Ask HN: What are the limitations on EV service life? | Hacker News Reader

Ask HN: What are the limitations on EV service life?

7 pointsKon-Peki33 comments

I came across this chart today [1] that compares the greenhouse gas emissions of ICE vs EV over the "life" of the vehicle. Reading the fine print, I find that they are considering 200,000 KM (120,000 miles). That just seems unreasonably low. Modern ICE cars easily hit 300,000 KM with routine maintenance and maybe one or two repairs. What about EVs? It seems that as long as you replace the battery every ??? KM, it should last indefinitely. But in reality, that is not going to be the case. What will the limitation be? My guess is electronics/software failure. At some point (15-20 years) there will be no compatible replacement parts aside from what was stockpiled during the production run.

[1] https://www.iea.org/data-and-statistics/charts/comparative-life-cycle-greenhouse-gas-emissions-of-a-mid-size-bev-and-ice-vehicle

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https://www.forbes.com/sites/carltonreid/2022/08/01/electric...

> “Almost all of the [electric car] batteries we’ve ever made are still in cars,” said Nissan executive Nic Thomas.

> “And we’ve been selling electric cars for 12 years,” he added.

> It’s the complete opposite of what people feared when we first launched EVs—that the batteries would only last a short time,” he reflected.

> It’s clear that most EV batteries will outlast the vehicles they were installed in, and even then, they have a worthwhile second life before they need to be stripped down for recycling.

> “At the end of the vehicle’s life—15 or 20 years down the road—you take the battery out of the car, and it’s still healthy, with perhaps 60 or 70% of usable charge,” said Thomas.

> “Taking the battery out [of an electric car] and putting a new battery in is not a viable proposition. It’s more sustainable to take the battery pack out of the car after 20 years, recycle the car, and reuse the battery.”

(My note: the motors Tesla uses in the latest vehicle builds is supposedly rated and validated for a million miles of service, to be seen in the field of course: https://electrek.co/2018/10/15/tesla-drive-after-million-mil...)

The thing about the inherent reliability of electric motors seems important to me. Gasoline engines are shot after 4-6000 hours of operation. Where industrial electric motors last for 25-50,000 hours and can be rebuilt. Same is true for the inverters. And it feels like electric's are more repairable. (minus the smartphone on wheels thing Tesla has going on)

I feel like that's going to push manufacturers to increase the lifespan of the other components. Historically the short engine/transmission life limits the life span of the car which is why you don't for instance see any market for replacement interior parts. 20 year old car with cracked trim piece? Not manufactured. But if in 2 years you have a lot of mechanically perfect EV's with shot interiors? Seems like a market.

From my experience of working on a few Teslas, I would say they are easier to repair than most ICE cars. Well at least the newer ones (model 3 and Y).

The point being from that chart, you are in the net positive in terms of lifetime emissions very quickly, so quickly in fact even if the car truly did only last 200k km you'd be net positive vs. the average gas car that lasts twice as long.

Modern cars (anything made in the last... 10-30 years, depending on how generous you are with the definition of 'electronics') all have electronics in them of some sort. People go through the same process with any old car as well; parts aren't made anymore, replacements are purely through parts from salvage or through aftermarket components... etc. At some point, it becomes non-economical to repair a vehicle, as stuff does inevitably break and the value of the car approaches zero.

Not sure how the part availability is any different for an EV. You can't run an ICE car if the engine ECU goes bad, for instance. And aftermarket ECUs are ruinously expensive generally, especially for an 'old' car.

EVs have vastly fewer wear components compared to ICE cars, so in terms of things that can even possibly wear out... there's just fewer things to go wrong.

One point... I think car manufacturers are required to stock parts for 20 years or so.

It's 10 years in the US, which may be barely 120k miles for many folks.

Right, so I was not suggesting that EVs will not last as long as ICE vehicles. It appears to be the opposite. The question is what kind of thing will cause an EV to be EOL. I am thinking that it's not the battery at all.

ICE cars have a healthy 3rd party ecosystem that keeps them going for a long time. As a design decision, EVs seem to be hostile to that concept, to the point that I think this is what will cause the vehicle to be scrapped rather than any other reason. Legislation may come around to address that issue, however.

I'm not sure how the ecosystem that exists around ICE cars is comparable to an EV.

Let's go down the list of parts:

* Suspension components: Same between EV/ICE, no changes there

* Brake components: Same between EV/ICE, no changes there

* Tires/wheels: Same

* Infotainment: Similar issues - unless you rip out the dash there's not really anything comparable in most modern ICE cars to replace it. It's all integrated and if that breaks you're hosed.

