Electrical line noise while charging at 240V

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Christopher

Well-known member
Joined
May 5, 2011
Messages
118
Location
Santa Cruz, CA
Okay, I was asked to move this discussion out of the modded EVSE thread, so here goes, from the top:

After receiving my modified L1 EVSE and the corresponding adapters for my 240V dryer outlet, I'm hearing significant electrical noise from various devices with speakers in my condo while charging at 240V. Most annoyingly, I hear it from my computer display (an Apple LED Cinema Display) and boy is it bloody irritating after an hour or so! It's also audible on a set of powered computer speakers as well as across all the speakers in my home theater driven by my Sony ES receiver/amp, though less so. I believe it to be power line noise (as opposed to radiant).

1) The noise is generated only when charging at 240V, not when charging at 120V and of course never previously.
2) The noise occurs with different devices (though not everything) and on every circuit I tried. It occurs on circuits with or without GFCI. These outlets do pass ground testers.
3) This same noise is audible directly from my electrical subpanel while charging at 240V. It's normally silent. (My subpanel is up in my living space, two flights above my garage.)
4) My 240V source is a dedicated 30 amp circuit for my dryer with the old style 3-prong outlet. (NEMA 10-30)
5) Two noise filters tested against the computer display didn't help. Another old noise filter (SL Waber WaveTracker) that I dug out of the closet fried itself (flash+burnt smell) when I tried to use it. (It had been sitting in storage for many years.)

I eventually broke out a handheld AM radio, tuned it to find interference and walked around to find… AC electricity in my walls!! Amazing! ;-) Also, lots of noise down around in the garage, inside the car, at different specific points within the garage, along the charging line and the EVSE and a different kind of noise (static/white noise) around the plug adapter. But none of that is probably interesting.

Unless folks can tell me that all this electrical noise is normal and unavoidable while charging at 240V, I'm going to stop using 240V and go back to charging only at 120V. And I guess I need to get an electrician to come in and check this out. I'm not sure how I'm going to handle the raised eyebrows at the modified EVSE, but we'll see.

If you'd like to hear this electrical noise for yourself, here you go:
http://crimdom.net/misc/noise-sample.mp3

And if someone would like to drop by north San Jose and plug in their LEAF here to eliminate my car (and its on-board charger and noise filter) as the issue, let me know!
 
Where did you record the noise?

Are there any smells or any any electrical wiring or devices getting unusually hot?

I'm wondering if there may be a bad / loose connection that is part of the circuit when you charge at 240V that isn't part of the circuit at 120V. High currents through a loose connection is almost like having an AM radio station across the whole dial!
 
ElectricVehicle said:
Where did you record the noise?

Are there any smells or any any electrical wiring or devices getting unusually hot?

I'm wondering if there may be a bad / loose connection that is part of the circuit when you charge at 240V that isn't part of the circuit at 120V. High currents through a loose connection is almost like having an AM radio station across the whole dial!

That recording was made directly beneath the computer display speakers though, as I said, you can hear the same noise directly from the panel. (Speaking of which, I've got to go switch back to 120V now... bloody noise is giving me a headache!)

No smells, no hot wiring or devices. Note that this 30A 240V circuit is for my dryer and so it's been used at higher current for 18 years without trouble (or electrical noise). The LEAF's charger is a different beast, but lower current draw.
 
If it's easy for you to do, please also record at the panel and at the place where you hear it the loudest that isn't a speaker or audio device.
 
ElectricVehicle said:
If it's easy for you to do, please also record at the panel and at the place where you hear it the loudest that isn't a speaker or audio device.

I'm certainly not going to subject myself to that irritating buzz any longer tonight! ;-)

There were no places (other than the subpanel itself) where you could hear the noise without a powered audio device. And it really is the same sound at the panel, just more subtle. As such, I wasn't able to get a decent recording with cheap mics.
 
Aluminum or copper wiring?

You've run the dryer recently and when it's running you didn't hear any noise from the panel? Or is the dryer (high heat, first few minutes after you start it so the heating elements are sure to be on) loud enough to mask the noise?

You can PM me your address if you like, and I can stop by for a quick look (listen) sometime.

We'll see what Phil thinks also when he responds...
 
Try recording a GFCI receptacle with nothing plugged in while LEAF is 240V charging. How old is the GFCI (or the house) ?

