Trapped in snow hypothetical

insular1

While watching cars struggle to make it up the hill outside my house yesterday a question popped into my mind.
Supposing you got stuck in a snow drift in the middle of no where with a nearly full battery how long could you expect the car could run the heating for before battery died?

Anyone know roughly how long an ICE could maintain heat on a nearly full tank?

goz83

Too vague a question. Be it petrol, diesel, or ev, the variables are many. Cabin size, engine/battery size. Temperature selected. Outside temps. Car insulation.

insular1

Hmm ok let's say a 24kw leaf as (probably?) the most common ev in Ireland. In current temps what draw is there on the battery to maintain 20c if everything else is off?

goz83

Ok well I guess the heat to maintain 20c would draw ~2kWh so with a full battery (22 usable) that’s 11 hours.

Idling a diesel for that long couldn’t be good for it.

ted1

Has anyone being stranded at home do to loss of power causing an inability to charge

Calahonda52

ted1 wrote: »

Has anyone being stranded at home do to loss of power causing an inability to charge

No, the reverse, using the battery to keep the internet and gas heating going

OldMrBrennan83

This post has been deleted.

insular1

11 hours, plenty of time for a rescue! That's better than I thought. Thanks!

GreeBo

In the absence of high winds/wind chill you would be better off outside the car.
Car acts like a fridge and will suck the heat out of you and make you colder. (Obv once the battery is dead!)

KCross

goz83 wrote: »

Ok well I guess the heat to maintain 20c would draw ~2kWh so with a full battery (22 usable) that’s 11 hours.

I dont think it would need a sustained 2kW to maintain the heat based on the output I see in LeafSpy.

It uses that initially to get up to the temp but it would be using ALOT less than 2kW after that so I'd say it would last several days but I dont know exactly how long.

GreeBo

KCross wrote: »

I dont think it would need a sustained 2kW to maintain the heat based on the output I see in LeafSpy.

It uses that initially to get up to the temp but it would be using ALOT less than 2kW after that so I'd say it would last several days but I dont know exactly how long.

A lot easier to heat to 20c when its not -11c outside!

Orebro

You'd hardly bump it to 20 degrees in such a situation? Surely 17/18 would be plenty and extend the battery time even more.

unkel

KCross wrote: »

I dont think it would need a sustained 2kW to maintain the heat based on the output I see in LeafSpy.

It uses that initially to get up to the temp but it would be using ALOT less than 2kW after that so I'd say it would last several days but I dont know exactly how long.

+1

I'd say an average of a few hundred watts would be plenty to survive and be reasonably comfortable (in your winter cloths), so then you are talking 4-5 days. Melt the snow and drink it and anyone can do without food for a few days no bother.

Not so sure how long a petrol / diesel would last with a running engine. Anyone any idea?

GreeBo

unkel wrote: »

+1

I'd say an average of a few hundred watts would be plenty to survive and be reasonably comfortable (in your winter cloths), so then you are talking 4-5 days. Melt the snow and drink it and anyone can do without food for a few days no bother.

Not so sure how long a petrol / diesel would last with a running engine. Anyone any idea?

I thikn you are massively underestimating the energy required to keep something warm in the current temperatures.

There is no effective insulation in a car, so the heat is not going to last, it will be sucked out of the car *and you* very quickly.

https://www.heatershop.co.uk/roomcalculator?confirm=&roomwidth=2&roomlength=2&insulation=N&zone=B&north=Y&calculate=Calculate#MainContent

460W to heat a 2x2 room to 21C

KCross

GreeBo wrote: »

I thikn you are massively underestimating the energy required to keep something warm in the current temperatures.

There is no effective insulation in a car, so the heat is not going to last, it will be sucked out of the car *and you* very quickly.

https://www.heatershop.co.uk/roomcalculator?confirm=&roomwidth=2&roomlength=2&insulation=N&zone=B&north=Y&calculate=Calculate#MainContent

460W to heat a 2x2 room to 21C

460W is a lot less than 2kW though. thats the point.

