During the day when my solar is generating, car pulls 79A @ 241v. In the evening when there is no solar activity, car pulls 79A @ 235v. When I charge in the evening, the 0A voltage starts at 245v but drops to 235v when it hits 79A. Fluctuation at 79A while charging is +/- 1v. My car has not reduced power after 5.8.4.
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Cottonwood
Roadster#433, Model S#S37
Because the Public Pagosa J1772 that I put in is on an old pole transformer with a long, relatively small gauge wire feeding the house with some pretty good Voltage drops (most on the utility side of the meter), I am concerned about resistance triggers.
To do a test, I pulled out all of the heavy duty extension cords, adapters, etc, that I have in my kit from owning Tesla cars for 5 years. I put all of them that I could, in series with the 14-50 outlet in my garage and plugged in the UMC with its 14-50 adapter. The 0 current Voltage was 246 and it drooped to 232 Volts with a 40 Amp current. I was pretty full on the battery SoC, but was able to let this charge continue for 20 minutes with no reduction in charge rate. This is a resistance of 14V/ 40A or 0.35 Ohms. See Wiki American Wire Gauge; that is equivalent to about 275 feet of #8, Cu extension cord. The other way to look at this is between the transformer feeding my house and the car, there was 14*40 or 560 Watts being dissipated.
It seems the current reduction mechanism must be pretty tolerant of simple resistance. I wonder what the trigger is...maybe loose, intermittent connections?
To do a test, I pulled out all of the heavy duty extension cords, adapters, etc, that I have in my kit from owning Tesla cars for 5 years. I put all of them that I could, in series with the 14-50 outlet in my garage and plugged in the UMC with its 14-50 adapter. The 0 current Voltage was 246 and it drooped to 232 Volts with a 40 Amp current. I was pretty full on the battery SoC, but was able to let this charge continue for 20 minutes with no reduction in charge rate. This is a resistance of 14V/ 40A or 0.35 Ohms. See Wiki American Wire Gauge; that is equivalent to about 275 feet of #8, Cu extension cord. The other way to look at this is between the transformer feeding my house and the car, there was 14*40 or 560 Watts being dissipated.
It seems the current reduction mechanism must be pretty tolerant of simple resistance. I wonder what the trigger is...maybe loose, intermittent connections?
wcalvin
Member
Just guessing but I presume that what they want to detect is not voltage swings but source resistance increasing (that is what will cause overheating at some upstream junction). Detecting source resistance changes is simple: when voltage at the charger is varying, does the input current vary in unchanged proportion? It is Wheatstone Bridge type of problem.
Whoops... just got a false detection. Have to change my vote! Dropped into our office and am charging on our 208V 70A charge station. I guess the voltage got a little low (usually in the mid 190's at full power) because it dropped to 50A. Grrr... the entire electrical system of the building is only a year old. There's absolutely nothing wrong with it. This was caused by having 3 phase power source.
dirkhh
Middle-aged Member
I played around with this a bit. Sat in the car and manually changed the charge limit down to 20A and then up to 40A. Plugged in again. Charged fine at 40A.
When I came back home in the evening I simply plugged the car in without anything and it again charged at 40A.
I'll keep observing the behavior...
When I came back home in the evening I simply plugged the car in without anything and it again charged at 40A.
I'll keep observing the behavior...
Dirkhh,
I'm trying to picture what you are seeing better. When you say the voltage varies between 237V and 241V, do you mean when you start charging (no load) the voltage is 241 and then under full load (40A), it drops to 237V, or do you mean that during charging you watch the voltage fluctuate between 241V and 237V?
Peter
I'm trying to picture what you are seeing better. When you say the voltage varies between 237V and 241V, do you mean when you start charging (no load) the voltage is 241 and then under full load (40A), it drops to 237V, or do you mean that during charging you watch the voltage fluctuate between 241V and 237V?
Peter
dirkhh
Middle-aged Member
Under no load it shows 247-249V. As the current increases voltage drops to about 240V. And while charging it varies between 237V and 241V
What is the period on the oscillation between 237V and 241V?
The S should appear to the power grid as a constant and almost entirely resistive load (provided there isn't an issue in the S itself). You shouldn't be seeing any real oscillations on the voltage. When my car charges anywhere from 40-80A my voltage is constant and only varies slightly (by a couple of volts) over a period of 10's of minutes as the wires warm up slightly.
Peter
The S should appear to the power grid as a constant and almost entirely resistive load (provided there isn't an issue in the S itself). You shouldn't be seeing any real oscillations on the voltage. When my car charges anywhere from 40-80A my voltage is constant and only varies slightly (by a couple of volts) over a period of 10's of minutes as the wires warm up slightly.
