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Warming up the battery before driving in winter conditions

Discussion in 'Canada' started by AndrewKo, Jan 14, 2015.

  1. AndrewKo

    AndrewKo Member

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    Hey guys,

    In the cold winter, do you guys warm up the battery for a couple of mins before driving? I tend to turn on the heat from my phone but i'm not sure if thats considered warming up the battery or not?

    What do you guys do (if anything)?
     
  2. iKhalid

    iKhalid Member

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    Yes, in 30 minutes before in my case. It warms up the battery as well when the heater is on. It takes the energy from the wall instead of the battery, and you will be more comfortable in a heated cabin, of course.
     
  3. Doug_G

    Doug_G Lead Moderator

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    It isn't necessary; the car will drive just fine. The only thing is you may have no regenerative braking and the power might be limited (although it's not like you can floor the pedal in super cold conditions anyway - the wheels will spin).

    More to the point, heating the battery up takes a lot of power. If you're plugged into AC then I would definitely preheat for half an hour, as this will reduce battery cycles. If you're not plugged into AC then the only benefit really is comfort. It take more battery power to preheat if you're not plugged in.
     
  4. RAM_Eh

    RAM_Eh Member

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    You should overnight charge as close as possible to you leaving in the morning. In my case I have it set at 4AM. The battery is still warm when I leave between 7 and 8 AM.

    Charging and driving are the only way to warm up the battery. if that is what your asking.
     
  5. mnx

    mnx 2013 P85

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    Is it actually bypassing the battery and feeding power to the HVAC etc. directly? Or is charging the battery from 89.9% -> 90% repeatedly much better for it than charging it from 70-90%?
     
  6. Doug_G

    Doug_G Lead Moderator

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    You can't charge and discharge a battery simultaneously. Even with the batteries connected to the circuit the power is going directly into the heaters.
     
  7. mnx

    mnx 2013 P85

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    :redface: Thanks Doug! I guess I should have done a quick search before asking a dumb question.
     
  8. wayner

    wayner Active Member

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    Or having it in a warm enviornment. My garage generally stays above 0 - the last couple of days of extreme cold my car has been about 3C when I turn on the climate about 10-15 minutes before leaving. Would I still benefit heating the car 30 minutes ahead of time when I am starting at 3-7C? I am plugged into my HPWC at this time.
     
  9. EdA

    EdA Model S P-2540

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    I HATE having no regen, when home and it is below 25F I generally increase the charge limit and start the heater about 10 minutes before leaving. I don't always remember. At my office its a different story, using the heater to heat the cabin doesn't help with warming the battery (I haven't tried multiple cycles of heating the cabin).
     
  10. Doug_G

    Doug_G Lead Moderator

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    I wanted to write a more comprehensive answer, so here we go. There are four possibilities:


    1. You are going on a long trip, and the car is plugged in. Mandatory to pre-heat via App for at least half hour. This heats both the battery pack and cabin, and uses AC power to do it. Personally if I have the time (e.g. I'm waiting for the charge anyway), I'll do it twice (turns off after 30 minutes) for a full hour of preheat. You will save a great deal of driving range by doing this!
    2. You are going on a long trip, and the car is NOT plugged in. This is a bad situation, but preheating will make it worse by consuming battery power without the car going anywhere. Hop in the car, dial the cabin temperature down to minimum, crank up the seat heaters to compensate, and don't drive too fast. Keep an eye on your usage and hopefully you have a fallback charging location along the way.
    3. You are not going a long distance, and the car is plugged in. Strongly recommended to pre-heat via App for half an hour. Even ten minutes is useful though.
    4. You are not going a long distance, and the car is NOT plugged in. Preheating is optional; mainly for comfort and convenience. Preheating will not only make the cabin warmer, it will give you some regen braking. That said, you're using battery power to heat the car, so it is a little extra wear-and-tear on the battery pack. Personally in this situation I just preheat for 10 minutes, mainly to warm the cabin.
     
  11. mibaro2

    mibaro2 Member

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    Here is my normal work day:
    I have scenario 3 when going to work in the morning. I have now got use to this routine...first thing I do when the alarm goes off (after hitting snooze a few times) is connect to the app and start the car preheating. Funny how quickly that behaviour became a habit. It's nice getting into a warm car with regen.

    Leaving work, I have scenario 4 (although my work will install a charger in the spring :smile: ) . Preheating the car uses a lot of battery range, but if I know I can spare that range, I'll preheat it and be happy. If not, I get into a cold car with no regen and am not a happy camper. If I have to leave suddenly, starting the car heating while I put on my coat and walking to the car gives me some regen and a slightly warmer car ).
     
  12. mnx

    mnx 2013 P85

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    My drive most mornings is a 1.8km round trip to drop off my 7 y/o at school. It seems pretty wasteful to me to pre-heat even if connected to AC. Thoughts Doug?

    I try to manually set charging each day so it finishes at 7am each day so the battery is as warm as possible for any morning driving...
     
  13. mibaro2

    mibaro2 Member

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    I time the charging like that also. More often than not, the charging hasn't finished ( roughly 50km left to reach my charge limit)when I am leaving, so I figure the battery is still plenty warm. I find it helps, especially during this cold spell we are having.
     
  14. Doug_G

    Doug_G Lead Moderator

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  15. Jgdixon

    Jgdixon Member

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    The link doesn't work Doug
     
  16. Doug_G

    Doug_G Lead Moderator

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    It will... Blog posts take a little time to approve.
     
  17. Bighorn

    Bighorn Member

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    One thing I didn't see mentioned is regarding what sort of power the plug is providing. If the car's heater is drawing ~6kW and the battery heater is drawing the same, then the plug can't provide adequate power without 240V/50+A and dual chargers. Seemingly, the battery would be providing some energy if the plug is providing less than 12kW. This pre-heating would clearly hobble the ability to add charge to the battery if it were being done simultaneously.
     
  18. Keenan84

    Keenan84 Member

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    Hi Doug, was just creeping on some peoples profiles and I saw you are an engineer. Just wondering if you were a civil engineer? sorry for the random question, lol.
     
  19. Doug_G

    Doug_G Lead Moderator

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    Nope, electrical. I do try to be civil though.
     
  20. FourBucks

    FourBucks Member

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    There's no such thing as a "civil" engineer! (Mechanical myself...)
     

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