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submitted 11 months ago by misk@sopuli.xyz to c/technology@lemmy.world
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[-] roofuskit@lemmy.world 71 points 11 months ago* (last edited 11 months ago)

Is this really an article saying heat pumps are more efficient than resistive heaters? Yes, that is why heat pumps exist.

The biggest issue is the battery itself. If it gets cold enough you can have difficulty even charging an EV outdoors. I would be a lot more concerned with whether or not my battery is well insulated and heated. Heat pumps are great and should be the default, but unless you're going really far or have a very low range EV it's not a huge issue.

[-] bluGill@fedia.io 17 points 11 months ago

You still need resistive heat as heatpumps don't work below about -20C and those temperatures happen to at least some car buyers.

[-] GissaMittJobb@lemmy.ml 14 points 11 months ago

heatpumps don't work below about -20C

I don't think that's true? There are cold weather models that can work at COPs > 1.5 at -30C. Are we talking about a sizing constraint for the model here, perhaps?

[-] foggenbooty@lemmy.world 6 points 11 months ago

There are, but then I think you'd have problems with the effective rang of the AC in the summer. To my knowledge this is all about at what temperature the coolant is a liquid and when it's a gas (because that's how you exchange heat).

A traditional AC only needs coolant that does this at summer temperatures. A heat pump tries to use one that will work at colder temperatures as well. A cold weather heat pump goes even further but I think there is a sacrifice in AC efficiency in the summer.

Somone please correct me if I'm wrong. But I'm not sure if a do-it-all extreme cold and extreme hot heat pump exists, and as a car manufacturer you want to put in the one that will fit most cases, as opposed to a house which only needs to operate in the range of the climate it is built in.

[-] Cocodapuf@lemmy.world 1 points 11 months ago

It would make sense if the two stage heat pumps use different liquids in the different stages. I don't actually know how these are made, so I can't assert that this is how it works, but I would be surprised if it worked any other way.

[-] roofuskit@lemmy.world 3 points 11 months ago

Yes, they should have both.

[-] MagicShel@lemmy.zip 14 points 11 months ago

I know the resistive heater in my Volt can't compare to the heat put out by the ICE. Often in the winter we'll have to run the ICE to keep the cabin warm enough. It does have heated seats and wheel, but my wife is the type to set the heat to max until it gets too hot rather than just picking a temp and hitting auto to let the car manage it.

If the heat pump can put out more heat for less energy, that would be a boon. That might be the second biggest issue (next to range) that has my wife vetoing an all-electric car. She gets the next vehicle, but I want the one after that to be a full EV.

[-] AA5B@lemmy.world 13 points 11 months ago

Fwiw, I’ve never had a lack of heat from my cars heat pump. It even warms up faster than a gasoline engine would. Most importantly, I can turn it on remotely to get warm before I get in the car. I never had that with a gas engine

[-] TowardsTheFuture@lemmy.zip 12 points 11 months ago

Yeah and a lot are moving to heat pumps if they don’t already use them.

https://www.recurrentauto.com/questions/which-electric-vehicles-have-heat-pumps

There’s a list of models that have them.

[-] PlantJam@lemmy.world 6 points 11 months ago

If you have two cars, one EV and one ICE is a great option. I do recommend whoever is more enthusiastic about EVs get the first one, though.

[-] GreyEyedGhost@lemmy.ca 13 points 11 months ago

Yes, resistive heat is expensive, but that's only part of what makes heat pumps in cars more effective. They don't just heat your cabin, they heat your battery so you maintain range while it's cold out. Here's an article with more details and some pretty infographics.

[-] Ulrich@feddit.org 8 points 11 months ago* (last edited 11 months ago)

It defintely is a huge issue, considering resistive heaters use 3x as much energy. Most EVs have a "low range" and anything you can do increase it without adding more batteries and weight and cost, especially in winter, is a huge advantage.

[-] roofuskit@lemmy.world 3 points 11 months ago* (last edited 11 months ago)

The lowest range EV in the US is 114 miles. The average commute is 52 miles. Most EVs sold in the US have a range of 250 miles or more. So a resistive heater eating 10% of your range is way less of an issue than your battery not charging properly in cold weather. Again, heat pumps should be available, but they aren't going to save you if cold weather kills your battery.

[-] Ulrich@feddit.org 8 points 11 months ago

The average commute is 52 miles. Most EVs sold in the US have a range of 250 miles or more.

No one cares about "average commute" when buying an electric car and considering the offered range. They're thinking about long trips.

So a resistive heater eating 10% of your range is way less of an issue than your battery not charging properly in cold weather.

Who said anything about batteries "not charging properly"? What does that even mean?

heat pumps should be available, but they aren't going to save you if cold weather kills your battery.

We're not talking about killing batteries, we're talking about electric range. Heat pumps extend your electric range and 20 miles can absolutely be the difference between making it to the next charger or not.

[-] Jolteon@lemmy.zip 0 points 11 months ago

If only plug-in hybrids existed...

[-] frezik@midwest.social 1 points 11 months ago

Which have a whole bunch of issues of their own. Like increased mechanical complexity, and that you might use gas so seldom that it becomes significantly water by the time you do need it.

