Thermal Management Fan Turns Off When Plugging In

Discussion in 'Clarity' started by Steven B, Oct 3, 2019.

  1. Steven B

    Steven B Active Member

    Has anyone else noticed this:
    When I arrive home after driving on battery and turn off the vehicle, the thermal management fan (one of the large ones in the front) sometimes continues to run. I understand that this is normal behavior if the system decides the coolant needs to be cooled down.
    What I do not think is appropriate is that as soon as I plug in, the fan stops. Every. Time. At first I thought it was just coincidence but too many times now. What possible explanation could the engineers have for not permitting the TMS fan to run while the car was plugged in? Since I have the vehicle on a charge schedule, it isn't even starting to charge immediately when plugged in.
  2. KentuckyKen

    KentuckyKen Well-Known Member

    Uh oh, call the exterminator, I sense another software bug. It will be interesting if others have noticed this.

    With ambient temps up to the high 90s and garage temps up to mid 80s, I have yet to hear the radiator fans run after turning the car off. And only once have I heard a gurgling kind of noise from the rear of the car. Also, the 3 times this summer I charged mid day after driving ~35 miles in EV, I didn’t hear the fans either.
  3. Andrew97

    Andrew97 Member

    That's strange my fans never operated after i turned off the car. You should check it out with Honda or search deeper in the forum.
  4. leop

    leop Member

    I charge with a 16 amp, 120V charger. The coolant pumps come on quite often when charging during the late Spring, Summer, and early Fall (just south on Indianapolis). The front fans come on sometimes when charging during the summer months. The Clarity is in an attached garage (unheated).

  5. Mowcowbell

    Mowcowbell Active Member

    That's exactly my experience. I've pulled into my garage in 100F temps, and the fans shut off the moment I pressed the On/Off button on the vehicle. I typically charge with a Level 2 16amp EVSE, and never hear any fan noises while charging, no matter the temperature in my garage.
  6. fotomoto

    fotomoto Active Member

    Energi's do the same thing (except it's the internal fan for the air-cooled battery) . A few owners leave the car ON till plugging in and then the fan continues to run. This workaround doesn't work for me as I have TOU charging that starts many hours later and the battery has cooled by then anyways.

  7. 4sallypat

    4sallypat Active Member

    In the heat where I live, the fan always turns on about 5 minutes after I plug her in (L1).
    The fan seems to take the charge time longer. Used to charge in 6 hours, but with the heat and fan on, it takes 8+ hours for the same daily.
  8. KentuckyKen

    KentuckyKen Well-Known Member

    Another of many reasons why I have great faith that Honda engineered the BMS to protect our batteries to the extent that I don’t have to worry much about babying the battery to the point that it’s time consuming or inconvenient to do so.
    MPower likes this.
  9. Hoon

    Hoon Member

    The longer time may be related to the higher capacity during warmer temperature than from the fan running.
    I also remember hearing the fan running while charging.

    I use the OEM EVSE on 240V with an adapter in between. It charges about 18%/hour. I usually time it with 20%/hour in my mind and remotely turn off the charging as I'm fine with 70-80% battery for daily commute. Being plugged in, I turn on the remote climate control in the morning 10 minutes before I head out.
  10. insightman

    insightman Well-Known Member

    I can hear the fan running after I return home on a hot day and plug into my 48-amp ClipperCreek EVSE.
  11. Claire Green

    Claire Green Member

    after owning my Clarity for almost a year, I have learned that the car is way smarter than me with all it's computers and black boxes so I've learned to trust the car to do what is best for it. But like you I too am curious why it would stop the fan when clearly it is needed or else it will not be running when you turn "ignition" off. Only possibility/explanation I can come up with is to save the 12v battery since turning off "ignition" stops the traction battery from charging the 12v battery under the hood and I assume the cooling fans use up a lot of amps.
  12. Kerbe

    Kerbe Active Member

    I will sometimes hear a fan come on while charging (especially when the temp is close to 100F) using a 30A EVSE. I've also noticed that they will come on when using a public EVSE on a hot day, as well, but they've not yet run on their own when the vehicle is powered-down and unplugged.

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