Feb 8, 2015
wk057 @NigelM, You're probably aware, but this is most likely from the surge power needed for high demand loads. Generators do not spin up to demand instantly, and there is a relatively large amount of time between demand and the generator meeting the demand. Many LED bulbs and dimmers won't run when the voltage or frequency drops out of range, which will often happen when something large tries to kick on while on generator power (refrigerator, A/C unit, etc). The Model S ramps up current draw at a rate that most generators could easily keep up with, instead of a quick surge to full power.
That said... I'm surprised the Model S doesn't flip out in this situation. My guess is you're not maxing out the charge current. (40 or 80A)�
Feb 8, 2015
FlasherZ So now it's not the FW, but the UMC that is the problem?
I have the same UMC you do. I've charged at probably 70 to 100 different locations using it and J1772 at various points over two years, and the car has only backed a few times: memorable ones were when a bad ballast in a high bay fluorescent fixture caused enough of a fluctuation that the car was convinced there was the danger of an arc-fault and another time when the wiring was a bit questionable (long run on an undersized wire).�
Feb 8, 2015
NigelM Thanks for the note. Yes, we have 3 AC units and 100% LED lighting so I recognize the issue but you make a good comparison to the Model S ramp. I'm not an expert on generators but always believed that the output wasn't very 'clean' so I was surprised that Model S charged at 80A with no problem (=relevance to this thread) and that's happened maybe 5 or 6 times total over the last 2 years (so different FW versions).�
Feb 8, 2015
FlasherZ I have a 25 kW genset at home, and have charged at the full 40A while the rest of the home loads were running (A/C, etc.). The HPWC isn't on the generator panel so I can't test it, but in my case the car didn't back down on the genset.
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When the load significantly jumps on a generator, the frequency goes out of spec (< 60 Hz) for a short bit until the engine can adjust - the generator slows the engine down for a fraction of a second. This isn't what the car is looking at - and in a good switching power supply, the frequency disruption for a short period of time won't cause any problems (and really won't even be seen). Now, if the genset is underpowered for the load applied, you start to see a significant voltage disruption, but I've seen that cause an outright error in charging where the Tesla goes to red-ring, rather than backs off.
The car is looking for a voltage / resistance disruption signature similar to that of an AFCI.�
Feb 9, 2015
qwk You know exactly what I mean. It really doesn't help by making excuses for Tesla. Google melted UMC and after that, go measure the pins on the adapter end. They are the main issue, when the UMC is run on the ragged edge in sunny hot weather. Tesla decided to use tougher plastic on the adapter side(the adapters weren't where the melting started, but it was the cheapest, quickest change. Together with limiting charging to 30A, that was the solution.
I should probably also mention that the few UMC's where the owner cut the adapter off, and replaced with just a 14-50 male plug, have had absolutely no melting, and ran much cooler as compared with a Flir. That isn't just a coincidence. My guess the reason Tesla didn't do this is it gives no option for 120V charging without using Frankenstein adapters.�
Feb 9, 2015
Lloyd http://en.wikipedia.org/wiki/Buck%E2%80%93boost_transformer
What about installing a Buck and Boost Transformer to help stabilize your power supply to the car??�
Feb 9, 2015
qwk I forgot to mention that you are a very knowledgable guy, but I can't help but wonder one thing. You harp on everyone about electrical safety, but Tesla gets a pass? They can design and sell a product that works on the very cutting edge of safety(and sometimes crossing over into very unsafe territory, and melting), and that is ok to defend? Everyone else has to err on the side of caution except Tesla? I'm sensing a very unusual bias here....�
Feb 9, 2015
bonnie I've deliberately stayed out of this thread for a number of reasons (mostly because I suspect I just irritate qwk). But c'mon, give him a break. There is clearly something going on here, something that Tesla has not yet determined as root cause. Nigel has mentioned another owner with similar problems.
Let's give a long-standing Tesla supporter and owner the benefit of the doubt.�
Feb 9, 2015
FlasherZ No bias. You blame a software feature that gives very few other people an issue and demand Tesla remove it. Then you blame the UMC's melted pins.
If you go search for my posts, I didn't give them a pass at all and I said I think the UMC melting problem (I had it twice) was going to be a serious problem. That generated a recall. I then stated that their fix (like you mentioned, above) was a bit questionable and that we'd need to keep looking at how hot these connectors get. The comments about a potential re-design of the UMC also fit into this as a long-term fix.
But do I believe that's the reason your car is backing off? No.
(Edit due to original post being done on a mobile phone with fingers way too fat.)�
Feb 9, 2015
FlasherZ I would, if there would be a dialogue about solving the problem instead of demand for Tesla to remove the safety feature with little willingness to track down the issue. As I've said up-thread, the fact that this charging fall-back is not more widespread points to an environment-specific problem or some failure of the gear in the car. Some people are having success after their master charger is replaced; others have had to narrow it down to a misbehaving appliance, or an overloaded transformer.�
Feb 9, 2015
AmpedRealtor Forgive me if this was already asked, but did OP have an electrician check his wiring and power supply for anomalies? That would seem to be the logical thing to do.�
Feb 9, 2015
qwk Thanks Bonnie! I have no doubt that Tesla is going to solve this issue�
Feb 9, 2015
dhanson865 you keep saying that the OP demanded they remove a safety feature when in fact he hasn't. He simply asked to have working charging for his car.
They can keep the safety feature and add an override interface/capability.
They can keep the safety feature as is for the fleet and allow this one car to be on a different firmware that has the safety feature at a different threshold for his car.
They can keep the safety feature and improve it so that it doesn't trip as much but is just as safe
They can keep the safety feature and replace parts on his car (if his car is somehow different enough that the general threshold doesn't apply)
They can keep the safety feature and replace his UMC (if the UMC is an issue)
I've seen plenty of suggestions on how to fix the issue but I don't agree with you saying he demands they remove the safety feature. I don't get the impression that he wants to exert his will on other car owners. I just get the impression that he wants his car to be usable.�
Feb 9, 2015
qwk Thanks! You are right, I don't care how it's done, just so it's done. I guess its hard to understand this problem for others when their car is charging fine.
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You do realize that this car datalogs, right?�
Feb 9, 2015
FlasherZ In the first page, he says that the "entire problem" is Tesla's feature to limit charging current when it detects a signature that would indicate an arc fault:
It would be extremely unwise for Tesla to have one specific car on a special firmware just because of an environmental problem that exists either in his power supply or his car.
It would be extremely unwise for Tesla to permit an override of a safety device (the NEC doesn't list an exception to the AFCI breaker rule just because an owner has a misbehaving appliance).
Yes, Tesla *could* improve the safety feature, but they have to keep it just as safe. However, the fact that most owners are not having this problem points to an issue in qwk's environment -- a bad charger in the car, a misbehaving appliance on the grid, a bad transformer. He reports this happens in many different places, and I'd be willing to bet that it's something internal to the car. He mentions the poorly-designed UMC being the primary source of the issue, yet he's had the UMC replaced, and many of us use the very same UMC models in the same summer heat without the resulting back-down in current. I do concede that many more people have suffered the melting-pins problem, but I haven't seen many reports of that post-adapter-recall.
So when people have stated that they believe it could be a problem in the car, he had this to say:
I'm not willing to believe that. qwk believes it's "all firmware" because he wants them to rip the feature out of the car or give him the ability to override a safety feature that is detecting an arc-fault signature. There is a problem somewhere in his environment, or we'd all be complaining about unnecessary downshifting in current.
The truth is that most cars are charging just fine, without a problem, in the same situations as qwk's. I understand the problem, I really do, as I've seen my car downshift the charging current due to a misbehaving appliance -- it's just that he's not following the logic in following through to identifying and repairing the root cause of the problem instead of eliminating the symptom. He has said he wants Tesla to remove / override the safety checks in the system for him. My argument is that he needs, with Tesla's help, to find the root cause here - because if the problem was indeed "all firmware", many more of us would be experiencing it. Like qwk, I charge in many different situations, at different campgrounds, in the heat of the day, with the same UMC model that he does. So what's the difference between his experience and mine? His environment - his specific car, or his specific locations.
Years ago, I worked in an IT organization that installed some software to test vulnerabilities in their IT systems. It crawled through systems and used some automated methods to try and identify security faults. When that software was turned on and let loose, it caused crashes of 5 major database systems that brought the company to a screeching halt. So how do you fix that? Do you just say "well, just don't scan then"? Or do you fix the underlying vulnerability that made the system crash in the first place?�
Feb 9, 2015
TEG For what it is worth, and somewhat anecdotal, but an associate told me recently that his Sig model S recently started charging at 30A on his home UMC, where it used to do 40A charging all along. I am not sure if the change coincided with a recent firmware update, or some other cause (such as changes with his power characteristics.)
