How much do electric car batteries degrade?
sustainabilitybynumbers.com133 points by xnx 3 days ago
133 points by xnx 3 days ago
> At that point, a Tesla will have more than 80% of its initial capacity, and in some cases, even more. So people will probably give up their car, well, well before the battery gets close to becoming a burden.
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.
That's statistical. A small number will start their exponential degrade at 80%, but most won't. Some might get to 60% before they start it. So if you're at 83% at 200,000 miles you don't really know whether you have 50,000 more or you have 200,000 more on the battery. And "exponential degrade" doesn't mean it's particularly fast. It means it's faster to degrade from 80 to 60 than it is from 100 to 80. You're not going to get 500,000 miles out of driving until the battery hits 60% but you might get a substantial fraction.
The rest of the car almost certainly doesn't have 200,000 more miles in it, so who cares?
Why do you think a vehicle with 200,000 miles on it doesn't have 200,000 more miles in most of the components? It isn't remotely difficult to imagine that being possible. One of my ICE vehicles was 299,648 miles when a component in the transmission gave out. The only reason I didn't repair it was around a decade earlier someone had bent the frame. If I had been willing to replace that part, I would still be driving it today.
People replace vehicles because they want and can afford replacement ones, not because they are mileage limited.
> People replace vehicles because they want and can afford replacement ones, not because they are mileage limited.
That isn't quite true. It is often because it is uneconomical to keep.
The issue with many older vehicles is that it just starts costing more to repair it than the car is worth. You are constantly putting in good money, after bad and the the costs keep going up over time. At that point it is often better to buy another vehicle.
I could have kept my 2007 Vauxhall Astra going for another 100,000 miles. The issue is that the car was worth £600-1000. Each repair was costing upwards of £300.
I could buy another second hand Vauxhall Astra with the amount of money I was spending on the car yearly. It just wasn't worth it.
This is just a bad application of sunk cost. The reason why you spend 300 pounds to repair a 1000 pound car is because it is a known item. If you buy a used one for 600 pounds, it may need even more repair than the one you already have.
Repairing a known item makes sense when the costs are small compared to a replacement. I have old bicycles that are worth nothing and I am quite happy to spend maybe £50-£150 in components to fix. Costs are much lower than buying a new good bike or trying to find another good second hand bike (which I would need to fix anyway).
However that frequently isn't the case with car. It is £300-1000 every time I need to get it repaired. This happens at an increasing frequency as the car ages. This can then add up to several 1000s quite easily.
e.g In the last year I owned that Astra I had to to fix the following issue (all costs include labour):
- New Clutch (and it needed to be towed to the garage as the clutch wouldn't engage). £1000 for clutch replacement, £150 for the tow. I also needed to rent a car to drive to a funeral. That cost me another £100-200 IIRC. So we we are up to £1350.
- Car would randomly go into Limp mode. New sensor cost £300. Vehicle was never really fixed. It just went into Limp mode much less, so there was another problem somewhere. Which would need another trip to the garage.
- Service. This flagged several issues with the car. All these small repairs was another £800.
I am already upto £2,450 and I know I've forgotten stuff. I bought the car for £4000 originally.
If it was something like a classic barn on wheels Volvo which are bullet proof, or a classic Rover like a Rover P5. I might be willing to keep dumping money into it. But it isn't, it is a Vauxhall Astra.
With 4k I would to go for a Focus or Fiesta, I think you're always risking trouble with a Vauxhall? The Focus of around 12-14 years ago, particularly, was seriously over engineered which is why you still see so many of them around.
I had one for 4 years, approaching 200k miles, it came to grief at the hands of a 95 year old lady driver. Her car was wrecked, the Focus stood up well but, alas, even the minor repairs required were deemed uneconomical.
No help to you, admittedly, but if it assists anyone else avoid a similar issue...
The Astra G and H 1.7 cdti variants were really good. Newer ones not so good from what I have heard.
Ford Focus around the same time period are indeed decent. Going to try to get one at some point.
If the rest of it seems solid, then it can be worthwhile. But if you start spending 300 every 3 months then you're just throwing money down the drain.
Again that's statistics. Some 200,000 mile vehicles have 200,000 more miles on them. Some don't. If you can live with that uncertainty, you can save a lot of money.
Most Diesel Engines (even ones well looked after) won't last after 300,000 miles and will either need to be rebuilt or replaced. A replacement Diesel Engine is several thousand pounds and that is before labour.
