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Comment by gnicholas | Hacker News Reader

Absolutely. My local paper's environmental columnist recently rented an EV and chronicled the experience. [1] There were so many compromises involved, largely related to charging/range. For example, she had to walk in the cold (Maine) from her hotel to her car, which she was charging overnight elsewhere. She also had to skip part of her trip due to lack of range.

The columnist concludes the sacrifices were worth it, given her dedication to environmentalism. The vast, vast majority of people would not choose her experience to be a little greener.

1: https://www.almanacnews.com/blogs/a-new-shade-of-green/2024/...

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It's all about charger coverage. As a large group we rented 2 Volkswagen ID.4's in Norway over the Christmas holidays (think -4 degrees F so we were getting about half the advertised range) and it was never a limiting factor. Anywhere we went we could top up, from the grocery store down to the cabin that was quite out in the boonies, never had to fight for a charger spot either.

It is not about charger coverage. When I have a 7:00 flight after an all day meeting I don't want to or can't budget the time required to fully charge an EV on my way to the airport. It's all about time.

That's about there not being a charger in the lot that the rental company uses as a matter of course when rentals are returned to them.

> -4 degrees F so we were getting about half the advertised range

Does this mean the electricity you paid for went half as long?

(ev exp is ltd bc my cars are 30y-60y)

At cold temps you lose range a few different ways: First heat in an EV isn't free, this is usually where it gets you. People get in go "oh man its cold" and crank up the heat and there goes range. When you see one of the "this person ran out of power waiting in line at the Tesla charger in winter time" pictures this is how they did it.

Second battery efficiency goes down.

Finally, the battery usually is constantly doing the regen breaking thing but in cold weather it doesn't to save pack wear until you get the pack warm again

Shouldn't a couple regen braking events be capable of dumping a boatload of heat?

At least last time I checked, Teslas had rather anemic battery heaters. IIRC they’re around 6kW.

6kW is not enough to make a big dent in required mechanical braking, and it’s also not enough to quickly heat the battery pack, especially when operated intermittently.

I thought GP was referring to generating heat for HVAC, which is an interesting idea. I assume one challenge would be getting the warmth from the brakes to the cabin.

A gadget to recover heat from a disk brake would certainly be interesting, but it sounds complex, messy and expensive.

A bigger battery/coolant loop heater sounds more straightforward — the mechanism to convert kinetic energy to current is already there.

Yeah, from what I've read, Tesla max regen is 60+kw. Does it just lockout regen braking until the battery pack is "receptive"?

It limits max regen power, and the limit is variable. There’s a cute little indicator on the dash.

The problem is that cold batteries can't charge or discharge quickly. From the battery's point of view, regenerative braking is the same as fast charging (just for a very short period of time). When the battery is very cold (or almost full), Teslas regen as much as they can, then use the friction brakes to keep a consistent feel for one pedal driving. The battery does have fluid pumped through it for heating/cooling, but it can take some time before the pack is warm enough to charge/discharge at its rated capacity. The longest I've had a cold battery notice is 20 minutes, and that was after my car sat at 0ºF overnight.

My thought was to use the regen braking electricity for (more) resistive heating when it has nowhere else to go. It's an extra thing that only gets some use (depending on climate), but not a very expensive extra thing and takes some load off your pad/rotor brakes.

The battery is warmed by the heat pump (or if you have an older model, the resistive heating coils). That component can only take so much power. A more powerful heat pump would cost more, take up more space, and weigh more. My guess is that Tesla designed their heat pump based on these tradeoffs.

I think you are missing the most important effect of cold: more air density at terrain level, which creates way more drag on the car.

The density of air at 20ºC (293ºK) is 1.204kg/m^3. At -10ºC (263ºK) its density is 1.341kg/m^3, or 11% denser. For a Model 3 moving at 100kph, about half of its power is used to overcome air drag and half is used to overcome rolling resistance. Air drag is 1/2 * density * velocity^2 * coefficient of drag * area, so an 11% increase in density means an 11% increase in drag, so a ≈5.5% decrease in range. That's significantly less than typical cold weather range loss.

Most of the range loss comes from climate control. In a combustion car, the majority of the energy in the gasoline is turned into heat. In cold weather, you just dump some of this heat into the cabin to keep it warm. An EV's efficiency is a disadvantage in this case, as it needs to use energy from the battery to heat up the cabin.

