's very noticeable in mine (though I tend to notice things like this a lot); it's louder when accelerating from standstill as the rest of the car is so quiet, and also when regenerating hard, e.g. downhill or when the engine is putting electricity back in the battery buffer while in Hold/Mountain modes. Nothing to worry about.
 

·
Registered
Joined
·
3,036 Posts
I agree that it is almost certainly the DC-DC converter under the boot.

I have read quite a few posts regarding this over the years but didn't notice it until I used the car with the rear seats lowered.

Lift the rear deck with the car switched on to confirm the noise.

Hope you get Amped up soon. (y)
 

·
Registered
Joined
·
2,752 Posts
Yep, it uses the air under the floor and the chassis to get rid of excess heat from the inverter. One reason you must never try and use it as some kind of extra boot space, under the false floor!
 

·
Registered
Joined
·
2,752 Posts
It is if you like cheese when you get home :)
 
1 - 14 of 14 Posts
Top