I reported this issue to Nissan back in early February. They have been very cooperative and diligently working on it all the way back to Japan (Tsunami/earthquake & all). Some more info will be available within a couple of weeks. I can't say a lot more ... but do NOT charge a 2008 Tesla (not sure whether 2010 is affected due to PEM re-design) and a LEAF at the same time.

If it's not too inconvenient go back to 120V charging, and use the 240V only when needed.
 
I don't think it's unavoidable - a good many people would be complaining if this happened to everyone.

I'm not really qualified to say more on this issue since it isn't happening to me and I don't want to misrepresent anything, but from what I do know, I believe Phil's earlier guess pointing the finger at the noise filter in the LEAF is on target. The only reason I'm saying anything at all is because you deserve to know that you're not alone and that the issue is being actively investigated by the approriate parties. If the other person who is having this issue (you know who you are) wants to chime in now that the cat is out of the bag, that has to be their choice, I won't out them. Their original decision was to keep quiet pending the results of the investigation - after all, there's no point in starting a panic like happened with the A/C issue (which quickly got out of hand here).

For now, just know you're not alone and that it's being looked into. I'm sure the cause will be figured out in time and taken care of appropriately. Stay tuned. In the mean time, perhaps a decent surge protector with line filtering at each of your offending devices will tame the noise?

EDIT: Looks like as I was typing this, the "other person" posted just before I did. Oh well, at least now you know. :D
 
Christopher said:
Okay, I was asked to move this discussion out of the modded EVSE thread, so here goes, from the top:

After receiving my modified L1 EVSE and the corresponding adapters for my 240V dryer outlet, I'm hearing significant electrical noise from various devices with speakers in my condo while charging at 240V. . . . . . . . . . . . . . . . . . . . . .
Hey! . . . . you mean I'm not the only one? One of our 2 PV inverters buzzes when 240V charging starts. but it seems to go away after a few minutes. Very strange.
 
I'll just make one comment and let it go. Since the modded Panasonic EVSE - or any EVSE for that matter - simply closes a relay and lets the power flow to the vehicle, it's highly unlikely that it could play any roll in generating EFI. Such EFI problems would almost certainly have to lay elsewhere.
 
The fact you audibly hear the noise at the sub-panel is stunning.
With really high levels of radio frequency, such as at the transmitter of a very high power radio station, it is possible to hear the song that is playing audibly at the power connections. But that is at a staggering level of radio frequency energy.
RFI (radio frequency interference) can be picked up by a lot of devices such as all the systems you mention with speakers.
But for you to hear the radio frequency buzz at the sub panel, is likely that the sub panel has a bad / loose termination.
I guess its theoretically possible that the RFI could be causing the whole panel assembly to buzz, but more likely a loose connection.
The sub-panel should definitely be checked carefully by a very competent electrician. With the panel cover off, may be able to pinpoint the location the sound is coming from while doing the 240V charging.
I would not use 240V charging until the sub-panel is checked out.
The sub-panel may have had a problem all along that the RFI has helped pinpoint.
I haven't charged my new Leaf yet, but I'll be listening carefully when I do for RFI.
I agree with mogur, is unlikely this has much of anything to do with the EVSE. Much more likely this is an issue with RFI from the Leaf charger.
 
mogur said:
I'll just make one comment and let it go. Since the modded Panasonic EVSE - or any EVSE for that matter - simply closes a relay and lets the power flow to the vehicle, it's highly unlikely that it could play any roll in generating EFI. Such EFI problems would almost certainly have to lay elsewhere.
There may possibly be a rare bad EVSE out there ... but the key word is RARE, to highly unlikely. A few of them might have a "buzzing" sound which may come from a bad relay or contactor (*big* relay). This is not the noise/issue we are talking about. The Panasonic EVSE is not the source or cause of what is being described in the OP. Neither would a 240V EVSE be.

A couple of weeks ...

If you have something buzzing that's expensive, and it can't be unplugged (or at least turned off) while the LEAF is charging at 240V ... try using 120V charging for the LEAF for a while if at all reasonably convenient or possible ...
 
Thanks everybody for your input!

