# Which is better when stuck in a traffic jam in winter: combusion vehicle or Tesla?



## garsh (Apr 4, 2016)

With the recent snow-storm caused traffic jam on I95 in Virginia, I'm seeing a few articles talking about how much worse it would have been if people had been driving electric cars instead of combustion cars.

https://www.baconsrebellion.com/wp/...better-to-have-a-gas-or-electric-powered-car/
https://www.washingtonpost.com/opin...ffic-catastrophe-with-only-electric-vehicles/
All I see in these articles are opinions based on biases, but no actual experiments or calculations. I think we can perform some calculations and get some actual estimates.

*How long can a gas car run the heater?*
This article presents a pretty easy method for figuring out how long a car can idle, and therefore, how long it can generate heat.
https://www.autotrader.ca/newsfeatures/20190201/how-long-can-you-stay-warm-on-a-tank-of-gas/Using values for my Hyundai Tucson, which is a very efficient little SUV:

1.6 liter
16.4 gallons = 62 liters
My Hyundai would use (1.6l * 0.6) = 0.96 liters every hour while idling.
So with a full tank, it could generate heat for (62 liters/0.96 liters per hour =) *64 hours*.

*How long can an old Tesla Model 3 run the heater?*

This article has some good information on energy used by the heater in Model 3s (the Model Y will be identical). The tests here were run by a Tesla owner in Norway.
https://www.teslarati.com/tesla-model-3-heat-pump-test-video/
My Model 3 is one of the old ones with a resistive heater.
It will use 2,170 watts to maintain a comfortable temperature.
My car has a 75kWh battery.
With a full battery, my car can run its heater for *34 hours* (75000/2170).

*How long can a new Tesla Model 3 or Y run the heater?*

New Model 3s and Ys have a slightly larger 82kWh battery.
Plus they come with a heat pump, and according to the above article, that only needs 735 watts to maintain temperature.
So a new Model 3/Y can run the heater for *111 hours*.

*Conclusion*

In the Hyundai, I could run the heater at any temperature I desired, since combustion engines produce a LOT of waste heat. But regardless of the setting, I would only have heat for 64 hours because I can't instruct the car to idle any slower.

In the Tesla, the energy used is proportional to the difference between outside and inside temperatures. So real world scenarios can differ. But if I want the battery to last longer, I can run the heater at a lower temperature.

If I end up being stuck in a traffic jam in winter, I'd probably prefer to be stuck in a new Tesla with a heat pump than in my Hyundai, and my Hyundai rather than my current Tesla. But all three are in the same order-of-magnitude ballpark. No matter what kind of vehicle you drive, try to keep the tank/battery full during bad weather in case you end up in this scenario.

UPDATE: fixed gallon/liter math messup in ICE idling time calculation and updated the Conclusion. Thanks @shareef777 !


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## shareef777 (Mar 10, 2019)

Where did you get the .96gal/hr idle rate? Should be .96L/hr, which is .25gal/hr which gives you ~65 hours. Also, think the issue is that for the ICE vehicles you always fill to the top. EVs are likely to ~80%, and if you spend all the power to stay warm, you can't really have someone bring you a jug of "fuel" to get home.


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## Klaus-rf (Mar 6, 2019)

You're also assuming that you still have 75-82Kwh available form a cold battery to run the heater. I recall reading here that people get about half the range with cold batts. versus warm/hot ones I don't do much cold here (Southern Arizona_) so I have no personal experience.


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## DocScott (Mar 6, 2019)

Anecdotally, I had a mini-version of the I-95 nightmare occur to me not long after I bought my Tesla (2017 RWD M3). An early-season snowstorm in New York snarled surface streets around my work place. It took me more than 7 hours for what was usually a 25-minute commute, and most of that was trying to get out of the neighborhood around my work. I'd allowed my range to get down below 100 miles before the storm, so I had some reason to be worried.