[ Yes, this thread needs more factual data, not just stories, but... ]�
Feb 9, 2015
qwk The issue has been sent over to engineering to come up with a plan. I will keep you updated.�
Feb 9, 2015
jerry33 No question that edge cases are the hardest problems to solve.�
Feb 9, 2015
Cosmacelf +1 flasherz. Too bad you had to waste your time digging through qwk's posts to point out what he wrote. Yes qwk, there is a problem, but Lord, you do make it really, really hard for people to help you.�
Feb 9, 2015
NigelM Mod note: no pile-on needed here. OP was understandably frustrated, Tesla are doing the right thing, let's just wait and see now.
Edit: and thread title amended to be more descriptive following discussion.�
Feb 9, 2015
spaceballs Actually if the car charging hardware isn't working 100% the datalogs reading could be wrong, so AmpedRealtor still has a valid point.�
Feb 9, 2015
FlasherZ The good news is that he's now in contact with engineering, on the road to tracking down the root cause. Hopefully qwk's frustration will be subsiding a bit as they figure out what's causing it to back off.�
Feb 10, 2015
AmpedRealtor I'm not sure what data logging has to do with your electrical wiring. All the car's logs can do is tell the engineers what type of fault or error occurred. It won't tell them what specific part of your electrical and power supply system may have triggered that error or fault. The car isn't psychic and doesn't know what's behind your walls. That's between you and your electrician. Obviously the car is encountering something in your electrical system that is causing a fault. You've gone through multiple UMCs, all of which exhibit the same behavior. The logical next step would be to have an electrician check your wiring for anomalies.�
Feb 10, 2015
FlasherZ ...or look at the charger in the car - I've seen at least 2 individuals say on this forum that a replacement of their master charger fixed this issue for them.
I'm confident now that engineering is involved they'll find the answer. Or at least have a data point so they can improve things.�
Feb 10, 2015
brianman I've only skimmed the thread, but I must admit I'm somewhat intrigued by the idea of finding a couple Model S owners to join me on a road-trip to qwk's place to try his outlet.
On the flip side...
@qwk - If you find yourself in the Seattle area, you're welcome to try my 14-50 outlet with your car. Also we could try various combinations of outlet/umc/car to try diagnosing over some tea.�
Feb 10, 2015
dhanson865 I wish everyone on this thread were as positive and useful as you are. Nice to see that post.�
Feb 19, 2015
DavidM It's great that you don't have the issue, but it's clear to me that thousands of customers have this issue - including me. I used my Model S and UMC for 14 months and charged at 40A without any issue. Then after FW 5.8.4 the car refused to charge at 40A. It backs off to 30A. I've had multiple visits from the power company and electricians and Tesla Service center personnel and everyone says the 50A circuit is fine and line voltage is within acceptable levels. The tolerances in Tesla's firmware update are too aggressive. As a result, thousands of customers are no longer receiving the charging capability that they paid for (40A at home).
Basically if you don't have squeaky clean voltage coming to your panel with minimal fluctuations, you will likely have issues trying to charge at 40A. It's counterproductive when owners who don't have the problem scold those who do, as if it's their fault. Since the car requires electricity to be used as intended, I consider it an expensive appliance. Every appliance must be designed to work within the same tolerances that the power company deems to be acceptable. Tesla now requires tighter tolerances for Model S. This is bad for business, and it's getting out of hand.�
Feb 19, 2015
Rheazombi Unlike a dishwasher, all Tesla needs is one horrible garage or house fire to pretty much screw over their entire plan for widespread EV adoption. They're obviously erring on the side of caution.
People need to get their wiring checked out and fixed because by definition that shouldn't be happening.�
Feb 19, 2015
swegman Rheazombi, DavidM said he has had numerous visits by his electric company and his electricians (plural), and that they indicated there is no problem with his line voltage and wiring. So, at least for DavidM, it does not appear there is anything with respect to his house wiring that needs to be fixed, as you suggest, but rather something with the car (software or hardware) that needs fixing.�
Feb 19, 2015
dsm363 Didn't realize I was scolding him but I was pointing out his asserting that Tesla seemed to have done this to him on purpose and the fact that he's gone through 6 UMCs (with a few of them melting at the adapter) is unusual and maybe there is more than just the software in his case. I certainly didn't blame him the individual. And yes, Tesla does need to figure out what is going on in situations like this. As I said in the post you quoted:
�
Feb 19, 2015
hiroshiy Just my 2 cents... After upgrading to 6.1, my car charges at 71A rather than 80A. Think same issue? The voltage fluctuates from 202V to 199V. Very big fluctuation ;-)�
Feb 19, 2015
scaesare While my car doesn't stop charging, I also get the current reduction to 30A occasionally. It started happening months after I got the car after one of the firmware updates (I forget which, but the 5.8.4 mentioned above sounds about right).
My voltage drop when the car starts charging is only about 4%. I've checked this both day and night... and the voltage drop varies very little. At my normal 3am charge start time I don't have significant other load in my house except for air conditioning running during the summer. Even when that kicks in it doesn't change the voltage drop much.
The other trigger point that has been discussed is line noise. There are very few loads in my house that possibly trigger during my overnight charging timeframe: HVAC, dishwasher (occasional), coffeepot, or refrigerators. Three of those have motor startup loads which can cause some line noise. The rest of my house loads are pretty static.
The car will happily charge for weeks at a time with those loads going on or off all the time without issue. Then occasionally, like this morning, it will be reduced. This is particularly annoying as I time the charge to end as I'm goging to leave in the morning, so I have a nice warm pack on these winter mornings. Starting some days with 25% less charge than intended on single-digit temp days can be a bit of a pain.
I've eliminated the dishwasher as the cause. The other loads always kick on and off while the car is charging, and don't cause issues 95% of the time. I suppose it COULD be line noise generated by the timing of 2 or 3 of those appliances kicking on at the same time... but I have my doubts.
What's odd is that I have LOTS of other noise inducing items in the house: a rack of servers, a dozen other computers/DVR's/STB's, a couple dozen lighting controllers/dimmers, etc... lots of things with switching power supplies or PWM circuits that generate EMF. None of those seem to bother it the slightest.
So if the issue is not line voltage, then whatever other threshold is triggering it seems a bit overly sensitive.�
Feb 19, 2015
TexasEV @qwk, it's been 10 days since this issue was sent to engineering. Do you have an update?�
Feb 19, 2015
DavidM There were a few garage fires 18 months ago. Part of the blame was faulty wiring. Part of the blame was the UMC adapter. I'm not convinced that the firmware changes would have eliminated all possibility of fires. One bad electrician can bring a house down regardless of how Tesla changes the firmware. Actually, Tesla has tweaked the firmware's charging parameters multiple times since 5.8.4. I know this because right after 5.8.4, if voltage thresholds were exceeded, sometimes my car would back off to 30A, and sometimes it would stop charging completely. A subsequent firmware update fixed the problem of unintended charging termination.
Since you're VIN 43,000+ all of these changes happened before your car was delivered. Fourteen months is a long time to live with a washing machine whose "turbo wash" mode doesn't work (analogy), after it worked for the initial year.�
Feb 19, 2015
FlasherZ No, it's exhibiting a problem you didn't know you had.
I'll say it again: the Tesla, power-wise, is *the* largest load that 95% of its owners will ever place on their electrical system in terms of kWh. You could even have a 48 kW stove, and it would still come nowhere NEAR the load and stress the Tesla puts on your electrical system. Similar to the newly-required AFCI breakers, the Tesla is looking for indications that an arc may be occurring.
The Tesla is seeing an electrical system signature of either high-resistance or arc-fault - which could be due to any number of things. In any case, it is a problem with your electrical system, as evidenced by the 95%+ of Tesla consumers who don't experience the problem on a regular basis. If it were truly a matter of bad thresholds set, we'd see a much higher case of it.
It is an indication of a fault somewhere in the electrical grid; whether bad transformer, bad appliance, bad wiring, or bad charger in the car itself.
I keep seeing people talk about "voltage tolerances" and such... please read the following (because it seems like it's being ignored): the tougher problems are NOT a matter of "voltage tolerance" and looking at the display on the car - as I said above. The power company will attach a voltmeter or a line analyzer meter at the service entrance and will look at the average voltage and frequency. They will not always see the instantaneous signatures that drive the downshift. They will tell you "250V, 60 Hz, everything's fine on my end" -- but if they can't measure the effects of reactive power from a bad appliance power supply or a bad starter capacitor, they won't always see it.
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The power companies don't always bring the right equipment. They'll typically bring a line analyzer which will watch the voltage and frequency and note any anomalies. These devices will not necessarily catch the arc-fault signature that's throwing the cars into downshifting.�
Feb 19, 2015
scaesare Given that the max power you can charge your Model S at is 20kW, what do you mean by this?�
Feb 19, 2015
FlasherZ If it doesn't happen over 80% of the time, it's not the voltage drop tolerance that is your issue.
There are two things to watch for: bad motor starter capacitors, which will generally dim incandescent bulbs significantly upon startup; and electronics with bad power supplies, where reactive power can make the voltage jump instantaneously.
Do you have a shared transformer with another home? Those loads could cause problems.
