[samketchup]

It's not a myth at all, and Tesla's "rating" is a lie. Look at data on Prius battery packs and what Toyota rates them for(100-150k). I understand I'm comparing a hybrid to an EV, but there is much more data and I actually trust Toyota.

Buying an EV with 100k miles and the original battery pack for 20k is a bad idea.

[gridspy]

Lithium-ion battery lifetimes are based on charge-discharge cycles.

The Prius battery is far smaller (about 5-10x smaller) than a Tesla battery, so it is cycling charge / discharge far more often.

So you'd expect the same quality battery to last 5-10x less miles in a Prius than a Tesla driving the same distance. It's likely that Tesla's investment in battery quality and active temperature controls mean the Tesla battery is also treated better and higher quality.

Topping that battery up with a generator in the Prius complicates things, both reducing kWh used per mile (some from generator) but also allowing a discharge - recharge cycle to occur multiple times in the same trip.

[cyberax]

There are multiple sites that track real-life Tesla battery degradation. It averages at 12% after 200k miles: https://insideevs.com/news/664106/tesla-battery-capacity-deg...

I have a Tesla, and I use it in the worst possible way for the battery: road trips with deep discharges and frequent 100% fast charges. I'm at 100k miles, and it degraded by 9%.

[rootusrootus]

> I understand I'm comparing a hybrid to an EV

I don't think you do. Prius's have only recently started using lithium ion batteries, for one. And they cycle the small battery a lot faster than a BEV. Everything we've learned from hybrids suggests BEVs will get hundreds of thousands of miles from the battery (and so far, from the cars which haven driven that far, this has proven correct).