GreeBo

KCross wrote: »

460W is a lot less than 2kW though. thats the point.

Its a lot easier to heat a room than a metal car sitting in -11C is my point.

You seals will shrink allowing cold air inside
You will need to crack a window so you dont poison yourself, again allowing cold air in.

pablo128

Carry a shovel with you along with suitable clothes hat and gloves. A bit of shovelling will warm you up quickly and you might even be able to free your car and continue your journey.

unkel

unkel wrote: »

............

Not so sure how long a petrol / diesel would last with a running engine. Anyone any idea?

Well loads of stuff will return 50mpg when cruising at 60 ish mph.
55l / 12 gallon fuel tank would then let you cruise for 10 hours.
Considering you'd be at 2000rpm ish and be encountering aerodynamic issues and lugging the car about obviously I'd think it logical enough to presume that at idle (800rpm) the thing could go for 3 or 4 times as long
So 30/40 hours.

liamog

GreeBo wrote: »

Its a lot easier to heat a room than a metal car sitting in -11C is my point.

You seals will shrink allowing cold air inside
You will need to crack a window so you dont poison yourself, again allowing cold air in.

Car's aren't sealed enough to have a risk of poisoning if you leave the heating on.

GreeBo

liamog wrote: »

Car's aren't sealed enough to have a risk of poisoning if you leave the heating on.

Its either sealed enough that the build up of CO2 (not carbon monoxide) will cause you problems OR its not sealed enough and so you will freeze.

You cant have it both ways

pablo128

GreeBo wrote: »

Its either sealed enough that the build up of CO2 (not carbon monoxide) will cause you problems OR its not sealed enough and so you will freeze.

You cant have it both ways

There are usually 1 way vents in the quarter panels.

GreeBo

pablo128 wrote: »

There are usually 1 way vents in the quarter panels.

So either you are getting fresh air or you are not.

Fresh air will be sub zero.
Stale air will have increasing levels of CO2.

pablo128

GreeBo wrote: »

So either you are getting fresh air or you are not.

Fresh air will be sub zero.
Stale air will have increasing levels of CO2.

Recirculating air in a car will contain approx 5% fresh air. Believe it or not, car makers spend millions developing vehicles to be used in all types of conditions. They will have realised a thing or 2 about heating in cars over the last 100+ years.

GreeBo

GreeBo wrote: »

So either you are getting fresh air or you are not.

Fresh air will be sub zero.
Stale air will have increasing levels of CO2.

With the heating on the air is coming in through a pollen filter or not through a pollen filter.

As said if on recirc you are still getting some fresh air as part of the mix.

The fresh air you mention is heated before it gets into the cabin That's what the ole heater thing does

GreeBo

Augeo wrote: »

With the heating on the air is coming in through a pollen filter or not through a pollen filter.

As said if on recirc you are still getting some fresh air as part of the mix.

The fresh air you mention is heated before it gets into the cabin That's what the ole heater thing does

Agreed, but this air is well below freezing, so heating it to aint cheap.

Add in the heatloss through the complete lack of any insulation and I think people talking about a few hundred W are way off the mark.

Thankfully I will never need to find out.

goz83

GreeBo wrote: »

Agreed, but this air is well below freezing, so heating it to aint cheap.

Add in the heatloss through the complete lack of any insulation and I think people talking about a few hundred W are way off the mark.

Thankfully I will never need to find out.

The OP said to use current temps. Its not well below freezing in dublin. I was in the car earlier and outside temp was 4 above.

GreeBo

GreeBo wrote: »

Agreed, but this air is well below freezing, so heating it to aint cheap.

Add in the heatloss through the complete lack of any insulation and I think people talking about a few hundred W are way off the mark.

Thankfully I will never need to find out.

