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

Phantom Charge Start

Discussion in 'Model S: Battery & Charging' started by scaesare, Feb 21, 2015.

  1. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,927
    Location:
    NoVA
    So.. my VisibleTesla installation just sent me an alert at 12:15am via email that my car started charging. It's not scheduled to do so at that time.

    I have VT scheduled to command my car to start charging at 2:30am:
    VTSched.jpg

    As a backup (in case my computer reboots and VT isn't running for some reason), I have the in-car schedule set to start at 3:00am. I just went out and verified that's correct.

    And yet the car is charging. I haven't driven it today, and it was down about 3% from it's normal 90% "weekend" charge level. But I don't ever recall it deciding to "top off" at a time other than when I have had scheduled.

    Odd. Has anybody else seen this?
     
  2. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    I don't use scheduled charging, but was thinking that seems like "topping off" behavior to me. I don't know, though - don't know what topping off behavior is like for those who use scheduled charging. Last night charged as expected?
     
  3. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,927
    Location:
    NoVA
    It did.

    I have VT running consistently, and I don't recall ever getting a notification of a charge-start at an unscheduled time.

    That having been said, it's unusually cold at the moment, and I didn't drive the car at all in the last 28 hours... so maybe it is top-off behavior. The charge went from 87% back to 90%, as best I can tell.
     
  4. David99

    David99 Active Member

    Joined:
    Jan 31, 2014
    Messages:
    2,048
    Location:
    Brea, Orange County
    From what I understand if the state of charge drops below a certain limit, the car will top off. I have never seen it as I drive every day. But there might be other trigger points, like temperature. Who knows.
     
  5. andrewket

    andrewket 2014 S P85DL, 2016 X P90DL (soon 100)

    Joined:
    Dec 20, 2012
    Messages:
    5,042
    What FW are you running? I installed .167 yesterday, and use scheduled charging via the car at 1am. I didn't drive yesterday (snowed in) but it did very short top-off charge at 1. But then this morning at 5:something I received an alert that the car started charging. It didn't actually charge from what I can tell, or if it did it immediately stopped since it was at the desired SOC (90%). If you're running .167, perhaps this is a bug?
     
  6. aviators99

    aviators99 Model S - R140

    Joined:
    Jan 1, 2010
    Messages:
    1,452
    Location:
    Weston, Florida, United States
    The "top-off" behavior is supposed to follow the scheduling rules, and from what I've seen it does. Could it have been the battery heating system? I believe if the battery gets too cold it will start the temperature management system, which will also have the side effect of charging the battery.
     
  7. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,748
    Location:
    Texas
    Almost certainly battery heating is the answer.
     
  8. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,927
    Location:
    NoVA
    Combining responses to several posts:


    I'm running the .115 flavor of 6.1. I went out and verified it was indeed charging.. and VT confirmed the same. It went back up to 90%.

    It certainly could have been battery heating.... I've just never seen/been notified before for that to happen. That having been said, it's been pretty cold here recently, and that's first time it's been sitting that long without being driven I think.

    I guess I should clarify that although the car had been sitting for 28 hours when the event occurred, it had only been about 14 hours since the car finished it's previous night's charge up to 90% (from ~11%). In my experience, that warms the pack up to operating temp in my garage. My garage isn't well insulated, so it was probably in the mid-to-high 30's in there yesterday... so not THAT cold. But maybe it had been sitting long enough to make the pack heater kick in.

    Although, interestingly Visible Tesla reports not only current draw from the AC source (40A max for me), but also the current in to the battery (which is 21-22A). Typically if I have other draw on the system (such as when I have cabin heating on) while charging, I'll see the battery current drop down to 14-16A as a result of the heaters drawing some power.

    I believe​ that when I looked at during the event, it showed a "full" battery current reading. So that would seem to imply that it was all charging, and no power being used for heating anywhere. I may be mistaken here however. (it was late and I was sipping on an adult beverage to keep me warm during the storm :wink:)

    I'll see if it happens again.. although it's quite a bit warmer today...
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,748
    Location:
    Texas
    The act of charging alone heats the battery, and at close to freezing temperatures that was probably all that was required.
     
  10. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,927
    Location:
    NoVA
    But the point was that it started charging at a non-scheduled time of it's own accord. The suggestions here are that because it woke up to heat the pack, it also started charging.

    Although charging the pack does indeed have the side effect of warming it, I don't think there's any evidence that the car will wake because the pack is too cold, an opt to use charging as a heating method rather than the TMS...
     
  11. SW2Fiddler

    SW2Fiddler Bannd Member

    Joined:
    Mar 19, 2014
    Messages:
    1,689
    Location:
    Houston TX
    If the Gremlins movies and Jimmy Buffett have taught us anything, it's that it's always after 3AM somewhere ;)
     
  12. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,748
    Location:
    Texas
    Probably not [no evidence], but has anyone been looking for this behaviour? My car sits outside in close to freezing weather, but I don't know if it has ever done this. I have it set to start charging at 02:30, and I suspect that on most days the battery hasn't cooled down enough to start heating. I have VT, but I never use it as every time I start it, it tells me the car is sleeping peacefully. And what you experienced may just be one of those things that needs a reboot to fix.
     
  13. scaesare

    scaesare Active Member

    Joined:
    Mar 14, 2013
    Messages:
    3,927
    Location:
    NoVA
    Good point... I'll remember the "no feeding after midnight" thing too...
     

Share This Page