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Comment by jonnycomputer | Hacker News Reader

I think I still wish that battery-swapping was the main "refueling" method; I hear that battery swapping infrastructure is being built up in parts of Asia for small vehicles (like scooters and mopeds). I mean, theoretically, simply swapping out batteries--and just paying a fee to the batter swapper station--would work very efficiently (and quickly). Coordination problem maybe.

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Tesla tried out battery swap stations about 7 years ago [1]. They assessed that demand wasn't high enough. Basically, it cost money to do battery swaps (which paid for battery swap infrastructure), whereas supercharging was just the cost of electricity.

On a first principles basis this kind of makes sense. Supercharging has effectively no moving parts. The plug doesn't even have a tab. That's less maintenance and pieces that can break over time. On the other hand, battery swapping has a ton of moving parts, and would require the car to have additional hardware.

[1] https://en.wikipedia.org/wiki/Tesla_battery_station

Isn’t there also a concern on battery quality? If batteries are expensive, then you don’t want to swap a good one for an older or reduced capacity battery, but you would have no way of knowing a priori how good the replacement might be.

I don't understand why this is a concern. In this scheme you swap out batteries instead of re-charging them; you don't own them, you're contracting with a service to provide them as needed. Theoretically, you could buy the car battery-less and be asked upon purchase which battery service you'd like to sign up with.

But batteries are heavy, so quite possible that a battery swap would end up taking as long as supercharger charge anyway.

NIO does battery swap[1][2].

[1] https://www.nio.com/nio-power

[2] https://electrek.co/2023/10/09/nio-completes-30-million-glob...

cool!

Do you own an EV?

I've noticed that battery-swapping seems to be mainly suggested by peope who haven't owned an EV, or have owned an EV where fast chargers are not common.

Or people like me who don’t have the ability to install an EV charger where they live and don’t have the prospect of it any time soon.

My recent experience in a rental Tesla solidified that even with the 250kW chargers, having to go elsewhere to charge it is a big deterrent to buying one. Even in Los Angeles, the Supercharger network isn’t dense enough to overcome this for me.

Yes, there are a lot of people for whom EVs don't yet make sense because they can't charge it overnight where they live (like apartments). And so this really brings home how offbase the parent comment is: maybe they don't own an EV because it doesn't make sense for them to own an EV given how it works for folks in the suburbs, but not elsewhere.

Won’t charge times be like sub 10 minutes with the upcoming 1000V power capabilities?

Though what would be really clutch about battery swapping is that the overhead of battery maintenance could be offloaded from the owner and amortized into the price of a swap. I imagine there would have to be a battery standard so that cells could be serviced at an individual level on the swap provider’s end during maintenance.

Charging for Li-ion is not power, but rate limited, to 15 minutes at minimum. 4C or "4 times as its Ah rating" is considered fastest possible speed within reasonable degradation. Up-rating only allows larger battery packs to charge closer to that speed.

No. Not until we get to solid state batteries. There already are 800V batteries from multiple brands (Porsche, Hyundai, Kia to list a few) yet charge times have remained near 20 minutes.

Most supercharger stops are less than 10 minutes anyway. Very few people are ever charging their battery at a supercharger from 5% to 80%. They’re putting a little bit more in so that they make it all the way home.

Not on a road trip. You primarily charge from 10 to 80% at like 250kw and it takes 15-20 min.

I said most for a reason. Road trips are waaaay less than 1% of driving.

And as more and more hotels add L2 Tesla charging, more Tesla owners can charge overnight away from home. If I do trips to Oregon from Seattle, I never supercharge anymore.

I never supercharge unless I’m on a road trip and neither do the other Tesla owners I know. We all have wall chargers. So Supercharger use is 100% road trip for my cohort. I also doubt road trips are less than 1% of driven miles. Road trips are at least 30% of my odometer.

The canned response against swapping is it forces both chassis(4.5k lbs) and battery pack(1.5k lbs) to be able to maintain structural integrity of its own, and that that is just redundant for already heavy cars.

Structural integrity is an issue. Another one is battery quality and care. When a battery pack has a high residual value, and you're taking it with you, there is a real risk of quality mismatch, fraud, theft, and abuse in and around the battery swap. I may have a brand new car, with a near perfect battery; if I go on a trip and do a couple of battery swaps, I'm going to be pretty unhappy if the battery I get back at the end of the chain of swaps is 5 years old with only 75% original life.

That's even before the risk of malicious owners. I'm sure there would be many attacks, but one that comes right to mind is intentionally swapping in low-quality cells into swapped batteries to extract and sell the new high-quality ones you pull out.

I think I don't understand this criticism. The idea here is that you swap each time you're getting a new charge. You're not investing in any one particular battery, you're investing--as a car owner--in a service that maintains quality of it's "fleet" of batteries. You don't "own" the battery, and if the charging service gives you a shitty battery, you go back and have them swap it out for another one. You're approaching this from the perspective of someone who think's they've invested in a hunk of lithium and doesn't want to come out on the bad end of an exchange. But you buy the car battery-less, and sign up for a charging service that gives you one.

That has generally not been the approach I've seen in the market. Most programs expect you to charge your battery for your daily driving. Battery Swap is for long-distance and fast-charging only. Even if swapping was common, I still think there is risk, it would just be on the charging network, and getting a swap would be like renting a car or other expensive item. The battery would be checked for damage after every use, and damage or excessive wear found would be assumed to be the fault of the most recent renter, regardless of that accuracy.

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