Although sometimes I was completely stopped, I was often creeping forward down some street or other--I kept trying to find routes out of the neighborhood--heading back in was pretty easy; every route out was very very slow.

My range was dropping alarmingly as the night wore on, so I started trying things to slow the drain.

Amazingly, the biggest effect was turning down the brightness on the touchscreen! Once I did that, I became confident I'd be OK. I also turned down (but not off) the heat and switched to parking lights when completely stopped, but the touchscreen was the biggest jump.

And yes, there were ICE vehicles running out of gas that night...


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## skygraff (Jun 2, 2017)

Additional factor when stopped is CO; especially if accumulating snow may get over the exhaust.


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## TrevP (Oct 20, 2015)

The latest thing started with a FUD Facebook post blaming it on EVs with dead batteries.

https://www.usatoday.com/story/news...d-not-cause-snowstorm-traffic-jam/9085526002/


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## shareef777 (Mar 10, 2019)

Klaus-rf said:


> You're also assuming that you still have 75-82Kwh available form a cold battery to run the heater. I recall reading here that people get about half the range with cold batts. versus warm/hot ones I don't do much cold here (Southern Arizona_) so I have no personal experience.


That's a bit excessive. I live in Chicago with a not well insulated garage. Always get the snowflake icon when leaving in the morning due to the cold battery, but the worst impact I've seen in 3 years of winters is losing a third, and I've attributed that to running the heat and heated seats. I've tested without using the heater or heated seats and notice battery isn't impacted much if I slow down appropriately. The cold weather really only impacts the battery because of the loss/limited regen, slow down appropriately as to not waste energy and impact is minimized. This is our first winter with our Y (heat pump) and the impact hasn't even been noticed.


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## garsh (Apr 4, 2016)

Anecdote from a Tesla owner who was actually stuck in the I95 snowstorm.


__ https://twitter.com/i/web/status/1479087709713014788


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## garsh (Apr 4, 2016)

shareef777 said:


> Where did you get the .96gal/hr idle rate? Should be .96L/hr, which is .25gal/hr which gives you ~65 hours.


Thanks! My Americanism strikes again!
I'll fix that in the OP.


shareef777 said:


> Also, think the issue is that for the ICE vehicles you always fill to the top. EVs are likely to ~80%, and if you spend all the power to stay warm, you can't really have someone bring you a jug of "fuel" to get home.


I don't think that's much of an issue. Sure, many will only charge an EV to 80-90%, but most EV owners will charge it to that level every day. For a gas car, most people will wait until the fuel level drops below 1/4 tank before filling back up, so on any particular day you're likely to have much less than a full tank.


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## Mr. Spacely (Feb 28, 2019)

Funny. We get a different debate here in Florida during the summer. Which would you rather have-- ICE or EV in the event of a hurricane? When a storm is approaching and everyone is out fighting to top off their gas tanks, I just slide my app to 100% charge. When the power finally goes out and it is miserably hot and sticky, I can sleep comfortably in my car in the garage for 4 or 5 nights. Don't ever try to run an ICE in a garage. 

What about a hurricane evacuation? ICErs say that you'll run out of electricity. Yes, EVs will rung out of juice after 4-5 hours of moderate driving. but remember you need electricity to turn on gas pumps too. 

Anyway I think Model 3 could keep you warm even longer than you calculated if you used the seat warmers as the primary source.


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## garsh (Apr 4, 2016)

TrevP said:


> The latest thing started with a FUD Facebook post blaming it on EVs with dead batteries.
> 
> https://www.usatoday.com/story/news...d-not-cause-snowstorm-traffic-jam/9085526002/


FYI, that was an earlier snowstorm in California rather than this I95 snowstorm in Virginia.


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## Jim H (Feb 11, 2017)

garsh said:


> Anecdote from a Tesla owner who was actually stuck in the I95 snowstorm.
> 
> 
> __ https://twitter.com/i/web/status/1479087709713014788


I wondered about how Tesla's would do in an I95 situation. 
Just did a camp mode trip about a month ago for a long weekend, using camp mode. The camp mode kept temps great and really dd not use that much battery. 
Good to see a first hand report from someone that was stuck in a similar situation.