Peter
dirkhh
Middle-aged Member
I see fairly random and frequent "oscillation" up and down one volt. So it will switch between 239 and 240 every few seconds - which to me seemed to be nothing more than measuring errors. Next time I charge it may be 238/239. But it never varies by more than a couple of volts during any 30 minute stretch. I see the same on the supercharger. The voltage is never constant. It always goes up and down - and on the supercharger it tends to go up and down by 2 or 3V.
rbergquist
S946 - VIN 1017 & M3 2327
Warning tripped and reduced charge to 30A and then it shut it off. Called Tesla service & they reviewed logs. Turned out to be the UMC cable had heat damage. Tesla provided replacement.
I also had the warning trip and reduced charge to 30A. Tesla reviewed the logs and states that they are observing voltage spikes. I took my UMC and vehicle to the service center and everything tested out OK and they suggested I call an electrician to check the house side. Charged when I returned home today and haven't received any errors yet. Charge completed at 40A.
Now here's an interesting result. A friend of mine is currently charging on a 208V, 70A charger. He reports that twice now it's backed off from 70A to 51A, but after a while "recovered" back to 70A again. That is without any manual intervention whatsoever.
My charging was dropping from 30 amps to 40 at home on the 14-50 with UMC and giving the charging error. I emailed Tesla about this and they tracked the logs for awhile. They replaced the onboard master charger today which seemed to resolve the issue as of the charge I did today.
Tech said that they logs showed it constantly ramped down to 30 amps after one hour of charging, but also showed some odd current ramping down in logs prior to the software change. They figured something has wrong in the charger and the new firmware found it. I had already tested my wiring and no issues were there, so glad to see a legitimate issue show up.
The tech said they have been getting many calls about this, mostly from people who regularly use extension cords. I guess that in the past it would warn about a high connection cable impedance but now will shut it down under that condition.
The techs and engineers at Tesla are monitoring this closely to refine the algorithm, so let them know if you having problems. They can track and read all of these logs remotely, if you flag it to them as an issue. They do not routinely poll these records from the car though, nor does the car send any error message to the mothership for a charging cable issue.
Tech said that they logs showed it constantly ramped down to 30 amps after one hour of charging, but also showed some odd current ramping down in logs prior to the software change. They figured something has wrong in the charger and the new firmware found it. I had already tested my wiring and no issues were there, so glad to see a legitimate issue show up.
The tech said they have been getting many calls about this, mostly from people who regularly use extension cords. I guess that in the past it would warn about a high connection cable impedance but now will shut it down under that condition.
The techs and engineers at Tesla are monitoring this closely to refine the algorithm, so let them know if you having problems. They can track and read all of these logs remotely, if you flag it to them as an issue. They do not routinely poll these records from the car though, nor does the car send any error message to the mothership for a charging cable issue.
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islandbayy
Active Member
The way it sounds, it is much to sensitive. I'd like to see what specifically they are measuring for.
I for one am NOT updating to 5.8.4 until this is worked out. If I HAD my choice (Service center updated me without telling) I'd still be on 4.5 as I have had constant trouble on 5.6 and 5.8 flavors.
At home, I can charge no problem at 40 amps. I have a 60ft run from my breaker box to my outside charge on my garage. Starting Voltage is 242 usually. And when charging at 40 amps, I drop down to about 230-232v. I have 200 amp service to my home. When I flip on the cloths dryer, voltage drops about 2v to my car. so 228-230v. When Air Conditioner kicks in, Voltage drops to about 215-217. Nothing wrong with my service, everything is proper. Part of the problem, I'm on a under-sized transformer and at the end of the string of 15 houses being fed by that transformer.
Given the fluctuations, I most certainly would get limited charging speeds, if not cancelled charging all together! This would be un-acceptable, given I need at least 120-150 miles/day range, and I have a 60kW battery, so not much room for error. A Simple toggle on the settings menu would resolve the problem. It would allow people to turn the feature on to see if their is a problem. If their is constant cut-outs, and it has been deemed OK by a electrician or power co etc... or in my case, known fluctuations due to under sized transformer (2012, the hottest summer in around 50-60 years in Milwaukee County, we saw voltages drop as low as 200-210 under the load!!!) it can then be turned off. Or in other words, turned off due to "nuisance tripping".
I for one am NOT updating to 5.8.4 until this is worked out. If I HAD my choice (Service center updated me without telling) I'd still be on 4.5 as I have had constant trouble on 5.6 and 5.8 flavors.
At home, I can charge no problem at 40 amps. I have a 60ft run from my breaker box to my outside charge on my garage. Starting Voltage is 242 usually. And when charging at 40 amps, I drop down to about 230-232v. I have 200 amp service to my home. When I flip on the cloths dryer, voltage drops about 2v to my car. so 228-230v. When Air Conditioner kicks in, Voltage drops to about 215-217. Nothing wrong with my service, everything is proper. Part of the problem, I'm on a under-sized transformer and at the end of the string of 15 houses being fed by that transformer.