I'm not bladdering on about a few hundred W .........just pointing out that you were totally incorrect with the "You will need to crack a window so you dont poison yourself, again allowing cold air in." speel

GreeBo

Augeo wrote: »

I'm not bladdering on about a few hundred W .........just pointing out that you were totally incorrect with the "You will need to crack a window so you dont poison yourself, again allowing cold air in." speel

I didnt say that you were. Unless you consider yourself to be "people"?

goz83 wrote: »

The OP said to use current temps. Its not well below freezing in dublin. I was in the car earlier and outside temp was 4 above.

Weather over the last few days has dropped below -5 at night.

GreeBo

Also, most of the air isnt coming in through a vent, unless you believe your car is airtight other than the air vents...?

Freezing air will be coming in everywhere.

pablo128

GreeBo wrote: »

Freezing air will be coming in everywhere.

No it won't ffs. If it was, there would be thick ice on the inside of every car parked overnight by now.

GreeBo

GreeBo wrote: »

Also, most of the air isnt coming in through a vent, unless you believe your car is airtight other than the air vents...?

Freezing air will be coming in everywhere.

So with the fan on most of the air will be coming in from "other than the air vents"?

Did you ever drive with no fan on and the car fogs up?
Why would it do that?

TBi

My i3 went through about 5% per hour at -1C yesterday. Don't ask why i was in the car for an hour

That was with fresh air coming in and being warmed up to 20c in cabin. So about 20 hours off a full battery, more if i'd put it on recirculate for a while.

liamog

Did you not hear about all the people who die of CO2 poisoning because they are on a long drive and didn't crack the window open.

TBi

liamog wrote: »

Did you not hear about all the people who die of CO2 poisoning because they are on a long drive and didn't crack the window open.

Yep it's an epidemic! I always drive with all 4 windows fully down and roof down for this reason!

(/s in case anyone doesn't realise)

GreeBo

Augeo wrote: »

So with the fan on most of the air will be coming in from "other than the air vents"?

With the fan on obviously more air will be coming through the vents as its forced air.
My point was that thats not the only source of air, and also the other openings allow warm air to leave the car.

Augeo wrote: »

Did you ever drive with no fan on and the car fogs up?
Why would it do that?

Why?

Because the warm air I am breathing out condenses on the cold surfaces.

Warm air being able to hold more H2O than cold air.
Thats why it doesnt happen in summer.

GreeBo

liamog wrote: »

Did you not hear about all the people who die of CO2 poisoning because they are on a long drive and didn't crack the window open.

So now you agree that there is air coming in from other than the vents?

Which is it? You keep changing sides.

GreeBo

TBi wrote: »

My i3 went through about 5% per hour at -1C yesterday. Don't ask why i was in the car for an hour

That was with fresh air coming in and being warmed up to 20c in cabin. So about 20 hours off a full battery, more if i'd put it on recirculate for a while.

Interesting, but I dont believe the power consumption or temperature drop would be linear. An hour isnt long enough to draw conclusions imo.

liamog

GreeBo wrote: »

So now you agree that there is air coming in from other than the vents?

Which is it? You keep changing sides.

Take a little more time to read my posts.

liamog wrote:

Car's aren't sealed enough to have a risk of poisoning if you leave the heating on.

Greybottle

A standard petrol or diesel car (1.6-2.0l) will use 0.9-1.3l of fuel per hour in idle depending on circumstances, equipment being used etc.

So a typical 50l tank will run for 40 hours give or take. It's a matter of heating the car up in cycles. If you are caught in a snow drift the snow around the car will have an insulating effect, but you have to exit the car every so often to make sure air can get into the engine and out via the exhaust.

I learned the above whilst working in Siberia in the 1990's. But you always carried spare fuel, a proper sleeping bag, reindeer skins, proper clothing, gas cooker, spare food and a box of emergency supplies with you anyway, so in theory you could survive a number of weeks if stranded. Of course you always told someone where you were going and checked in with them when you arrived.

GreeBo

Greybottle wrote: »

A standard petrol or diesel car (1.6-2.0l) will use 0.9-1.3l of fuel per hour in idle depending on circumstances, equipment being used etc.

