TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

PEM, Motor, Battery Temps - Why does the motor hold a higher temp just sitting?

Discussion in 'Roadster' started by wiztecy, Dec 10, 2012.

  1. wiztecy

    wiztecy Active Member

    Joined:
    Apr 29, 2012
    Messages:
    2,712
    Location:
    Santa Cruz, California, United States
    So I've been observing my Temps on the OVMS and trying to make an understanding of the motor temp when the car's been sitting. My Roadster has been sitting over the weekend, haven't taken it out where my SOC was at 50%. I'm charging the Roadster right now and I see the following temps:

    PEM - 38C
    Motor - 60C
    Battery - 16C
    Ambient - 28C

    The the nights have been dropping down to 7C.

    Why does the motor show such a higher temp? Is it being warmed up for some odd reason? I've been making this observation for a while and even when I'm not charging, that the motor holds a way higher than ambient temp. The motor is steel/aluminum/alloy, I'd think it be really close to ambient if it hasn't been up and running for a few days. It also sits below the PEM so no heat is rising to it.

    Any clues?
     
  2. doug

    doug Administrator / Head Moderator

    Joined:
    Nov 28, 2006
    Messages:
    15,912
    Location:
    Stanford, California
    What VIN do you have? Roadsters 1.5 use the motor has an inductor in the charging circuit. You could be seeing Joule heating in the motor coils.
     
  3. wiztecy

    wiztecy Active Member

    Joined:
    Apr 29, 2012
    Messages:
    2,712
    Location:
    Santa Cruz, California, United States
    #268 which is a 1.5 model. Thanks, makes logical sense now :)
     

Share This Page