Battery warming speed

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.

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.

I wish we could see the battery temperature.

rdrcrmatt said:

I wish we could see the battery temperature.

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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.

apacheguy said:

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.

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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".

jerry33 said:

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.

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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.

Cottonwood said:

when the battery is pretty cold, it can take an hour or two to get the battery completely warmed up.

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

Cottonwood said:

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.

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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.

abasile said:

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

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

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apacheguy said:

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.

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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.

Cottonwood said:

turn on the cabin heat, and keep turning the cabin heat back on every 30 minutes.

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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.

invisik said:

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

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This has been my experience.

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

AmpedRealtor said:

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

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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.

AmpedRealtor said:

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

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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.

Cottonwood said:

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

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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.

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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)

Cottonwood said:

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

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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.)

abasile said:

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?

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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.