Cold Weather Observations

[larryh]

Here is an interesting article posted at the C-MAX forum regarding the effects of cold weather on the Leaf and the Volt:

 

http://news.fleetcarma.com/2013/12/16/nissan-leaf-chevrolet-volt-cold-weather-range-loss-electric-vehicle/

 

The Volt's range was reduced from 43 miles to 20 miles at 32 degrees.  Below 25 degrees, the ICE comes on.  The Leaf's range was reduced from 70 to 50 miles at -15 degrees.

Edited December 19, 2013 at 12:44 AM by larryh

[larryh]

I have noticed now in the winter that my 8 mile, one-way commutes to and from work take about 2.2 kWh of plug-in energy in EV mode as displayed on the trip odometer when climate control is turned off.  During the summer, they took about 1.7 kWh of energy.  The roads are dry and clear.  So the only difference is the temperature.  Does it really take 30% more power in the winter to overcome additional resistance/friction than in the summer?  It is expected the transmission fluid viscosity is higher in the winter, but does the cold make that much of a difference?  Are there other forces at work?  Not only does the battery provide less energy in cold weather, the heater consumes a significant amount and apparently the car also has to overcome significant additional resistance/friction in the winter.   All of this significantly impacts EV range.

Edited December 20, 2013 at 11:00 AM by larryh

[larryh]

Apparently, there are a number of factors for the increased energy consumption in winter driving.  Cold weather increases density of materials including air and lubricants.  The result is:

 

- Lower tire pressure.  Mine was down 5 lbs until I added more air. 

- Increased rolling resistance even when the tire pressure is properly maintained.  Rolling resistance due to stiffer tires can increase by 20% or more in cold weather.

- Increased aerodynamic drag since the air is denser.  That drag can increase by 10% or more in cold weather.

- Increased viscosity of lubricants requires more energy to overcome the extra drag. 

 

There are other factors as well:

 

- Higher electrical loads (less daylight means more headlights, rear defrosters, blower for climate control, etc.)

- Winter blends of gasoline provide less energy than summer blends.

- Its takes longer for the ICE to reach optimal operating temperature. 

Edited December 22, 2013 at 09:39 PM by larryh

[Fat Fusion]

All good points there Larry.  I just look at it like I look at my power bill.  It fluctuates throughout the year based on temp as well.  I think I'm going to just skip the preconditioning going forward.  It's so easy to remote start on my smart phone and it works so much better that I don't really see the need to precondition in central/northern CA.  

 

Come to think of it, the experience of driving most of my vehicles changes with the seasons.  The Mustang has 444 HP and is an animal in the winter with the cold dense air.  But it can't get traction which is far superior in the summer with the super sticky 285's.  The Falcon convertible works best in colder conditions but the top is always down since it's pretty tattered at this point making winter driving a bit chilly.  It is best at night in the summer with its black vinyl seats.  The truck really is most like the fusion in that it likes hot weather and gets more miles per gallon in the summer, 17 to 15 in the winter.   

[larryh]

Since you get more energy out of the HVB when it is warm and charging warms the HVB, setting the charge time so that charging completes just before your GO time helps ensure you get maximum possible range from the HVB when you leave.  Remote start and preconditioning also warm up the battery, by increasing ambient temperature as well as by discharging/charging the HVB.  With remote start, the battery is not fully charged when you leave.  It is fully charged with preconditioning.  However, if you can make to work and back without running the ICE, then remote start is probably more efficient than preconditioning. 

 

In my case, preconditioning uses a lot of energy (up to almost 3 kWh).  However, it allows me to drive to work using significantly less heat from climate control than I would otherwise.  Without preconditioning, the ICE would start and use more energy than that used for preconditioning.  I am unable to make it to work and back (16 mile commute) without running the ICE during the Winter when it is colder than about 20, so I am looking for ways to extend my range.   If only I had place to plug into at work (or a heated garage).

Edited December 22, 2013 at 10:36 PM by larryh

[FusionDad]

Folks,

 

This is a fascinating discussion.

 

I have only Summer experience driving across the country with my son in our Fusion Energi.  He has the car now in Kentucky, while I'm in Virginia.

 

However, I have 32 thou miles' and 18 months' experience with our other car, 2012 Prius Plug-In Advanced.  

 

I recognize all the general symptoms you all have written about here - the drastically lower Winter EV mileage above all.  In Priusland, most of us know to block the Prius engine grilles partially or once in a while fully to somewhat restore mileage.  Of course, Fusion Energi (at least our Titanium model) has active grille shutters which is a very nice feature to regulate engine temps.

 

The Prius Atkinson cycle engines, like the Fusion Energi Atkinson cycle engines, tend to run cooler than the Otto cycle engines we all grew up with.

