[FAQ] - Why do EV's take such a big "hit" in cold weather…new owner overview

[daveo4EV]

it's well known to most potential EV owners that cold weather range takes a big hit with an EV - this surprising some people is a core reason in my opinion that has caused EV's to fall out of favor recently - I'm hoping this is temporary and EV's will come back and we're in a normal adoption curve for "new tech" - time will tell…

what is less well known is "why" EV's take the big range hit - other than "it's cold"

over the years this topic has been extensively discussed in other EV forums…so this post will list the top "issues" that on a combined basis add up to the total range hit we all know and love with our favorite EV's

each one of the factors below are a significant impact to battery capacity - but when you combine all of them it becomes even worse…cold weather driving is an EV's nemesis and really a perfect storm of EV "weaknesses"…

• Cold LiON cells are less efficient at "giving up power" - if you ask a cold LiON cell to give up electrons more electrons are "lost" to overhead and less current/voltage is provided
• Cold LiON cells have less total capacity - they do not have as many kWh's to give when they are cold - so there is less total power available
• cold air is more dense, and above 40 mph aero-dynamic loads are significant consumer of available battery capacity - it take more power to move the EV at 60 mph in 24F air vs. 62F air…and aeroloads have a V^2 (velocity squared) component - so it gets really expensive to move things around in colder denser air
• road conditions tend to be worse in the winter - so you have greater rolling resistances just from general road condions
• if you have winter tires - they are less efficient than all season or summer tires
• all season/summer tires are less efficient if they are colder
• those pesky cabin occupants want to be kept warm while driving - so more battery power is used to heat the cabin - and heating a cabin is actually more expensive than cooling the cabin in the summer - so more battery power is "lost" to cabin temperature maintenance which is lost range
• the battery also wants to be kept warm so some battery power is used to heat the battery and keep it in an ideal temperature range (partly to address items 1 & 2 on this list) heating the LiON cells "unlocks" some additional efficiencies and capacity vs. leaving them cold…
  • but it's a fine line to spend battery power to heat a cell to gain capacity/efficiency - it's easy to lose more power than you gain…
• cold batteries can not charge as fast as "warm" batteries - and it's really really expensive to get a battery into ideal temperature range at 14F ambient temperatures - so your charging stops will be longer because you can't charge a cold battery at it's maximum charge rate
  • also the charging equipment might be derated in cold conditions so it may not have as much power to "offer" a cold battery
• more power is "lost" during the charging session to cold LiON battery cells so less power "lands" in the battery during charging causing charging to take longer…

each of the items listed above are significant impacts to over all battery capacity/efficiency and therefore range you can drive, but I think you can see the combined impact of all of these factors leads to significant overall capacity loss for current generation EV's - it's all the factors combined that make winter and EV's simply suck- frankly I'm surprised they do as well as they do given all the factors…

but the good news is most of these factors are mitigated and removed when the weather turns back to warmer temps (45F and higher) and you start to claw back/reduce the impacts of these factors, and by the time you're mid-50's and low 60's there is ilttle if any impact at those temps and EV's start to perform really really well…

at the moment there is little that can be done with these factors, and my best advice is go in "eyes open" - your EV is not as good in 14F weather as it is in 57F weather, but with some planning it will still work and hopefully for daily driving duties the loss in range is not a factor - but for road tripping plan accordingly and plan ahead if you're trying to go for distance and it's 45F or less along your route, there is virtually nothing you can do to mitigate or overcome the factors listed above - so forewarned is forearmed and plan accordingly!

 

[Yves]

All the items you list are true, but I feel only 2 really contribute to significant range loss, speed and climate control … that last one is very visible I see in my iX or ID3 the immediate impact on predicted range in some cases the climate is responsible of more then 50% of the “lost range”. Seat and steering wheel are hardly noticed and if you charge before driving the cold IONS are not really as bad, leaves us with the density of AIR … Pretty sure 80% of the loss can be attributed to Climate control and Air density / speed …

So that leaves us with a simple trick, charge and heat the cabin before you depart … you gain back up to 50% of that “lost range”

 

[Salmonfisher]

Yves
I am surprised you see such an effect from air conditioning. Do both your cars have a heat pump.l? On my Polestar with heat pump I do see a loss in range in cold weather (cold in UK is usually only 0 C or just below) but nothing anywhere near 50% and air conditioning does affect it but not by that much. Since my early enthusiasm for turning it off and relying on seats I now just leave it on and stay comfortable and live with the reduced range which is only 10% or so. The cold air drag and loss of battery capacity at low temperatures seem to have much more affect.