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## garsh (Apr 4, 2016)

Klaus-rf said:


> You're also assuming that you still have 75-82Kwh available form a cold battery to run the heater. I recall reading here that people get about half the range with cold batts. versus warm/hot ones I don't do much cold here (Southern Arizona_) so I have no personal experience.


Here are the details about living with an EV in a cold climate.

There is some loss in efficiency, due to things like cold bearings that cause friction to increase. It's just a few percent though.
A cold-soaked battery will have some amount of energy inaccessible. The potential energy is still in the battery, but can only be accessed once the battery has warmed up.
Sure, you can lose half your range through a combination of cold-soaked battery, loss of efficiency in cold weather, snow-covered roads, and having to run the heater. But that's not actually relevant for answering the question "how long can I run the heater".
If you've been driving and then you get stuck in traffic, your battery has already been warmed up, so the "cold-soaked" energy loss won't apply. Keep some car systems on so that the battery continues being used and stays warm enough to deliver all of its energy.


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## JasonF (Oct 26, 2018)

I would say just don't get on the highway when a snowstorm is coming. This is old wisdom from when I used to live in southwest Ohio and work in Kentucky - if I waited for snow to start, I got stuck on the highway. I learned fast, though, and started taking surface streets during snowstorms. Why don't more people think of that? Because we tend to think in silly terms like if we get on the highway we'll be going faster, and can maybe get a head start on the snow, or that it's the shorter or more direct route. Getting stuck on the highway in a snowstorm is preventable!

Another thing that preventable is starting a day when a storm is coming with less than a full charge. If you know a big storm is coming (hurricane or snowstorm) and you have to be out, top up to at least 90% if not 100% just in case. It's not just EV owners who forget to do this, quite a few ICE car owners don't top up because prices are higher and/or there are lines before a storm, or because it's cold/wet out.

And finally you can lower the battery consumption quite a bit by turning the temperature in the car down and using seat heaters. Don't turn it down so far that you can see your breath and you're shivering - all you need is just a few degrees difference. You'll also be more attentive if the car isn't extra warm and lulling you to sleep because sitting there is so boring.


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## skygraff (Jun 2, 2017)

Thinking about Chicago (LSD snowmageddon), another benefit to being in an EV when the storm starts burying cars is that very little (none - submarine mode?) air intake is required to keep the systems running unlike combustion.

I remember the advice after that storm was for people to keep their cars off until the cold started to get unbearable then, get out to verify intake and exhaust were clear before starting to warm up and repeat the cycle. Like mentioned above and first-hand, EV could just go camp mode and hunker down.


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## B_E_V (Apr 17, 2021)

My take is that while the Battery/Gas lasted, I would be safer (CO), more comfortable (Camp Mode), and more amused (Games etc) in a Tesla. However, if I actually used up all the Battery/Gas while stuck in traffic, CURRENTLY most locales would find it easy to get me some Gas to get going again, but difficult to give me a Charge where I was parked. That will change as BEVs become more common. Especially once bi-directional BEVs can share some charge. 

Of course in both cases, shame on me for running all the way down to empty while stuck. I should have asked some other vehicle if I could share their heat instead.


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## mrwug (Aug 4, 2021)

One thing that seems often overlooked is that most people rarely leave home with less than 80% SoC. With an ICE vehicle, you're probably going out with 2/3 tank or less.


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## GDN (Oct 30, 2017)

I know this is about a specific incident that already happened, but while it seems the EV could have or did do just as well stuck out on the road, it can do even better if you find yourself at home without heat. Last year during the period many North Texans were out of power for 5 days - I had two very nice warming cabins standing by in the garage. We were lucky and didn't have to use them, but when we saw what was coming we charged both to 90%. You can safely use an EV in the garage like this because you aren't generating carbon monoxide which would be a guaranteed death sentence from an ICE. So while not only will I be warm I can charge my phone, I can watch Netflix and be entertained.

