That is how much of the battery capacity is hidden by the battery management system when the car is new and then slowly doled out as the battery ages to make for the appearance of very slow degradation even though the individual raw cells would be wearing out quite a bit faster? If this were true what you would see is after this excess capacity was exhausted would be battery capacity falling off a cliff eventually, though this data seems to show a couple hundred thousand miles of consistent capacity with no cliff.
SSDs do a similar thing for capacity and wear with a sizable proportion of capacity reserved to replace bad blocks as the SSD ages.
Whenever I make this comment almost everyone responding is just guessing about how I'm wrong and new chemistries are so much better, etc.
I'll also offer up an example. The Polestar 2 (prior to 2024) has an advertised 78 kWh battery, but also clearly only 75 kWh available for use. That's about 96% right from the factory. So presumably it's doing what you're saying, but it's also not a secret. It's also a way to prevent regular 100% charges from happening, which have proven to accelerate degradation.
Using the word "cheating" has a very negative valence, but it's not exactly a secret that EV batteries are not designed to use their full "raw" capacity. The manufacturer is quite clear that you should avoid charging to more than 80% on a regular basis as it will degrade the battery faster. What matters is not that the batteries are capable of some theoretical "raw" capacity but that the advertised capacity is correct, just like with SSDs. It doesn't strike me as cheating that SSDs have more capacity than what is advertised on the (proverbial) box.
>The manufacturer is quite clear that you should avoid charging to more than 80% on a regular basis as it will degrade the battery faster.
This is one of the things that doesn't add up. If the article says you can drive a tesla 200,000 miles and still have a mid-80s percent of total battery capacity left, why are car manufacturers being so clear about charging patterns to "save" the battery? With the std deviation bars in the graph showing a pretty small distribution, it would seem charging behavior doesn't matter (of course there will be people who don't follow the guidelines and if so there should be an expected much wider distribution)
The facts from studying the mechanics of raw cells of earlier lithium chemistries, the advice from the vehicle manufacturers, and the data in this article do not add up.
>Tesla extended the range of some Florida vehicles for drivers to escape Hurricane Irma
In this case a selection of Tesla vehicles were temporarily "upgraded" from 60 kWh to 75 kWh, that's 25%!
https://www.theverge.com/2017/9/10/16283330/tesla-hurricane-...
Tesla's packs first produced in 2017/18 for the model 3 represented largely the industry's first mass produced packs that will largely fail naturally, not due to pack engineering issues (failed cells, leaks, cooling, etc...). Before that required a much higher pack replacement rate, and other manufacturers have the same issues.
More modern EVs with full liquid thermal management and newer cell revisions and chemistries seem to be holding up much better over time.
Some chemistries like LFP have even greater cycle and calendar life in return for a bit less energy density. Ford and GM are both betting big on these for their future entry-level EVs and I think they will end up being a common choice where maximum range isn't the customer's primary concern.
Don't forget that beside the chemistry issue in hot environments, the original Leaf only had a 24 kWh battery, so you'd have a lot more cycles than say a 60 kWh or 90 kWh battery. If you assume it is good for 1,000 equivalent charge cycles, and assume you 3.5 miles/kWh, than your 24 kWh battery would be good for 84,000 miles. A 60 kWh pack would be good for 210,000 miles, and a 90 kWh pack is good for 315,000 miles. A new Chevrolet Silverado EV has a 200 kWh pack (which, if you can squeeze out 2 miles/kWh, would be good for 400,000 miles).
And with a small battery it is more likely that you'd need to charge up to 100% and discharge closer to 0%, which is also harder on the battery.
Still, while this removes a primary concern of mine, there's still one major hurdle that cannot be bypassed as far as I can tell (yet): If you have shared parking, there's essentially no way to charge your car. Maybe if it's an outdoor parking lot you can rely on solar power somewhat, assuming you're in a good situation for that?
Still, my point is that my parking space isn't actually mine, so I can't modify anything in the garage. Assuming superconductors aren't figured out any time soon, this appears to be an impossible solve, which cuts their consumer market significantly.
Also, not exactly the same thing, but they could remove those warranties and instead get some nice replaceable battery cells in there. Let me turn a thing to unlock it, pull out that one cell, and replace it. But maybe I'm a little more wrench-y than their customers want to be?
The neighbourhood I used to live in London (where almost nobody has off-street parking) installed chargers into lamp posts. This BBC article has more details and photos https://www.bbc.co.uk/news/business-67518869
A second option is more slow chargers installed places your car spends a lot of time parked, like offices or transit stations if you park and ride.
