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The cold hard truth about electric vehicles in winter

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Re: The cold hard truth about electric vehicles in winter

#51

Post by jeffrallen »

brianwawok wrote: post #14
jeffrallen wrote: post #5

Earlier quoted context omitted.

The heat pump is for the batteries. If there's some heating/cooling left over, it's for the meatbags.

I don’t think many people are driving around in winter with a 30 degree cabin temp. IME meat bags get priority at all times except while supercharging, when the temp can go pretty wild while it focuses on the battery.

I drive a Renault Zoe which has a heat pump and air-cooled batteries, and I can tell you that the Renault engineers were very protective of the battery. I've never had a problem with the cabin temperature, but it's clear that the HVAC system is sized and optimised for the batteries. For example, when charging cold batteries, the blower revs up much higher than it would ever go for the cabin.

Re: The cold hard truth about electric vehicles in winter

#52

Post by tonymet »

There are other winter issues as well. Door handles freeze, LCD screens fail, cameras and headlights are iced up, stability control fails

Complex systems are convenient in ideal conditions but they suffer in extreme conditions.

Expect more extremes winters in the coming years (as mild winter trends reverse).

Re: The cold hard truth about electric vehicles in winter

#53

Post by simfree »

vanous wrote: post #47
simfree wrote: post #33

Earlier quoted context omitted.

OP should have gone by percentage of battery left, and just left the car plugged in. Not plugging in when arriving and letting the battery freeze (cold soak) overnight, unplugging after 30 minutes of 1.5kW level 1 charging and basing his entire decisions on what the car's guess-o-meter says for remaining milage is pretty crazy IMO. Seems like OP chose to do the worst thing possible at each juncture to ensure a bad ch…

I am all for EV, but if besides needing to take care that I plug my phone and my watch every night I must also not forget to plug in the car and if I forget, I must apologize at work for not coming in, or my kids cannot go to school... just because it easily can get to -15°C here... then it feels like a technology issue and not like me doing the worse thing possible...

If you plug in every night and miss a night you can almost certainly make it to work the next day, unless your a supercommuter with an older EV that had a small 24kWh pack.

Re: The cold hard truth about electric vehicles in winter

#54

Post by petermcneeley »

swayvil wrote: post #45

Flywheels. What's the state of the tech for that? Surly that's where we should be developing. Last I heard they're very efficient. In theory it has no ceiling, storagewise. And it certainly isn't constrained by a chemical reaction. The only downside is keeping it from blowing up. Right?

My friend you have come to the right place. https://news.ycombinator.com/item?id=34079497

Re: The cold hard truth about electric vehicles in winter

#55

Post by hinkley »

I wonder how much of this can be addressed with active versus passive cooling of the batteries.

One of the folk tricks with cold starting regular vehicles is to run the radio for a little bit, in order to warm the battery up just a little to help with cranking the engine. If you conserve the waste heat in the battery banks until the batteries hit 50ºC for instance, then they would spend less time at ambient temperatures once you start moving. Some of that could offset/be offset by the cabin heating system, if you did it right.

But I think the math comes down to the question of whether cooling a battery to freezing reduces the potential energy in the battery, or just the recoverable energy. I think it's the latter, and if so then how much recoverable energy can you increase by converting a given amount of that energy into BTUs to warm the battery?

Re: The cold hard truth about electric vehicles in winter

#56

Post by saturn_vk »

vanous wrote: post #47
simfree wrote: post #33

Earlier quoted context omitted.

OP should have gone by percentage of battery left, and just left the car plugged in. Not plugging in when arriving and letting the battery freeze (cold soak) overnight, unplugging after 30 minutes of 1.5kW level 1 charging and basing his entire decisions on what the car's guess-o-meter says for remaining milage is pretty crazy IMO. Seems like OP chose to do the worst thing possible at each juncture to ensure a bad ch…

I am all for EV, but if besides needing to take care that I plug my phone and my watch every night I must also not forget to plug in the car and if I forget, I must apologize at work for not coming in, or my kids cannot go to school... just because it easily can get to -15°C here... then it feels like a technology issue and not like me doing the worse thing possible...

But that's a thing you learn. Just like you learn to check your oil level before starting in a conventional vehicle. Everything has its own set of things you have to know

Re: The cold hard truth about electric vehicles in winter

#57

Post by PhasmaFelis »

simfree wrote: post #33
justahuman74 wrote: post #27

Earlier quoted context omitted.

The 115v lines just arent enough, it may have been quite ok using a 240v though (from say a dryer plug)

OP should have gone by percentage of battery left, and just left the car plugged in. Not plugging in when arriving and letting the battery freeze (cold soak) overnight, unplugging after 30 minutes of 1.5kW level 1 charging and basing his entire decisions on what the car's guess-o-meter says for remaining milage is pretty crazy IMO. Seems like OP chose to do the worst thing possible at each juncture to ensure a bad ch…

If the "guess-o-meter" is so bad that it leads reasonable people to wildly wrong conclusions, I'm hesitant to blame that on the user.

If all the factors you described are understood by humans, why aren't they factored into the display algorithm? If the car is going to drain battery for an hour getting warm before it can start to charge, then say that on the display.

Re: The cold hard truth about electric vehicles in winter

#58

Post by Enginerrrd »

GalenErso wrote: post #32
brianglick wrote: post #28

Earlier quoted context omitted.

You wouldn't really need a heated garage (at home, anyway) if you had a 220 volt charger. That should be able to overcome any charging challenges in extreme cold, anyway. Relatively easy to get that into your garage. Also - if you arrive at your friend's place in the winter and park overnight, you won't lose a ton overnight if the car's just parked there.

Meanwhile, with an ICE car, you don't need to worry about having a garage, nevermind a heated one; the right charger, warming a pack, losing fuel overnight, or taking three hours to fully charge. I can pull up to any gas station and fill my tank in 2 minutes. And my gas isn't magically evaporating if it's a little chilly. The 30 different requirements for EVs to work in cold weather are too complex and prohibitively…

Yeah, the biggest thing EV proponents seem to miss is that you don't need to force it to be 100% for everyone. Confine any mandates to urban centers where it makes sense, you can get buy in from everyone and solve 95% of the problem. At that point there will be lower hanging fruits than the last 5% or w/e.

Re: The cold hard truth about electric vehicles in winter

#59

Post by TedDoesntTalk »

simfree wrote: post #46
gambiting wrote: post #41

Earlier quoted context omitted.

But......EVs do work in cold weather? You lose a bit of range, but so what? My ICE car also gets worse mileage in winter. And if you're talking about extremes - then there's a reason why block heaters with external power connections are very common in certain places - even the best ICE struggles to start in -40C or less.

18Mpg becomes 10Mpg or worse in the winter in my experience. EV driving can be more efficient if you don't let your battery cold soak for hours, or equally inefficient if you do leave your car unplugged overnight.

I live in place that routinely goes below freezing in winter. I’ve never noticed gas mileage change because of temperature. I would definitely notice a difference of 8 MPG. Where do you get that info? Is it personal experience? If so, where do you live?

Re: The cold hard truth about electric vehicles in winter

#60

Post by jeffbee »

guerby wrote: post #4

Fun test by Out of Spec Reviews on his Tesla Model 3: https://www.youtube.com/watch?v=i-c8AUeKs5c I Deep Froze My Tesla And Immediately Plugged It Into A Supercharger To See What Happens. I believe Bjørn Nyland did some similar testing too a while ago.

JHC the embodied carbon of just the junk in the driveway behind that guy is more than the lifetime carbon footprint of a typical African.
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