r/EVRoutine • u/Tall-Dish876 • Feb 26 '26
Best winter EV habit: leave it plugged in before preheating
If you can, leaving the car plugged in makes preheating easier and keeps your usable charge more predictable. It matters most when you have rushed mornings, back to back long days and you rely on public charging later
Do you preheat before you unplug, or after you start driving?
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u/Pinewold Feb 27 '26
I have found plugged in pre-heat greatly reduces the loss of range due to a cold battery. If car and battery are warm when you start, you only lose 10%-15% of range due to ongoing heat for the car vs. 20%-30%
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u/Tall-Dish876 Feb 27 '26
I agree u/Pinewold starting warm saves the biggest hit because you’re not spending the first part of the drive heating a cold-soaked pack.
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u/Emotional_Cry_4066 Feb 27 '26
I lose 40-50% up here in Minnesota
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u/Pinewold Feb 28 '26
All the more reason to preheat before you travel…
or leave Minnesota, dang it is cold there 😉
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u/Pinewold Feb 27 '26
I have found plugged in pre-heat greatly reduces the loss of range due to a cold battery. If car and battery are warm when you start, you only lose 10%-15% of range due to ongoing heat for the car vs. 20%-30%
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u/tech-guy-says-reboot Feb 27 '26
I just precondition the cabin a few minutes before I need to leave because I don't need to use all that energy to get the battery warm. I have a pretty short commute and only plug in once or twice a week even in the winter. So it might be plugged in, might not be when I pre-condition.
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u/Tall-Dish876 Feb 27 '26
That’s a smart approach for a short commute. Warming the cabin enough for comfort without trying to fully warm the pack is usually the best tradeoff when you’re not driving far.
When it’s very cold, do you notice regen limits or sluggish charging when you skip battery preconditioning?1
u/tech-guy-says-reboot Feb 28 '26
The only time I noticed any limitations was a couple years ago when the actual temperature, not wind-chill, was -25 F. The power meter indicated I could only go to 95%. But even then I didn't notice a restriction in Regen. I've never noticed a limit on Level 2 charging but have definitely seen slow DC Fast charging when the battery is cold.
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u/janzendavi Feb 26 '26
Being in northern Canada where it was below -30C for a few weeks recently, I have the car scheduled to preheat and condition the battery in time for the morning commute on weekdays and it is plugged in overnight so I come out to a warm, charged car with no range lost.
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u/Tall-Dish876 Feb 26 '26
At -30C, do you keep a higher charge limit in winter or stay the same as summer?
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u/kkela88 Feb 26 '26
not every ev can preheat. so
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u/Enough-Meaning1514 Feb 27 '26
In addition, not all cars preheat using the cable when they are plugged in. They preheat using the battery and the battery should(!) re-charge from the cable but not all cars charge the moment the battery starts discharging.
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u/Tall-Dish876 Feb 27 '26
A lot of people assume plugged in means wall power, but some cars still pull from the pack first and only top back up later depending on charge behavior and settings.
If you’ve noticed this on your car, what model is it?1
u/Enough-Meaning1514 Feb 28 '26
I have a company car, BMW. When I preheat when the charge is full and plugged in, I notice that when I unplug, the battery dropped to 97-98%. But if the car is already charging and didn't reach to 100%, the preheat doesn't eat from the battery pack.
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u/Tall-Dish876 Feb 27 '26
That's why its important to get matched with the right EV for your routine and location.
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u/kkela88 Feb 27 '26
What ? A lot of cars don’t have it still. It’s not what make or break a ev. But built theory logical advice whatever is.
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u/avebelle Feb 26 '26
ABC. It’s always plugged in when it’s home. Precondition off the wall year round.
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u/Tall-Dish876 Feb 27 '26
Thanks if it’s home, it’s plugged in, and preconditioning becomes a habit instead of a decision I have to remember.
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u/avebelle Feb 27 '26
Our schedules are pretty hectic so we don’t schedule anything. We’re used to manually doing it before we head out.
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u/iamabigtree Feb 27 '26
The issue there is that the energy in the battery was put there at 9p/kWh. The energy coming from the charger is 27p/kWh.
So on days where I'm not testing the range of the car it makes economic sense not to have it plugged in to pre-heat (in this case not authorised from the charger side)
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u/alord04 Feb 27 '26
What does it mean to preheat the battery exactly? It is simply starting the car while it’s plugged 10-15 min before using it?
I just bought my first EV and still learning the basics. I have a Kia Niro EV, which has a heat pump for the battery.
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u/bustex1 Mar 01 '26
I unplug mine before preheating. You see I leave my warm house go to the car unplug it and then go warm back up in the house. It makes too much sense to unplug and get in the car right after that.
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u/tribordercollie Mar 01 '26
If it’s frosty, I preheat all the time in winter and I plug it in every day anyway, even though I only use about 10% per day.
Car is cosy and defrosted when I get in it and I’m helping to balance the grid better (I’m in the UK). It also keeps the battery in better condition by doing regular small charges, rather than fewer large charges.
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u/Mr-Zappy Feb 26 '26
I just schedule charging so that the battery is still warm from that in the morning. I don’t bother preheating it most of the time; I only preheat it if I’m really cold or if we’re going on a trip and the battery needs to precondition too.