A third option is using a fast charger somewhere you go once or twice a week. Like grocery stores, gyms, etc. Costco for example is adding fast chargers to their stores, which should be fast enough for a full charge by the time you actually get in and out of Costco.
Replacing cells in a pack can be difficult. You want all the cells in the pack to have roughly the same capacity and voltage curve, so that you can connect them all together and charge them at the same time.
GM says that their Ultium batteries are segmented into modules, which each module having its own Battery Management System, and that it supports mixing and matching modules of different degradation and even cell chemistry.
But anything that adds complexity to the pack beyond being cells packed in as densely as feasible is going to add costs and reduce maximum energy storage.
I think the long term answer here is that there will eventually be a used and remanufactured battery pack market for popular models, just like you can get a used or remanufactured engine today.
I don't think this will ever happen. It's the worst case in most every sense. You're talking thousands of chargers, for most parking structures, to solve a problem that's mostly about current battery tech/infrastructure. When battery tech is ready for general use, this won't be needed.
Slow chargers are pretty low-tech devices, just a 208V-277V circuit with a device that handles switching, ground fault check, and potentially payment. These are going to be cheaper and easier to install and maintain than fast chargers, and I think adding them to workplaces is going to be easier than covering individual apartments.
That certainly won't cover all needs, which is why I listed other alternatives as well. The answer will be a blend of these solutions where each makes sense.
But that's all still treating EV charging in the old world ICE model which everyone is familiar. When people are talking about wanting more chargers everywhere a car may be parked, like offices or transit stations and other parking structures, that isn't a need, that's a market opportunity unavailable to ICE. You can't put a gas pump in every parking space, but you sure can put an ordinary electric outlet. We can distribute the charging "problem" of a car far more easily than the current centralizing forces of gas logistics. It's an amenity that anyone who owns a parking lot or garage can offer to encourage walkability to nearby businesses and/or homes. It's a possible revenue source for other parking lots or garages that love low margin business models like electricity metering and/or think they have a captive enough audience to charge whatever margins they like, to make the bottom line grow.
We don't need those things to happen. We've driven gas engines for enough decades without that. We want those things to happen. We expect market forces to eventually deliver those things, as soon as the market better figures out what EV charging disrupts in parking lot planning and operations/maintenance. You can't expect your gas car to have more gas when you come back to it in a parking lot, but an EV can have a slightly higher charge almost anywhere it is parked for a while and that's a game changer that will slowly spread as the market finds the fun (and profit or marketing opportunity) in it.
Presumably over time shared parking areas will get upgraded with charging infrastructure to keep attracting tenants.
Charging on public infrastructure ought to get there in time but the really big benefit of electric cars comes when it charges at home on cheap electricity and the only time you worry about charging it at all is when you do a long trip and you have to charge it at the half way point for 30 minutes.
All this to say, if the demand is there then shared parking structures will install them. I live in a city with a fairly high percentage of EVs, but it will continue to spread.
For city commuters, this would probably be more than good enough.
A bit of an aside: I think part of the public perception problem is calling Level 1 "chargers" and not just "outlets". At so many points in our discourse, especially in the US, we've let car manufacturers sell us this idea of "gas-pump-like capital-C Charger" as something bulky and "hard/expensive to install", but really most EVs just need more wall outlets, classic, boring electrical outlets. Sure, the US can blame Edison that we don't have Level 2 as a default outlet and our cheapest/easiest outlets are Level 1, yet still we need to stop underestimating L1.
The other thing beyond "don't discount L1 as a reliable way to charge" (slow and steady charges the race car, eh) is "don't discount the power of destination chargers". Everywhere you park is a possible place for a charger. If you can't get one easily at home, maybe your employer can build one. Your grocery store and your church or bar or pickle ball court or other third place can build one. (Especially Level 1. Outdoor outlets have always been a thing, moving them a little closer to parking spaces shouldn't always be a big deal. Boring old electrical outlets are "everywhere" already, we just aren't always yet in the mode of thinking about them, their ubiquity, and how they can charge our cars, while we eat or shop or work or hang out or play or sleep.)
> Assuming superconductors aren't figured out any time soon, this appears to be an impossible solve, which cuts their consumer market significantly.
What does that have to do with EVs? The inflection point for adoption is solid state batteries, and there are some experimental factories under construction. (Solid state batteries don't loose charge when parked and can charge about as fast as filling a tank of gas.)