 

[W1NGE]

Yves
I am surprised you see such an effect from air conditioning. Do both your cars have a heat pump.l? On my Polestar with heat pump I do see a loss in range in cold weather (cold in UK is usually only 0 C or just below) but nothing anywhere near 50% and air conditioning does affect it but not by that much. Since my early enthusiasm for turning it off and relying on seats I now just leave it on and stay comfortable and live with the reduced range which is only 10% or so. The cold air drag and loss of battery capacity at low temperatures seem to have much more affect.

Depending on region the heat pump is not standard and not obvious to most what the advantage of having one is.

 

[KJohn3333]

Having had a Jaguar Ipace EV for 4 years I would say I lost about 30% range in cold weather doing mainly stop/start short journeys of just a few miles. On a full 100% charge the range for me was always at least 60 miles (If not more) below the maximum claimed range even in hot weather and driving conservatively in Eco mode.

For this reason I'm not expecting the Macan 4 with 21" wheels that I'm getting in January to ever exceed 260 miles on a full charge. Although I accept some people will get more range driving at constant motorway/highway speeds over longer distances.

 

[Salmonfisher]

Having had a Jaguar Ipace EV for 4 years I would say I lost about 30% range in cold weather doing mainly stop/start short journeys of just a few miles. On a full 100% charge the range for me was always at least 60 miles (If not more) below the maximum claimed range even in hot weather and driving conservatively in Eco mode.

For this reason I'm not expecting the Macan 4 with 21" wheels that I'm getting in January to ever exceed 260 miles on a full charge. Although I accept some people will get more range driving at constant motorway/highway speeds over longer distances.

I think this is key. Short journeys really hit range even more than the cold. The vast majority of my mileage is on 150 mile journeys or more largely on motorways. In cold weather the predicted range can be quite low for first 10/20 miles and then climbs back to much nearer the summer range. This is why I never believe the predicted range as I always beat it and often by between 10 and 20%. The plus of short journeys is it’s easy charge cheaply at home so range becomes irrelevant

 

[Yves]

Depending on region the heat pump is not standard and not obvious to most what the advantage of having one is.

I have 2 cars with WP and one without, as soon as I put heating on the loose the same amount of range

Yves
I am surprised you see such an effect from air conditioning. Do both your cars have a heat pump.l? On my Polestar with heat pump I do see a loss in range in cold weather (cold in UK is usually only 0 C or just below) but nothing anywhere near 50% and air conditioning does affect it but not by that much. Since my early enthusiasm for turning it off and relying on seats I now just leave it on and stay comfortable and live with the reduced range which is only 10% or so. The cold air drag and loss of battery capacity at low temperatures seem to have much more affect.

I have one with WP and one without this weekend I put on the heating and saw almost identical loss of range predicted toggling of or on ... around 30km's off with 8C ambient ...

The difference between an ID3 with and without WP is measured to be 8% range impact so I thought the difference would be more, but hard to tell ... but an indication heating has a big impact, with or without WP ...

 

[whitex]

The main mitigation for cold weather EV driving is to plan ahead and preheat your car and its battery from shore power prior to departure. Shore power can either be AC EVSE or DC charger. That's what departure timers are for. This will extend your range as the car starts with an already warm battery and cabin.

Note on DC charging during multi-day road tripping. At the end of a day's drive, if you are planning to DC charge, charge before turning in for the night, or the battery will be cold in the morning which will result in slow DC charging. If you need max range next day, preheat the car using a departure timer, then top it off at the DC charger before departing (battery should be warm enough to handle top end of SoC charging, if not, do some hard accelerations to warm it up further). Of course even better is to stay somewhere with a destination charger, then the car can charge overnight and pre-heat from shore power using departure timer.

 

[W1NGE]

The main mitigation for cold weather EV driving is to plan ahead and preheat your car and its battery from shore power prior to departure. Shore power can either be AC EVSE or DC charger. That's what departure timers are for. This will extend your range as the car starts with an already warm battery and cabin.

Note on DC charging during multi-day road tripping. At the end of a day's drive, if you are planning to DC charge, charge before turning in for the night, or the battery will be cold in the morning which will result in slow DC charging. If you need max range next day, preheat the car using a departure timer, then top it off at the DC charger before departing (battery should be warm enough to handle top end of SoC charging, if not, do some hard accelerations to warm it up further). Of course even better is to stay somewhere with a destination charger, then the car can charge overnight and pre-heat from shore power using departure timer.

Timers don't work with DC remember unless different on J1.2 / Macan EV

In my experience my battery doesn't get warm enough to make a difference as I only preheat for a short time.

Using shore power to preheat doesn't work in isolation and needs to be combined as part of a charging session. Again this is my experience and may be attempting something different.

Using automated off peak charging periods may also be problematic as the charging may complete long before your departure time and if not reliably using shore power then the HV will take a hit.

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