* Motor/engine components: Nothing similar exists for EV space, but also maintenance requirements for EV motors is basically non-existent.

* Battery components (on EV): Not a thing on ICE cars, but similar stuff has existed in Hybrids for awhile. 3rd parties do rebuilds of hybrid batteries already; there's people doing rebuilds of EV packs now too.

What specifically do you think exists in the 3rd party ecosystem for ICE vehicles that doesn't for EVs? Batteries? Motor replacements?

I think the problem is that people think Tesla vs. EV. Tesla is repair hostile.

Because the software is the thing that matters, and the behavior of the software is exclusively controlled by the OEM, it’s not unreasonable to assume that the life or operation of the car will be impacted by manufacturer action. After all, Tesla has already made retroactive adjustments to range, etc in post-repair scenarios.

What happens when Ford decides your rebuild is “unsafe?” Software is being used to bypass warranty law.

Tesla batteries are surprisingly durable. Even after 250,000 km, they average less than 10% degradation [0]. After 300,000 km, even 1 standard deviation is less than 20% degradation [1].

Of course, your mileage may vary. Degradation is influenced by many factors. Many believe that only charging on Superchargers increases degradation because high charging rates generate a lot of heat which is bad for the battery. Also, storing the car at 100% charge will as well. Elon denies both of those, but I don't believe him. I only charge my Model 3 to 70% for daily driving, and only use Superchargers on road trips. After 3 years and 20,000 miles, my battery is showing no degradation.

[0] https://electrek.co/2018/04/14/tesla-battery-degradation-dat...

[1] https://insideevs.com/news/525820/tesla-battery-capacity-ret...

> your mileage may vary

I see what you did there.

Historically they said it was good to charge your lithium laptop battery's to 90% and discharge to 10%

I learned the hard way to not let my phone sit at 100% all the time.

When COVID hit and I started WFH, I just left my phone plugged in all the time. After 3 months, the battery started swelling.

Now, it may have been coincidence, but I doubt it. Now I only charge every other day, staying between 20% and 90%. I really wish I could configure an automatic charging limit without rooting the device or using some external method.

Does USB-C expose/communicate charge level (I think it can negotiate voltage)? Could be interesting to create a small in-line controller to set min-max charge.

What I've heard of people doing is getting a smart power outlet and use IFTTT to check the battery and tell the power outlet to shut on or off based on current battery.

Some of that could have just been where you were leaving your phone plugged in all day. A lot of the issues with degradation (and swelling) are heat management rather than charge management. Modern phones have no fans or cooling loops and make the assumption that they move enough through the air over time (even just sitting in people's pockets/purses/cases) that the heat they radiate isn't radiated back at them. Sitting on a hard, slow to cool surface such as an average table at all times of day, the phone's heat may have nowhere to go.

It's useful to point this out in the context of EVs too: the EV batteries we've seen with the worst degradation had poor heat management (most model years of the Leaf up until recently, some early model years of Tesla's Model S); supercharging is an issue in battery degradation not just because of the rapid change in charge states but the rapid increase in heat released by the battery that has to be managed carefully (and away from the battery); EV batteries are expected to have longer lives and less degradation than phone batteries even of the same battery chemistry easily and simply because cars have the space for active heat management components (coolants, fans, heaters, etc) that phones have shaved in trade-off with more passive tools in order to maintain smaller pocket sizes.

I’ve supercharged the majority of miles on my 2018 Model S over 100k miles and only have 6% degradation on my 100kw pack. N=1.

> My guess is electronics/software failure. At some point (15-20 years) there will be no compatible replacement parts aside from what was stockpiled during the production run.

What about the age-old problem of rust? Most cars, even most (all?) EVs, are still made of traditional metal frames and body parts. That's usually what tends to fail in unrepairable ways first, even with ICE cars.

Yeah. I'm in southern Quebec, and with the road salt here, its not uncommon for car frames/bodies to become damaged beyond economical repairability from rust while the propulsion is still working fine.

In fact body work in general on cars tends to be way more expensive than mechanical work.

> What will the limitation be?

My guess is that the sticker shock from replacing battery packs on older electric cars is going to be the blocker for a lot of people. It's going to feel tough for a lot of people to justify a $10K+ expense in one shot for an older electric car, even if that expense makes the electric car run perfect again for another decade+.

To be fair, older ICE vehicles also come with their share of problems and necessary repairs, but those repairs are usually in piecemeal fashion, you might have a $300 repair one day and then need a $700 repair 6 months later of course. But it's rare that an older ICE vehicle has any single $10K+ repair: even replacing the entire engine out of a typical ICE vehicle probably wouldn't come near that.

