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Alert 278 BSM: V_ess too high at start of precharge

Discussion in 'Roadster' started by Botbldr45, Mar 22, 2014.

  1. Botbldr45

    Botbldr45 Member

    Joined:
    Oct 11, 2011
    Messages:
    513
    Location:
    Sedona, Az
    Any clue what that means. I got it twice when I tried to initiate an extra cooldown cycle in the Tattler.
    It is followed by the annoying "Drivetrain Problem Service Required"
    Since it has only happened when I tried to force an extra Cooldown cycle from the Tattler I am puzzled.

    Any ideas?:confused:
     
  2. djp

    djp Roadster 2.0 VIN939

    Joined:
    Aug 28, 2011
    Messages:
    1,108
    Location:
    Toronto, Canada
    V_ess is the voltage level of the pack. It sounds like the Tattler is trying to force a charge when the pack voltage is already above the target SOC, which the BMS is complaining about.

    It might help to switch to Range mode, then you'd be below the target SOC.
     
  3. Botbldr45

    Botbldr45 Member

    Joined:
    Oct 11, 2011
    Messages:
    513
    Location:
    Sedona, Az
    I like that answer because it sheds some light. The SOC, however, is lower than the target set on the a tattler and the battery temp is higher than the target temp set on the Tattler. My thought is that trying to force another cool down cycle, which IS set to Range mode by default, may not be a good idea. I sent a message to one of the guys that wrote the beta2 program and hoping I will get an answer before a long drive. I did restart regular charging in standard mode a few minutes ago and all is well ....... so far.

    We are actually having a sunny 60s sort of day for a change and a nice show off drive in Annapolis is in order. Maybe if I give 992 a good wash she will feel better!!!
     

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