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Comment by mrtksn | Hacker News Reader

> Electric batteries are getting better faster

Are they? Any sources on that?

Besides, the issue with batteries is that you carry dead weight all the time regardless of how much energy they have stored in and that weight is very high, making the driving experience "not for everyone". I guess, the weight also would mean higher asphalt and tire consumption, which as I read recently is the prime polluter of the driving activity.

I don't know if fuel cells actually have a promising feature or not, but I like seeing people working on alternatives to batteries. Light vehicle propulsion is something to be desired, it opens up possibility for aviation too.

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> Are they? Any sources on that?

https://pushevs.com/2021/01/10/guoxuan-unveils-a-cobalt-free...

FTA:

2009: 95 Wh/kg

2015: 140 Wh/kg

2019: 190 Wh/kg

2020: 212 Wh/kg (191 Wh/kg at pack level with JTM)

Context: this chemistry, while inexpensive and durable, was always thought as something that didn't stand a chance against other, denser ones in applications such as EVs.

Currently it seems that it crossed the threshold of having all the parameters - price, durability and energy/power density - good enough to essentially replace NMC/NCA long term. Especially given that it uses no cobalt or other high-demand materials.

Tesla already uses LiFePO4 in some of its Chinese-made Model 3s, without much of a weight penalty.

well there are many more weight sensitive applications that would benefit by a better solution than dead weight battery methods; I own a TM3 and enjoy the EV experience but do realize there need to be alternatives to eight hundred to thousand pound packs.

From planes to motorcycles and so on. Both are more sensitive to weight than any four wheel vehicle. plus portability may be an issue for some uses that battery packs will never overcome.

Even the trucking industry has to worry about weight and it may take an excessive amount of weight to get similar ranges to the diesel trucks we have even after swapping fuel and motor for batteries and its motor.

Regardless, all solutions being offered end fossil fuels and that should be the primary concern.

There are studies that suggest it's not the absolute range per charge of an electric vehicle that matters, it's how quickly you can extend that range. If you look at ICE cars nobody worries about range despite some of them having abysmal fuel consumption and range. But with a refill taking minutes, and gas pumps being ubiquitous and able to serve a large amount of customers simultaneously without interfering with the capacity of nearby stations, this is never a real issue.

Battery energy density is increasing and that's great. But if I were to venture a guess this mostly benefits people who can spend several hours to fully charge them, like at home. A battery that can add 200-300Km of range in 10-15 minutes would probably do a lot for the people who can't charge at home.

But this also introduces the next issue: large scale quick charging. Being able to quick charge a substantial number of cars simultaneously takes a lot of power. Having quick charge and a big battery on the car doesn't help at scale unless all charging stations are prepared to deliver the same (maybe giant banks of batteries taking the role of the underground fuel tank).

There's no silver bullet when it comes to clean driving. It's a lot of incremental advancements mixed in with some revolutionary ones which need both time and investment. And perhaps a bit of change in human psychology.

A battery that can add 200-300Km of range in 10-15 minutes would probably do a lot for the people who can't charge at home.

Fortunately this is already the case in cars with 250kW charging capability.

That being said I don't think habits from combustion engines can and should translate to EVs, so you don't need such quick chargers in cities - cars are normally stationary 90% of the time. Lamp post chargers are a cheap and easy to install solution:

https://airqualitynews.com/2019/05/02/1000-ev-charge-points-...

Better still, their output could be throttled so as to not introduce too much demand.

There are cars that charge up to 350KW but that's not realistic for large scale deployments since the infrastructure development doesn't seem poised to keep up with the EV purchase boom. A gas station can easily service 20 cars simultaneously every couple of minutes. Charging 20 cars at 150-350KW for every charging station brings us to some mind boggling numbers today.

EV will have to be able to do both though. Slow charge for constant parking charging - one charger for every parking spot, and quick charging at dedicated stations which would presumably be equipped with everything needed to cover the potentially huge demand.

Charging 20 cars at 150-350KW for every charging station brings us to some mind boggling numbers today.

