Charging cuts down to 75%, Tesla says... it's my house.

SabrToothSqrl · Mar 20, 2015

So, I believe Tesla when they say it's my house, but I'll explain the setup, and hopefully someone can assist.

2013 S85, dual chargers. Brand new Mobile Connector (new as of the 16th).

Charges just fine 80-90% of the time at a solid 40 amps all charge long.

I've started leaving my desktop on, running Visible Tesla to try to identify patterns.

House built 2008, 200 amp service.

NEMA 14-50 in my garage. Located 1 foot from the breaker panel. Literally 1 foot.

With this short run 8 gauge should have been fine. I made sure to use 6 gauge.

50 amp breaker.

Plug car in. Sets up at 40 amps. Walk away. 90% of the time... all good. 10-20% of time.. gets knocked down to 30 for no rhyme or reason.

Car is inside a garage approx 55 at the coldest. Nothing is on the circuit other than this NEMA plug, which was installed a week before my Tesla purchase.

All wiring is correct, modern, etc. I do live in a fairly rural location, and own a generator as our powers been out for up to 4 days before.

The lights have dimmed on occasion from PP&L power. I also run a UPS on my desktops and my TV due to this.

My house uses propane heat, so central heat, water, and stove are all propane, and would have no 220v draw or high amps.

The dryer is electric... but that's not usually on all night and even at 30-40 amps is still 80/200 amps.

So, my question to those with these things... do I.. Call PP&L? (My electric carrier) or call another electrician?

Nothing on the mobile connector gets hot. Nothing smells. No melting or burns, nothing wrong I can see.

What do I do next?
Charging at 40 amps is not critical to my life... but still... kind of irks me... and makes me rethink the idea of purchasing a HPWC.

Thank you!

rlang59 · Mar 20, 2015

SabrToothSqrl said:
The lights have dimmed on occasion from PP&L power. I also run a UPS on my desktops and my TV due to this.

Couldn't that have something to do with the issue?

FlasherZ · Mar 20, 2015

See my FAQ in my signature for more information, there's a specific question in there.

If you want the details, you can read this thread:
Very frustrated with software limited charging

Bottom line, there is something going on in your electrical infrastructure that is triggering the car's mechanism that protects your wiring. It could be due to a loose connection, undersized wiring, undersized transformer, or a misbehaving appliance (bad motor start capacitor, etc.) Because it happens only 10-20% of the time, it's unlikely to be a loose connection in your receptacle or a problem with your branch circuit; so you'll have to start looking elsewhere.

You noted your lights dimming, it could very well be that you have "dirty-ish" power coming from the power company. They problem is that many power company repair people assume the only electrical loads we have are incandescent lights and toaster ovens, and they're likely just to place a meter on your power - or at best a long-term voltage analyzer - and declare your service fit.

I would start by trying to isolate loads in your home. Does it only occur at dinner time?

Then look at how you're connected to the grid - does your home have a dedicated transformer, or do you share with a neighbor?

Then I'd call the power company. Tell them that when the Tesla detects voltage fluctuations, it backs off for safety reasons. Ask them if they have a line analyzer that they could leave on your service for a day or two; during that time, exercise the charging to see if it triggers, and ask them to look at any anomalies.

SabrToothSqrl · Mar 20, 2015

Thank you guys for the feedback!

I'll see if they can set me up with the analyzer. There is a green electrical box about 2 houses down from me. I can't imagine I have my own transformer. I have to get more data from Visible tesla to come up with the patterns.

FlasherZ · Mar 20, 2015

SabrToothSqrl said:
Thank you guys for the feedback!

I'll see if they can set me up with the analyzer. There is a green electrical box about 2 houses down from me. I can't imagine I have my own transformer. I have to get more data from Visible tesla to come up with the patterns.

That big green box is likely your transformer. It may be the case that it's undersized. Take a look at how many of those boxes are in your neighborhood, and how they might be shared. In my case, I have a dedicated transformer, but in my subdivision, there are 2 other transformers serving 7 homes. If they're undersized, your neighbor's power demands could be playing into your charge current reduction.

Also keep in mind that 200A service doesn't mean all components are rated at 200A. My 200A service was fed by a 2/0 AL cable (NEC calls this good to 135-150A, although power companies don't have to follow that) and a 10 kVA transformer, which is a load of about 40 amps or so considering reasonable PF. Now, those transformers are generally good to twice their capacity for a while, but they might determine it's undersized when you tell them of the loads you have.

