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Comment by JohnFen | Hacker News Reader

I wouldn't buy a used EV because the battery pack is that much closer to needing to be replaced, which effectively totals the vehicle.

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I don't understand where this thinking comes from. It's not based in fact. These Tesla batteries degrade very slowly. And so if in 5 years you've lost 15% of the range, it still gets you anywhere you need to go including road trips with all of the Superchargers!? "totals the vehicle" is just nonsense and I wish more people understood the reality.

> I don't understand where this thinking comes from.

My observations, which certainly don't reflect the current state of the tech (although if I'm buying a used EV, I'm not buying the current tech). But that's my bias nonetheless. I do think I overemphasized this, though, because while this is what makes me shy away from the idea of used EVs, it's not the reason why I avoid buying cars that are too new (which includes pretty much all EVs).

It's not an observation because it's not something that you've observed.

Here's the truth based on an observation: Tesla's battery capacity degrades 12% after 200k miles. Source: https://insideevs.com/news/664106/tesla-battery-capacity-deg...

200k miles is effectively the lifetime of a car. Average US person drives 10k miles so that's 20 years of driving.

Tesla's warranty "guarantee at least 70 percent retention of battery capacity over 8 years and 100,000 miles or more". Source: https://www.motortrend.com/features/tesla-battery-warranty/

And latest chemistries are even better. In 2020 Jeff Dahn (who leads battery research group in Canada funded by Tesla) published a paper about million mile battery. Source: https://www.electrochem.org/dahn-unveils-million-mile-batter...

Since Tesla funds Dahn's research, they get the IP. This is just in the lab but those advancements are trickling, over time, to Tesla's battery making (and not just Tesla: every battery maker does research to make batteries cheaper and last longer).

Supposedly, first-gen Leafs were known to have pretty nasty degradation due to lack of sufficient cooling. Combined with an already short-range battery, and the belief that you'd need to replace the battery frequently was justified.

Key word: WAS

Of course, modern EVs, and basically all Teslas, have bigger batteries with better cooling, so it's no longer an issue. But the belief won't die, just like how people still make memes about Java being slow as if it's still 1998.

One could say the same about a combustion engine, really. Battery packs last way, way longer than most people think because they analogise it to phone batteries which are quite different. The resale value of a degraded pack is also going to be higher than most people assume, I think. Unfortunately we have not had plentiful EVs with good battery packs for long enough to show this to the average consumer.

I guess the question comes down to how does one know if the battery pack is good? When I buy a regular used gas car, I can get all sorts of diagnostics about it out of the OBD2 port, pull a spark plug and stick a scope into the combustion chamber to see if there's any issues (e.g. on the walls).

With an electric car, how can one tell if the pack has been charged all the way up to 100% all the time (vs. the much better 40-70% range)?

This is the "term premium" of batteries it seems, and I honestly don't know if there's a reliable answer.

At least on our PHEV, when you read out the battery module state with an OBDII reader, you get to know not only the current estimated capacity but also how much time it's spent at various states of charge, how much time it's spent being charged and discharged at different currents, how much time it's spent at different temperatures, and a completely absurd amount of other diagnostics.

I'd feel a lot better about the state of the battery if I bought one used, rather than the state of the ICE. It's possible to borescope it, but you have no way of telling how long the previous owner went between oil changes, if they flogged it out to redline regularly, etc.

With my electric car, I can plug into the ODB port and get highly detailed information on the health of the battery. Far deeper insights than what I get plugging into an ODB port on an ICE.

Getting into the technician menus on Teslas is well documented, they also report a ton of data and can do a lot of diagnostics on the battery.

you just need to know the SoH (state of health). If that's 90% then you've lost 10% of the range at new. The lower the SoH for the same vehicle make, model, year and driven kms, then the worse the car has been treated. Simple as that.

I'm reminded of various videos on Youtube where they dissect grenaded engines. "Oh look, the Cummins in your pickup dropped a valve seat. That's going to cost you $50K."

The average car today lasts 12 years, or 200,000 miles, with 300,000 miles possible with luck and good maintenance. Modern EV batteries are designed to last longer than that. Moreover, EV battery capacity loss is nonlinear: most (I've read 80%) of the eventual loss happens in the first couple years.

So if you're looking for a car with the least amount of battery degradation between purchase and EOL, buying a used EV rather than new is actually the better decision.

Would you never buy a used ICE car because replacing the engine would effectively total the vehicle?

Batteries last a LONG time assuming the vehicle manufacturer has put proper heat and SoC management into the battery controller (ie, not a Nissan Leaf).

I thought my 7 year old Ford Focus EV would be half the range of its 110mi battery by now but it still posts near-perfect range (it's lost about 5%).

A recent analysis of 10,000 EV vehicles shows that they only lose about 1.8% capacity per year[0], so they are perfectly useable up to 150-200k, which is the same general useful lifespan of ICE vehicles. [1] EVs and Plug-in Hybrids cost less to maintain than ICE vehicles. [2] Over 200k miles, ICE vehicles are about double the maintenance cost of EVs or Plug-in hybrids, and EVs are slightly more than Plug-in hybrids.

-At 50k miles; EVs $600, Plug-in $1,050, ICE $1,400.

-100k miles; EVs $2,000, Plug-ins $2,600, ICE $4,400.

-200k miles; EVs $6,300, Plug-ins $5,900, ICE $12,300.

EVs use about 30kWh to go 100 miles [3] and at the US national average for electricity [4], that would be about $ 9,978 to drive 200k miles. ICE vehicles vary, but 35 mpg combined is pretty average for compact cars. At the US national average for gasoline [5], that is $ 17,548 to drive 200k miles. Plug-in hybrids use about 29kWh to go 100 miles and about 48 mpg. Just assuming 50/50 driving on gas or electric, that’s about $11,220 to drive 200k miles.

So maintenance and fuel cost over 200k miles would be roughly:

-EVs $18,852

-Plug-in Hybrids $17,120

-ICE $29,848

[0] https://thedriven.io/2024/09/19/new-study-finds-vast-majorit...

[1] https://www.caranddriver.com/research/a32758625/how-many-mil...

[2] https://arstechnica.com/cars/2020/10/owning-an-electric-car-...

[3] https://www.perchenergy.com/energy-calculators/electric-car-...

[4] https://www.energybot.com/electricity-rates/

[5] https://gasprices.aaa.com/

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