That's as much as seven electric locomotives at maximum - many more are currently in motion all around Europe, China and Japan.

It's a problem, but a solvable one. The technology is here, and is much cheaper than an equivalent hydrogen infrastructure.

Almost every problem is solvable if you throw enough money at it. My point isn't that we're stuck with an unsolvable situation but that EV manufacturers are driving up sales faster than they, governments, or other companies are building the infrastructure to support them. There are 1.2bn cars on the road, even a fraction of that fast charging is a higher load than anything we regularly do now. And that's on top of what we already consume. Imagine just 5 locomotives running at maximum in close to every gas station today and you'll visualize the magnitude.

And all that is a problem only as far as people planning today under the assumption that they can just quick charge in 15min and it can only get faster. But they ignore the aspect of scaling. We are nowhere near providing quick charge capability as people imagine when they make such assumptions. And we won't be in 2030 either, when many manufacturers decided to have a fully electric fleet. Which isn't to say that we should stop buying EVs, we should just stop making unrealistic assumptions under best case conditions when planning or comparing tech.

It's the kind of assumption people get wrong even when thinking of household items like an electric stove. If each element is 2.5-3KW the assumption is they'll operate at that level even when running together. Then they scratch their head when the food just doesn't seem to get cooked as fast as they expected all of a sudden. Scaling up never comes to mind.

As for hydrogen, the best business case for it probably does not overlap the one for BEVs. It should target everything batteries can't, as many other commenters here pointed out. Some public transport operators are building as we speak fleets of fuel cell trains (to the tune of hundreds of millions) because overhead lines are missing in many areas they service and the alternative is diesel. There's a case to be made for quick "diesel like" refueling especially when in the hands of organized operators.

The unrealistic assumption remains that fast charging would be the default when all the cars on the road are electric simply because the status quo with ICE is "fast charging" (once a week or fortnight; people also tend to forget that not all cars "fast charge" at once with ICE either). Slow/trickle charging is a real paradigm shift versus the status quo. More and more evidence continues to mount that fast charging is by far a small exception in BEV ownership over steady usage patterns of trickle charging.

Exactly. People have to wrap their heads around the fact that "fueling" a BEV will not follow the same philosophy as fueling an ICE. And it shouldn't, it should play to the strengths of BEVs. They can be charged anywhere, at home or on the street, you can even "produce the fuel" at home if needed. So as long as you can install a charger in every possible (legal) parking spot a BEV can stay more or less constantly charged. Quick charge might be reserved for when you really need to be quick about it. Or maybe some more advanced battery swap tech and process.

And charging stations will probably not reach gas stations level of efficiency any time soon, certainly not by the time most manufacturers go for BEV only fleets. The point isn't that "all cars fast charge at once" but that today any one of the dozens of gas stations in any city will serve multiple customers at once and offer a hefty range in a matter of minutes. The difference is even more visible if you go to more extreme situations, like a highway gas station in vacation season, where cars queue up to every one of the dozen pumps despite their substantially longer range.

Again, none of these issues are insurmountable, they just require a lot of investments in infrastructure and a change in mentality. But whenever someone compares hydrogen to battery tech saying "BEVs can quick charge too" it's clear that they don't understand how things change at scale and what's the strong point of each tech.

But I think he's right that's a mind-boggling amount of power. Those are gigantic engines running full out.

Doesn't seem to mention anything about recharge time, which in a transport situation Hydrogen will win 9/10.

refueling with H is gonna blow battery recharge times out of the "water"

I wouldn’t be so sure. We have experience with fast chargers, and know how fast and what it costs for EV fast charging.

But how would a H2 fueling station work? Customers would have to make an extremely tight coupling, and while the compressors pressurize the customers tank. I expect that will take longer then petroleum refueling. And the cost? The bill will have to compensate the fueling station for same fairly exotic tech.

We know fuel cell technology works, and it may have a really important niche. I don’t think we can assume it will be able to compete with EVs on cost and charging time.

> But how would a H2 fueling station work?

