200 Wh/mile to use heater?

[MountainPass]

We have superchargers in Indiana on all the major routes. No need to be uncomfortable. The biggest issue you'll face here is the average speed is 80+ mph which hurts efficiency.

Sasha also makes me ride in the car with the windows up and no AC in the summer, so I think it is not a matter of superchargers, but his own obsession with efficiency. We made the trip from Indianapolis to Toronto with only 2 supercharger stops, it was very cool.

 

[derotam]

I'll use my heater in addition to seat heater in the winter thank you very much. I am not going to dress like an eskimo to stay warm IN MY CAR! Do you people not use heat in your home as well and just "dress for the weather"? lol

 

[Birdman325]

My commute from home to work (downtown Toronto) is about 9 km. I have a HPWC in my garage and the car is parked over night indoors - The garage is not heated but is a “part of the house insulated garage” so it does not get that cold. When I drive down, I park in an underground garage. In other words, for 90% of my driving - “efficiency” is not relevant. I could be using the most inefficient tires, blasting the heat and never pre-warming, and still generally should be ok for most driving.

Having said that, ever since I discovered just how much energy the heater takes (the difference between an average of 250 wh/km when it is on, and 150 wh/km when it is off for my one way commute) I find myself driving in the cold (with the seat heater on and the main heater off) just to see how low I can get the wh/km!

 

[ℬête Noire]

Sasha also makes me ride in the car with the windows up and no AC in the summer, so I think it is not a matter of superchargers, but his own obsession with efficiency. We made the trip from Indianapolis to Toronto with only 2 supercharger stops, it was very cool.

Clearly you're not a married couple because my wife will NOT put up with that, so I definitely have a different mode of operation when she's riding. Mind you two people vs one is a very different place with the heat and humidity budget.

For me; It's a bit of the "efficiency bug" and just that drive to fidget & tweak with a problem (obviously something that's also in Sasha's personality), probably what started it. More-so now it is a connection with the world passing by that had been missing for years. It's no convertible but experiencing the seasons and fluctuations is something I found I missed. ¯\_(ツ)_/¯

 

[JeffK]

How much energy the heater uses per mile depends on your speed... so it's not really a good measure.

The heater should be measured in kW and usage depends how long (time) your commute is and the temp outside (heat losses)

 

[ℬête Noire]

How much energy the heater uses per mile depends on your speed... so it's not really a good measure.

The heater should be measured in kW and usage depends how long (time) your commute is and the temp outside (heat losses)

The HVAC system running flat out is something like 8-10kW in the Model S, that's with full heater plus AC drying the air. That's roughly what the Model 3 is, too, although I have only seen approximations so far and accounting for how motor unit is [assumed to be] used for bringing up the battery pack heat makes it kinda tricky to separate out the HVAC and everything. But that's not what get used outside of the first part of your trip unless you're in an extreme situation.

Once your cabin reaches steady-state it can cut back quite a bit, it just has to replenish what the vehicle loses minus what the occupants generate, plus manage the moisture the occupants generate (primarily via their breath). That is partially influenced by how fast you're traveling as air passing over will draw heat off the outside of the vehicle faster. So even though time and outside temp are the prime factors, that increased heat loss rate will partially offset the speed and traveling at 2hrs at 80mph versus 2hrs at 30mph won't be the same.

 

[JeffK]

The HVAC system running flat out is something like 8-10kW, that's with full heater plus AC drying the air. But that's not what get used outside of the first part of your trip unless you're in an extreme situation.

Once you cabin reaches steady-state it can cut back some, it just has to replenish what the vehicle loses minus what the occupants generate, plus manage the moisture the occupants generate (primarily via their breath). That is partially influenced by how fast you're traveling as air passing over will draw heat off the outside of the vehicle faster. So even though time and outside temp are the prime factors, that increased heat loss rate will partially offset the speed and traveling at 2hrs at 80mph versus 2hrs at 30mph won't be the same.

Exactly, I'm more concerned with set distance such as a daily commute. Heater energy usage during an avg of 20 mph for 25 miles (rush hour in a snow storm) or 60 mph for 25 miles. All conditions equal, heat usage per mile is less if I arrive at my destination faster.

 

[SageBrush]

I am not going to dress like an eskimo to stay warm

Hyperbole much ?

 

[ℬête Noire]

Exactly, I'm more concerned with set distance such as a daily commute. Heater energy usage during an avg of 20 mph for 25 miles (rush hour in a snow storm) or 60 mph for 25 miles. All conditions equal, heat usage per mile is less if I arrive at my destination faster.

Just that it won't be 2/3 less for the 60mph. On top of the higher loses/min from the speed, depending on where you store your car, the brining up to temp portion of that trip can dominate the heating cost.

 

[derotam]

Hyperbole much ?

Depends on where you are driving and in what weather.