 

I finally installed a Toyota Canada Engine Block heater in our Prius this Fall.  I'm very happy with it - plug it into an extension cord every morning right as I get up and get the paper before any other actions.  By the time I roll to work, the car warms up within 30 seconds and defrosts the windshield fast.  Note: this Prius lives outside all year.

 

Larryh - you mentioned that your Fusion Energi has an EBH installed.  Any lessons learned in EBH use so far this Winter?  BTW - my experimentation with our Prius EBH points to two - three hours as optimal time.  Of course, I live in Northern Virginia outside Washington DC, and not in Minnesota.

 

I'm thinking of helping Son by getting an EBH installed at the next Fusion tune-up but I'd like to hear from the community first.  Thanks in advance.

[larryh]

I responded to your other post regarding the engine block heater.  I park the car in an attached garage and use preconditioning from my 240 V charger.  That allows me to drive to work in a warm car.   And allows me to drive entirely in EV mode when the temperature is not below 0.   When the outside temperature is below zero, I will try the engine block heater and see if that reduces the gas consumed by the ICE for my commute to work.  That is the only benefit that I can think of that it could provide for my commute to work--the car is already warm from preconditioning.  The commute is relatively short, only 8 miles, or about 12 minutes.  Unfortunately, I have no where to plug in on my way home from work so I can't use the engine block heater or precondition the car.

 

I also have a longer weekend commute of 57 miles.  The best strategy for that commute is to get the ICE to run immediately to warm up the car and reserve EV operation until after the engine is warm.  The engine block heater would probably speed up the process for this case.  For the return trip, I only have 120 V outlets.  Preconditioning does not work with the 120 V charger.  So I will try the engine block heater instead for my commute back this weekend when it will be below zero.

Edited December 29, 2013 at 02:31 AM by larryh

[larryh]

The following graph shows the MPGe for my 60 mile commutes for the past six months as reported on MyFord Mobile.  The plot displays MPGe as a function of temperature to show the affect of temperature on mileage.  The mileage drops from about 68 MPGe at 78 degrees to 42 MPGe at 0 degrees.  -4 F is the coldest so far during these commutes.  I recharge the car at the destination using the 120 V charger.

 

Edited January 2, 2014 at 12:54 AM by larryh

[larryh]

The following graph shows MPGe for my 8 mile commutes to and from work as reported by MyFord Mobile for the past 6 months. As in the previous plot, this graph displays MPGe vs Temperature to show the impact of temperature on mileage.  Any MPGe above 70, the yellow line, is when I operate the car completely in EV mode.  Below the yellow line, the ICE has turned on.  The wide dispersion at lower temperatures is due to preconditioning.  I precondition the car in my attached garage (which is about 20 degrees warmer than the outside temperature) prior to leaving for work.  The car then sits outside all day at work in the cold until the drive home.  I don't have access to a charger at work.

 

Two things to note, I am able to drive to and from work completely in EV mode as long as the temperature is above 25 degrees.  Otherwise, the ICE will turn on during the return trip.  Secondly, even with preconditioning in the morning, when the temperature is below 0 degrees, the ICE will turn on.  The EV mode is set to EV Now when permitted by the car. The ICE turn on threshold for EV Auto mode is above 0 degrees.

 

For both the 60 mile and 8 mile commutes, I get the best mileage when the temperature is in the 70s. 

 

 

Edited January 2, 2014 at 12:56 AM by larryh

[tseibel76]

Great graphs larryh! What I find the most interesting is how similar the two graphs are. I would have expected consistently higher MPGe numbers for the 8 mile commute, since you can stay in all EV more. Great information!

[tseibel76]

I've started experimenting with EV Now in the cold. It appears it keeps the ICE off more than EV Auto, but only by a small margin. I'll keep testing.

 

The other day it was -10 F here all day. The car had sat out all day at work. I had set it to EV Now. When I started it up after work, the ICE did not fire right away (no climate). In those conditions in EV Auto, it would fire right away. It did eventually fire on the drive, but did not seem to run as much.

 

Then, at about 45% SOC, the car went back into EV Auto and said EV Now was not available. Thoughts?

Edited January 4, 2014 at 12:29 PM by tseibel76

[jeff_h]

Then, at about 45% SOC, the car went back into EV Auto and said EV Now was not available. Thoughts?

 

Did you turn on the front defrost alone?  I've found on more than one occasion that turning this on without the panel or floor as well will make the ICE come on no matter how much I've tried to avoid it.  It may not be a strict rule but seems to happen for me when trying to stay on 100% EV and that tanks it.

