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Battery coolant heater failure

Discussion in 'Model S: Battery & Charging' started by Atebit, May 17, 2015.

  1. Atebit

    Atebit Member

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    On a road trip, car kept aborting charge at Glen Allen VA SC. Then I started getting the navy triangle and "do not drive" message, as well as systems check failure. Roadside pulled logs, said indeed don't drive it. So I ended up in a rental and the car ended up flatbedded back to Raleigh the nest morning.

    Diagnosis: failed battery coolant heater. Picking it up later this morning, hopefully no more issues.
     
  2. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    Raleigh SC works on Sunday for stranded owners? Nice!
     
  3. Atebit

    Atebit Member

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    This all started Thurs evening. After we got the rental we continued our trip. Flatbed had the car in Raleigh by mid-morning Friday & it was done by Sat morning. It's waiting for me now in the parking lot. So no Sunday service there, but they make up for it by providing over-the-top service the other six days of the week.
     
  4. GoBlue88

    GoBlue88 Member

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    So this same failure happened to me on my way to Las Vegas this past Friday. I noticed some strange charging behavior before I left my house in Carlsbad in the morning - I had charged it to 90% the night before and then when I woke up Friday morning I set it to top it off for a range charge which was estimated to take 1 hour and 10 minutes. I left about 1 hour 30 minutes later with a full battery (242 RM - 85 kWh battery) but the car didn't think the charge was done. The center screen kept showing the "estimated time to completion" message with no estimated time. I hadn't seen that before on other range charges, but I had a full battery so I didn't think anything of it.

    About 2.5 hours later I pull into the Barstow supercharger with about 52 RM left. There's 2 other cars charging but nobody using 1A so I take 1B. Plug in, things are looking normal. I'm about to walk over to the gas station to get a coke when all hell breaks loose on the dash: first charging winds down to zero, then "check charge cable" warning with red light of death on the charge port ring, then "12 V battery low", then "pull over immediately, car may shut down", (even though I wasn't driving), then "systems check failure", then "car may not drive". I try unplugging and replugging the charge cable - no change. I try rebooting both screens, no change. Car refuses to be put into Drive. Oh boy. Call Tesla roadside assistance, they pull the logs, and their next words are "you need to be towed". ARRRRRGGGGHHH. Here I am at the Barstow supercharger on my way to a weekend in Vegas to meet some buddies and I have a dead car. :crying:

    This is where things brighten up. Tesla arranges for Enterprise of Barstow to pick me up at the supercharger and arranges for a flatbed to tow the car to the Costa Mesa service center, all within a matter of minutes. Within half an hour I'm headed out of Barstow in a monster GMC Yukon, having left my car at the supercharger. 30 minutes after that I get a call from the towing service saying they have my car and are headed to Costa Mesa. All of this paid for by Tesla. Name a stealership in the entire COUNTRY that would have done that for me.

    By Saturday night Costa Mesa had it fixed - the service invoice said "replaced battery coolant heater due to low isolation". Apparently the unit failed just like what happened to the OP of this thread, and now I have a new one. Stayed in Vegas until this morning and drove that behemoth Yukon to Costa Mesa, picked up my car in a matter of minutes, and headed south to Carlsbad. Gotta hand it to Tesla's first class customer service - in almost any other make with a catastrophic failure my weekend in Vegas would likely have been ruined and/or I'd still be trying to figure out how get my car fixed and back. Instead I still got my weekend in Vegas and the fix and the rental cost me nothing but about a 25-minute delay to my arrival time in Vegas, AND I already have my beloved Model S back.

    This was my first "must supercharge during the trip" trip even though I've had the car for nearly 2 years. I hope my second one lets me get to my destination in the same car I started with. :scared:
     
  5. apacheguy

    apacheguy Sig 255, VIN 320

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    Wow, I had no idea that a battery heater failure would bring down the entire car. Sure, I could imagine charging/acceleration/regen limits, but the car should still operate. It's very odd you were able to drive it from full down to 52 miles without any indication of a fault.
     
  6. GoBlue88

    GoBlue88 Member

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    According to one of the Tesla guys I talked to, starting to supercharge escalated a minor fault to a major one. A lot of heat coming in from a supercharger.
     
  7. brkaus

    brkaus Member

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  8. Kalud

    Kalud Member

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    Sorry for you misfortune, bad timing!

    The charging behavior that you describe before the event is 100% normal. While reaching near 100% the pack starts to do some balancing where is would try to balance each groups of cells to the same voltage. This takes time and its hard to estimate the time needed. The car will always show "Estimating time remaining" often for more than an hour. But you're like 99.9% full anyway so you can leave.

    I've observed that graphically multiple time. You can see in the following graph that the State of charge is 100% at the 38 minute mark but it still continues until battery current (not wall current, actual in-car charger's output) drops below 2A at the 86 min mark (1:27)

    Here's how it looks like:

    Untitled.png
     
  9. GoBlue88

    GoBlue88 Member

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    Thanks Kalud. Interesting.
     
  10. apacheguy

    apacheguy Sig 255, VIN 320

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    Right, SpC generates a lot of heat meaning the pack heater should not have been needed at all. Odd.
     
  11. GoBlue88

    GoBlue88 Member

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    I thought the coolant "heater" also cooled the coolant if necessary, but admittedly I have limited technical knowledge as to how all this works.
     
  12. Kalud

    Kalud Member

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    They are two different units, a resistive heater and an AC Chiller.
     
  13. GoBlue88

    GoBlue88 Member

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    Huh. So then apacheguy has an interesting question: why would a coolant heater failure during supercharging trigger a total shutdown?

    Here's the diagnosis from my invoice:

     
  14. Kalud

    Kalud Member

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    The HV Battery heater is using the high voltage of the battery as power source (400V approx) and for some reason it had an isolation issue (current leakage perhaps or something like that). The battery systems detected the condition and opened the contactor to protect everything, leading to multiple faults (and eventually 12V low battery as its no longer supported by the DCDC converter, from HV source)
     
  15. apacheguy

    apacheguy Sig 255, VIN 320

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    Ah, interesting. So hypothetically it could have been a short in the heater electronics causing it to draw all this current which wasn't accounted for. BMS panicks and opens the contactors. Wonder why these heaters have been shorting out.
     
  16. GoBlue88

    GoBlue88 Member

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    Yeah, would be interesting to know what the rate is for this particular fault. I didn't find many reports of this on a quick TMC search and hadn't heard of it before I experienced it.
     
  17. GoBlue88

    GoBlue88 Member

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    2nd attempt at a "must supercharge to reach destination" trip completed successfully. Drove from Carlsbad to Scottsdale and back last week for a golf trip, with Supercharger stops in Yuma, Buckeye, Quartzite, and Indio round trip. No issues, and it was a great drive.
     

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