My service was upgraded to 400A, fed by 350 kcmil cable (good to 250-280A via the same tables) and a 37.5 kVA transformer (rated ~150A). Power company tells me that the transformer should be sufficient to run 2 HPWC's, house load, and my machine shop without an issue.

SabrToothSqrl · Mar 20, 2015

PP&L

Well, I called PP&L, and the woman didn't seem too thrown at my whole 'I own an electric car' situation.

They are sending someone to "check the lines' outside the house. That's apparently the demarcation point, then I'd need an electrician.

I doubt they will find anything wrong... just because that's my luck, but I guess we shall see.

- - - Updated - - -

FlasherZ said:
My service was upgraded to 400A, fed by 350 kcmil cable (good to 250-280A via the same tables) and a 37.5 kVA transformer (rated ~150A). Power company tells me that the transformer should be sufficient to run 2 HPWC's, house load, and my machine shop without an issue.

At who's expense yours or theirs? Thanks I'm working on exporting the Visible Tesla data now in to excel so I can poke around.

FlasherZ · Mar 20, 2015

SabrToothSqrl said:
Well, I called PP&L, and the woman didn't seem too thrown at my whole 'I own an electric car' situation.

They are sending someone to "check the lines' outside the house. That's apparently the demarcation point, then I'd need an electrician.

I doubt they will find anything wrong... just because that's my luck, but I guess we shall see.

Yeah, you're probably going to get the usual repair guy, who'll put a meter on it and say "yup, 240V, we're good". If you get the chance to talk to him, tell him that the Tesla is sensing some intermittent disruptions and ask if he can put a line monitor on it for a day or two to record anomalies it sees. Tell him you see occasional dimming lights that aren't generated by your appliances kicking on, and that the Tesla also sees them. Ask what size the transformer is, and how many other neighbors are sharing the transformer, and what size cable is connecting your meter to your transformer.

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SabrToothSqrl said:
At who's expense yours or theirs? Thanks

It depends.

In my case, their expense - except for the meter pan installation. They supplied me with the meter pan, but I was responsible to install it, along with the service entrance conductors. They were responsible for everything north of the meter, to the transformer.

Now, that's not the case everywhere. In fact, I think it's rare - and most power companies have told customers it would be their responsibility for the drop from the transformer to the meter. In some cases, power companies have even told customers that a transformer upgrade would be their responsibility, which is untrue.

See this case:
Incoming utility cable capacity - A cautionary tale - Page 2

In that case, the transformer was undersized and PG&E claimed it was his responsibility.

santana338 · Mar 20, 2015

One other thing that is easy to check is the voltage drop. You can measure the voltage with a simple voltmeter at your NEMA 14-50 plug with no load. Then plug your UMC back in and charge at 40A. You might even want to turn on the dryer just to max out the load. If you have another 240V location also measure there while the car is charging. You can also use the voltage the car is seeing if you don't want to try charging and measuring the voltage at the same NEMA 14-50 outlet. If you see the voltage drop below 220V, that is something the power company will have to take seriously.

In my case I was dropping below 220V. They put an analyzer on my line and determined my voltage was OK, but the flicker was over spec. So they upsized the transformer and the service line. Now the voltage drop is much less.

SabrToothSqrl · Mar 20, 2015

Visible Tesla shows voltage anywhere from 203-250.... wow I never knew... Excel proves useful!

sorka · Mar 20, 2015

I had a similar problem with my lights dimming at no reason. PG&E put a line quality monitor at my house and left it running for a week. They determined that the transformer at the end of my cul-de-sac was faulty and replaced it. Haven't had the issue since.

sefs · Mar 20, 2015

Is 203-250 for anywhere you ever charged, or is that just at home? If you have <228V you have issues.

SabrToothSqrl · Mar 20, 2015

Pending the outcome of the 'person visiting to check the outside lines' I'll ask if they can do the line quality monitor... where does that go? how does it install? How does it provide them feedback?

Thanks!

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sefs said:
Is 203-250 for anywhere you ever charged, or is that just at home? If you have <228V you have issues.

My House. I'm organizing the excel data now from VT. Actually, I take that back. I have had some superchargers, I'll check the date/times, but I'm fairly sure on Wednesday at midnight it's in my garage

sorka · Mar 20, 2015

203 volts is way way too much of a drop. My POS water heater draws 50 amps and my voltage drops from 248 to 245 when it turns on.

sefs · Mar 20, 2015

If you have 203V you have major issues. When they come to meter you service, start charging your Model S to increase the load. Have you metered at your main breaker? There should be little difference, only the voltage drop due to the 1 foot 6 AWG plus the UMC cabling.

beeeerock · Mar 20, 2015

Given you have seen long outages and can easily justify your own genset, it makes me think you're really quite a way down the line on a lonely road! Farm power at best, and the fluctuations you're seeing could be caused pretty much anywhere on that system. If there are any industrial users with large motors, perhaps some big well pumps, they could be taxing the system at startup... for all you know, the wind could be blowing branches onto the lines. In other words, it's possible (likely) the system you're on is already taxed to the limit.