Everything sum up.

I don't have the exact numbers there but the HVAC system should draw ~2kW at full throttle. Giving an average of, let say, 160Wh/km (speaking of a recent Tesla M3 for example) at highway speed. Over an hour of full throttle heating you would have consumed in heating an extra ~10% of what you spent to move the car. So OK, maybe air drag increase is not the worst offender here but it's not just the HVAC system.

...

While writing this I searched a bit and according to this [1] when there is really cold temperature and the battery still haven't got warm, it can draw 5-6kW at the beginning. Anyway when driving motors heat up, the heat is used to warm the battery, the battery heats up as well and all that heat is used by the heat pump to warm the inside of the vehicle.

[1] https://insideevs.com/news/452464/tesla-model-y-heat-pump-sy...

I have a PHEV and when I turn on the heat as I'm pulling out of my garage, the range is cut by 30%. This has nothing to do with drag since I'm backing out at 2 MPH. It's just about the HVAC system, which uses a lot of power. I typically just use the seat warmer, but when my kids are in the backseat I have to run the heat as well.

I very much doubt this. I've never seen this having a notably measurable effect on ICE vehicles in Massachusetts winters (which can be cold but aren't notably arctic).

Because ICE vehicles don't have "range issues" so you just don't notice it.

Yes. You use twice as much electricity to go the same distance.

Gas cars lose efficiency in the cold too, but it’s less drastic. Only stats I can find are 15% loss at 20F (which is a lot warmer than -4F).

Also, charging tends to be much slower in the cold as batteries need to be warm to accept full charge rate. If you’re cruising on the highway it’s usually not too bad, but if you start from an overnight stop and then try to immediately charge the car you could be waiting for the battery to warm up.

> Does this mean the electricity you paid for went half as long?

No, the battery simply isn't able to hold as much energy because the chemical process that makes it work "slows" down (my basic understanding of electrons, someone feel free to correct me).

My brother lives in Maine and has two electric cars. I have one and travel in Maine a few times a year. It's a particularly bad state for charging. I'm not sure why that is.

I imagine the temperature doesn't help. Compared to CA (where the columnist is from), the average temp is probably 20° colder, which could cut 15% off the range.

This is unlikely to be the central factor, given that Norway, one of the few inhabited places which is colder than Maine, has the highest rate of electric car ownership in the world.

That's in spite of the range issue, and is due to the Norwegian government carrot-and-sticking heavily towards electric. Maine has no such incentives, and is sparsely populated, which doesn't play to the strengths of electric cars.

Norway has huge financial incentives for buying EVs, including exemption from VAT and registration fees. This has added up to billions of USD in subsidies, [1] and is why there are so many EVs in Norway. I'd be very surprised if their neighbors, who have similar climate but fewer incentives, see the same rate of adoption.

Norway shows that you can have EVs in a place that is very cold if you shovel cash at buyers. It doesn't prove that weather wouldn't be a central factor in a place like Maine.

1: https://www.oecd.org/climate-action/ipac/practices/norway-s-...

Also worth noting that in Norway, they will often have cars with engine block heaters (https://en.wikipedia.org/wiki/Block_heater), with associated plug points in parking spaces/places.

Makes it much easier if there's already infrastructure.

Maine is sparsely populated, but most of its population is concentrated in a narrow strip along the coast. Actually, this is probably true of Norway as well.

Yeah, the cold hurts the range, but not all that much. The central (I was going to say "main") thing is that Maine is a charging desert.

Bar Harbor, the destination of most of the out-of-state Teslas, has almost nowhere to charge. I went to a hotel once which promised to have 4 level-2 Tesla chargers. All of the spots were occupied by ICE trucks. I went in to point out this problem to the clerk. She shrugged her shoulders and said, "they're probably our customers." Apparently the chargers were just there to lure in suckers. "Yes, we have chargers, but good luck using one. They tend to be parked in by ICE pickup trucks. We're helpless to do anything about this." I failed to check to see whether the trucks had Maine plates. They didn't look like typical customers of this hotel.

Around Portland things are a bit better. And new stations are being put it. It's just behind neighboring states.

Probably some combination of:

- It's a cold state in winter and there's at least the perception that you don't want an EV in places with cold winters. (I see few enough Teslas in the wild in exurban Boston.)