> Also, not exactly the same thing, but they could remove those warranties and instead get some nice replaceable battery cells in there.
Battery exchanges are impractical because the battery is part of the frame.
I don't think superconductors solve anything in the EV charging space, and certainly wouldn't make L2/L1 charging easier to install for shared parking / street-side parking. An L2 charger uses something like a electric clothes dryer circuit, with 240V at 40A. Or somewhere in the 6-10 kW range, to recharge you overnight.
Can they not see that this is because of correlation and not causation. Why would an EV be given up at 150 - 200K when it has much less moving parts and stressors compared to the traditional ICE based vehicles?
Also there becomes a crossover point of residual value where a car involved in an accident becomes cheaper to total than to repair, which is probably what takes a lot of cars off the road.
That mileage may stretch longer if the important parts of an average EV drivetrain can run without major service for significantly longer than the average ICE drivetrain, which seems like a likely possibility.
(ETA: Also the EV is so much more the "software-defined" car than anything, and the lifecycle of software versus tech debt and long term maintenance is going to be a large issue, even though the cars are mechanically simpler, the software is something making up for that in its complexity.)
> I hope manufacturers realize this and make the battery easy for DIY removal
This seems to be the case so far. A lot of scrapped cars' batteries seem to be going directly into second use in a second car. A lot of the manufacturers are also prepared for future "power wall" secondary uses of depleted batteries, but so far there has been too much of a market for the used batteries in second cars for used (even depleted) batteries to build a "power wall" market for used batteries. (Tesla's brand of that concept that sounds a lot like the generic term so far has almost exclusively been using new batteries for their products. Nissan's brand that no one has ever heard of, dedicated to used batteries only, has scarcely built or sold anything and is in danger of shutting down as an effort.)
The economics of used EV batteries is already a fascinating thing to watch, and something we'll probably see get more interesting rather than less.
And a lot more like by be lethal too.
If I had a 10% loss in fuel economy, I’d be looking for something wrong and fixing it.
Not -50F either. 10F and such.
To get back to EVs though, I'm not really sure they will last any longer than current ICE cars. Engine reliability has gotten good enough that a worn engine normally isn't the reason a car gets taken off the road. IME the main killer is either body rust or just too many small parts being worn out to where it isn't cost effective to keep repairing. Suspension parts will wear faster on an EV, since they're heavier than equivalent size ICE cars. I've driven a lot of mechanic specials over the years, and of the 7 cars I've sold to salvage yards only 2 were due to engine issues, the rest were either body rust making them unsafe or just too many things wearing out.
If you lose 15% range in a gas car, ok, you have to get off one exit earlier to refuel. No big deal. But if you lose 15% range in a electric car, that is sometimes the difference between being able to make it to the next charging station (especially DC fast charging) station or being stranded by the side of the highway and needing a specialty tow.
The classic topic in every EV "debate." Gas car drivers can't imagine having the equivalent of a 7 gallon tank. EV drivers can't imagine having a tank that isn't full every morning when you wake up.
That's just because they don't receive appropriate maintenance. In my family we had plenty of Italian and german cars, we maintained them, most hit 300k+ kilometers. Our 9000$ Lancia Y still worked fine after 350k+ and we only got rid of it because it cannot enter Rome due to emission restrictions.
I think they also had problems with timing belts? Google results are suggesting me that they had to halve the change interval, possibly because of our shitty roads. Volvo belts also last for 10 years in their native Sweden but only 5 years here.
NiCads suck, you find NiCads in like old AA rechargeables and cheap toothbrushes.
I don't know for sure if NiMH last longer than Li-Ion but I've had much the same experience with my Prius - Old as hell and everything but the battery failing
That isn't predictive at all of NMC or LFP chemistries though (and I'm not going through multiple charge cycles per drive), but a fun anecdote. It was an entertaining project opening up the battery pack and identifying/replacing the bad modules.
In the end, other parts of the car were dying too, and the final straw was California's refusal to allow aftermarket catalytic converter replacements, and the Toyota's price (with no competition) was more than the vehicle was worth.
So far my two EVs, both NMC chemistry (Kia and Rivian) are at 80,000 and 30,000 miles respectively, with no noticeable degradation.
Battery was at 87% of capacity.
The big problem was cold snaps. It had the older heating system and would lose a lot of charge in the cold. Our 2022 Model Y with the newer heating system doesn't lose nearly as much charge in cold snaps.
What prevents the same advancements from being applied to phone batteries?
