Lights flicker when I finish charging off HPWC@80a

[Comso]

I did a bit of forum searching, but I didn't find anything similar.

When I stop charging my car (P85d) off my HPWC @ 80a, the lights in my house flicker. It doesn't seem to harm anything, but unstable power isn't a good sign. I had my HPWC professionally installed by Tesla's recommended Electrician (who has done well over 100 of them), and the house is less than 10 years old with 200a service.

I preheated my car earlier today as I was going to go out, then changed my mind and stopped the preheat. When I stopped it, the lights flickered. The car wasn't charging at the time, so this was just the car HVAC that did it.

Is this common? Anything I can or ought to do to prevent this?

Suggestions?

 

[islandbayy]

I did a bit of forum searching, but I didn't find anything similar.

When I stop charging my car (P85d) off my HPWC @ 80a, the lights in my house flicker. It doesn't seem to harm anything, but unstable power isn't a good sign. I had my HPWC professionally installed by Tesla's recommended Electrician (who has done well over 100 of them), and the house is less than 10 years old with 200a service.

I preheated my car earlier today as I was going to go out, then changed my mind and stopped the preheat. When I stopped it, the lights flickered. The car wasn't charging at the time, so this was just the car HVAC that did it.

Is this common? Anything I can or ought to do to prevent this?

Suggestions?

It's technically "not" the car. It's the utility power. When the car first starts to charge, or draw utility power at all, it is a slow ramp up to whatever the amperage draw setting is. So as it draws, and voltages from the mains drops, it's not as noticeable, as it's a smooth curve for the most part. When heating or charging stops, it's a sudden drop. This sudden change means a high voltage spike then level off. This is where you get the flicker from.
This could mean a number of things.
1: Could be undersized wiring from the pole to your home.
2: Could be a under-sized transformer
3: Too many homes on transformer (see above).

And a handfull of other things. For the most part, nothing to really worry about. But, it might be a good idea to see what size transformer is serving your home. If it's a 25kVa (The normal in my area....), especially serving 2 or more homes, call your utility and insist on a upgrade, as when your charging at 80 amps, that is 20kW alone, let alone any other loads from your house or other homes connected.

My utility will be upgrading my transformer within the next few weeks. I have been BEGGING for a upgrade (Currently a 25 Serving 8-10 homes!!!!) for about 3 years now. Finally I wrote a nasty letter. They just jacked our rates up 51% (Yes, that is correct). So I demanded a 51% improvement in service. I told them that I have been very calm and very nice and polite trying to get my voltage issues resolved. I told them come summer, my neighbors have there AC's running, I will be plugging my car in at 80 amps, and turning on my AC, Space heaters and every other appliance I own, and we can see what the results are (Blown transformer...) as my homes utility service alone exceeds that 25kVa transformer, let alone 8-10 other homes on the same one..... I got a phone call back VERY quickly telling me engineering is getting everything ready for the upgrade...

Anyways, I hope that helped!

 

[Comso]

This could mean a number of things.
1: Could be undersized wiring from the pole to your home.
2: Could be a under-sized transformer
3: Too many homes on transformer (see above).

Thanks - I'll call the utility and ask them to address it.

We're dealing with freezing rain here tonight, so they've got their hands full restoring power for now. I'll save my whining about flickering lights caused by my electric car for after that!

 

[dan-l]

What kind of lights do you have? CFLs and LEDs are sensitive to small voltage fluctuations, particularly when combined with a dimmer circuit. I have an electric on demand hot water heater and the dimmable LEDs in our kitchen regularly flicker when we open the faucet. If your incandescents flicker, that's worth following up on.

 

[Comso]

What kind of lights do you have? CFLs and LEDs are sensitive to small voltage fluctuations, particularly when combined with a dimmer circuit. I have an electric on demand hot water heater and the dimmable LEDs in our kitchen regularly flicker when we open the faucet. If your incandescents flicker, that's worth following up on.

I've got all of the above, but it's actually the incandescent pot lights that I notice flicker the most. The UPS I have on my media server in the basement alarms every time as well.

I'll call the power company.

 

[sefs]

Are the incandescent lamps on a dimmer? If they are, see if you can recreate the issue with just a lamp plugged into the wall with an incandescent bulb. I would also be sure the outlet is on the same line (split phase has line A and B; some call them legs) as the flickering lights are. Does this happen only at the beginning and end of charging, or for the duration of charging? If it is happening during charging with a non dimmable incandescent, I'd be concerned; especially if it is occurring later in the charging session. The car charging is a pretty steady load, and shouldn't be causing constant flickering. If it is just occurring when you cease charging rapidly, it's just the voltage drop decreasing in your service conductors due to the instantaneous decrease in load; much like a start/stop of an A/C unit or well pump. FWIW I have LED bulbs in my ceiling fans that are dimmable that will always flicker when my clippercreek contactor is closed and my car is charging.

 

[mknox]

Thanks - I'll call the utility and ask them to address it.

It could be undersized wiring in your home as well. It is normal for utility voltage to vary under load, and the utility is responsible for the quality of power only up to the demarcation point (typically the meter).

CSA guidelines for nominal 120/240 volt supply is 110/220 to 125/250 volts under normal conditions. Under extreme conditions the range is 106/212 to 127/254 volts. In the extreme range, the utility is required to correct the condition on a "planned and programmed" basis, but if beyond the "extreme" range it must be dealt with immediately.

Your utility can check the voltage under various conditions and advise you of the outcome. Even in the normal range, a variation of 15 volts could cause the flickering you mention.

