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Battery warming speed

Discussion in 'Model S: Battery & Charging' started by invisik, Jan 3, 2015.

  1. invisik

    invisik Member

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    Hi,

    Does the battery warm as quickly when using HVAC to heat versus while charging?

    For me, it seems to warm more quickly while charging.

    Wondering your experiences. Thanks.

    -m
     
  2. jerry33

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

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    The quickest appears to be charging plus HVAC with range mode off. Heating while charging is far quicker than HVAC, which makes sense because the act of charging creates internal battery heat whereas HVAC only warms the coolant which then warms the batteries.
     
  3. ahm

    ahm Member

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    I believe the optimum battery warming occurs when you are on shore power and are warming the cabin.
    Nick Howe had a video piece on this subject. Search for News From the Frunk on YouTube.
     
  4. rdrcrmatt

    rdrcrmatt Member

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    I wish we could see the battery temperature.
     
  5. invisik

    invisik Member

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    Ah, so the climate control just heats the coolant. That explains a lot of why I observe it takes much longer to heat that way. That also helps explain when the car interior has reached the set temperature and the car switches to cooling or super low heat that it's essentially not heating the coolant any longer.

    That is extremely frustrating when trying to plan to pre-heat.

    Timing the charge to finish, as frequent recommended, still seems like the most effective way to pre-heat.
     
  6. apacheguy

    apacheguy Sig 255, VIN 320

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    I might be wrong, but can't Roadster owners see pack and PEM temp on their displays? Don't understand why Tesla didn't build in these same capabilities to the Model S.
     
  7. jerry33

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

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    The Roadster owners have access to a lot of things that we Model S owners don't have access to. I hope the reasoning is time to develop the display and will eventually show up in some future release rather than "lets dumb down the display".
     
  8. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I agree, and when the battery is pretty cold, it can take an hour or two to get the battery completely warmed up. When I am going on a winter hypermile adventure, I always leave at least 2 hours of charge time before departure, start charging then, turn on the cabin heat, and keep turning the cabin heat back on every 30 minutes. Also, I set the cabin heat to 79˚F. or so to really heat soak the entire interior. Doing this, I can often leave HVAC off for 30 minutes or so after departure before the cabin cools down enough that I need to turn the heat back on.
     
  9. abasile

    abasile Independent Software Eng.

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    Is your car normally garaged or parked outside? (I know that Pagosa can get quite cold.)
     
  10. apacheguy

    apacheguy Sig 255, VIN 320

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    Shouldn't there be a way to initiate a pack preheat without wasting all that energy going to heat the cabin as well? If I knew that it took 2 hours to condition my pack, I would want to spend 1:45 min just heating the pack and the final 15 min to heat both the pack and cabin.
     
  11. invisik

    invisik Member

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    Is the coolant circulating the battery when the HVAC is on, or does it start circulating after the car is on? That one diagram someone posted of a diagnostic screen a long time ago looked like there were multiple valves/paths for coolant to go.

    Not really sure how to tell. I imagine it should be circulating to the battery.....?
     
  12. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    In garage, usually at about 40˚F. It was 0˚F. this morning, 16˚F. now at 5pm.

    - - - Updated - - -

    Heating the air in the cabin is quick, but it takes a while to heat soak the cabin. Once the cabin heats up, the power to the cabin heater drops a lot. I'm fine with spending a few Joules from shore power to well heat the cabin and contents before a long winter drive. Storing heat in the cabin is a another form of storing energy in the car.
     
  13. jerry33

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

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    I timed this the other day and it appears that V6 has changed the time that the heat stays on to 15 minutes down from 30 in prior versions. I don't know why they did such a silly thing. I would have increased it to an hour, or better yet make it user settable.
     
  14. scaesare

    scaesare Active Member

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    This has been my experience.
     
  15. AmpedRealtor

    AmpedRealtor Active Member

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    Instead of using HVAC, why not just bump up the charging by a few percent? This will heat the pack for charging, right?
     
  16. jerry33

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

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    It will, but not as much as if you set the timer to stop about the time you are ready to leave, and then also use the HVAC.
     
  17. scaesare

    scaesare Active Member

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    As jerry33 mentions, a sustained charging session is probably the most effective, but I've used the method you suggest as well... set the car chargepoint for an additional 5%, and let it charge for 20-30 mins before I go and it definitely helps the pack more than HVAC does.

    For the last 5 minutes I kick on the HVAC for me and the family as well....that way both pack AND people are nice and toasty. :)
     
  18. slipdrive

    slipdrive Member

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    Keeping with the winter freeze theme: I finally found a solution to cold feet when running around in freezing weather in and out of the car with the dog, etc, ... which kept me trying mostly in vain to heat the floorboard area, etc. "ThermaCELL" heated Insoles (Cabelas, REI, Amazon). Wireless Li-ion polymer 5 hour cells, quick recharge. Between using Cottonwoods technique of deep pre-heat plugged in, and my new warm feet, all is great in the Model S this winter.!! (8 degrees this morning)
     
  19. abasile

    abasile Independent Software Eng.

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    40˚F isn't all that cold. This morning my Nissan LEAF's battery was at about freezing (32˚F) as we park outdoors. As much as I've complained elsewhere about the LEAF's regenerative braking, even at freezing (and 21% capacity loss) there's at least some regen available, though it was less than 10 kW. Does your Model S allow some regen when the battery is cold? How warm does the battery have to be for you to have 20-30 kW of continuous regen available (enough for a graded mountain descent) at, say, 60-70% SoC?

    I'm just wondering how much "prep" a Model S (or X) might require during winter before leaving our home at 6100' elevation and descending to the nearest freeway at 1200' elevation, involving 2 miles at elevation followed by a 14 mile descent. (Doing that descent in the LEAF with a cold battery is no fun, as we sometimes have to make multiple stops to let the friction brakes cool down. Thankfully the LEAF mostly just lives on the mountain nowadays, shuttling us around the small towns up here. A Tesla would be nice for our various trips off the mountain.)
     
  20. jerry33

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

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    I park outside and today it's -4.6 C. All I do is insure the charge stops close to when I'm ready to leave, and preheat the car for two or three 15 minute cycles with range mode off. This will allow close to 30 kW of regen (about 50% or maximum) for the first few miles on more or less level ground. If you were going downhill, the regen would warm the battery up even faster than it does for me as the motor would be creating heat. If I lived where you did, I'd probably still have to use the friction brakes a bit, but not that much.
     

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