I understand the frustration - I really do... but what frustrates me is the attitude that it's Tesla's fault, rather than a responsibility to track down whatever source is causing the problem. The car is seeing an arc-fault signature. And those with that attitude want to point at Tesla and say they should turn the safety feature off so that arc faults aren't detected anymore.
"My anti-virus keeps saying I have malware. So I think Windows should just stop looking for malware."
It's not going to be a cumulative number of "noise inducing" items; it's going to be one of them. The example I cited earlier: a bad ballast in a fluorescent fixture introduced enough to trigger an AF signature.�
Feb 19, 2015
FlasherZ A stove or electric heat unit rated at 200A would still never come close to the continuous charging load that the Tesla puts on your infrastructure.
It is *the* largest load that most homes will ever see.
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Arc faults can happen anywhere - loose transformer terminals, for example - and that would be PoCo responsibility. However, you're leading toward a conclusion of most people -- most people think of the branch circuit / appliance impacts. This is because of the recent requirement (NEC 2014, just being adopted now) that AFCI breakers are mandated for every 120V branch circuit. That is designed to protect against the most typical arc faults in homes (someone stretches a cord that tears apart the conductors, a plug is dislodged just enough that it pulls to the edge of an outlet contact, etc. An arc fault signature is a high voltage (simulating "open circuit") immediately dropping to a lower voltage as the arc is completed and current begins flowing (similar to an arc welder).�
Feb 19, 2015
scaesare Ah you meant with regarding time... well assuming you aren't cooking stuff for long periods of time, yeah.�
Feb 19, 2015
Lloyd http://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter
AFCI will not protect against arc on the supply side however, only the branch circuit.�
Feb 19, 2015
FlasherZ Yes, although arc fault != AFCI. AFCI detects arc faults behind the device, looking for that arc-fault signature.�
Feb 19, 2015
wycolo > These devices will not necessarily catch the arc-fault signature that's throwing the cars into downshifting. [FlasherZ]
My electric coop carries line-fault detectors in their trouble trucks. Quickly solved a long standing transformer leak one mile from here that had been causing me grief on shortwave for many months. Said it could have continued for many more months and thanked me for the tip. LF Detector is basically a shortwave receiver operating around 27 mhz.
So this could be an example of a trouble source that goes undetected indefinitely yet is strong enough to cause various forms of mischief.
--�
Feb 19, 2015
FlasherZ Even if you're cooking things for well over 3 hours, the elements still cycle - this is why an oven is considered an intermittent load. Power is on to the element until the oven hits the target temp, then it cycles off. Stove top elements heat up until they reach target temp, then turn off. Charging loads just turn on and stay on until done at full blast.�
Feb 19, 2015
scaesare Yup, that's why I mentioned motor loads specifically.... and the ones I mentioned regularly run 100's of cycles without triggering anything with the Tesla. Nor do I see incandescent bulb dimming.
My electronics loads are static. They are on 100% of the time the Tesla is charging, and again, they don't cause issue 95% of the time.
Now I'm not saying one of those couldn't be the cause. I'm saying that it's odd that it's not the cause the other 95% of the time. Starter capacitors don't tend to behave badly, and then get better for a majority of the time, then behave badly again. They typically wither fail outright, or follow a downward linear path where they get progressively worse.
Ditto switching power supplies and other electronics. They tend to either introduce noise or they don't.
I do, and that thought has occurred to me.
That's not my mindset. I'm not against replacing a failing or potentially dangerous piece of gear. However I also am of the mindset that if I had a starter capacitor that was failing 18 months ago, I'd probably have seen it degenerate by now. If I have a noisy power supply in my server rack that's on 24x7, the causality wouldn't likely be so random.
While I don't want t blame Tesla for faulty in-home gear... it's not also unreasonable to suggest that it's possible that the algorithm is TOO sensitive and might be tripping in cases where other equipment is operating within spec.
Not necessarily. I have lighting controllers that get upset when two specific pieces of equipment with switching power supplies are plugged in. Either by themself is fine. Both together cause line harmonics that cause an issue.�
Feb 19, 2015
FlasherZ That's a good point - if they don't know what they're looking for, they may use the wrong equipment. I know the line analyzer that my co-op normally deploys when someone complains about voltage sags won't catch these. If you tell them that the Tesla downshifts because of "voltage fluctuations", they're likely to pull out the analyzer and leave it sit for 24 hours, then tell you "all's good". If you tell them that the Tesla detects signatures that look like arc-faults, they may use different devices.
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I agree that it could be too aggressive. My point is that something looks like an arc fault, and until it's found, Tesla can't make a determination as to whether it's too sensitive or not. I'm sure they're looking at all the data coming in and making some decisions. They may turn down the sensitivity, and it might very well be ok.
I phrased it a bit wrong and can clarify: There is the chance you could have a large number of devices that could enter oscillation loops and could trigger the algorithm, but it's unlikely, in my opinion. I do agree that you can see other types of effects in sensitive electronics. The Tesla, however, is looking for an arc fault signature - which is unlikely to be hit regularly by such a coincidence.
To your point on starter capacitors: for what it's worth, I've seen a motor-start capacitor be "bad" for a very long time (years) without failing to start the motor. You have to define "bad" -- if "bad" means the motor doesn't start, that's different than "bad" means the motor draws 100A for nearly 1 second (which will cause a voltage drop).�
Feb 19, 2015
scaesare I thought you said stove?
Typically stove elements stay on at a given power no?
(although I admittedly thought the idea of a 48kW stove was a bit odd)�
Feb 19, 2015
wycolo I only went 1/2 mile with my portable receiver using various frequencies. Power Co say they use a microwave frequency and it never fails, as long as they drive along all the lines for a good distance until the noise signal eventually diminishes.
Some arcs run a long time when the conductors don't get hot enough to burn back fast enough to extinguish the arc. [syntax!!]
You can always get fast response from the PoCo if you say 'power leak'. :wink:
--�
Feb 19, 2015
FlasherZ The idea of a 48 kW cooktop or oven or combo is indeed silly... that would be an intense appliance. The point is that the Tesla at 20 kW is far more of a stress load on the average home than an intermittent appliance with a higher rating. The only exception I've really seen is that some electric heat storage systems.
Nearly every cooktop uses elements with varied duty cycles rather than current/power limiting techniques.
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The problem with using that detector is that you need a constant arc fault to detect, and I doubt that's going to be present in many of the cases here.�
Feb 19, 2015
scaesare Yeah, that's certainly a likely issue. I guess I'm wondering what the continuum is.
They obviously made a change in one of the 5.xx firmware releases. Prior to that this issue wasn't (widely) reported. Then there was a media sensationalized garage fire, and then we started having instances of (seemingly random) current reduction.
This is not unlike the pack puncture/fire and the subsequent reduction in the extent the car would auto-lower the suspension. When Elon stated that the pack fire was a extreme outlier and the car was perfectly safe as-is, the attendant suspension change seemed like a bit of an over-reaction. The was some significant customer discontent, and the change was re-evaluated in light of other options.
I'm suggesting here that if the change was made in light of the notorious garage fire, yet the system also trips on common and safe non-faulting situations, it might be worth re-evaluating how unsafe the original behavior was.
Out of curiosity, do you have any insight as to how that's accomplished? Do you suspect specific monitoring circuitry within the system, or is simply algorithmically determined based on voltage & time?
I'm assuming the latter, as this was a software change that implemented it (unless they enabled hardware functionality previously dormant).
True. But as you mentioned before, you can often see effects of something like that (lights dimming, hearing the motor startup sequence "struggle", etc....
I wonder how common all of this is... maybe it's time for a poll.
And to your earlier comment, I wonder if my neighbors will notice if I disconnect their main every night for a few weeks to try and isolate other houses from the problem. :wink:�
Feb 19, 2015
wycolo > The problem with using that detector is that you need a constant arc fault to detect, and I doubt that's going to be present in many of the cases here. [FlasherZ]
Well at least it is science. The next step here might take us into the realm of the occult, as we await findings/results from TM Engineering.
--�
Feb 19, 2015
FlasherZ They added the feature in response to that fire, that's when it started. They didn't have current limiting before that. 5.8.4, I believe.
In that case, the garage fire was caused by a loose wiring connection to the outlet in the garage. It's unknown whether it was a "glowing" connection (e.g., non-arc but high-resistance), or whether there was an arc fault present - at least based on the preliminary report that I read. More fires in infrastructure are caused by "glowing"/loose connections because of their static nature. Perhaps they would tune the algorithm to tune out the arc fault sensing, which would make more of the difficult-to-solve cases go away.
It's important to remember, though, that there's still a problem SOMEWHERE that would be desensitized.
I don't have any first-hand knowledge as to the specific algorithm. I suspect it's a high-resolution monitor of voltage and time at a sub-second level (which would likely mean firmware-based monitoring by the charger).
I know way too many people who just assume lights dimming for 1/2 second on motor startup is perfectly normal.