I expect as battery prices fall, car manufacturers will start offering free battery upgrades as an included service with the sticker price. Today people are actively paying $40K for a new car. As batteries get cheaper, some manufacturers might race to the bottom and just try to offer cars for as cheap as possible, like imagine a 300 mile range Honda Civic for $10k. Others might still charge $40k but give you goodies like a fresh battery every five years.

This will never happen. Car manufacturers today are moving away from one-time-fee models and trending towards subscription-based models (see all the hub-bub around the BMW heated seat subscription). If anything, it'd be the opposite: Pay some smaller up-front cost, but a monthly 'battery service' fee or something instead.

Also, I highly doubt there will ever be a car in the $10k new segment (at least in the US); it just isn't feasible with the demands of consumers for other things (safety, regulations, infotainment, interiors, etc). Even if the battery cost approaches zero, there's more than $10k worth of car (not in BOM, but what it would sell for) in probably every car today.

Sure, that’s a viable model as well! Either way I think the market and industry will find a way to make it work for the consumer such that they won’t feel like an EV is just a hidden $10k charge in 10 years.

Nobody worries about a hidden $10k cost for an engine replacement (which, after labor... is probably what it actually costs for many vehicles if you want a brand new engine) 10 years down the road either. I treat this as a similar thing. If you actually want to redo it, you buy a used battery with less miles on it for much less than a new battery. Just like an engine/transmission/etc.

The only difference is you lose range as the car ages... although for a gas car, it probably gets less efficient with age too (but, this is much less noticeable thanks to refueling times)

I just sold my 12 year old Subaru that needed a full engine swap. The quote was "about five grand for the crate engine, about five grand for the labor, and that's if we don't find any other problems. Given what happened, there are definitely going to be other problems."

To explain, radiator hose broke, all coolant was lost, and we were about a 2 hour drive from a cell phone signal in > 100 degree heat with no other traffic around. It was life or death. I do not regret flogging that engine until it died.

This is a unique time for used cars, and people are uniquely stupid about Subarus.

"Sticker shock" implies that there will be a moment where people are "forced" to price check. I don't think that assumption holds with EV battery reality.

Battery degradation isn't a binary state "working"/"broke" like many ICE components that need repairs. Battery degradation is a slow percentage effectiveness drop. It is often qualitative ("the battery is exactly 3% worse than when I bought it ten years ago"), but the "working"/"broke" decision process is still very subjective ("does 3% matter?" "does 7%?") with different people making different choices.

But the big thing is that it is a slow shift over time with plenty of time to get used to whatever the new normal is. As the owner you slightly adjust charging stops over time, or you stop trying to hypermile it in quite the same way. A lot of it in subtle ways that you barely notice. There's no "red letter" day that comes where the battery is so much worse than the day before it that you immediately think "time to buy a new battery".

Similarly, a person buying a used EV, they may have no idea what "true when brand new 100%" felt like at all. The state they buy that car in is their benchmark, the car has always been at that state for them. That's their "100%", that's the battery state that they expect (and they'll deal with any further slow fall off from their similarly to the previous owner).

There's no "sticker shock" moment in any of that.

If EVs see a big industry of battery replacements, and right now that's a Big If (because many cars aren't even built to support it and there's no current reason to demand that they need to be), it's going to be a "flipper" market (somewhat similar to home sales). It's going to be the used car middlemen (the auction houses, the used car dealerships, etc) making "sell as-is or flip" type decisions weighing the price that they think they can get in the used car market with the battery as-is versus the price that they think they can get in the used car market with a fresh battery. No person is going to directly see that sticker price. They'll indirectly see it reflected used car prices, but used car dealers don't want "sticker shock" from potential buyers so it'll continue to be sold as just the usual spectrum of used cars and "current market prices" and that may be very indirectly reflected indeed.

When I'm talking about sticker shock, I'm more talking along the lines of the psychology of having an older EV.

My thinking (that I might be very wrong about) is that many people are going to eventually realize how much replacing car batteries cost. I don't think most people fully realize that reality right now. I think most people would feel very weird about throwing another $10K+ into an older EV and would view that as wasteful. That's probably going to be reflected into whatever resale and restoration markets exist over a long timeframe.

Technically speaking, you make some good points about decaying batteries. They do decay very slightly over time. But I lived with a fading phone battery for a while because it was still barely serving my needs and I was being a little cheap and lazy to bother with getting it fixed. At one point, the battery just decayed enough to stop filling my daily needs and I had a real problem and had to get a replacement quickly. Of course, car batteries and car usage patterns are different than phones, but there does come a day when your batteries die off to the point where it doesn't fill your needs anymore and many people are going to learn that lesson at some point.