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[-] ikidd@lemmy.world 50 points 11 months ago

Actually, I'm surprised they weren't using them long before. It's basically AC with an extra valve. Thought they get priced like they're some sort of new technology.

[-] jqubed@lemmy.world 29 points 11 months ago

There was never really a need in ICE vehicles since they can primarily use waste heat from the engine.

[-] Ulrich@feddit.org 9 points 11 months ago

Pretty sure they meant EVs

[-] tb_@lemmy.world 4 points 11 months ago

Pretty sure @jqubed@lemmy.world meant to explain why they weren't a thing in cars in general

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[-] lemming741@lemmy.world 9 points 11 months ago

Vapor injection is the new technology. It's why older heat pumps were useless below 32f.

[-] ikidd@lemmy.world 8 points 11 months ago

Vapor injection becomes an excuse to downsize the compressor and lowers the cost, it seems. You could easily go lower than 32 if you oversized the pump before EVI, but those were only in specific heatpumps.

[-] echodot@feddit.uk 4 points 11 months ago

I suspect the reason for that was that the pumps used in car ACs are not really very powerful. They were alright for cooling the car down, but for heating heat up in a cold environment you need a fair amount of throughput, they work if you have the throughput, but you need it to be there.

They work by pulling ambient heat out a large part of the outside and dumping it into the small inside. You need many times the contents of the interior to warm up if it's a cold day outside. Thus you need a lot of air and if you want it to happen in a reasonable time frame you need quite a powerful little motor. The ones on houses are fine because they're huge anyway.

[-] Ulrich@feddit.org 8 points 11 months ago

It uses the same amount of energy to create cold as it does to create heat.

[-] Photon@feddit.org 1 points 11 months ago

Well it's about temperature differences, those are larger in winter I guess. On the other hand there is a lot more radiative heat load in summer...

[-] Chronographs@lemmy.zip 4 points 11 months ago

They also need to be able to get the cold side colder than the outside air so once it gets too cold they don’t really work. There can also be some problems with condensation but when they do work they’re great.

[-] kameecoding@lemmy.world 1 points 11 months ago

I reckon they thought seat heating and steering wheel was enough, and it kinda is for the most part

[-] king_tronzington@lemm.ee 22 points 11 months ago

As someone in a rural state, cold weather range is one of my chief concerns. I work from home but on the weekends travel to far away backcountry areas to ski.

I'd like to get a full EV when my current lease expires(2.5 years) but the pool of cars that are affordable, have AWD, and 300 miles of range(aka 180-225 in winter) is quite limited.

[-] chronicledmonocle@lemmy.world 18 points 11 months ago

You're probably a better candidate for a plug-in hybrid.

[-] king_tronzington@lemm.ee 9 points 11 months ago

Yeah I'm coming to terms with that now lol. Debating between leasing with the hopes to get a full EV after another 3 years, or just buying a PHEV.

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[-] ramble81@lemm.ee 4 points 11 months ago

Check out the 2023 Q8 e-tron. There’s usually good lease deals on them and they meet that list. Wait for them to come off lease and you can get them at a steal. I’d recommend the 2022 but those had a smaller battery pack and wouldn’t meet your range.

[-] king_tronzington@lemm.ee 2 points 11 months ago

Good call, looks interesting. I'll take a look

[-] kameecoding@lemmy.world 1 points 11 months ago

Ignore that guy, Kia Ev9 is better

[-] jqubed@lemmy.world 2 points 11 months ago

Chevy Equinox? I guess it depends on what you call affordable and how long the $7500 federal tax credit survives

[-] king_tronzington@lemm.ee 1 points 11 months ago

Not a bad option but still below 300 miles with the AWD.

[-] noxypaws@pawb.social 2 points 11 months ago

What's the upper end of affordable for you?

[-] king_tronzington@lemm.ee 1 points 11 months ago

I'm paying ~$450/month for my lease now(Hyundai Tucson), but I could probably afford up to $1000/month if it's something I really liked.

[-] nonfuinoncuro@lemm.ee 2 points 11 months ago* (last edited 11 months ago)

I'm paying $599 for my 2024 EV9 with 280 miles

[-] king_tronzington@lemm.ee 1 points 11 months ago

NGL that thing looks like a pop tart box 😂.

Also I definitely don't want/need a 3rd row of seats.

[-] noxypaws@pawb.social 2 points 11 months ago

Gotcha! I'm not great with the intricacies of leasing, but take a quick look at Lucid Air. Their site claims "from" $700-730 monthly for 36 month lease. And they're supposed to be ridiculously efficient with great range

If that's not really your jam (I wouldn't blame you), maybe Hyundai Ioniq 6, Kia EV6, Cadillac Luriq, or Polestar 2, probably with my personal preferences in that order

Or take a walk on the sub-300 mile wild side and pick up a used Taycan wagon!

[-] frezik@midwest.social 2 points 11 months ago

In 2.5 years, the EV market will look very different. Just the last year has shifted a lot around with the used market (such as Hertz cycling out a bunch of Teslas and offloading them cheap).

[-] weed_scientist@mander.xyz 1 points 11 months ago

Just leased an Ioniq 6 and been loving it. Depending on what you consider affordable, it checks your boxes! I leased mine during a major sale and with a trade in, though.

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this post was submitted on 07 Jan 2025
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