Growing up here in the midwest, power disconnects are rarely accessible. First responders are trained to cut the seal and pull the meter. When I lived in California for a while, the requirement for an accessible, outdoor disconnect as foreign to me - and were I a teenager in those times, would have been a constant source of pranking.�
Feb 19, 2015
DavidM FlasherZ - "I understand the frustration - I really do... but what frustrates me is the attitude that it's Tesla's fault, rather than a responsibility to track down whatever source is causing the problem."
I must disagree with you. They designed a product. Advertised it. Sold it. Then a year later they reached into our homes and crippled it with a firmware update to reduce their potential liability. If they are not convinced that their product can't consistently and safely charge at 40A in a residential environment after being properly installed, they shouldn't advertise it as such. And for current customers, partial refunds would be appropriate.
Tesla is a commercial company who has designed an electrical "appliance" that draws more electricity than any other residential appliance. They know this fact. They also know that a measurable percentage of their customers cannot consistently charge at 40A, even though it is advertised that they will be able to do so. Tesla now has evidence that the firmware in the Model S does not consistently allow charging at 40A for many of their customers. The residential electrical environment is what it is. If Tesla is concerned that ALL of their customers cannot safely charge above 30A, then they should design all of their cars to charge at no more than 30A - done. This is not a science project for the homeowner (or his contractors) to try and maximize usability. Products with a plug either work as advertised, or they don't work as advertised. Whether an appliance draws a lot of current, or a little current doesn't matter. The company selling the product has the responsibility to figure out what will work within an approved residential electrical system.
Tesla should publish the residential requirements for various charging solutions that they sell. But they don't. I did an experiment and tried to charge while everything else in my home was turned off. No washer/dryer, no dishwasher, no heat pumps, no oven, etc. The only running appliance was the refrigerator. The car still reduced amps to 30A. Whatever mystery issue the Tesla firmware is finding, it's probably coming from the transformer or the capacitor banks (external to the house). But the power company says everything is within tolerances. Since I don't think the Tesla electrical engineers are idiots, I have to believe they don't want the Model S to continuously charge at 40A across the UMC. I don't seem to be hearing very many customers with the HPWC complaining about current reduction. FYI - the HPWC has no adapter, and has much thicker cabling. It's a much safer product than the UMC.�
Feb 19, 2015
Lloyd They do specify 40 amps at 240 volts. If the electrical wiring in your home can't maintain 240 volts at that load, then your results WILL be less than ideal. Tesla has done the right thing by limiting charging when anomalies are detected. It's for your safety!! In most cases 30 amps is plenty to charge overnight.�
Feb 19, 2015
FlasherZ A very small percentage of owners have situations with their electrical connections which throw out signatures of a dangerous condition called "arc faults". A very high percentage of owners (in excess of 95%, it seems) can charge at 40A or 80A without a problem on a regular basis and do not exhibit the symptoms. The old 80/20 rule seems to apply here.
If there's anyone not looking at the big picture, it's you, because you're frustrated that you have a problem and it's not simple to find. Your solution, then, is to blame Tesla and tell them to turn off the safety feature and/or eliminate the ability for those without a fault in their infrastructure to charge at 40A.
Another analogy: 95% of computer owners don't have malware on their computers, so Windows Defender doesn't report a problem for them. But you do -- and since you're constantly getting "you have malware" notices and Windows goes into protection mode for you, that you demand Microsoft should rip out the Windows Defender completely and force everyone to operate in heavily-restricted mode. Does that seem anywhere NEAR the right answer?
What you're saying above is that just because you have a problem in your electrical connections, you want every owner punished by having Tesla force 30A on everyone. So, all HPWC's go away, just because my dad only has 60A service in his home? Everyone should be restricted from charging at 40A, just because of a bad ballast I had in a fluorescent fixture in a shop?
And a suggestion that this is some kind of weird conspiracy from Tesla to keep people from charging 40A across the UMC, despite tens of thousands of people who successfully do it daily without a problem? C'mon, that's just daft. With the exception of the bad ballast I had in the shop, my UMC charges at 40A just fine in several locations, from campgrounds to shops to my machine shed.
Just because it doesn't happen to me on a regular basis doesn't mean I don't, or can't, understand the problem. I understand it quite well, from several different positions - marketing, engineering, customer, etc. If it were randomly happening to 80%+ of the cars out there, then I'd say yes, Tesla needs to fix it. But it's not -- and the effects are hitting a very number of limited people who are steadfastly REFUSING to find the problem. You're not listening when I tell you that the average power company "voltmeter on the meter lugs" test won't show you the arc-fault signature that causes the car to back off.
If you turned off EVERY other breaker in the house, and your car *still* backed down, then you still have a problem, period -- it's just not located within those areas you turned off. It could be your transformer. It could be your service wiring. It could be because you have an undersized service drop over a very long distance to your transformer that gives off a high-resistance signature. It could still be the car's chargers.
That is not Tesla's fault (unless your car's charger or UMC are found to have a fault). Period. And if you disagree with that, I'm sorry you feel that way and my best to you, but I can't respond to someone who thinks that exception cases should manage the norms.
EDIT: Clarified that it's not Tesla's fault as long as your specific UMC and car's chargers are not found to be at fault... obviously it's Tesla's fault if there was a defect in your specific model.�
Feb 19, 2015
brianman [1] Given that Tesla doesn't have a "large by auto industry standards" fleet, just 1 owner having an issue is a "measurable percentage". I'm not sure this means much.
[2] I don't know if we have enough data to assert "many". Tesla might, but I don't think TMC does.
[3] No. I prefer not to begin this particular race to the bottom. Thanks but no thanks. As an example: I've only been able to reliably get 5A on some 120V circuits, but that doesn't mean I think it's sane to gimp the planetary charging capabilities of Model S vehicles to < 4A@~100V.�
Feb 19, 2015
dsm363 Agree. Makes no sense to derate to vast majority of customers to 30A if they aren't having issues.�
Feb 19, 2015
qwk Not really. I haven't really noticed the car stop charging or drop the current since that time, but I haven't exactly been watching for it either(haven't had a time crunch charging session lately). SC says logs look fine. Engineering is mum on the issue. I suspect, and hope they alter the threshold for the next firmware release, so it isn't so sensitive. The voltage fluctuation during the incident that started this thread was a whopping 2V.�
Feb 19, 2015
qwk Agreed with everything except the refund part. I don't need any money back. All I want is the same charging capability I bought back.
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This is about as wrong of an assumption as one can make. I would be willing to bet that most cars just charge overnight, and the owners don't notice or even care whether or not the car charged at the full 10kW.
For some reason, a few posters here either have an extreme bias, look through rose colored glasses, or just have comprehension issues. Please name another company that sells manufactured goods with a certain spec, then after purchase, takes it away. I have honestly never seen something like this happen before except with Tesla. It started with auto-lowering on the air suspension cars...�
Feb 19, 2015
wk057 @FlasherZ - I'm curious, where do you get the information that the Model S is operating with arc-fault detection? I've not seen this noted anywhere in any documentation.
The voltage drop based charge current reduction is easily reproduced, but from what I understand of the charger and such I'm not quite ready to jump to the conclusion that it is operating with arc fault detection in place.�
Feb 19, 2015
Canuck Some people agree with you and some don't. The ones who don't shouldn't be labelled with "extreme bias", "rose colored glasses" or "comprehension issues." It can simply be a difference of opinion based on a review of the facts. At least that's how I see it.
Also, cars still do auto-lower (the halting of that was only temporary) and they've always charged at 40 amps. Saying Tesla is unlike any others doesn't mean much to me because they are in uncharted territory (thankfully) so comparing them to others is not of much use. Also, please note I have supported you and understand your frustration (although my posts here got moved to another thread). I just want to put things in perspective. Both sides have valid points in this thread and there's no need to look for underlining motives other than a difference of opinion.�
Feb 19, 2015
mkjayakumar Qwk: Please name another company that gives more and more features than what they gave you when you got the car.�
Feb 19, 2015
DavidM With all due respect, I didn't ask for more features. I just want to keep the ones I paid for. I had 40A charging for over a year, and then Tesla took it away. Yet, Tesla still advertises you can charge at 40A with the UMC on a 50A circuit.
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@FlasherZ
When you purchase a product, it should work as advertised. I have already established that "I don't have a problem with my electrical connections". This is backed up by the experts at the power company. They publish what their standards are (240V, +/-5%). Fluctuations within that range are considered to be acceptable. Fourteen months after my sale, Tesla has incorporated OTHER standards which they refuse to disclose. It's Tesla's standards that have created problems for some unknown percentage of Model S owners. You say 95% don't have a problem, but actually you have no idea. Your analogy regarding the Windows operating system would only apply if Microsoft sold you Windows, and then removed some of the capability that you purchased. Since you're an electrical engineer of some sort, you're just fine with tinkering and doing your own troubleshooting to make your car work as advertised. However, everyone is not an electrician, nor should they have to be to own a Model S that functions as advertised.