[tseibel76]

Did you turn on the front defrost alone? I've found on more than one occasion that turning this on without the panel or floor as well will make the ICE come on no matter how much I've tried to avoid it. It may not be a strict rule but seems to happen for me when trying to stay on 100% EV and that tanks it.

I didn't make any changes to the climate settings when it happened. It just showed up on the screen while I was driving. The ICE had already been cycling due to the cold and heater.

[larryh]

Great graphs larryh! What I find the most interesting is how similar the two graphs are. I would have expected consistently higher MPGe numbers for the 8 mile commute, since you can stay in all EV more. Great information!

I think the physics of cold weather overwhelms all other factors. 

 

For EV operation during the 8 mile commutes, at around 70 F, the best MPGe is around 160.  At 0 F, it is around 100.  Thus it requires 60% more energy at 0 F vs. 70 F.   These numbers assume preconditioning the car. 

 

For the 60 mile commute, the best MPGe at 70 F is around 70.  For 0 F, it is around 42.  It requires about 67 % more energy to operate at 0 F vs.  70 F. 

 

The 60 mile commute requires relatively more energy probably because the ICE needs time to warm up to reach optimal operating temperature.  It doesn't operate as efficiently until then.  In addition, the impact of preconditioning is less for longer trips.   I am able to use the the heater sparingly for the 8 mile commute since the cabin temperature will not cool off that much during the 13 minute drive.  However, for the 60 mile drive, the commute time is 75 minutes.  The heater is required to keep the car's interior warm.  The coolant temperature cools very rapidly when the ICE isn't running.  After about 3 or 4 miles, the electric heating element has to turn back on heat the interior.  The ICE simply has to run more to keep the cabin warm.  To prevent the heating element from turning on, I am forced to frequently switch operation between EV Auto and EV Later.  In the summer, I generally switch to EV Later when going 60 mph or more. 

 

So probably 60% more energy is required due to the physics of cold weather, i.e. greater aerodynamic drag, more resistance, greater fluid viscosity, etc.  Another 10% is probably required just to keep the car's interior warm and inefficiency of the ICE until it reaches optimal operating temperature.  Does an electric motor require more power to operate when it is cold vs warm?  Does it have an optimal operating temperature like the ICE?

Edited January 4, 2014 at 02:00 PM by larryh

[larryh]

I've started experimenting with EV Now in the cold. It appears it keeps the ICE off more than EV Auto, but only by a small margin. I'll keep testing.

 

The other day it was -10 F here all day. The car had sat out all day at work. I had set it to EV Now. When I started it up after work, the ICE did not fire right away (no climate). In those conditions in EV Auto, it would fire right away. It did eventually fire on the drive, but did not seem to run as much.

 

Then, at about 45% SOC, the car went back into EV Auto and said EV Now was not available. Thoughts?

 

The car seems to behave differently when I precondition the car in the garage which is about 25 degrees warmer than the outside temperature vs. leaving it outside in the cold. 

 

When I leave the car outside in the cold (below 0 F) and use EV Auto, the ICE will come on soon after turning on climate.  I have climate on manual.  If it is sunny out and the car is warmed by the sun, I can leave climate control off.  However, the ICE will eventually start after about 3 miles even in EV Now.  The battery charge is initially around 50%, but within 3 miles it rapidly falls.  When it reaches about 20%, it disables EV Now mode and the ICE starts.  I'm not sure what criteria is used to start the ICE, whether it is more than just the SOC of the HVB.  An experiment would be to see how far I could go if the car were outside and fully charged with climate control off in EV Now mode.  Does it disable EV Now mode before the SOC reaches 20%?  That is generally not possible since the windows will most likely frost up long before then. 

 

I find the the threshold for turning on the ICE for EV Auto vs. EV Now to be significant.  As I mentioned in another post, engine coolant temperature is also a factor in determining when the ICE comes on. 

Edited January 5, 2014 at 06:09 PM by larryh

[larryh]

Did you turn on the front defrost alone?  I've found on more than one occasion that turning this on without the panel or floor as well will make the ICE come on no matter how much I've tried to avoid it.  It may not be a strict rule but seems to happen for me when trying to stay on 100% EV and that tanks it.

 

I do not notice any difference when selecting the floor, windshield, or panel vents as long as I am in manual mode. 

[jeff_h]

I do not notice any difference when selecting the floor, windshield, or panel vents as long as I am in manual mode. 

I stay in manual mode, personally I hate auto mode as I want to control the speed of the fan.  Here is the behavior that normally happens for me, maybe I am using the controls in the wrong way or the wrong order, who knows. Maybe outside temps could also be a factor, the below occurs in temps around 20-40F, which is not known as 'cold' in MN or MI or similar locations - no need for jabs about VA weather as my relatives in WI already handle that quite well.  Anyway -

 

1) With climate off, I go to climate and choose the front panel (middle on MFT screen) and it tries to go to auto, I hit the fan speed to turn it down and out of auto - then add the defrost button (top, on MFT screen) and ICE stays off.

