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How cold is too cold for the battery?

Discussion in 'Model S: Battery & Charging' started by sorka, Jan 1, 2017.

  1. sorka

    sorka Active Member

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    Merced, CA
    I'm in the Sierras at our time share and it was 17F this morning at around 5:00 AM. The car is plugged in but only to a 115 volt outlet. It was charging all night long and the charge went from 50% around midnight to 65% this morning when I went out to check it.

    Will the car use the battery heater to keep the battery from getting too cold when it's only plugged into a 1.2KW shore power?

    Is it bad for the battery in any way to sit overnight in this temperature? Does the answer change if it's not plugged in?
     
  2. Chopr147

    Chopr147 Active Member

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    Maybe some of our friends to the north can answer this from experience. The only difference I see is a much less efficient battery. And of course lowered regen rates
     
  3. sorka

    sorka Active Member

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    Oh, and I just found the thread that said if you have range mode on, it prevents battery heating. I had range mode on so I guess the only heating I would have gotten was the small amount of generated from charging at 1.2KW. Assuming at least 95% of that was transferred to the actual charge, I guess we'd be looking at 50 watts or less of actual heating from charging.
     
  4. ecarfan

    ecarfan Well-Known Member

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    I believe when the car is plugged into shore power it will attempt to keep the battery above some minimum temperature, thought I do not know what that temperature is.

    I doubt that it is "bad" for the battery to be out in 17F weather, but if it wasn't plugged in it would be severely power limited and regen limited. It will still be limited plugged in at 17F but not as much.
     
  5. Saghost

    Saghost Active Member

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    As I understand it, cold won't harm the battery at all, but it limits the safe power delivery and especially the ability to safely accept charge. I read somewhere that when the pack hits around 32F, charging has a good chance of plating metallic lithium onto the anode, but I'm not quite sure.

    I don't think the car will use to battery heater to warm the pack if plugged in and not charging unless the car is on; while charging it will warm the battery as needed.
     
  6. Lloyd

    Lloyd Well-Known Member

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    San Luis Obispo, CA
    From the owners manual:

    "Temperature limits
    Do not expose Model S to ambient temperatures above 140° F (60° C) or below -22° F (-30° C) for more than 24 hours at a time."

    The car will do what it can to protect the battery. It will use shore power if the car is plugged in. Always better to have the car plugged in if it is available.
     
    • Informative x 2
  7. fasteddie7

    fasteddie7 Member

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    uniontown PA
    I have been running my model s all winter, with some days being 0 degrees Fahrenheit. When I first plug into a cold battery the charge is slower and speeds up over time while charging. Plugging into a "regular" 3 prong 110 outlet only gives me around 4 miles of charge per hour regardless of ambient temperature and how cold the battery is. Plugging into a hpwc starts off slow and increases as the battery warms up. If I precondition the car a 110 actually loses range. The vehicles software is pretty smart and even if I have to jump in and drive without preconditioning the vehicle limits regen and top performance until the battery is the correct temperature. I wouldn't worry.
     
  8. DMC-Orangeville

    DMC-Orangeville 85D and John Deere 5100E

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    Most of the questions on cold weather driving can be answered here: Cold Weather Driving
    Doug lives in Ottawa....and it can get cold in winter
     
  9. ReddyLeaf

    ReddyLeaf Member

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    17 F is no problem. Just keep it plugged in and charging on the L1. Eventually it will fill, probably another day or two. Also the L1 is probably closer to 85% efficient. I use it exclusively at home, but in the unheated garage where it rarely gets below 25 F. The limiting factor is the electrolytes in the battery which freeze somewhere near 4 F. The car will run a heater to keep the battery from freezing as long as there's charge available (either internal or external). I keep my battery more full in winter just for this reason and don't worry about degradation since the temperature is so low very little degradation can occur.
     
  10. GSP

    GSP Member

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    As others have said, 17 F (-8 C)is no problem for Li-ion batteries. They will store less energy, and provide less power. They will charge slower, and may require heating before they can be charged at all. When warmed back up, they will perform normally again, with no damage. They will even degrade slower when stored at cold temperatures (all chemical reactions are slower when cold).

    However, if it gets cold enough to freeze the electrolyte, the battery will be bricked (freezing destroys the cells). Most Li-ion batteries freeze at about -40 F (-40 C). (NOT 4 F, that must be a typo)

    At these very cold temperatures, be sure to follow the instructions in Tesla's owner's manual (posted above). If you can not avoid leaving the car exposed to -30 F (-34 C), make sure it is plugged into a reliable power source, preferably 208-240 V.

    GSP
     

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