I personally love the motors in EVs, but I think there's so many problems around their mass usage that society hasn't realized and grappled with yet. Personally I think there's going to be a lot of disappointed EV owners in the future.

It does sound like you are thinking about it too much like phone battery degradation. EV battery degradation is nothing like that, and trying to analogize from phones makes battery degradation seem like a much bigger deal than reality says it actually is.

A giant factor here is that modern phones use passive heat management (they rely a lot on air resistance for cooling rather than finding room/space for fans and coolant) and most EVs use active heat management of one sort or another (they have room for fans/coolant/heaters/etc; and need them for cabin and passenger HVAC anyway). Heat is the biggest impact on degradation. A car does not degrade in the same way that a phone does.

Current statistics are that outside of EV models with known bad heat management (many Leafs, early Teslas), degradation is rarely to never a problem and is "always" in single digit percentages of maximum range after 10 to 15 years. (A loss of 7% of a 350 mile range over 10 years is barely 25 miles it drives less per charge, and almost imperceptible a shift at roughly 2.5 miles change per year.)

You can argue that current statistics may still be "too early" for statistical significance, especially given that huge caveat that there are entire models that need to be tossed as outliers. But that's also its own indication that early adopters have helped iron out R&D kinks in EV battery heat management and industry standards are only getting better. I know statisticians that think that single digit percentages may even be too big and too pessimistic and that there are a few more outlier car models to toss that haven't been already and that we'll see even better statistical model in a few more years.

(ETA: It's also important to note that of the statistical outliers, few have seen battery replacements even post-degradation. There are some Leaf owners that have replaced their batteries, but the vast majority of Leafs still have their first battery in whatever "degraded" state they are in.)

There's also the cosmetic wear and tear to consider. Depending on the demographic of users, this might easily be the main reason for an upgrade way before the car is not longer technically viable.

Agreed - having to flip an AppleCar onto its roof to charge it will no doubt produce premature wear (though one would wonder if that’d be planned obsolescence instead). :shrug: :jk:

Plastics. I think Plastics are going to be the biggest maintenance surprises in EV lifetimes.

We tend to think of plastics as "forever products" but most plastics are only truly guaranteed/rated for 15-20 years of active use. They just degrade in weird ways compared to other materials we expect to last. (And just being in a car dealing with all sorts of finger touches and all the jostle and motion of a moving vehicle can be quite "active use".)

My first car was an ICE I sold near its 15 year birthday. I severely under-utilize my cars, so it was still under 70K miles. The biggest push for me to sell and replace it was that the plastic knobs for its manual A/C controls had all started to break (and I was using pliers to adjust A/C, which is not fun, and quite dangerous while on the road), and even the manual window cranks were starting to have issues, and even the glove box was plastic and started to get real finicky about opening/closing.

Most EVs use touch screens and a lot of automatic controllers so there's fewer "common touch" plastics in an average EV than that first car I had, fewer manual knobs and cranks that can break, but there's still plenty of plastics holding up those touchscreens and in cup holders and other glove boxes/drawers/shelves/containers throughout the cabin interiors.

Most of that is "aesthetic" problems that don't truly impact the operation of the car, but as the user of the car you spend most of your time dealing with the cabin interior and problems with the cabin interior are easy to notice and easily become annoyances.

Cars aren't built to modularly replace the cabin interior (unlike some RVs which experience some of these same problems as they age but there's something of a market in refurbishing them every decade or so), so often the limits of cabin interior quality will be the "surprise" limits on car lifetime.

(ETA: Just to underscore, as my ICE example suggest, plastic degradation is not a new problem at all to cars, I just think that the circumstances that lead to it being a problem to me in ICE vehicle were unusual enough, because of low mileage. A high mileage ICE vehicle has a lot more problems to deal with before anyone even notices the plastics issues in the cabin interior. An EV even with high mileage may not have anywhere near as much in the way of serious maintenance problems, so plastics degradation may be the first maintenance issue some owners see/experience.)

> We tend to think of plastics as "forever products" but most plastics are only truly guaranteed/rated for 15-20 years of active use. They just degrade in weird ways compared to other materials we expect to last

That was the case for one of my cars, but only for a rarely used part: the push button for the release of the fold-down rear seats. Being exposed to the sun all the time (via rear window) caused them to deteriorate after about 7-8 years to the point where they had a huge hole in the middle of them (otherwise flat button). But plastic in the rest of the car, when I eventually got rid of it at about 11 years old, was still all fine.

That said, I think more modern cars are more tolerant of environmental degradation (vs. from daily average use) now.

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