daveo4EV
Well-Known Member
- First Name
- David
- Joined
- Jan 28, 2019
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- 33
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- 646
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- 973
- Location
- Santa Cruz
- Vehicles
- Macan Turbo,Cayenne Hybrid, 911(s) GT3/Convertable
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- #1
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"…
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!
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…
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!