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My HPWC almost melted down!!!

Discussion in 'Model S: Battery & Charging' started by DoctorJJ, Jun 19, 2015.

  1. DoctorJJ

    DoctorJJ Member

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    I got a notification that my charging was interrupted on my P85D this evening. It has been working flawlessly since December, when I received the car. I walked out to the garage and noticed that the charger was not green. I checked the breaker. It was not tripped. I went over to the HPWC to hit reset and could feel the heat coming off of it. I went back and flipped off the breaker, disconnected it from the car, grabbed my FLIR I7 and pulled the cover. The highest reading I saw was 441 degrees Fahrenheit!!! Check out the pictures below. The wire that is hot, look down below the hot spot and see the cooler area where it looks like the wiring gets fatter. That is where part of the insulation melted to and sagged down creating a thicker area of insulation. Up toward the top of that wire, where it hooks in, the insulation is almost completely melted off. I have a pic of the cord where it plugs into the car for comparison. The 112 it registers feels pretty warm when you grab it to unhook. The 441 degrees is just crazy! Glad it didn't burn down my house!!

    image.jpg

    image.jpg

    image.jpg
     
  2. FlasherZ

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

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    Definitely a good thing, and a reminder why occasionally it's a good idea to check the torque on wiring connections, especially for high-current loads.

    I'm guessing the cable's connection wasn't torqued as tightly as it needed to be. I'm assuming this is the original cable. Let your service center know and they'll come replace it, ensuring the torque is proper.
     
  3. DoctorJJ

    DoctorJJ Member

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    It was the original cable. It had never been touched. I did check it with a wrench and it was tight. The hottest point on the FLIR was right at the crimp on that cable. I suspect it wasn't crimped properly.
     
  4. m6bigdog

    m6bigdog Member

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    #4 m6bigdog, Jun 20, 2015
    Last edited: Jun 20, 2015
    Definitely not good...
    Yours is not the only HPWC showing high temps on a FLIR.
    http://www.teslamotorsclub.com/showthread.php/32704-HPWC-IR-Pics-(more-fun!)


    I anticipate you were using the HPWC at 80 amps?
    FYI, Reducing the charge current significantly reduces the internal power dissipation.
    The heating factor is the square of the charge current so at 56 amps the heating would be reduced by 50%.

    While others disagree, I recommend decreasing the charge current if the maximum 80 amp charge rate is not necessary, as is the case for overnight charging; as that will reduce the heating and most likely prolong the life of your HPWC.
    http://www.teslamotorsclub.com/showthread.php/48097-HPWC-Reliability-an-Overnight-Charging-Strategy


    Please give us an update on the replacement unit with FLIR images if possible; for the record.
     
  5. S4WRXTTCS

    S4WRXTTCS Active Member

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    Thanks for the reminder to image my HPWC with a FLIR camera when it's new to compare against what the thermal image is down the road.
     
  6. LJordan

    LJordan Member

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    Just curious... What rate were you charging at and what size is the breaker?
     
  7. smilepak

    smilepak Member

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    Hmmm seems to be a lot of issues with hpwc
     
  8. wk057

    wk057 Senior Tinkerer

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    Looks like that's the wire from the two wire junction that is after the connection to the charging cable. So, even replacing the charging cable wouldn't have caused this.

    I'm surprised this wasn't caught when the charger was first installed...
     
  9. tinm

    tinm 2013 S85 Owner

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    DoctorJJ, is your HPWC running at 80amps? 40?
     
  10. m6bigdog

    m6bigdog Member

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    I anticipate the HPWC performed normally or at least was not that abnormal when it was new.

    It is with repeated heating & cooling (expansion & contraction) of the copper wire in the crimp/solder lugs and screw type wire terminals that cause the connection to fatigue, loosen; which makes the wiring connection generate even more heat until the connection fails all together.

    I have know idea if the HPWC has an internal thermal cutoff(would be nice), however with that much heat in the enclosure it is possible the unit shut down because one of the internal fuses elements melted; as they have a thermal characteristic that makes them subject to environmental heating as well as the heat generated from the current flowing through the fuse element itself.
     
  11. kennybobby

    kennybobby Member

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    #11 kennybobby, Jun 21, 2015
    Last edited: Jun 21, 2015
    Buy a lotto ticket

    Your luck is good right now. Glad that the system shut down the charging session.

    So you think that the crimp under the heat shrink sleeve loosened over time?

    hpwc_terminals.jpg

    hpwc_terminals1.jpg
     
  12. Chris1howell

    Chris1howell Member

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    This is an area af great interest in the Open Source EVSE community. We are doing a lot of research it temprature monotoring and throtteling. We have implemented several temprature thresholds to reduce current by 25%/50%/75% then shutdown if temps continue to rise.

    Here is an image of temps during a 40A charge session.

    Untitled.png
     
  13. scottm

    scottm Active Member

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    How about installing a fan in or nearby the charger and just switch it on while charging?
     
  14. Chris1howell

    Chris1howell Member

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    Normal heating (like shown in the graph) is okay, it is the run away heating that is very dangerous. The goal with OpenEVSE testing is to find reasonable set points to reduce current (and heat) when tempratures get to component ratings to ensure no instability.

    An event like the OP had with 400F+ temps would be caught early as the enclosure ambient temprature would rise significantly triggering the critical set point and shutting down.

    A fan in the enclosure would be of little help to reach 400F+ the resistance would be generating 100s of watts of heat. The best solition is to notify the user and fix the issue.
     
  15. Dbitter1

    Dbitter1 Journeyman Member

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    The number of people in this forum that just happen to have a FLIR lying around blows my mind. Are you all professional electricians on commercial switchboard equipment?
     
  16. brucet999

    brucet999 Active Member

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    I guess I'm just stupid, but I cannot make anything out of your three graphs of what is supposed to be of temps during a 40A charge.

    Graph one goes instantly up to 42,000 somethings then drops instantly to zero. I don't think that's temperature; high even for Kelvin. Milliamps?
    Graph two starts at 40 units and climbs to 60 units. I guess that could be ºC, equivalent to 104 to 140ºF
    Graph three starts at 30.2 and steps erratically down ultimately to 29.7. Definitely not temperature; too high for watts; amps?
     
  17. EarlyAdopter

    EarlyAdopter Active Member

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    Just a tech gadget geek here. You can pick up a FLIR for under $1000 now. Just a few years ago they were $5000+. That has widened ownership considerably.
     
  18. FlasherZ

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

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    I have the Seek Thermal device for my phone. Cheap man's FLiR @ $199. :)

    Definitely not as good as the real thing, but it finds the heating / cooling leaks just fine and measures the temps reasonably well. I use it to find where the honeybee clusters are located within the hives in winter. Random factoid: at temperatures below ~55 deg F, honeybees gather tightly into a cluster that maintains a 93 deg F internal core, so it's easy to see where they are in the hive just by taking a thermal pic from the outside. :)
     
  19. Chris1howell

    Chris1howell Member

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    Graph 1 is current in milliamps
    Graph 2 is EVSE internal temprature in C
    Graph 3 is the ambient temprature in my Garage in C (fluctuation is sampeling noise)
     
  20. EchoDelta

    EchoDelta Member

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    I got a FLIR One - http://www.flir.com/flirone/ - before I used to rent one at Home Depot twice a year, for energy efficiency projects, but this has been fantastic.
     

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