 

[ℬête Noire]

Depends on where you are driving and in what weather.

I've driven several hours with no heater in -25C to -30C (cooling as the sun went down). A light jacket was all that was required (although footwear was something else, those had felt liners, and I was using leather+knit liner mitts). The biggest PITA was constantly having to use the window scraper on the inside because there was no heat due to no fan.

There was probably a small amount of heat radiating through the firewall from rather the modest ICE (it was a 'vette, a Chevette ), or at least enough heat from the ICE to offset the wind cooling at the bottom by the pedals. But the amount a couple people can heat the air around them is fairly substantial.

 

[SageBrush]

Depends on where you are driving

Herdon, VA ?

Compare and contrast to the North Pole:

 

[JPUConn]

Heater draws ~6kw. In the S/X this draw could be reduced to 1.5-2kw and rely on drivetrain heat but this is not in the 3.

If you’re doing 60 mph then 6000w (6kw) will use 100 wh/mile. So if you’re going half the speeds with the same heater draw it will be 100 wh/mile penalty.

I lucked out and got a charger at a client ~160 miles away that I often take round trip in my 3 without charging so I’ve gotten used to running with the heat off. Was quite a different experience with the heat on this leg as I hadn’t plenty of extra range but the consumption difference was meaningful.

 

[Twiglett]

As others have mentioned heater use can't be measured in watts per mile. Its also entirely dependent on what temperature differential you're trying to achieve. Obviously its going to use more power to get the car from 40F to 80F inside the car compared to 65 to 80F.
I really don't care and use whatever I need.
It was a big deal with my low range EV but not at all relevant to my regular use.

 

[Big Earl]

Heater draws ~6kw. In the S/X this draw could be reduced to 1.5-2kw and rely on drivetrain heat but this is not in the 3.

If you’re doing 60 mph then 6000w (6kw) will use 100 wh/mile. So if you’re going half the speeds with the same heater draw it will be 100 wh/mile penalty.

I lucked out and got a charger at a client ~160 miles away that I often take round trip in my 3 without charging so I’ve gotten used to running with the heat off. Was quite a different experience with the heat on this leg as I hadn’t plenty of extra range but the consumption difference was meaningful.

It's only 6 kW if the heater is on full blast. It will ramp down to 1-2 kW as the cabin comes up to temperature (more if it's very cold outside). I can't think of any situation where you'd be driving for more than 10 minutes with the full 6 kW of cabin heat unless you had the system on HI with the windows open. X also has an additional 1.5 kW rear heating unit if it's equipped with rear climate control.

No Tesla can use drivetrain/motor heat to heat the cabin. There is no liquid heater core in the HVAC system ... all they can do is route that waste heat to the battery to assist with keeping it warm.

 

[PoitNarf]

Since I received my Model 3 about three weeks ago, I have almost never seen anything under 300 Wh/mile. Usual range for me was easily 350-450 Wh/mile. Since it was new I didn't think much of it but eventually realized I had pretty poor range. I noticed a few guys talking about not using their heaters as much so I decided to turn it off and now I can reach 225-280 Wh/mile easily with even the seat warmers on and music at 60%+ volume.

Is this normal? If so, how many others also sit in the cold during longer trips to save on watt hours?

NJ driver here as well. Yeah that's pretty much what I've been seeing. For highway driving averaging around 70-75 MPH with the heat set to 70 and my seat heater on as well I've been averaging around 290-300 Wh/mi for highway driving over the past 2 weeks.

 

[EVDRVN]

Those in a cold climate may consider using the seat heaters on all seats for a few min to warm the surfaces, this can make a big difference in radiant "feel" and the heater takes a long time to warm surface materials.

 

[JeffK]

It's only 6 kW if the heater is on full blast.

Mine's closer to 7 (6.8 kW on high)

 

[JPUConn]

Those in a cold climate may consider using the seat heaters on all seats for a few min to warm the surfaces, this can make a big difference in radiant "feel" and the heater takes a long time to warm surface materials.

Heated steering wheel and a way to keep the windshield from fogging and I’d never turn the heater on.

 

[mike123abc]

I try to run without heat when I do my long work drive. Once or twice I week I have to drive 230 miles (AWD 19") before I reach a charger. I run the heat up hot (78%) for about 30 minutes before leaving to be sure it is warm enough, and have the battery charged to 100%. When I leave I cut the heat and just use the seat warmer and drive no faster than 70MPH. Can do it with about 10% left when I arrive at the next charger. When I got the car and had to use the AC, just charging to 100 and limiting speed to 75 was enough to make it.

But, when Tesla puts their promised supercharger (was listed as coming in 2018, but hopefully they get it done in 2019) along the route I will no longer do all that, but will just charge to 90% and crank the heat and enjoy it like the luxury car it is supposed to be!