A main reason range is significantly reduced in cold weather is heating the passenger compartment and the battery. It would be nice if Tesla would show energy usage of this heating and how much it is effecting range. This can help people appreciate the issue and perhaps get them to reduce cabin temperature and use the seat heater more and perhaps wear long sleeves on long drives.
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Tesla should show how much energy is going to heating
- Thread starter cstork
- Start date
Akikiki
A'-Lo-HA ! y'all
Doubt that. Maybe its second or third. Biggest use - during cold weather - is going to be heating the battery to opium operating temperature. And no more reason to believe people will appreciate the quantity than anything else that they do and should consider - such as walking in front of traffic with their phone stuck to their face or smoking. If I had a vote what Tesla is working on for software, it would be concentrate on AP and FSD. Stop feeding my car games.
Or maybe it would be better just to be comfortable and enjoy the car?
I'd also challenge that heat is such a big item for longer drives. Shorter ones, maybe.
I'd also challenge that heat is such a big item for longer drives. Shorter ones, maybe.
AlanSubie4Life
Efficiency Obsessed Member
My understanding is that the car does not heat the battery when driving. Perhaps @ZOMGVTEK could confirm (I think he said he's seen that happen one time but it seemed spurious).
Here's an example where the snowflake came on after a while of driving more slowly in extreme cold conditions - which suggests the battery is not being actively heated - it's being heated by residual waste heat from discharge (and any incidental waste heat from the motors is likely cycled through the coolant system too):
Is reduced range in cold just from heating the car?
I'm not in a location where I can speak knowledgeably about this topic (and doesn't appear you are either!), but you'd think that on this forum we could get pretty definitive comments from people on battery heating - my understanding is that it only happens if the car is plugged in and being warmed up, or when navigating to a Supercharger (and it's obvious even without the on-screen message that it is taking place due to the noise). It's a very obvious noise that occurs when it's happening so I'd think this topic could be resolved definitively one way or the other.
From an efficiency perspective, it does not really make sense to burn extra energy to heat the battery when driving (except for Supercharging), so I tend to believe the people who say it generally does not happen.
I agree with the OP that the single largest factor impacting range in cold weather (there are several factors) is the cabin heat/HVAC.
I lost 22 miles of range last night with 2 hours of dog mode use, with climate set to 67 degrees and outside temperature of 50 degrees, as an example of the impact heating would have on a ~120 mile drive even in fairly mild conditions. That was starting with a prewarmed car, too. This was totally expected - 2.5kW steady state in those conditions is totally within expectations.
Since driving at 80mph uses about 300Wh/mi for me, that's 300Wh/mi*80mph = 24kW. So that 2.5kW load would reduce my range by about 10% when driving 80mph. If I were driving 60mph, my consumption is closer to 250Wh/mi, which is 15kW, so in that case heat would reduce my range by about 15%. The slower the travel, the worse the impact (%-wise) is.
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I don't believe the battery is heated while driving. I've had conditions where regen was entirely disabled due to battery temperature, and it didn't actively heat the battery. This does make sense, since the way the car heats the battery is horribly ineffective at doing so while moving at speed in cold weather. The drive units have a fair bit of surface area, so any airflow across them when its double digit negatives really limits the achievable temperatures. The coldest i've driven the car in so far is single digits F. I should see double digit negatives sometime this winter, if the car sits a while to really soak in, ill see how it drives without preheating.
This is something the Chevy Bolt and Volt do quite well. I'd love to see Tesla have an energy stats page where you can see data on where the power is going, including use of climate control and how much energy was expended through the drivetrain vs how much was recaptured through regenerative braking. I like the clean design of the energy page today, but offering additional data somewhere would be a nice addition. It's not critical, but I'm always interested in how things like my driving impacts energy consumption versus use of climate control.
AlanSubie4Life
Efficiency Obsessed Member
Don't forget about the trusty little Spark EV! It also tracks this information.
coconutboy84
Member
ElectricIAC
Good-Natured Rascal
Maybe this is a change they can implement now that supercharging also cost for ancillary use and not just what is added to car..
beachmiles
Member
For a renter with no home or workplace charging and a 80 Mile daily commute these decently sized scraps of energy are not chump change.