The one near my home seems to work, by observing people using it (it's colocated with a gas station) pretty much just like a normal gas station. I'm sure the coupling hardware is quite special, and it might take a little longer (or not) for a similar range fuel load, but when people fuel their Mirais it's the same basic flow as with gas vehicles, pull up to the pump, hook it up, fuel, and go from a drive-in pump, not a parking space. So, it's on the same basic ballpark, UX wise, not the “well, if I was on a long trip and needed to fuel, it's okay because i’ll just time it with a meal/rest break” kind of thing that is used to justify BEV charging not being excessively inconvenient.

BEV charging isn't "excessively" inconvenient because you charge it like your phone: plug it in every night before you go to bed. You might not have 100% charge every morning, but that's no different from fuel, most people rarely have 100% in the tank. What is different is an ICE or a Hydrogen tank is never going to have more in it when you wake up in the morning than before you went to bed. That's a paradigm shift. (It is okay that on long trips you time a recharge with a meal/rest break, because that is the rare exception, not the week to week lifestyle.)

Would you stop 15 minutes and have a cheap charging session, or 5 minutes and have an expensive one ?

Hydrogen is not instant to refuel so the time difference is not too crazy.

Depending on how you look at it, most of my recharging is effectively 15 seconds. Because I charge at home, it is just the time involved in pluggging the car in, and I'm done.

Can Hydrogen charge at home?

For ~98% of the days of the year, I don't have to even go to the gas station. For long trips, I'm not sure there's really a difference between a 5-10 minute gas station stop and a 30-40 minute supercharger stop.

I'm actually not asking this tongue and cheek but do fuel cells weigh significantly less when they are empty? I would think that a hydrogen fuel cell would functionally weigh the same empty or full, so itd be the same issue as batteries, no?

The new version of the Mirai has a fuel cell that weighs 25.5kg for the fuel cell and power converter and a 5.6kg hydrogen capacity, so proportional to the weight of the cell the fuel is significant, but proportional the weight of the vehicle, not really.

Structural battery, where the battery is part of the structure is actually making the weight very competitive.

We are only in the start of how batteries are integrated and eventually all manufactures will move to structural packs.

The driving experience is already really good, a heavier feeling is actually prefer by most people.

>heavier feeling is actually prefer by most people

Any sources on that? Is this coming from a poll or questionnaire or is it your opinion(because Tesla?)?

Some people like pineapple on their pizza, others eat marmite at breakfast but the heavy car likers is a first for me.

People keep buying heavier cars and the average weight goes up over time. It's the market version of "preference"; people might say they prefer it but they choose more features most of the time.

This claim also needs sources but even if true Are they buying heavier cars because of the weight or they are accepting a trade off in exchange for more features like larger carrying capacity?

Are there instances of people installing ballast to their light cars in order to make them heavier?

There’s been a long term trend toward bigger vehicles for decades. When gas prices locally went above 3.5-4$/gallon the trend reversed quickly. But it’s since returned.

It’s an arms race. It’s hard to feel particularly safe if there are significant fractions of mobile homes barreling down the road toward you. Owning the larger vehicles isn’t fun when you need to park for that matter.

I know about that trend in the US but I don't think that it's fuelled by the desire of having heavier cars. Cars getting heavier is a byproduct of cars getting larger. Heavy batteries don't bring that benefit.

That’s my point. People probably aren’t looking at curb weight directly but they’ve been buying vehicles with characteristics which increase weight.

Though some are looking at curb weight. On the consumer side, it's part of the marketing of vehicles like the Hummer. (On the production side, it's precisely why some vehicles have gone as close to the "commercial truck line" as they can get away with to avoid extra taxes, street restrictions, and license requirements.)

Cars getting larger and heavier is a byproduct of environmental and safety regulations coupled with the consumers' desire for a constant amount of usable space and payload.

More exhaust cleaning and more complex motors cost weight. Sturdier frames are also heavier. Compare e.g. the door thickness of a modern car with one from the 1990s. You can also compare the door's weight. The door will be heavier for the modern car and the thickness will cut away more from the interior space provided (since exterior dimensions are somwhat "fixed" in perception per class of car). Sit in a 1990 era Golf1 and compare to a modern Golf7. The modern version is more cramped on the inside despite being larger on the outside. And it is a good deal heavier.