Given the fluctuations, I most certainly would get limited charging speeds, if not cancelled charging all together! This would be un-acceptable, given I need at least 120-150 miles/day range, and I have a 60kW battery, so not much room for error. A Simple toggle on the settings menu would resolve the problem. It would allow people to turn the feature on to see if their is a problem. If their is constant cut-outs, and it has been deemed OK by a electrician or power co etc... or in my case, known fluctuations due to under sized transformer (2012, the hottest summer in around 50-60 years in Milwaukee County, we saw voltages drop as low as 200-210 under the load!!!) it can then be turned off. Or in other words, turned off due to "nuisance tripping".
NigelM
Recovering Member
I'm assuming there is a screen alert when you return to the car (IIRC someone mentioned it in one of the threads), but did anyone post a photo?
I guess many folks are like me: I plug in every evening but the car is set to charge at 3.00am and most days it would be fully charged (even if it dialed back) before anyone gets in it anyway. I wouldn't know it had dialed back if there's no screen report....
I guess many folks are like me: I plug in every evening but the car is set to charge at 3.00am and most days it would be fully charged (even if it dialed back) before anyone gets in it anyway. I wouldn't know it had dialed back if there's no screen report....
InTheShadows
Active Member
There is a possibility this is caused by a transformer running at its max. Cold weather can really tax them especially if the utility is running them at max with multiple homes with electric heat.
The power outage could easily cause a strain on the transformer with everyone's heat, freezers, refrigerators, etc. all coming on at the same time and working for hours to warm the houses back up.
This is a typical charging scenario measured when charging via my J1772 the day after Christmas. I'm measuring the current and voltage at the wall. See also http://www.teslamotorsclub.com/show...uring-the-Total-Energy-Consumption-of-Your-EV
(Axes are scaled so that the swings are more visible.) Total voltage swing during the charge is about 0.7% of the nominal voltage and current swing is about 0.3% of my nominal 30A charging current. The voltage drop during the charge is about 1.5%. I haven't had any current reductions with this level of "noise" in the charging supply.
(Axes are scaled so that the swings are more visible.) Total voltage swing during the charge is about 0.7% of the nominal voltage and current swing is about 0.3% of my nominal 30A charging current. The voltage drop during the charge is about 1.5%. I haven't had any current reductions with this level of "noise" in the charging supply.
I'm limited to 30A at home on a 14-50, but I didn't really pay attention before the new update. my UMC is on a 14-50 in my garage that shares a 125A circuit with my Clipper Creek CS 100 (80A) at the end of my driveway. I still get the typical 79 A on the clipper creek. I did attempt to charge at a chargepoint at a local store a few days back and had it dropp way down, with the warning that I was either using an extension cord or there was a faulty wiring.
At first, this kind of irked me, feeling like Tesla rushed to release the new software but the J1772 was 2+ years old and didn't really plug in all that well. After having some time to think about it, I think this is a good thing. It's hard to admit some times that we are still at the beginning, that in many respects the mass adoption of this technology is still in it's infancy. I've had a shift in my thinking a bit and now feel positive that Tesla is zeroing in on finding a sophisticated way for the car to prevent overheating, whether it be from a faulty UMC or some other bad connection and this is a very good thing. The road to EV adoption is going to be a bumpy road but I suspect Tesla will nail it with some time, making a significant advancement in risk management that will likely benefit the whole industry. Few things in our home draw large amounts of current for long periods of time without being hard wired, it would not surprise me if the standard for EV charging needs to be beefed up a bit to account for the new variants we are introducing into home usage. I would suggest that everyone try and take a deep breath and simultaneously be prompt in alerting Tesla to any issues you come across while at the same time keeping a positive attitude, knowing you are helping to advance one of the biggest shifts in transportation technology in history!
At first, this kind of irked me, feeling like Tesla rushed to release the new software but the J1772 was 2+ years old and didn't really plug in all that well. After having some time to think about it, I think this is a good thing. It's hard to admit some times that we are still at the beginning, that in many respects the mass adoption of this technology is still in it's infancy. I've had a shift in my thinking a bit and now feel positive that Tesla is zeroing in on finding a sophisticated way for the car to prevent overheating, whether it be from a faulty UMC or some other bad connection and this is a very good thing. The road to EV adoption is going to be a bumpy road but I suspect Tesla will nail it with some time, making a significant advancement in risk management that will likely benefit the whole industry. Few things in our home draw large amounts of current for long periods of time without being hard wired, it would not surprise me if the standard for EV charging needs to be beefed up a bit to account for the new variants we are introducing into home usage. I would suggest that everyone try and take a deep breath and simultaneously be prompt in alerting Tesla to any issues you come across while at the same time keeping a positive attitude, knowing you are helping to advance one of the biggest shifts in transportation technology in history!
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