Also the cabin heater is constantly being used even when it's 90F degrees outside and all you are trying to do is cool the car to the tune of 1-2kw.
Disable the cabin heater in the M3 by unplugging the CAN connector to the cabin heater : TeslaModel3
If you have to worry about energy use, don't use it. If you don't have to worry about energy use, use it.
What's so tough about that?
Stop worrying about the freaking car. Way too much range anxiety going on here.
(And yes, heating is indeed chump change)
Ballpark math. 4 hours of highway driving drains the battery. 4 hours of heating consumes more than 10% of said battery capacity.
Heating is a helluva bigger factor than, say, using Aero covers vs plain wheels.
So, no, not chump change.
And people are asking for data, just like displays of efficiency, temperatures, and odo. It's just numbers. It doesn't hurt others, if some people like to look at it. And it's not moving heaven and Earth to implement in software.
timk225
Active Member
My 55 mile round trip to work and home yesterday used about 90 miles of battery power, due to having the heater on. Heaters use power. I remember reading somewhere a year or so ago that the heater can use up to 7 kw/hour, not sure if that's right or not.
coconutboy84
Member
Heating isn’t chump change in canada. What an ignorant comment.
Vaillant
Member
In my previous car (Volt) when you were not moving, you could see how much energy the HVAC was using. On a hot day, the AC would be about 1 to 1.5 kW. On a cold day, the heating would get up to about 6 kW. So, I’d say your 7 kW value is reasonable.
640k
Member
i think it's as simple as this - tesla needs to ditch the wh/mi model. it's useless, provides no valuable information and worst of all, doesn't show the whole picture.
a stacked area graph or even just an active line bar with an average reading would be more effective than what we have now.
as much as i wanted to jump on the "just drive the car" bandwagon, taking long trips in any temperature below 60° takes a considerable amount of planning. at the end of the day, the car is almost always using some energy. why not be transparent about it?
- your trip wh/mi is always different from your energy usage. why? the energy graph is an average of the last 5/15/30 miles, regardless of charging, stopping or other factors. so you get two different readings on both numbers. even if you take a long trip, with consistent readings throughout, your numbers will often be different.
- any sort of auxiliary usage is not represented in the throughput number being provided. HVAC, seat heaters, lighting, wind, cold, rain, etc. are all "absorbed" in the "whole" of the number that's represented in the wh/mi. i think it's safe to say that this is the reason for so many of these threads (mine included) and causes range anxiety due to the simple fact that there is little to no meaningful data to calculate actual "range to empty".
a stacked area graph or even just an active line bar with an average reading would be more effective than what we have now.
as much as i wanted to jump on the "just drive the car" bandwagon, taking long trips in any temperature below 60° takes a considerable amount of planning. at the end of the day, the car is almost always using some energy. why not be transparent about it?
Birdman325
Member
I agree. Even something simple as driving between Toronto and Montreal, (only about 525 km) with a fair number of superchargers between them, when the winter temp is -5 to -10 degrees C and there is a decent wind with some snow on the road, even the LR takes more thinking than "just drive the car".
640k
Member
TBF - my phone will say something stupid like "battery should last until 1:00a" and then i'll watch a video and 5 minutes in, the phone dies. i think we all understand that more accelerator = more energy throughput, but even if i rag on a standard ICE car, i can still calculate what my penalty is.
Wh/mi is essentially an absolute metric, your starting point for every other consideration. Then you can subtract individual circuit measurements, if TM would be so inclined to provide them. They could also be expressed as wh/mi for easy comparison to the summary wh/mi. Graphs of these would be useful.
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WilliamG
Hinge Fanatic
I would absolutely love some data on how much power is being used by individual parts of the car, e.g. the heated seats, HVAC, - heck, - even the brightness of the LCD display itself. I'd totally geek out on all the data.
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