So a typical 50l tank will run for 40 hours give or take. It's a matter of heating the car up in cycles. If you are caught in a snow drift the snow around the car will have an insulating effect, but you have to exit the car every so often to make sure air can get into the engine and out via the exhaust.

I learned the above whilst working in Siberia in the 1990's. But you always carried spare fuel, a proper sleeping bag, reindeer skins, proper clothing, gas cooker, spare food and a box of emergency supplies with you anyway, so in theory you could survive a number of weeks if stranded. Of course you always told someone where you were going and checked in with them when you arrived.

+1

The biggest killer for an ICE is the exhaust getting blocked and the car filling with Carbon Monoxide, it can be as quick as 7 minutes.

Another positive for EVs!

+1 on intermittent warming of the car.
You are not going to get it or keep it at 20C in current conditions.

You just want to keep it above freezing so you dont die of exposure.

GreeBo

GreeBo wrote: »

With the fan on obviously more air will be coming through the vents as its forced air.
My point was that thats not the only source of air, and also the other openings allow warm air to leave the car.
........

But the topic is asking how long can you run the heating for.... so the fan is on

GreeBo wrote: »

Also, most of the air isnt coming in through a vent, unless you believe your car is airtight other than the air vents...?

Freezing air will be coming in everywhere.

insular1 wrote: »

...... how long could you expect the car could run the heating for before battery died?

Anyone know roughly how long an ICE could maintain heat on a nearly full tank?

goz83

GreeBo wrote: »

Weather over the last few days has dropped below -5 at night.

Thats straining to suit your point. We can at least agree that average temps over 24 hours are 0.

unkel

I have looked at local temp on my phone many times day and night over the last 48 hours and it nearly always said -1 (with real feel temps varying between -12 and -16), but in your car of course there is no wind chill factor to speak of

TBi

GreeBo wrote: »

Interesting, but I dont believe the power consumption or temperature drop would be linear. An hour isnt long enough to draw conclusions imo.

I was in the car for about 3 hours. Preconditioned and i drove for about 40 minutes of it... 56% when i checked. 45% 2 hours later. I'd started with a full battery :S

GreeBo

goz83 wrote: »

Thats straining to suit your point. We can at least agree that average temps over 24 hours are 0.

Average is feck all use. The min is what you need to care about if you are stranded outside.

I'd prefer 24 hours of -1 than 12 of +10 and 12 of -10.

unkel wrote: »

I have looked at local temp on my phone many times day and night over the last 48 hours and it nearly always said -1 (with real feel temps varying between -12 and -16), but in your car of course there is no wind chill factor to speak of

There is no wind chill directly on you, there is however on your car.
All the heat coming out of your heater is trying to heat the cold structure of the car, the wind is busy whipping away all that heat.

TBi wrote: »

I was in the car for about 3 hours. Preconditioned and i drove for about 40 minutes of it... 56% when i checked. 45% 2 hours later. I'd started with a full battery :S

You said "dont ask why I was in the car for an hour"

I'm not following your description of what you were doing and when you were driving/not tbh.

TBi

GreeBo wrote: »

You said "dont ask why I was in the car for an hour"

I'm not following your description of what you were doing and when you were driving/not tbh.

Just trying to help the OP. I think i'll stop commenting on this thread now. Especially after your wonderful contribution!

GreeBo

TBi wrote: »

Just trying to help the OP. I think i'll stop commenting on this thread now. Especially after your wonderful contribution!

As am I.
I just cant follow your post regarding your 3 hours in the car.

However, if you cant post without getting personal then I'm happy for you to stop posting tbh.

BoatMad

I read through this thread , as a general comment , GreeBoo , stick to the day job , you have very little understanding of Heting cooling and car systems in general . For a start a car static takes far far less to heat it then moving through cold air at 60 mph !!!!

Based on the newer Leaf , I say you'd have 24 hours or more on the the efficient heat pump , far more then needed to be rescued

GreeBo

BoatMad wrote: »

For a start a car static takes far far less to heat it then moving through cold air at 60 mph !!!!

Maybe i missed it, but did anyone argue this point?