Regarding your comments about the transformer (down the street), or the capacitor bank (further away), these aren't even things that a homeowner owns or controls. This equipment belongs to the power company. If their experts say they are functioning properly, and none of your other residential appliances are having issues, then you're fighting a losing battle, unless you have an EE degree, lots of test equipment, and a lot of time on your hands (which isn't the case for the average Model S owner).
I find it interesting that after UMC adapters burned up, and new UMC adapters were shipped to all customers, there was a dramatic price cut on the heftier High Power Wall Connector. It's as if Tesla wants most customers to use the HPWC on a daily basis (in lieu of the UMC).�
Feb 19, 2015
Lloyd Which other of your appliances draw 40 amps for 8 hours and require a tollerance of +-5% ?�
Feb 19, 2015
scaesare It seems odd for this capability to have been included as a HW/FW capability yet only have been activated after the garage fire I referenced above (when it almost certainly was).
Are you sure this is the specific event it specifically designed to trigger on for current reduction?�
Feb 19, 2015
FlasherZ It was said by Tesla when they introduced the feature that the car looks for voltage fluctuations that would indicate wiring problems and safety hazards, in which arc faulting would sit. A wide variety of cases have been listed in the various threads here that tend to fall into two categories: 1) the "extension cord" voltage sag that occurs as the result of ramping up charging current and getting a higher voltage drop than expected - this happens nearly every time in those cases that are experiencing it, and 2) those that are more intermittent in nature. My own observations at the shop with the bad ballast were of this second type, where I can guarantee good infrastructure all the way back to a dedicated transformer, and sufficient stable voltage with no other loads at the particular shop that caused my car to back off. The repeated switching of a defective ~200W ballast - on a dedicated 120V circuit - caused the car to back off.
So the bottom line is that I can't specifically confirm that they have purchased licensing rights to an arc-faulting algorithm, but the effects of their algorithm are the same, and it aligns with that second class.
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Yes:
http://www.nytimes.com/2014/01/15/automobiles/citing-charging-concerns-tesla-issues-a-recall.html?_r=0
The "over-the-air" update they referred to was the charging current reduction in 5.8.4. The fire report makes note of an extremely high temperature point inside the receptacle itself, indicative of a loose connection.�
Feb 19, 2015
FlasherZ And it can, on a proper electrical system. I have definitive proof in my garage.
Tesla also "advertises" this:
...which means you're not guaranteed you'll get 40A charging current.
I am willing to guarantee that if I attach a scope to your power lines, flip your main breaker off, then back on, that I will see voltage on your main busbars shoot up well over 300V for a sub-second period of time. Would you like to take that bet?
You're just not going to see it, because you're not looking for it. Your power company isn't going to see it, because you're looking at it averaged over time, and not the instantaneous effects.
It's clear that you're going to continue to hold your conspiracy theories about the UMC's being Tesla's dirty secret and me being some sort of agent here to suppress any liability related to it or something like that: I'm not being paid by Tesla, TMC, or anyone else to have the views that I do. I think Tesla's doing the right thing by protecting its customers, and it's primarily because my house nearly burned 15 years ago from the conditions (unrelated to Tesla) that the software feature protects against. Assuming you and Tesla have tried isolating the issue by using a loaner/replacement UMC, should you replace your UMC with a wall connector, my money would be on your car still backing off its charge current.
I think that you're an exception and not the norm, because there is only a vocal minority complaining about this on TMC and Tesla Motors forums, with tens of thousands of customers. I don't accept your assertion that most people experience it and just don't know it because they charge at night, because you can see it when you use the mobile app or if you're charging during the day. Those people who are exceptions can do one of three things - 1) accept that you're an exception and enjoy life with a beautiful piece of machinery; 2) fix the exception by finding the problem; or 3) fix the exception by going to an alternative that puts you back in the mainstream. I've told you where you can look, but you're ignoring it because a power company man in the van put his voltmeter on and said your voltage is between 228V and 252V.
My best to you in resolving your situation, should you choose that path. There's nothing else that I can offer that will change your mind, and -- to the others here -- I'll let the evidence stand for itself. I'm proud that my Model S looks after my safety.�
Feb 20, 2015
scaesare I understand the grage fire is what prompted the FW change. I was the one who referred to that initially.
What I'm asking for is are you sure of what the car is triggering on to reduce current? Could it perhaps be voltage fluctuation that the car is too sensitive too or EMI that's confusing it.�
Feb 20, 2015
Electric700 This reminds me of a similar situation with the Chevrolet Volt, which was released in 2011. For the 2013 model year Volt, Chevrolet introduced a change where the charge current over 120 V would automatically default to 8 A, as opposed to staying at 12 A. Many people complained about the change because it required manual intervention to go back to 12 A. After Chevrolet explained that it was due to safety concerns, I think most people understood that it was for their own protection.
I really like how Tesla decided to do it with the Model S, where the current is lowered if the software detects potential issues with the line.�
Feb 20, 2015
FlasherZ Without access to the algorithm, I can't tell you definitively. This is based upon observation and the evidence that I've seen here. We can draw some conclusions from the implementation, cases, and the frequency of its occurrence as reported here and in the TM forums.
If it were EMI-triggered, you would have a far greater occurrence of the cars backing down given the wide variety of environments - residential, commercial, industrial. My home, for example, is a case where EMI is a monster and if it were the case I would expect to see the car *hate* my home. I have a couple racks of 1RU electronic IT gear (with lots of wireless), I have a machine shop with plenty of motor loads, I use PowerLine Ethernet for connections to outbuildings. As a sign of a troubling EMI environment, my X10 & Insteon automation only works occasionally (and I haven't bothered to track down the EMI interference to apply filters, but I'm guessing it would be rather expensive), despite using coupler/repeaters. My electric service is an EMI hell.
EDIT to add: If it were just a long-average voltage fluctuation, you would see it backing down far more often than it does, too. I recall one person here reporting that the power company had placed its line analyzer on the bus bars and found no more than a +/- 2V variance, with the car backing down sometimes and not backing down others. That would point away from a super-sensitive voltage drop algorithm and more toward that sub-second arc-fault type detection I spoke of earlier. I experience busbar voltage between 245V - 250V based on how loaded my service is at any given time.
So, to your other question - is the car too sensitive? Well, that's not a method question, but rather a quantity question. I believe we have enough evidence to conclude it's based on voltage (Tesla has said "voltage fluctuations" a number of times, along with what the evidence has suggested). It is difficult to balance: if you reduce sensitivity, you will miss some potential wiring problems until they progress into larger problems. It may be that the charger can't easily tell the difference between a reactive voltage surge and fall created by another appliance, vs. measuring the car's own effect on that. There is the potential that a redesign might help with that. However, I don't think we should continue to go down this path much further, because while I'm relatively confident that the evidence lines up with the theory that it's looking for an arc-fault-like signature, I'm less confident in how Tesla measures it or solutions for it.
I'm willing to accept that I'm wrong, by the way, and that it's something we haven't even considered... but there's only a limited number of things that the car can "see" attached to a branch circuit -- and we've largely covered them.�
Feb 20, 2015
redox Sony?�
Feb 20, 2015
tomas Apple also. And any Microsoft based PC. As well as any iPad, tablet, iPhone, android... Apps that don't keep pace with the OS will eventually become inoperable, or so neutered that they are useless. Users who don't keep pace with OS changes will lose functionality, access to new apps and features, and - in some cases - warranty support.
Come to think of it, this also happens with ANY software updated device. My Nest thermostat automatically downloads new software. It processed a download last winter that had benefit of connecting with smoke detectors, but in process could no longer keep battery charged without a hot lead from furnace... wiring requirement that was not initially there at installation.�
Feb 20, 2015
wk057 In an arc fault situation, maintaining the hazardous/undesired arc in an arc fault situation would generally be voltage dependent across the air gap, no? If it is a series arc fault (a break in one conductor) then a load would be required to make it happen, but I think perhaps my lower level electrical knowledge is failing me on grasping if a 25% reduction in *current* (thus *increasing* voltage) is sufficient to stop an arc fault situation in the first place. I'm not sure that reduction in charge current is an adequate safeguard against an arc fault anyway, which is why I'm confused about the nature of the algorithm. (Disclaimer: speculation, I could be wrong!) Every arc fault protection system I've seen to-date operates by completely interrupting the circuit.�
Feb 20, 2015
stopcrazypp I don't believe it prevents arcs directly, but rather reduces the risk of fire by lowering the amount of energy and heat through the conductors.�
Feb 20, 2015
FlasherZ Two thoughts (now firmly in speculation territory):
First, I don't even know if they're really trying to prevent arc faults, per se - they may just use an arc fault signature as an early warning indicator of a "glowing conductor" situation. When a connection is loose, there are times you'll experience an arc and then the conductor welds itself to the terminal (can especially be true on multi-strand wire). Once that happens, the arc fault gives way to a higher-resistance "glowing" connection. This is different than an arc-fault situation on an appliance branch circuit, where typically solid wire or solid appliance plug blades will be melting, increasing the arc - that's where you definitely want current interruption.