- It's a relatively poor state.

- I imagine pickups and the like are disproportionately represented.

- It's big and sparsely populated as you say.

A friend of mine who lives in Boston but owns a house on a bunch of land in northern Vermont finally got a Tesla when he convinced himself there was sufficient buffer for weekly trips between the two places.

Articles like that make it all sound so complicated and hard!

TBH, the experience of most Tesla owners is just put the dest in the map and charge when needed on the way.

The one clear problem that is highlighted in that article is that hotel, or more generally destination, charging makes a huge difference. People think it is all about getting there, but it really is the being there that can be tricky.

Rental cars magnify this problem, which is why it was so strange that Hertz expanded the fleet so rapidly. Scaling the same move over 3 years would have had very different results(*).

(*) Maybe other than maintenance costs. There were odd rental effects in that from the stories that I've heard.

> of most Tesla owners is just put the dest in the map and charge when needed

Do you think that's because it's far easier to charge your car at home while you are sleeping? And that renters who lack this convenience or face difficulty achieving it might be put out by the experience during a possibly expensive and rare vacation?

It's because Tesla's navigation automatically adds charging stops to the route. Also you add billing info when you set up your Tesla account (which the car is tied to) so you don't do anything besides plug in. While you're driving you can see on your car's screen how busy nearby chargers are, whether any stalls are out of commission (an extremely rare occurrence), and what the maximum charging rate is.

I've tried 3rd party chargers a few times and gave up on them. They're often broken or extremely slow. They usually require installing some app, and you don't know whether they're occupied or not until you get there. In contrast, Tesla's chargers are a consistently good experience. Without them, I'd simply never use my EV for road trips.

The Tesla supercharger team rarely gets enough credit. They do an amazing job behind the scenes to make all of that a reality.

I still use other charging networks from time to time. The best that I can say is that they are usable, but they are often frustrating in various weird ways.

I'm sure it happens. We get EV 'reviews' from time to time in some of the ev forums and reddits. I've noticed a common tendency to get this experience, then extrapolate it to the rest of the experiences as well. It isn't always a representative sample, though I understand why it happens.

But that's not why I mentioned Tesla. I mentioned them because there's so much weird industry caused complexity that they avoid. Need to charge the car you've just rented? Just find a supercharger and plug in. Not ideal necessarily, but at least it isn't hard.

Got a non-Tesla and need to use EVGo or EA? If you're lucky the card reader isn't broken. Then there's a decent chance it times out while communicating, because the order of events isn't intuitive for first timers. Cancelling the session at this point sometimes gets tricky too. Oh, and all of this is assuming the unit itself wasn't broken. If the card reader was broken, now you are downloading an app, tapping in card details, trying to figure out which stall to active, etc. And finally, you find out that the Bolt might require you to hold the cord just right for it to activate. EA used to have a whole video just on this detail. :facepalm

It can be a really terrible experience.

one of the primary complaints I've seen is the Tesla apps being inaccurate about charger availability - like 4 out of 5 chargers available here! And you show up and they're actually all taken with a huge line of people waiting.

So weird (and I'm not a Tesla apologist at all) but I have never in 5 years seen this happen - and I've driven across America 4 times in a Model 3.

In fact, mid drive Tesla will auto-reroute you to a supercharger station with more open slots if the one you're going to gets busy while on the drive. The UI is extremely accurate (like I can see open station numbers increment when a car pulls out).

Are you sure you're not hearing complaints about non-Tesla chargers?

yes this is specifically the Tesla charging stations in LA

> For example, she had to walk in the cold (Maine) from her hotel to her car...

Equivalently, she chose a hotel without chargers, or without enough chargers. How much extra time and money would it have taken to find a hotel with/near chargers?

Which travel search engines/ OTAs/ directories allow you to find hotels with L1/L2 chargers? (Do they list number and ratio of chargers/rooms?) Just like how most of these allow you to search on free parking, breakfast, wifi, disabled access etc., I see this as a feature that will become common then standard.

EDIT: to the down-voter, this is on-topic and substantive comment. Per my other comment here, the onus is on the rental company to actively incentivize behavior modification in first-time-EV-renting customers, help them plan their trip, not just to merrily slam them for fees. Assuming Hertz want loyalty and repeat business (if not, then this is a wider issue with them, not with EVs).

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