Also, they aren’t designed to last very long. One manufacturer could reduce the max voltage in the BMS (battery management system), or reduce the charging speed at high states of charges, to significantly increase the lifetime of the battery but they somehow don’t. Though you start to see some phone limiting their charge.
I looked into the secondhand EV market (in Norway). In doing so I read quite a bit of academic research to figure out the lifetime of an EV. Apparently the 80% capacity is the accepted end of life for an EV battery:
"For batteries, 80% of the initial capacity is referred to as the point after which it tends to exhibit an exponential decay of capacity and is considered an unreliable power source after this point for EV application" [1]
So, the Tesla the article talks about won't be much good, or at least not for very long.
I'm pretty sure Tesla early on 'sold' an optional range extension that simply allowed you to charge the batteries further for extra range, with part of that cost presumably covering an anticipated higher battery failure rate. IIRC there were also some times when there were hurricanes coming during which they OTA unlocked that for everyone in the affected regions as well to facilitate evacuations.
toomuchtodo•3h ago
TLDR These batteries are going to outlast the vehicle chassis.
Full Speed Ahead: EV Study Reveals Impacts of Fast Charging - https://news.ycombinator.com/item?id=37330024 - August 2023
jayknight•2h ago
I will admit that both of these are nagging on me. I fully intend for my next car to be an EV, but if I was buying today, this would be a factor. I drive a 2013 Camry (that I got used) that shows no signs of slowing down. I hope to drive it for at least a few more years. If the car is still reliable when it's time to send a kid in it to college, that's probably when I'll start looking for something new. And you can show me studies all day long, but my irrational brain is just worried that I won't be able to get 15+ years out of an EV because there just aren't that many 15 year old EVs driving around today.
geoffeg•2h ago
I've been curious about how the degradation compares to EVs. I'm aware it's different kind of wear and that there's different ways to mitigate and repair EVs vs ICE, but they both have their own lifetimes and loss of performance.
lpedrosa•2h ago
While it is true that your car might consume more oil, and some other component might need replacing, its range, assuming it has been serviced properly, should be similar to what you could get out of it new.
I do wonder if the sum of the costs of getting the ICE car back to mint condition will be the same as getting some cells replaced so you get full range again.
nicoburns•2h ago
Well, until it dies completely (or to the point that servicing it would be more expensive to repair than replace). Then it's range abruptly drops to 0. We won't know for sure until we have more older EVs, but it may well be that EVs last much longer than that at 70-80% range. Which, especially if starting ranges increase, may be a very useful amount of range.
neogodless•2h ago
So old EVs can be just like old gas cars - used around town rather than for long road trips.
sokoloff•1h ago
The car before that was a 1998 Mercedes diesel with 225K+ miles on it that retired only because of body rust not mechanicals.
It helps that I did all the maintenance, so I knew how reliable they were.
Cars are insanely reliable and people get irrationally fearful when a car turns 100K and then again at 200K.
neogodless•1h ago
What I said was what I think most people do. Not what is possible.
sokoloff•1h ago
But I think most people who daily drive 175K mile cars would rely on them for a road trip without much consternation.
PaulKeeble•2h ago
nicoburns•2h ago
The top commenter from the post just purchased a 10 year old EV that they judge to be perfectly good and unlikely to die on them soon.
I do think the anxiety about batteries is somewhat justified today, because the capacities are small enough that only have 80% capacity available could be a problem. But once the batteries are larger, I suspect EVs will actually last significantly longer than ICE cars on average.
toomuchtodo•2h ago
Here is a 2018 Model S with 400k miles on it, although it's original battery was replaced under warranty: https://insideevs.com/news/717654/tesla-model-s-400k-mile-ba...
(I tried to import a BYD vehicle to the US, with an unfavorable outcome)
hadlock•1h ago
toomuchtodo•1h ago
https://spectrum.ieee.org/ev-battery-life
https://www.nature.com/articles/s41560-024-01698-1
https://old.reddit.com/r/electricvehicles/comments/1jvwi14/g...
https://www.thejubjubbirds.com/hit-and-run-on-the-energy-tra...
SubiculumCode•2h ago
Animats•2h ago
Most scrapped cars in the US are chopped up into little pieces, run through a separator for steel, aluminum, and everything else, and end up at a steel mill to be made into new steel. In Silicon Valley, the chopping and initial separation plant is at the Port of Redwood City.
[1] https://www.trade.gov/data-visualization/used-vehicle-trade-...