To answer questions brought up since my last post:
- It's copper wiring.
- There is no line noise when doing anything else, including running the dryer. I just verified that the subpanel emits no noise either while running the dryer. (The mechanical noise of the dryer isn't audible from my living space where the subpanel is as the dryer is two flights down in the garage. This is a condominium.)
- My GFCI receptacles do not generate any noise directly. Noise only comes from subpanel and several powered devices with speakers (whether plugged into GFCI or not).
- The building and all wiring is 18 years old. I've lived here since it was built in 1993.
- I have returned to charging only at 120V. (I'm glad to hear that noise at subpanel is not normal.)
- The EVSE itself is not buzzing. The car makes it's usual noise while charging at 120V or 240V. Sounds like a reasonable noise to make to me.

I'm not interested in making any other recordings because I already moved gear around the house to test different locations and it sounds the same everywhere -- and it is a bit of a hassle.

It seems that the most likely culprits are either my LEAF or my subpanel. One thing I would like to do is test the charging of somebody else's LEAF at 240V here just to eliminate my LEAF's onboard components as the source of the electrical noise. It would only take a few minutes as the noise is immediately apparent. I'm in north San Jose near Montague Expressway and 880.

It would be nice to eliminate my LEAF before calling an electrician to check my subpanel. And of course if there is a difference between cars that would be great info to take to the dealer.

Thanks again all!
 
I haven't checked all the frequencies but I've herd zero RFI on my HAM radios which are only about 15 feet away from my Blink unit. I expected LOTS of noise, but was pleasantly surprised. I haven't listened to my inverter for my solar.....99% of the time, I charge after midnight when (last time I checked), there isn't much solar generation going on. ;)
 
Christopher said:
It would be nice to eliminate my LEAF before calling an electrician to check my subpanel. And of course if there is a difference between cars that would be great info to take to the dealer.
Yes, check another LEAF (and report back).

In my (non-electrician-professional) opinion: for a couple weeks ... don't waste money on an electrician on the subpanel. :)
 
LEAFer said:
Christopher said:
It would be nice to eliminate my LEAF before calling an electrician to check my subpanel. And of course if there is a difference between cars that would be great info to take to the dealer.
Yes, check another LEAF (and report back).

In my (non-electrician-professional) opinion: for a couple weeks ... don't waste money on an electrician on the subpanel. :)

Ah, *that's* what you meant by "A couple weeks..." earlier! Something's going to happen/change. Good, thanks for the tip. I take it that not all LEAFs may be affected so testing another LEAF is still worthwhile.
 
I've previously reported this too. It has nothing to do with the EVSE, but (I believe) the charger design. I hear the charging in my computer speakers (very faint), my dimmable CFL turns into one of those flickering candles, and X10 becomes unreliable. Maybe I'll take my scope home tonight and check it out. It's clear the charger is putting all kinds of noise on the line. This happened with both the Clipper Creek and the Blink.
 
turbo2ltr said:
I've previously reported this too. It has nothing to do with the EVSE, but (I believe) the charger design. I hear the charging in my computer speakers (very faint), my dimmable CFL turns into one of those flickering candles, and X10 becomes unreliable. Maybe I'll take my scope home tonight and check it out. It's clear the charger is putting all kinds of noise on the line. This happened with both the Clipper Creek and the Blink.
Only 3.3 kW and suspected of Dragon Breath EMI emissions on the power line? Urgghh! Definitely want to see the data on that. Can you please post your Oscilloscope traces of the charger at 120 and 240V? If the scope doesn't export images, I've used my digital camera to capture images from my oscilloscope (little battery powered scope I bought for personal use).
 
Taken at the EVSE plug (Blink)

This is not the full wave. What you see is zoomed in on the top of one leg and the bottom of the other leg. 20V/Div

Not charging:
IMG_8499r.jpg




Charging:
IMG_8500r.jpg



Apparently my crappy scope doesn't capture the screen persistence when you save screens, but overall there's about 8V of noise when it's charging. It's less than I thought it would be. Maybe someone with a better scope can get some shots... Soon after I bought this scope, Fluke updated their PC software that allows you to talk to it and decided us 105B owners weren't worthy of the update and so I'm left with software that only runs on windows 98. All the newer software doesn't support this scope.
 
Apparently something (probably the LEAF's internal charger) is not drawing current smoothly, but rather in a vary ragged, chopped way, almost as if one of the charger's power transistors is "blown" (open or shorted).

A scope to look at the AC waveform should show the problem.

Or, trying a "good" LEAF would be easy, and this UNUSUAL noise should disappear. Somebody offered to help, so invite another LEAF over to try L2 charging at your house.
 
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