So yes, larger exterior will get you a heavier car, but it isn't really consumers wanting ever larger exterior dimensions. It is consumers wanting a constant interior usable space.

All correct but you forgot a few details from that list

A lot of interior space reduction for a given vehicle volume comes from the space required for a passenger cabin to have an aerodynamic shape.

More "wasted" space leaves more room for crumple zones, airbags, speakers, computer modules, HVAC stuff, alternative drive-trains and all sorts of features throughout the car.

Basically every engineering group in an OEM has their job made easier by making the car bigger. Making the new generation 1" bigger than the last generation is an easy way for management to please basically all the stakeholders.

Vehicles at the compact end of the spectrum are moving toward the design characteristics of 1950s heavy equipment where the operator sits where he fits and that's it.

Mk1 Golf came out in 1976. The increasing size of the same model of vehicle is more due to brand loyalty retention. They know that in your teens and early 20s, you needed a cheap small car. As you get older, you may want more space to do more things, but you really loved your old car. So to keep you as a customer, they increase the size of the new versions of that car. The new car is still the same model as before, but now it meets your changing needs.

You will see that the Golf has gotten bigger, but now the Polo has taken over as the small car. The Civic is no longer a small car, and has been replaced by the Fit/Jazz. The Focus has gotten bigger, and the Fiesta has taken over as the small car. The smaller car still exists.

Compare a modern Polo to a Mk1 Golf. The Polo will be safer, quieter, more efficient, and probably not that much heavier. Same goes for any car that I mentioned above.

A heavier car feels more planted in relaxed everyday driving, less affected by NVH, more isolated from road imperfections and wind. The suspension will also be designed for a larger mass, so the added mass of people and freight changes the feel of the car less, as it is a smaller percentage of the car's own mass.

A heavy car is objectively worse when looking at handling, fuel economy, road wear, general pollution and crash safety, but greater mass feels safer and sturdier. If an object is very light, it subjectively feels less strong, even though it may not be.

Car purchases are very emotionally driven and buyers choose what feels best to them, even if it is objectively worse on many parameters.

For a non-car example, I prefer riding my relatively heavy 3-speed Dutch-style bicycle to my old aluminum-framed 8-speed sporty citybike, even though the latter is objectively faster, turns more crisply and has a better gear range. Simply because the heavier bike is less perturbed over bumps and the wider tires soak up imperfections better.

> heavier feeling is actually prefer by most people.

what ? nobody prefers it. there are people that tolerate it and those that don't know better. weight kills driving dynamics, everybody that claims otherwise does not care or did not drive a lightweight car.

I haven't heard that either, but I have read that the batteries at the bottom give the car a lower center of mass which can be a good thing in curves from my understanding, but that's different from just a "heavier feeling" which I don't see why anyone would prefer that.

> I haven't heard that either

Of course because it's absolute nonsense. We spent the last several decades trying to make vehicles lighter for their size, and nobody loads their car with bricks and sandbags to get that "heavier feeling". Lower center of gravity is great but completely decoupled from the overall mass of the vehicle. The fact that the comment came back from downvote graveyard is a testament that not only will people say anything to support even a ludicrous claim, many others will support it without batting an eye.

People would prefer it because it counteracts body lift, which reduces traction.

Even if people don't understand the physics of why it works, the handling impacts are pretty apparent, especially out of low-speed city or heavy-traffic driving.

The heavier feel may not be preferred, but it makes having a flexible, cheap suspension design much easier. For example small carthat weighs 1000kg may be be expected to carrier 4-5 adults, an additional ~350kg. To do this the suspension must be overly sprung (and possibly under damped) for a single driver. A 2000kg Tesla means that even without air suspension or adaptive shocks, it will ride much better with a single driver while still being a capable of a high payload. Having a large battery also moves the unsprung:sprung mass ratio favourably.

Specialty vehicles like sports cars and offroad trucksand where payload rating is not a concern function much better the lighter they are though.

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