Second, you're right that lowering the current will increase voltage and therefore increase the potential gap that could be covered with an arc; however, I suspect they're looking to protect the wiring more (and by the time an arc jumped the gap, I'd argue the voltage increase from a 25% decrease in current is relatively meaningless anyway). I think the more important element is preserving the wire -- in an arc welder, for example, higher current creates a higher electrode melt rate.
As a result, if they reduce the current by 25%, they get two things: under a case that migrates to a "glowing conductor" scenario, there's less heat through a higher-resistance junction (roughly half); and in the case of an arc, you get less of a wiring melt (although I don't even know if they're considering that as the primary issue to tackle).
Again, speculation on my part but I think that's where they're heading.�
Feb 22, 2015
wycolo If the MS originally had a non-peak reading voltmeter on the screen, could TM have changed it to a peak-reading vm simply thru a software upgrade? Wouldn't that be necessary to support FlasherZ's idea that it now can sense arc faults as opposed to just voltage variations within +/- 10% or so?
If I were qwk my next step would be to pull out my old crt scope and see what noise might be riding on top of the 240vac. But apparently his problem has abated for the time being. But DavidM continues with an identical issue - (big shameless hint!)
--�
Feb 22, 2015
SeminoleFSU In his defense, I had the same problem. Charged at 40amps just fine before the FW upgrade came along that dialed back the amps. When I charged at 40amps, the UMCs were getting hotter than they should. My first one was so hot I felt it was unsafe and had it swapped. Second one was cooler, but still hotter than I wanted to feel it getting for longevity. Some time later the first FW came out that dialed things back, and I've just let it do it's thing. I've noticed since then that the UMC is noticeably less hot when left to charge at the dialed back current 30amps. For me the difference in time didn't matter much because I can recoup all the miles I drive in my commute to work at 30 just fine... but it is also a little annoying to me that the UMC feels hotter than it should (especially in the summer) when charging at the full 40. This is a UMC that is in a garage, in the shade too.�
Feb 22, 2015
scaesare That's the crux of one of my questions: it seems the arc fault detection would need specific hardware support, thus it would have had to have been there all along in order for a firmware upgrade to take advantage of it.
Seems odd...�
Feb 22, 2015
FlasherZ Yes.
The read-out on the display is just that - a display of a point in time. It becomes an "averaging voltmeter" that measures Vrms when Tesla chooses to display that, and with the resolution that Tesla chooses to offer.
AC doesn't have static voltage. At any given instantaneous point in time, you'll see various voltages across the mains - from 0V to 350V (normal operation), perhaps even higher than that (reactive currents). Tesla won't display that - they'll display the Vrms, the voltage that most people understand, as it would just confuse everyone without a firm understanding of AC. If the charger has an ability to read a voltage, then its ability to detect arc-fault signatures is limited to the time-resolution of its voltage sensing and the ability of its microcontroller to devote the time to doing so.
It's not about what noise is normally riding over it, but catching the event that makes it downshift -- but even then, that won't tell you what causes it. It's pretty much a given that you're seeing a voltage fluctuation of some-sort, and it's a guaranteed (in my book) the scope would show that. It might give you a clue as to whether it's a reactive current that is driving a spike in voltage vs. a drain on voltage. It would be faster to demand the service center engage engineering to help you out - they know more about the situation (and perhaps they have some event logs that detail the type of failure detected).
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I don't want it to seem like I'm saying it isn't / won't be the UMC. I'm making an assumption that Tesla Service has already given him a loaner / replacement UMC, and we haven't determined that it's not even the charger. The UMC's clearly had a problem, but if the downshifting occurs after replacement of the UMC or on a replacement of the UMC, it follows that it's unlikely to be the UMC as a cause.
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It's just voltage sensing, limited to the resolution of your voltage sensing loop. Let's use an average 20V inverter DC arc welder as an example, because it's an easy way to visualize it. Prior to establishing the arc, if you were to measure the voltage, you'd find an open-circuit voltage of somewhere around 80V. As the arc starts, the air gap becomes conductive and the voltage drops dramatically (to 20V) as the circuit is established and current flows. Now, that's a simplistic case and the amplitudes mentioned assume a series arc-fault that the Tesla charging circuit was involved in. However, even if there's an arc fault that occurs in another branch circuit, the effects of it can be seen across the entire system and could be sensed by the Tesla.�
Feb 24, 2015
DavidM Since we're all pretty much topping off every night, or every other night, we're almost never "drawing 40A for 8 hours". One and a half hours at 40A would be more accurate. But yes, it's 30A or 40A continuous if the car's firmware permits. Even a 5 ton heat pump struggling to heat a house when it's below freezing outside won't continuously draw 40A for hours. Maybe just 30A. But it would do that all night and give it it's best shot at maintaining indoor temperature. Believe me, if it shut itself down, or if it's 40 degrees outside and it can't maintain 70 degrees inside, you'll be on the phone to HVAC contractor. 99% probability that when they leave your house, you're back in business for the foreseeable future.�
Feb 24, 2015
redox This is certainly true for me - and actually I've specifically set the amperage down to 15-20A in order to not stress charging components.
I wish this was done automatically though - there are times when I need 40A (pretty rare), but most of the time I'd rather tell the system "make sure I'm at X% charge by the time it's Y o'clock" and let it do its thing to minimize strain on components.
-- Greg�
Feb 24, 2015
TexasEV I don't know of any evidence that reducing the charging rate will significantly increase the life of the charging components. The car was designed to be charged at 40-80A with AC charging, and of course much higher amps than that with direct charging at superchargers. Maybe dropping to 15-20A is reducing your stress but I doubt it's reducing the charging components' stress.�
Feb 24, 2015
neroden For reference, I burned through 3 UMCs and finally told Tesla they had to replace my loosely-fitting charge port. (The new one is snug. Since then, no problems.) A lot of things can burn out the UMC... which indicates that it's a poorly designed piece of equipment, unfortunately.
Tesla still refuses to admit that the loose charge ports (present on early cars) were defective, even though other people had the same problem.
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If the update breaks something, they're warranty-bound to fix it -- or buy his car back from him.
He has a legitimate complaint. If Tesla's unwilling to fix it, Tesla should offer to buy his car back at its original sales price.
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I would expect this to generally address the problem, if done comprehensively.
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I should point out that I had this happen (along with all sorts of other charging problems and multiple burned-out UMCs) during the period when I had the defective chargeport.
Actually, qwk, your car was delivered less than a month after mine. I'll bet you your chargeport is defective. Is it kind of loose when you plug the cord in -- a lot of side-to-side slop? A good chargeport should be extremely rigid.
Demand that the chargeport be replaced, see if this fixes the problem.
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My actual charger was OK, but my chargeport was loose, the contacts behind it were corroded, etc. etc. qwk's car was delivered less than a month later than mine. I would expect that the entire chargeport apparatus would require replacement, if it hasn't already been replaced.
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That's because it's almost certainly Tesla's fault. The evidence is that the UMC is the weakest link in the circuit, and is skating on the edges of violating code. :-( Rather than fixing this, Tesla made a hypersensitive software algorithm, which reacts to stuff which no electrician dealing with a properly wired house would worry about. On top of this, people have had charger problems. And (like me) have had chargeport problems. Tesla has been slow to admit the existence of these problems and resistant to making the necessary replacements.�
Feb 25, 2015
FlasherZ You're not looking at the entirety of the evidence. There are people who report backing down who aren't even using the UMC (J1772 or HPWC), and there are tens of thousands whose UMC's are working without a problem. While I will agree that the UMC had a design problem that resulted in melting of the adapter which caused pins to loosen more, it is not the sole, nor primary reason that the car is reducing charge current. The number of reported UMC failures on this forum has dropped dramatically since the new adapters were put in place, to near-zero.
The charge port hardware coupling is a tough-to-engineer environment. It's extremely difficult to create a coupling that will carry 80 amps while - at the same time - remaining usable for daily plugging and unplugging. I've had my HPWC cable replaced twice because of the heat it generated (although I'd imagine with a contact cleaning kit I could have revitalized it a bit.
All that said, when the car backs off by 25%, it points to some type of problem in the electrical environment. Yes, it could be a piece of Tesla equipment causing the failures - charger, charge coupling, or EVSE - but that appears to be a bit random and less frequent than some here play it up to be; or it could be in the infrastructure feeding the EVSE; or it could be a misbehaving appliance. Bottom line - it's not something that should be ignored or should generate a request to Tesla to turn off the safety feature.�
Feb 25, 2015
Cottonwood Also remember that the car side of the charge port connection needs to handle up to 330 Amps on a Supercharger. On top of that the 330 Amps are DC which cause more corrosion problems than AC connections.
