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Charging Aborted Unexpectedly

Discussion in 'Model S: Battery & Charging' started by SteveS0353, May 13, 2015.

  1. SteveS0353

    SteveS0353 Member

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    This has happened a couple of times to me, and I think I've finally figured out the mitigation, so I thought I'd share for others who might experience it.

    My Model S is programmed to begin charging at 12:15 am to take advantage of TOU rates. A couple of times now, I've gone out to the car in the morning and it has not charged, and the only message on the screen was "Charging Stopped". The LED ring around the charge port was steady blue, indicating that power is available, but the car is not charging. If I unplug the charge handle and reengage it, the car will charge normally. I have an HPWC on a 60A breaker, with the HPWC is set to deliver 48A. The wiring on the charging circuit is sized appropriately, and when the car is charging at the full 48A, the car reports the voltage at 243-245V.

    Luckily, every time, I've had enough range for the day. The first time this happened, I took the car to the Service Center, and it happened there too. The SC pulled the logs, and the evaluation of the logs was inconclusive, but from past experience, they determined that the female pins on my charging handle had "loosened" and the pilot circuit connection between the HPWC and the car was intermittent. They sent out a crew and changed my HPWC cable for a new one.

    A few days later, it happened again - exact same symptoms and outcome. From my electrical engineering background, I agreed this looked for all the world like an intermittent connection. I procured some electrical contact cleaner, and with a cotton swab, cleaned out the charge port in the car, and the sockets in the charging handle. The cotton swab came out black, with gobs of grease and other foreign matter. The car charged normally the next few nights, but I had an appointment at the SC to investigate, so back I went. They pulled the logs again for the most recent incident, and determined that the on-board charger had lost the pilot signal as the charge session was beginning and had aborted the session. Under those circumstances, the charging session will not restart. The only way to restart it is to disconnect and reconnect. The SC technician agreed that cleaning the charge port pins had been the solution, but they proactively installed a new charge port.

    Moral of the story, keep the connections clean! This will now be part of my wash routine every month or so. There are several good electrical contact cleaners available which leave no residue but will help remove any impediment to a good electrical connection.
     
  2. wycolo

    wycolo Active Member

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    Tesla should test and recommend specific brands to use. I imagine WD-40 to be good here for use with Q-tips but let it dry thoroughly before connecting the charger as the fluid is flammable. Also good idea to peer into SpC plugs and wipe off the outer area with your hand before insertion. You never know what might have gotten in there!
    --
     
  3. JohnSnowNW

    JohnSnowNW Active Member

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    WD40 is hygroscopic...so I'm not sure that's the best thing to use.
     
  4. Lloyd

    Lloyd Active Member

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    WD-40 makes a contact cleaner. No residue.

    wd-40-specialist-11-oz-electrical-contact-cleaner-spray-6-case.jpg
     
  5. SteveS0353

    SteveS0353 Member

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    Thats the stuff!
     
  6. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    I used to have better stuff, left over from the CFC days... :)

    Use cotton swabs to gently remove the material, never use abrasives.
     
  7. mknox

    mknox Well-Known Member

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    I have had similar problems and considered the same solution. But I decided to ask my Service Center folks first, to be sure. They were adamant that under no circumstances should I use any type of contact cleaner and recommended that I only use a can of that compressed air stuff that you can buy for cleaning keyboards and electronic equipment. I tried that with limited success. If I wiped gently with a dry Q-tip, it would come out pretty dark and dirty. In the end, they replaced my UMC (for the second time - same problem) due to the loose connection and failure to charge.
     
  8. SteveS0353

    SteveS0353 Member

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    I specifically asked about the contact cleaner (no residue type, not plain WD-40), and they had no objections. This is another a example, I guess, of different SCs giving different advice. As long as the cleaner is inert to the plastics, I can't see a problem. To be clear, I didn't spray the stuff into the charge port, I sprayed it onto the Q-Tip and used that to wipe the pins in the charge port.
     
  9. Barry

    Barry Member

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    Steve,
    Have you put a voltmeter across the charging contacts on the car-end to make sure it's not hot (380+VDC) and safe to do what you did? I would hope that Tesla put diodes inline, but considering the current flowing when using a Supercharger, those would be pretty hefty diodes.
     
  10. thimel

    thimel Member

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    Barry,
    Tesla does much better than putting in a diode to protect people touching the contacts. They put in a contactor. The battery is not electrically connected to those contacts until a handshake between the car and the supercharger has been completed.
     
  11. islandbayy

    islandbayy Active Member

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    #11 islandbayy, May 13, 2015
    Last edited by a moderator: Mar 13, 2016
    Cleaning the charging port and handle pins and contacts does help immensely!
    After doing some experimenting, I've found that after a long time of not cleaning the pins and ports with a cotton swap, and then doing it, will yield a instant 1-2volt gain under full charge load, as resistance is reduced. Also notice that heating of the charge port seems to drop significantly at superchargers too. I am going to try cleaning some supercharger handles next time, see how bad they are.

    My results:
     
  12. SteveS0353

    SteveS0353 Member

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    I did not, and I don't believe there are humungous diodes to isolate the contacts. That would be a waste of power. However, there are two reasons I felt safe...

    1. The charging architecture of the Model S is such that the charging contacts are closed by the low-voltage (12V) electronics only after the handshake with the charger (UMC, HPWC or Supercharger) through the LV pilot circuit is complete and the car has verified that a charging cable is inserted, locked and the car knows what AC or DC the charger can provide. Only then will the car close the charging contacts. Similarly, the female contacts in the charging handle are isolated by a 2-pole HV contactor in the charger, and are not "hot" until the pilot circuit handshake is complete and successful. You can hear the contacts closing when the car begins to charge.
    2. There are multiple international safety standards that specify that hot electrical contacts can't be touched by "a standard finger". If the HV contacts in the charge port were "hot" without a cable inserted, there would be no way to get a finger in there to touch them.
     
  13. Barry

    Barry Member

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    Good explanation. Thanks!
     
  14. Moonwick

    Moonwick Member

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    All that being said, it's probably still not a bad idea to probe the charge ports with a multimeter before getting started. Better safe than sorry!
     

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