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OVMS motor temp

Discussion in 'Roadster: Technical' started by asgard, Jan 29, 2014.

  1. asgard

    asgard Member

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    My Roadster has been sitting indoors for 10 days at Dietsch Werks waiting for a new bumper to be shipped from Tesla. OVMS temps reports my motor to be 61C. The pack is fully charged in standard mode and the car is plugged in but it barely needs to charge for 60 seconds to replenish.

    The motor is stone cold. 61C can't be right. The batter reports 22C and the PEM reports 34C and ambient is 18C.

    Is it a case of bad data coming over the CAN bus?
     
  2. qwk

    qwk Model S P2681

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    Might be a case of joyriding.
     
  3. asgard

    asgard Member

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    Lol! The mileage has not changed on the OVMS readout :)
     
  4. qwk

    qwk Model S P2681

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    :tongue: I was kidding. It's most likely just a readout error. I guess you can look at the temps in the car(when you get it back), to confirm.
     
  5. thefortunes

    thefortunes Member

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    Where do you see mileage on OVMS (or is it from an SMS)?

    Are your temps white (current) or gray (stale)? Do they change if you wake the car?
     
  6. asgard

    asgard Member

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    Everything is via SMS. Is it a staleness issue?
     
  7. Curt

    Curt Roadster Signature #55

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    How do you get temperatures via SMS? I've only been able to see them through the phone app.
     
  8. asgard

    asgard Member

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    Update to the latest rev of OVMS. Then send the SMS command Temps?
     
  9. thefortunes

    thefortunes Member

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    Since I have the app, I only use SMS when I need to change or activate ACC parameters. In the app, you may have to 'wake-up' the car to get live temps.

    Maybe someone else can chime in regarding temps via SMS - I would assume that they would be updated nightly when the car wakes up to charge, but maybe not?
     
  10. Curt

    Curt Roadster Signature #55

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    Thanks! I didn't know about that new command.

    It works, but this looks troubling...

    Temperatures:
    Ambient: 4C
    PEM: 18C
    Motor: 0C
    Battery: 252C

    Should I be looking for smoke and flames from my trunk? :confused:
     
  11. markwj

    markwj Moderator, Asia Pacific

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    Most likely the temperatures are stale, as the car has gone to sleep. To reduce vampire load, the Tesla Roadster turns off the temperature monitoring subsystems when the car goes to sleep. On the Apps you see this as the temperature appears gray (for stale, sleeping) or bright white (for live, awake).

    If this is the case, the SMS reply you got back to the TEMPS command should have the word "(stale)" shown. Like:

    Code:
    Temperatures:
      Ambient: xxC
      PEM: xxC
      Motor: xxC
      Battery: xxC
      (stale)
    - - - Updated - - -

    Curt,

    That is bizarre. It looks like a signed vs unsigned problem, but I've never seen a negative battery temperature.

    Can you send me a PM (or eMail if you have mine) with the date/time you saw this, and your vehicle ID? I want to have a look at the logs.

    P.S. Actually 252C is not too bad. We originally stored battery temperature in a signed char (-128 ... +127 celcius), but had to change to signed integer (-32768 ... +32767 celcius) when we added support for the Think City vehicle. One version of that vehicle uses a Molten Salt battery that operates at 245 celcius (http://en.wikipedia.org/wiki/Molten_salt_battery). You actually have to heat it up, to melt the core, before you can drive it.

    P.P.S. Molten Salt Batteries should not be confused with Molten Salt Reactors (http://en.wikipedia.org/wiki/Molten_salt_reactor). Those operate at up to 1000 celcius, so could conceivably be monitored by OVMS (although you probably wouldn't want one in the back of your car, for reasons other than temperature) ;-)
     
  12. asgard

    asgard Member

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    Mark,
    None of the SMS responses have (stale) in them. However, the temps have not changed in 20 hours so they must be stale...
     
  13. markwj

    markwj Moderator, Asia Pacific

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    If your car is using the server, can you send me your vehicle id? I'll check the logs.

    P.S. If you send the car a HOMELINK command (or any of the charge commands), it will wakeup.
     
  14. asgard

    asgard Member

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    No my car is not using the server :-(. I only have SMS on my SIM. Did not want to pay ATT the $30/Mo they wanted :p.
    I did not send any charge or home link commands for the past 10 days. Just stat? And temps?
    Thanks!
     
  15. markwj

    markwj Moderator, Asia Pacific

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    Strange, I thought AT&T pay-as-you-go was <$10 a month.

    Anyway, for the temps try sending "HOMELINK 3", wait a few seconds then "TEMPS". See if that gives you live temperatures.
     
  16. asgard

    asgard Member

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    Ok that looks better!
    PEM 33C, Motor 31C, Battery 20C
     

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