In 2.5 years of MS ownership, my personal experience with instances of the 25% back down in charging current are very few, and in every one of those, the cause was something on the line side causing Voltage jumps. I have tried to purposely put in multiple extension cords, adapters, etc to make the current reduction happen without success. While I could cause almost 10 Volts of IR drop, I could not force the current reduction with Ohmic losses.�
Feb 25, 2015
redox To me it's just a general rule of electric/electronic components: heat shortens their lifespan. You seem skeptical, so if you are really interested you can read more about it here or here. Actually Google will turn up a lot of research and results.
When using a supercharger you're not stressing your on-board AC charger - other parts are being stressed, which are probably not under stress when charging @ 40A at home since they take a much larger beating at a supercharger, so I'm not worried about them when I charge at home. However, at home, I do worry about the AC on board charger.
I do appreciate that the system is "designed" to take 40A, but in engineering-speak, that means that its failure rate (or MTBF) is larger than some acceptable value. You can increase your MTBF if you lower the stress on the components. It's all statistics, so that doesn't mean I can guarantee my charger will last longer than someone who only goes for a 40A charge, but statistically, I think it should.
And maybe all this is non-sense and like you said it's all in my head of course... :wink:
-- Greg�
Feb 25, 2015
Cottonwood Hear, hear!
You can see some of my comments on the subject here: 85D First Impressions - Page 10�
Feb 26, 2015
neroden I'd like to point out that the two people making the main complaints here are working with tested, known-good circuits, where there's basically nothing they can fix from the wall socket back (to the point where the electrical utility has refused to consider the possibility of problems on its lines). This means their problems are almost certainly on Tesla's end, whether UMC, chargeport, or charger. (This is also the position I was in when I was having problems.)
(And if they are actually problems with utility company wiring, the only way to prove it is to blow out a transformer or wiring at the electric utility's end, so Tesla needs to make that possible. :biggrin: )�
Feb 26, 2015
FlasherZ neroden, I'm just going to point back upthread because I explained how power companies "check" their service, and how a misbehaving appliance can cause this.
It is definitely NOT "certainly on Tesla's end". It very well could be an issue with a UMC (but the vocal have replaced them already). It very well could be an issue with a charge port (but you noticed that yours was loose and perhaps they would too). It very well could be an issue with a charger in the car, and they need to go look at it. But the issue stands that there are tens of thousands of people not having a problem and a very few who do. That makes it an exception, not the norm.
But I've explained it all already upthread - and the very vocal minority just refuse to listen because it's difficult to troubleshoot and isn't as simple as just having Tesla turn off safety features. I'm sorry you're unhappy again.�
Feb 26, 2015
wk057 Of course it has to be Tesla's problem! Certainly not any of the underpaid and under-appreciated electrical contractors that did any of the premises or service wiring...
</sarcasm>
Honestly, though, I'm on the fence. I've had this dial back issue with my HPWC a few times (drop from 80 to 60A) while nothing else on my side of the meter could have possibly been the culprit (my HVAC being the only thing I can imagine being a large enough to make a difference that far upstream, and it was idle the last time this happened). I did all of the wiring between the service entrance panels and the HPWC myself, so, I know it's right and as good as it's going to get. As far as troubleshooting things on my end, I'm not really sure what else I could do.
My utility transformer appears to be shared with two other residences, each also with 320/400A service. Neither of them have EVs, and I don't think they have any large loads that would come close either. Nothing that far out should really have an effect on anything on my side of my meter.
IMO, Tesla's current-reduction algo needs some work. That's not saying it's always wrong, but I'd bet it has more false alarms than even early generation AFCI breakers.�
Feb 26, 2015
islandbayy I have evidence.
9 UMC's. Current one is now almost 1 year old.
First 8, I charged daily at 40 amps. First one delivered with car failed at 2 week point.
Varied times. But each and every one of the first 8 I used at 40 amps.
Current UMC, that is just a hair shy of 1 year old, I charge at 32 amps or less, accept when ABSOLUTELY necessary to recharge as quickly as possible. Most would last a month, then start causing errors.
Not, one, Single, Issue with my current UMC. I will also vouch, that temperature of the unit is considerably lower at 32amp.�
Feb 26, 2015
TexasEV You went through 8 UMCs in a year, and I am still on my first UMC after 20 months of charging at 40A every night. I have to think there is something different about our cars or our electrical service.�
Feb 26, 2015
islandbayy Add me to the group of people that are experiencing Charge Reduction with absolutely no issues with the premises. Sort of, I shall explain.
My home, is on a highly over-loaded (Or at least, over-subscribed) transformer being shared with at least 7 homes. I'm only one with a EV. Winter, almost no Electric Loads from other homes, Summer, AC loads nail that transformer.
Now, HPWC is 1 ft from breaker box. HPWC connected to 100 amp breaker by 2AWG (Larger then specified by Tesla). Breaker box is 5 ft from meter, fed by 2/0. More then large enough for my 200 amp service.
Meter being fed by transformer by 2/0. Though, transformer is far away.
Voltage Sag. Start at about 240v at no load, at about 40 amp load, drops to about 230v, at 80 amp load, drops to about 222v. At my home, the car will stay at 80 Amps for about 5-10 minutes before reducing to 60 amps. Despite the voltage drop.
Now, at my parents motel, they have a 70kW transformer.
During the summer, that 70kW transformer is feeding their motel, and 2 houses. So 4x200 amp services and 2x100 amp services. During the summer, the transformer is really loaded, but utility wont upgrade it as it is handling the load.
Now, the HPWC currently online (Had to remove the second one, as we ran out of available service without adding a second meter. I am working to resolve this by swapping loads between breaker panels and meters for the motel).
That HPWC, is located on the garage of the "Beach House". It is fed by one of the 200 amp services, and has that all to itself.
HPWC is 12ft from garage breaker panel, fed by 2awg. Garage panel fed from main panel by 2/0 Aluminum at ~13ft run. House Fed by 2/0 Copper.
During the winter, with the Motel Closed, the total load on the 70kW transformer is about 10kW. Thats factoring in the main house, 2 houses across the street, and misalenous loads. Either way, it's next to nothing considering the transformers size.
Voltage at the HPWC is STRONG. Start off at about 245v. At 40 amps, about 238v, at 80 amps, about 235v. So MUCH MUCH MUCH less voltage drop then my home.
The car will stay at 80 amp for a maximum of 30 seconds before backing down to 60, despite the much less voltage drop.
In the second instance, at the motel, I have had the utility out, checked all the lines, transformer to the house etc... noting wrong, wiring proper size, tight connections etc...
Now, one other note, before removing (temporally until i get the load situation resolved) the second HPWC, I gave er a good test. Now, this second HPWC, was literally next to the breaker box, that was 2 ft from the meter, that is connected with 2/0 directly to the transformer. So a total wire run with oversized wiring, from HPWC to the Transformer, was less then 25Ft. I'd gather thats considered really dang close.
Same result when charging at 80 amps. about 30 seconds and it was already backed down to 60 amps. This test was done once season was over, and motel closed, so all large loads were gone (motel portion is completely electric, the houses use gas for heat, so no real loads from the houses).
Voltage drop measured: ~248 no load, ~242 at 40 amps, Fluctuating between 239 and 240v at 80 amp load. So extremely little voltage fluctuation.
Still, drop from 80 to 60 amps. Makes no sense. It will sustain 60 amps all day, but doesnt like 80 amps. Utility put some sort of line monitor. They were a little vague on the details of it, but it was to test for "Noisy" power and "hickups" is how the utility worker said it. I might also mention, the 10 megawatt hydro plant is 2 miles away.
No explanation as to why it happens.
in fact, the ONLY, and I will repeat, ABSOLUTELY ONLY HPWC IVE EVER CHARGED AT THAT I DID NOT GET CURRENT LIMITED WAS AT Marshall Auto Body. Shout out to Scott for his awesome setup.
He has a 80 amp HPWC, a I believe 70 amp J1772 Clipper Creek, 70kW Solar Array, and is in the process of completing a CHAdeMo install at his body shop.
I will need to take that statement back, the HPWC's at the Highland Park service center I did not get current limited. But in terms of Non-Tesla owned HPWC's, EVERY other HPWC or 80 amp charging location I've visited (And it's A LOT) other then Marshall Auto Body has gotten current limited at some point to 60 amps during the charge session.
Please don't take this as a argument. I'm voicing my findings in this thread, as I'd like to find a solution to this issue. I will also add, I have a retrofit dual charger. My car was shipped with single charger. At time of retrofit, my master was also replaced as it would not communicate with the slave. I have had duallies for exactly 1 year now.
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The one delivered with my car was a First Gen I know that, not sure what the second and third were, every one after that was a second gen UMC.
I do keep a spare just in case, the first failure scared me, as at the time, Public charging was almost non-existent.
But over the course of the UMC's, I did notice a direct correlation between how long they lasted, to the amperage I charge at.
While I have a HPWC now, I rarely use it. My car is a outside car, my garage, is mostly a "Warehouse" for my online business, so in order to get the HPWC cable to reach, half the car will be sticking out of the garage.