If it was me, I'd go beyond telling the service guy you're seeing lights dimming and explain that the Tesla charging system is freaking out about them... that the charging system is designed to be sensitive to the needs of the grid and defaults down to a lower rate when it sees a drop in line voltage. The Tesla is designed to be a good grid customer, but pays for all the other customers who might not be responsible or ideal customers... and potentially for inadequate distribution infrastructure too! As a result, you're taking much longer to charge, which impacts your ability to do the things you need to do.

I'm going to guess that unless it's a simple "D'oh!" problem close to you, it will take an upgrade in the area to solve...

(edit) I see responses with 203V mentioned... all I can say is "I have no solution but I admire your problem!"

FlasherZ · Mar 20, 2015

SabrToothSqrl said:
Visible Tesla shows voltage anywhere from 203-250.... wow I never knew... Excel proves useful!

Yikes.

Good news is that 203 is considerably out of spec (228V-252V) and will likely cause them to take action... how often does it drop that low? If you can, provide the date and time and let them know that you saw 203V at that specific date and time via a 50A/240V circuit (so they don't assume overloaded small branch circuit).

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SabrToothSqrl said:
Pending the outcome of the 'person visiting to check the outside lines' I'll ask if they can do the line quality monitor... where does that go? how does it install? How does it provide them feedback?

Depending upon the monitor model, either they'll place it in your meter pan and connect it to the lugs at the base of the meter, or they'll attach it to the main breakers or busbar of your service panel (some models can't be exposed to elements). The device sits and reads voltage and logs any out-of-spec conditions (voltage and/or frequency) that it sees with time/date; some just store the anomalies in memory, others come attached to a little printer that prints the anomaly.

There are many different manufacturers and versions, so it depends upon how they're outfitting their trucks. If they simply place a voltmeter on the lugs and tell you things look okay, tell them it's intermittent and share your log data, and ask them if they can place a line analyzer on it for a day or two to look at the conditions.

sefs · Mar 20, 2015

Is the generator connected with a transfer switch? Automatic or manual (interlock)? If you have a transfer switch, most likely your meter got pulled. If the meter wasn't pulled carefully, the jaws can be very easily spread. If the jaws are no longer tight, you will have a poor connection, and it will drop voltage and heat up under load. This is how "smart meter fires" occur. Meters sit for years, and then they are swapped and the can jaws are damaged. Same would go for any meter pull, such as for installing a transfer switch or non-payment.

FlasherZ · Mar 20, 2015

sefs said:
Is the generator connected with a transfer switch? Automatic or manual? If you have a transfer switch, most likely your meter got pulled. If the meter wasn't pulled carefully, the jaws can be very easily spread. If the jaws are no longer tight, you will have a poor connection, and it will drop voltage and heat up under load. This is how "smart meter fires" occur. Meters sit for years, and then they are swapped and the can jaws are damaged. Same would go for any meter pull, such as for installing a transfer switch or non-payment.

His home was built in 2008, he's going to have one of the newer-style meter pans with the ejection/bypass lever, giving a 95%+ chance this isn't going to be an issue. They'll check for it, of course, but I'd suggest it's likely not that.

SabrToothSqrl · Mar 20, 2015

well, this may be interesting!

All of my low power charging... was while it was AT the TESLA Service Center!

HA! I just looked at the dates after sorting all the data by volts, amps, state of charge, etc. Then finally by date.

So, I know I still have the original issue, but maybe they were testing out my charging system at the Service Center as well...

I'll fix my data pulls to only be 3/17 on as that's when I got my new charger.

Good times... :cursing:

sefs · Mar 20, 2015

Okay, 203V is normal for charging Y-connected 3 phase line to line.

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FlasherZ said:
His home was built in 2008, he's going to have one of the newer-style meter pans with the ejection/bypass lever, giving a 95%+ chance this isn't going to be an issue. They'll check for it, of course, but I'd suggest it's likely not that.

PPL spec's horn bypass for 200 amp single phase UG. But the bypass isn't what I'm referring to: The action of pulling the meter, if not done completely vertical, can spread any of the four jaws apart. I just saw it this week from someone who did a generator installation and pulled the meter improperly.

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