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Comment by sn_master | Hacker News Reader

The best way to reduce carbon emissions is to keep using existing cars, whether gas or electric for as long as they're drivable. Electric (and ICE, to a lesser extent) cars have a very significant carbon footprint when they're newly produced.

Abandoning cars after a few years is far worse to the environment.

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It'd be best to just...not drive. Second best would be to actively pursue a mass-scale electric conversion so that we could reuse all those big metal chassis, tires, seats, etc in existing cars. It'd be far cheaper in terms of carbon footprint to replace a combustion engine with electric. Why aren't we doing that? Because retrofitting is hard and not very profitable. And yeah, we need a place to put the batteries too. Much better to just junk everything and build more stuff!

(Yes I know, most of the materials of a car will be recycled. But it's just another expression of our throwaway/can't fix that culture).

> It'd be best to just...not drive.

I wish it was that easy of a choice. Pre-COVID, using public transit would have made my daily commute (one-way) between 1.5 and 2 hours, compared to 20-30 minutes by car.

And where I live, we've been paying hundreds-thousands of dollars on each car registration renewal (% of the car's estimated value) for that new transit system, which might not even get used that much post-COVID because of the germophobia that inflicted society.

You missed a key reason - batteries are very heavy, and to achieve the kind of range that makes it practical for drivers to switch from ICE requires specifically-designed chassis layout and materials to accomodate battery weight in a suitable location to maintain acceptable weight distribution

With a breakthrough in energy storage technology e.g. solid state, this issue might go away, but right now it compels the production of vehicles specifically designed to be EV and relegates retrofitting to a hobbyist discipline providing relatively disappointing results in range and/or handling.

yup, most retrofitted cars get way less mileage than regular EVs (150 miles or less).

I get that, but cars have gas tanks, back seats, and trunks, too. Also, the actual electric engine is very small, leaving a lot of room in engine compartments themselves. The only reason we would need very large batteries is to have a very long range, which would not be necessary if we could have removable, modular batteries that are easy to replace at (what was formerly) a gas station.

EVa have back seats and trunks just like ICE, and they need to be usable by the vehicle owner just the same so I’m not sure I see the relevance.

For retrofitting, locating some batteries in the engine bay is possible. This seems to be avoided by ev manufacturers in favour of locating a monolithic battery pack under the passenger compartment, for weight distribution, simplicity, and (I assume) safety reasons.

Physically swappable battery packs isn’t feasible because of the sheer weight of the packs (a leaf 40k pack for example is 210kg). Plus each car manufacturer has different specs and shape packs. Fortunately we already have a completely fungible, extremely portable unit that can be hot-swapped into every EV at nearly any location just like petrol - a kWh of electricity. Today it takes a bit of time to fast charge, but again with visible-on-the-horizon breakthroughs in battery tech e.g. solid state, fast charge times could drop from ~30 minutes to 3.

Of course if you are designing an EV from scratch you want to put the weight of the battery low and in the center for best stability, but with a conversion you gotta find space wherever. Gas tanks are already pretty low and central for the same reason, but clearly an EV battery pack is a lot denser than a full tank of gasoline.

Swappable battery packs clearly wouldn't be a single piece, as there are going to be a variety of different bays and sizes. They'd need to be smaller, portable, and stackable, like rectangles or hexagons. It's not really that hard to do if you design for it. If the batteries are under the car then a lift or underground bay you drive onto is fairly easy to do. Or you could just have a kind of dolly that slides under the car and can detach/reattach them.

The fact that we never really thought in this direction seems like a blind spot. I mean, look at how pit crews for racing work. The whole car is designed to be swappable in seconds flat, and also for minimum weight and maximum speed. It's just engineering and design investment.

As a further elaboration on this point: range becomes far less of a concern with widespread charging stations. If every parking lot was covered with solar panels and every space had a charger on it, the "range" concern would evaporate pretty much immediately for day-to-day use; just plug the car in at every stop to top it off.

Range concern won't evaporate in the US anytime soon simply because of how far spread cities and forests are and how much people like to roadtrip, specially in the Summer. When I used to hike pre-COVID, I used to do 150 miles one-way easy, and sometimes even return same day.

I have back-of-the-napkin tried to scale mass conversion. The gotchas are (very) nice-to-have things like power steering that rely on engine pressure. Actual drivetrain is solved.

According to a relative who's worked in the industry most of his life, the carbon footprint just from manufacturing and disposing of batteries for electric vehicles is not compensated by the decreased emissions. I think the lifetime is ~5 years shorter than the "carbon neutral time" of using a battery over conventional fuel. Much of the research now is to either reduce the carbon footprint of battery manufacture, or to increase the lifetime of the battery to compensate, but the batteries themselves are apparently worse for the environment than the engines they're replacing.

Literally no one buying an EV is junking their car if its drivable. They trade it in where it offsets manufacturing another car.

And then someone buys it on the other end and junks their own car vs driving it for another 2-3 years. The more new cars getting bought, the cheaper used cars become and more inclined people become to junk their 100k miles used cars vs using them until they hit 200k miles.

You underestimate the size of the used car market. It's bigger than just one country.

Going to need to see numbers to back these claims; what I've seen says otherwise, granted the breakeven point is different depending on where you live:

https://youtu.be/6RhtiPefVzM

This video is comparing a new EV with a new ICE. I was talking about using an existing EV or ICE for longer time rather than buying an entirely new car. Of course it's easier to re-use ICE than most older EVs which don't have durable enough batteries.

Battery longevity is getting better; I need to find sources, but last I heard is with new cooling technology, they are starting to put lifetime estimates at 500K miles.

As for the tradeoff of new EV versus used ICE, the numbers in the video seemed to suggest to me that it's still in favor of EVs, just that the break even point is farther out. Other sources have run the numbers to show it's not the construction or EOL that is the largest factor in emissions, it's the actual use: https://youtu.be/K9m9WDxmSN8

It's really clear that EV's are just the better option for the environment. The only thing that beats them is public/mass transit or human powered (walking, cycling) transportation.

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