1a) From the above setting, when I remove the panel portion and leave it with defrost (top button on MFT) only, ICE then comes on and yellow light on lower center panel for front defrost indicator comes on.

 

2) With climate off, I go to climate and choose defrost button (top on MFT screen) - ICE immediately comes on and yellow light on lower center panel for front defrost indicator comes on.

[larryh]

I turn climate on, go to the climate screen, and select any of the vents:  windshield, panel, and/or floor.  That puts me in what I think of as "manual" mode.  The auto light is off.  It now stays in manual mode when I turn the climate on and off.

 

Note that when I turn off the climate control and then turn it back on, the fan speed starts out at the minimum speed.  It doesn't always seem to remember the previous fan speed setting when I turned it off.  I think fan speed remains in auto mode.  It probably is waiting for the heating element to warm up the heater core before restoring the fan speed?   This is rather annoying when I am trying to optimize climate use.  I want the fan speed to be restored to its original speed when I turn climate back on.   For my short 13 mile trip, there is no need to run climate for the entire trip after preconditioning the car.  I just turn it on occasionally to defrost the windows.  I also leave the temperature set to around 60 degrees to minimize energy usage for climate control.

Edited January 4, 2014 at 03:17 PM by larryh

[tseibel76]

I always leave my climate system on now.  I have it set to LO temp.  This does not seem to cause the ICE to fire at all (same as if I had the climate system off completely).  However, a benefit is that my windows don't fog up and the system always starts at wherever I left it when I shut the car off (usually, LO, lowest fan speed, floor).  jeff_h, it seems, from my experience, that if you leave one of the other modes on with defrost (i.e., floor or face vents), the defrost light does not come on and does not seem to be operating in "defrost" mode (which causes the ICE to fire).  I only run my defrost with either the face vents or floor vents (usually floor vents) at the same time.  This seems to prevent "defrost" mode firing.  

[larryh]

I left my car outside all night.  The temperature was about -15 F this morning.  Even in EV Now Mode, the ICE started immediately.  I had to put the key fob in the backup slot in the center console to start the car.   It wouldn't recognize the key fob otherwise.  The battery range shown on MFM was down to 11 miles from 19 yesterday when it was in the 20s.

Edited January 5, 2014 at 06:23 PM by larryh

[larryh]

I wonder how the backup slot in the console works.  Is this going to reliably start the car if the car fails to recognize the Intelligent Access Key (IAK)?  This is the second time the car has failed to recognize the IAK when left outside overnight in temperatures that reached -15 F.   After starting the car using the backup slot and letting it run for a minute or two, the IAK key works fine again.

Edited January 6, 2014 at 01:01 AM by larryh

[murphy]

There is a chip reader at the front edge of the slot.   The key contains either an NFC chip or an RFID chip or maybe something proprietary to Ford.  The key does not have to have batteries for the car to read the chip.

[Phatman]

Anyone having trouble opening their charger port door in this cold weather? I can't get my charge port door open. It maybe a coincidence but does the cold temperature has anything to do with it?

[tseibel76]

Anyone having trouble opening their charger port door in this cold weather? I can't get my charge port door open. It maybe a coincidence but does the cold temperature has anything to do with it?

I have noticed the door is a little more finicky in the cold, but I haven't had trouble opening it.

[larryh]

On my return trip home from work lately, it has been around 0 F.  I set the mode to EV Now.   I am able to drive about 3 miles before the ICE starts.  Eventually, I will get a notification that the engine is enabled due to system performance.  However, the ICE does not come on at that time.  It has basically switched to EV Auto Mode, but the left display still indicates it is EV Now mode.  In the Empower screen, the ICE turn on threshold outline now appears.  The threshold is normally absent in EV Now mode.  In addition, the EV now symbol below the battery icon, the square box containing EV, is now yellow, which I assume means it is disabled.  Finally, the fuel gauge, which is normally greyed out in EV Now mode, is no longer greyed out.  The display looks identical to what it would look like in EV Auto mode, except for the yellow box containing EV below the battery icon.

 

A mile later, the ICE does come on and I am no longer able to choose EV Now or EV Later modes.  The EV mode selection screen pops up on the display with the EV Now and EV Later choices crossed out.  The display is now the normal EV Auto display. 

 

I am not sure why the car displays an intermediate stage with a yellow EV icon below the battery icon before finally disabling EV Now and EV Later modes of operation and what criteria prompts the car to enter these two modes of operation. 

Edited January 8, 2014 at 11:43 AM by larryh