The UMC is more then enough, even when completly draining my battery. At 40 amps, I sustain about 235v on the UMC's circuit due to its run length to get all the way outside from my breaker box. 6 Awg at about 60 ft. As I lowered the amperage, so 39, 38, 37, 36 etc..., I noticed (Car under first year of ownership, UMC's are, at least according to Tesla, only under warranty for 1 year from purchase date of vehicle, or if ordered in the online store, 1 year from date of UMC purchase, no longer then that) that since the UMC was under warranty, experiment a bit with the amperage. Seems 32 was about the magic number. I usually charge much lower then this, 20 amps from 7pm to 7am is usually enough to give me a 90% charge on my 60kWh pack overnight, unless I get home much later.
I will add, UMC stays plugged in outside. It is in shade, and semi-protected from elements (rain) by a large roof over-hang.�
Feb 26, 2015
TexasEV So after the charger was replaced one year ago, you stopped having to replace the UMCs every month or so? Maybe this is more than coincidence.�
Feb 26, 2015
redox Like I said in my previous post: it's a matter of probabilities.
Smoking every day is known to shorten your life expectancy, but that doesn't mean that every once in a while you can't find a centenary who will tell you he's smoked all his life and is feeling great.
If you understand the statistical model, then you can decide if you want to make use of it. You will find people who have charged every day for a year @ 40A with no problems, and people who have charged 1 day @ 10A and broke their UMC. But 2 data points are not enough to be statistically relevant.
-- Greg�
Feb 26, 2015
FlasherZ When you say "I don't have voltage fluctuation", I have to ask how you measure that.
You are unlikely to be able to see the "voltage fluctuation" that the Tesla reacts to. This is especially true if you're relying upon the Tesla's screen or even a digital or analog multimeter. You need a more complex line analyzer - and in some cases a scope - to see the sub-second instantaneous voltage fluctuations that are triggering this algorithm. When I had the bad ballast in the shop, the Tesla showed voltage rock-solid at 235V. I can guarantee that the *only* load on the entire transformer was the Model S, and the shop's office light which consists of a single 8-bulb T54 fixture - 1 ballast per 4 bulbs. Every other load was turned off at the breaker panel.
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You can, however, draw conclusions based on the number of complaints versus the number of people who have purchased the car. It is indeed frustrating to see your charge current drop by 25%, as evidenced by those exceptional cases we're seeing here; so if this were happening at a higher occurrence than it is, you'd certainly see a much higher level of screaming than is currently seen here or on the Tesla Motors forums.
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islandbayy, have you asked your service center to have engineering look at your case? I think your willingness to help debug this is certainly something that Tesla could use as a solid data point. Connecting Tesla with your utility's engineering department (NOT repair, who will see if a light bulb lights up and call it good) to see why the car detects some type of a fault would be beneficial.
And I suspect it would lengthen the life of other devices attached to your utility connection.�
Feb 26, 2015
islandbayy I've had current UMC about a 1-2 Months before getting the Master swapped and slave installed. Which was much longer already then I've had any previous UMC. Exact dateage is fuzzy.
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Didnt say I don't have voltage fluctuations, but very minor, within a volt or two.
I measure with a nice Multimeter I have (Not the Harbor Freight Special).
Also, like I said, utility put a special line monitor and reported no issues. No Blips dips or chips. Yah a scope would be nice
I have contacted We-Energies about my home, I just got back in from trudging through 2ft of snow to get to the pole with the transformer. Cant read the exact rating of it, but got some other informaiton off of it. First time I've been able to see it in person. Avoid going back their (In forest) during the winter due to snow and deer crap, and during the summer, too many leaves on trees to get a good look, and that neighbor is a jerk and chased me off his property last time I tried (hes not home now hehehe).
Now, I did, last year, work with a engineer. They did find a voltage problem, but not at the transformer. The actual sub-station my street was on was severely over-loaded. Moved my whole neighborhood to another substation (Took about 3 hours with power off for it to be done). They thanked me for finding that problem.....
As for the transformer, no idea what KW rating it has, it's old though. And set up strangely. Seems to be fed by a single wire and a strange attachment?????? I'm starting a new thread with transformer and pictures. It's a Allis Chalmers. But anyways, will be starting a new thread to try and figure that thing out. Either way, it's physical size is about the size of most 25kW transformers I see.
As for parents Motel, Alliant wont give me the time of day any more.�
Feb 26, 2015
breser No they shouldn't. Tesla should buy it back after discounting the original sales price for use and damage. It's not like the owner didn't get some value out of the car for the time they had it. It's really absurd to suggest that any problem can have the owner demanding a full refund years later.
This sounds like a problem with the car not the HPWCs. I have a hard time believing that all of the HWPCs except a handful have had problems triggering current limits.
My experience with my first car was I always got 80A and never saw a current limit. Granted I had it for a limited period of time. With the 85D I'm having a weird issue where most of the time it only wants to charge at 79A on my HPWC (and I don't mean it only is showing 79A as the instantaneous amperage, I mean the selector lowers to 79A and it refuses to go to 80A). I mentioned this in my 85D thread and some P85D owners have come along and said they've had the same problem. Tesla is going to look into this issue for me on Monday, though today it let me raise it to 80A and stayed there. The P85D owners said the issue was intermittent for them. One of the P85D owners has another car that doesn't display the issue on the same HPWC.
I can't fathom what value a current reduction of 1A would have on an 80A setup. Before having had the 79A experience my opinion on this topic would have been very much that there's probably some real problem on these owners charging environments. But now I'm wondering if there aren't issues with Tesla's hardware and/or software. Yes I realize it's different behavior, but it opens the possibility that there are bugs in my mind.�
Feb 26, 2015
FlasherZ I asked Tesla previously and here's what they said:
Occasionally mine shows 79/80A and occasionally it will go to the full 40/80. I suspect there's a bit of a rounding element in it plus accounting for the overhead.�
Feb 26, 2015
breser I don't think what you're talking about is what I'm talking about.
Both my S85 and my 85D (the one time I've seen it actually got to 80A) bounces between 79 and 80A on the view of what current it's currently pulling (what I referred to as the instantaneous amperage in the last post). However, on my 85D the selector (that you can lower your current to) drops down to 79A and stays there. Trying to raise it to 79A while plugged in does nothing. Unplugging, you can raise it back to 80A. Then you plug in and most of the time it goes right back to 79A. My S85 never ever did this. Two other P85D owners have said they had the same behavior. One made a video and sent it to me privately to see if we were talking about the same thing. The other told me his P85D does this but the other Model S in the household never does this.
Anyway I'm not trying to derail this thread by turning it into a discussion on this 79A issue, since I don't think it's really the same thing. I was just using this as an example that Tesla may have some problems in this area.
Made a new thread on this issue over here:
HPWC Charging Limited to 79A�
Feb 27, 2015
FlasherZ Wow, that's odd... perhaps it's misreading the duty-cycle? I'll go post over there.�
Mar 7, 2015
islandbayy I think I defeated the charge limiter.... But it wasn't easy.... And not doing this every time I need 80 amps charge rate at home......
I went all out this time. Turned on all lights, dryer, 4 space heaters, coffee pot, and my BIG Air compressor. Calculated load, was about 70 amps @240v. This was enough to bring the voltage down from 244 to mid 230's (Didnt keep exact track, but it's on my charging video I'm making).
I then started the car charging via the app.
As the car ramped up the charging rate, voltage started to drop further, but, at the same time, I started turning off devices.
Started with the lowest power ones, coffee pot, and air compressor. Following that, I turned the space heaters down to 700 watt settings. Then turned off the space heaters one by one spaced out evenly. This allowed the car to continue to raise the amperage, without any more drop in voltage. Finally, I killed the dryer. That was a 30 amp load at 240 (tag rating).
This actually brought the voltages up by about 4v. It's all leveled off at 227v and holding steady. Currently, going on 1 hour and has not dropped charging rate to 60 amps yet. Usually, at home, it happens between 0 and 30 minutes no matter what.
Basically, by doing this, I lowered the range the car sees as acceptable voltage drop. So, instead of the car "Seeing" the voltage drop from 244 to 227, It's only seeing a drop from about 235 (Roughly) to 227.
Basically, now, the cars seeing that the voltage is 96.59574468085106 of it's starting voltage, instead of seeing 93.0327868852459 of the original starting voltage.
WOULD IT BE FREAKIN AWESOME IF THE CAR CHARGED LIKE THIS WITHOUT THE HASSLE ALL THE TIME (HINT HINT TESLA!!!!)�
Mar 8, 2015
NigelM No you didn't; you artificially lowered the starting voltage. It's possible to do that every time using a variable transformer but I don't see how anyone expects Tesla to do that with a car FW update.�
Mar 8, 2015
wk057 I think he was referring to the fact that the car actually charged at 80A properly all the time, not actually changing the voltage input in firmware.
Considering tricking the car with the lower starting voltage actually worked... yeah, should definitely be fixable in firmware.�
Mar 8, 2015
islandbayy WK057 is correct.�
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