Certain Smart Meter technologies can report voltage back to the utility. At the utility I work for, I have set up automatic alerts from the smart metering system set up to tell if we have over/under voltage, over temperature and the like so that it can be dealt with proactively.

 

[FlasherZ]

I've got all of the above, but it's actually the incandescent pot lights that I notice flicker the most. The UPS I have on my media server in the basement alarms every time as well.

I'll call the power company.

Just a guess, but I'll bet those pot lights are on an electronic dimmer (e.g., triac-based)? Electronic dimmers are super-sensitive to the voltage changes especially at lower dim levels with incandescent lights; they'll react strangely to changes. I'm guessing it's likely a combination of a dimmer plus a service entrance cable or transformer that is undersized.

 

[Comso]

Just a guess, but I'll bet those pot lights are on an electronic dimmer (e.g., triac-based)? Electronic dimmers are super-sensitive to the voltage changes especially at lower dim levels with incandescent lights; they'll react strangely to changes. I'm guessing it's likely a combination of a dimmer plus a service entrance cable or transformer that is undersized.

I think you guys are right, in that this only seems noticeable on those lights I have on dimmers. I'll do some tests this weekend to be sure, but as I have most of the lights in my house on UPB enabled dimmers, it seemed like it was all the lights flickering.

As well, this only happens when I disconnect or stop charging.

Thanks.

 

[FlasherZ]

I think you guys are right, in that this only seems noticeable on those lights I have on dimmers. I'll do some tests this weekend to be sure, but as I have most of the lights in my house on UPB enabled dimmers, it seemed like it was all the lights flickering.

As well, this only happens when I disconnect or stop charging.

Thanks.

It is also a sign of something that may be undersized a bit... when your car starts charging and as it ramps up, what does your voltage show on the Tesla at 0A and at 80A?

While the dimmers are sensitive, stopping charging shouldn't cause that much of an impact unless there's something a bit undersized.

 

[mknox]

It is also a sign of something that may be undersized a bit... when your car starts charging and as it ramps up, what does your voltage show on the Tesla at 0A and at 80A?

While the dimmers are sensitive, stopping charging shouldn't cause that much of an impact unless there's something a bit undersized.

A voltage variation at the car could be an indication of undersized conductor between the panel and the car, a problem with the utility's supply to the house or some combination. It would seem there must be a voltage drop at the panel if lights on other circuits are flickering. If a nominal voltage of 120 drops to 110 at the panel, the utility will not be required to take corrective action (although they may) and when the charging stops, the abrupt "bump" in voltage at the panel may cause the flickering. It's important to remember that the voltage variation you see at the car between 0 amps and 80 amps will very likely be less at the panel, and the utility will consider the service entrance voltage variation, not the variation beyond the demarcation point into the home. I mention this just to set expectations if you do contact the utility for assistance.

 

[FlasherZ]

A voltage variation at the car could be an indication of undersized conductor between the panel and the car, a problem with the utility's supply to the house or some combination. It would seem there must be a voltage drop at the panel if lights on other circuits are flickering. If a nominal voltage of 120 drops to 110 at the panel, the utility will not be required to take corrective action (although they may) and when the charging stops, the abrupt "bump" in voltage at the panel may cause the flickering. It's important to remember that the voltage variation you see at the car between 0 amps and 80 amps will very likely be less at the panel, and the utility will consider the service entrance voltage variation, not the variation beyond the demarcation point into the home. I mention this just to set expectations if you do contact the utility for assistance.

I concur. I ask what the Tesla shows to see if the drop range between 0-80A is much bigger than the expected drop of 3-5% that's expected. My guess is that, indeed, it is. As it has been described, I think he'll see a fairly significant change at the service entrance, but my guess is that it might not be enough for the power company thresholds.

There are also other ways of encouraging the power company should they not budge:
Incoming utility cable capacity - A cautionary tale - Page 2

*whistle*

 

[Modelxvin1365]

It's technically "not" the car. It's the utility power. When the car first starts to charge, or draw utility power at all, it is a slow ramp up to whatever the amperage draw setting is. So as it draws, and voltages from the mains drops, it's not as noticeable, as it's a smooth curve for the most part. When heating or charging stops, it's a sudden drop. This sudden change means a high voltage spike then level off. This is where you get the flicker from.
This could mean a number of things.
1: Could be undersized wiring from the pole to your home.
2: Could be a under-sized transformer
3: Too many homes on transformer (see above).

And a handfull of other things. For the most part, nothing to really worry about. But, it might be a good idea to see what size transformer is serving your home. If it's a 25kVa (The normal in my area....), especially serving 2 or more homes, call your utility and insist on a upgrade, as when your charging at 80 amps, that is 20kW alone, let alone any other loads from your house or other homes connected.

My utility will be upgrading my transformer within the next few weeks. I have been BEGGING for a upgrade (Currently a 25 Serving 8-10 homes!!!!) for about 3 years now. Finally I wrote a nasty letter. They just jacked our rates up 51% (Yes, that is correct). So I demanded a 51% improvement in service. I told them that I have been very calm and very nice and polite trying to get my voltage issues resolved. I told them come summer, my neighbors have there AC's running, I will be plugging my car in at 80 amps, and turning on my AC, Space heaters and every other appliance I own, and we can see what the results are (Blown transformer...) as my homes utility service alone exceeds that 25kVa transformer, let alone 8-10 other homes on the same one..... I got a phone call back VERY quickly telling me engineering is getting everything ready for the upgrade...

Anyways, I hope that helped!

Your ending had me laughing completely lmaos, its the same in nyc con edison is ridiculous and the still cannot get it right...