Then other things like hoses, anything rubber will perish and will be replaced. Everything starts going at some point and the cost mount up quick!
Where do you keep getting all this information from? Yes, there are some engines that suffer catastrophic failure well before 300,000 miles. But it isn't even most. I have rubber parts on vehicles that are decades old with no sign of degradation. Vehicles are not made of compost.
On a regular car 300,000 miles is like 20-30 years of use (approximately 30 miles a day). How many cars you see on the road today that are over 30 years old? I barely see any vehicles over 20 years old.
Things wear out on an engine over time, you lose compression over the time and thus power, you can have other components that will reach EOL. A lot of this starts happening on vehicles well before 200,000 miles. I know it does, I've had to deal with it. I am having to replace a knackered turbo on one of my vehicles, and I had to replace the belt tensioner and replace the timing belt, I've had to reseal the sump.
Rubber perishes over time. Regular maintenance and what conditions something subjected to can improve the life sure. I've replaced plenty rubber bits and pieces because they've perished. There is a reason they offer rebuild kits for some components, because those rubber / plastic parts go bad after a while.
These are just facts.
> On a regular car 300,000 miles is like 20-30 years of use (approximately 30 miles a day). How many cars you see on the road today that are over 30 years old? I barely see any vehicles over 20 years old.
I drive a '91 GMC Sierra. It has 138k miles on it right now. It was made in 1990, making it 35 years old.
> Things wear out on an engine over time, you lose compression over the time and thus power
I've not put it on a dyno, but qualitatively I'd say the 5.7L (350ci) v8 in my truck has 90% or more of its original power. The miles are much less important than how it was used. Mine belonged to my grandfather, so it wasn't exactly street raced.
> you can have other components that will reach EOL.
Sure. This is called "maintenance". It's an ongoing cost - and a compounding one, at that, if you don't stay on top of it. If you do, an older vehicle can be kept in excellent working order for not much money at all.
> A lot of this starts happening on vehicles well before 200,000 miles.
Sure. Most modern vehicles require their first major service at 50k-100k miles.
That's not a defect. That's how they are designed. Some parts wear faster than others intentionally, because they are meant to be replaced.
> I know it does, I've had to deal with it. I am having to replace a knackered turbo on one of my vehicles, and I had to replace the belt tensioner and replace the timing belt, I've had to reseal the sump.
The turbo failing is the only thing here that raises an eyebrow for me; everything else is just standard maintenance.
Modern turbos are doing a lot of work, and depending on the vehicle are often included to meet environmental regulations.
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More to the point, ICE vehicles are well-understood and can be both maintained and repaired by novices without significant risk. I recently bought my wife a 2019 F-150 Platinum. It was in excellent condition overall - interior and exterior are basically perfect - but had a massive oil leak around the timing cover. It had 97k miles on it.
We paid $22k for it. I put $1,500 in parts in it: replacing the $20 gasket meant tearing the front of the engine down, so I went ahead and replaced the cam phasers and all timing components at the same time. I expect it to last another ~60k miles before the next major repair.
I've already budgeted to replace the twin turbos and transmission over the next few years. Even with those costs amortized into my budget, and including the initial cost of the vehicle, I'm paying about 1/3 of what it would have cost me to buy a new vehicle of the same quality.
What's more, it gets ~24 MPG city and ~28 MPG highway. The only modification I've made to that effect is that I added a (~$300) soft tonneau cover to the bed.
My '91 GMC gets 12.5 MPG city... but its retail value is also ~$10k at most. I'd have to drive a lot of miles on a regular basis before it would make economic sense for me to replace it with something more efficient - and even then, I'd still want an older truck, because I don't particularly want to fill our shiny F-150's aluminum bed with gravel but have no problem doing the same with my GMC's steel bed that already shows 35 years of use.
From an environmental perspective, I bet I could drive that truck for the rest of my natural life before I consumed more resources or exhausted more pollutants than would be required to manufacture a new one.
> From an environmental perspective, I bet I could drive that truck for the rest of my natural life before I consumed more resources or exhausted more pollutants than would be required to manufacture a new one.
Unless you drive much less than the avarage this is not true, engineering explained [1] did a video about this, and comparing a 24 MPG to a 35 MPG car you produce more CO2 with the 24 MPG car compared to a new 35 MPG car (including the manufacturing) considering your GMC has much worse fuel efficiency that break even point would be much earlier. This is not even considering the impact of recycling... So the best thing for the environment you could do is buy a new more fuel efficient car.