In the future this will only improve as we have more vehicles with VTG so that the battery which we charged up in the car can just push that power right on into the house electrical panel.


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## garsh (Apr 4, 2016)

Someone ran another practical experiment.

Outside temp below 15° F for duration of test.
Cabin temp set to 70° F for first 12 hours
Cabin temp set to 60° F for next 6 hours
Tesla Model X w. 100kWh battery and resistive heater, charged to 90%
Tesla Model Y w. 82kWh battery and heat pump, charged to 91%
Results after first 12 hours

Model Y down to 58% (33% used), so 33 hours total possible from a full battery.
Model X down to 47% (43% used), so 28 hours total possible from a full battery.
Results after 6 hour additional test

Model Y down to 48% (10% used), so 60 hours total possible from a full battery.
Model X not available for this portion.


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## shareef777 (Mar 10, 2019)

So another interesting anecdote. My brother just came back from Minneapolis where temps were hovering around -20° F. He says that his Y's heat stopped working and he had to drive back to Chicago with no heat. Turning on any climate control would just blow cold air into the cabin, but it was necessary as his windshield would otherwise fog up. Had to make his hours long drive home in the freezing temp with only seat heaters to help his family out. Says that Tesla blamed the issue on a firmware bug.

Anyone else with a heat pump based Tesla experience heating issues in below freezing temps?

Found a related article: https://driveteslacanada.ca/model-y...-to-help-prevent-it-while-a-fix-is-developed/


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## JasonF (Oct 26, 2018)

garsh said:


> Someone ran another practical experiment.


That was "Dirty Tesla" - I just watched that video, and he made a couple of mistakes (that don't necessarily hurt EV's):

- I've mentioned on the forums here that a lot of people, especially those who bought a SR Model 3 as a first EV, have a bad habit of charging it the same way they charge their phones: They wait until the battery is near dead, and then charge it. Out of the now 4 SR Model 3's in just this section of my neighborhood, I can see them do exactly that - because they park in the driveway or street, and only plug in maybe once a week at most. If you get on the highway in a sudden snowstorm, that virtually guarantees your battery will die while you're out there. Though the same thing would happen with a gas car (more on that in the next point).

- There were a lot of assertions about that an EV would have to be towed if it dies, while a gas car could be refilled with a gas can and moved along again. This is a mistaken assertion, because when rescuers are trying to clear the highway, there is _no way in hell _they're going to wait for you to go and get gas and return. And they wouldn't bring their own gas can to fill up the dead gas cars, because it wouldn't be a _can_ to get that many moving - they would have to drive up with a fuel truck, transfer that fuel to cans, and then fill up each car. There is no way that's more time or money efficient than just towing away all of the dead cars and sorting them out later.

- The only place those assertions are correct about how ICE cars are easier to rescue is in a _single car _situation. If your car runs out of fuel and you're by yourself, it's easier to bring a gas can to a gas car than try to charge an EV out there. But even then, abandoning your car on the side of the road doesn't guarantee it will be there when you return, and walking a long distance in sub-freezing temps is dangerous. So cold weather is the great equalizer, and would probably see both EV and ICE on the bed of a tow truck.

But that said, I did enjoy his conclusion that longevity of an EV battery when stuck in a snowstorm is similar to a gas car. At the very least, long enough that rescuers would have removed all of the drivers and passengers from the cars by then to get them into warmth, food, and water for their safety, with a plan to clear the cars later while no lives are in jeopardy, and have the owners retrieve them later.


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## mrwug (Aug 4, 2021)

JasonF said:


> There were a lot of assertions about that an EV would have to be towed if it dies, while a gas car could be refilled with a gas can and moved along again.


That's not even universally true of ICE vehicles. I know certain BMW & MINI vehicles will suffer high pressure fuel pump damage if the fuel tank runs dry.


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