> Since over charging and completely discharging lithium cells shortens their life does that mean because they're never allowed to use their full potential would they actually last longer than a true 60 kWh pack?

I am not a mechanic, but off the top of my head, they should last longer, depending on how Tesla has implemented the limit. If Tesla put the artificial charge limits in the middle of the actual capacity, then that would mean you never discharge the last 7 kWh or overcharge the last 7 kWh. If they just make the battery shut down 15 kWh early, then I doubt the gains are as significant, since plugging in your car overnight will still charge it all the way to the top (which from my understanding is the more harmful thing to do).

I'd be very interested to see some research done by someone who knows more about batteries than me, would make a cool technical breakdown. It seems to me that (just like CPU throttling) battery "throttling" could potentially be a useful way to decrease failure. Of course, if you think back to Apple's kerfuffle with throttling iPhones as batteries aged, you can have a good, justifiable customer result that still makes customers angry if they're not informed or suspect you have other motivations.

To bring this conversation back to the original point of the entire thread, it is (for now) legal to circumvent DRM for maintenance. So question: your battery starts failing on your Tesla car -- you buy a completely new battery from a non-Tesla producer that supports 75 kWh. You get a non-Tesla mechanic to install it. As part of the installation process, you break the DRM and allow the battery to be used to its full capacity.

Problem? No problem? When you bought a Tesla, were you paying for a 60 kWh rated battery or were you paying for a 60 kWh car?

Followup question, suppose you find out that Tesla (or any other electric car company with similar policies) has implemented battery throttling poorly for your car. Rather than rotating cells or putting a limit on how full cells get, the battery throttling just disallows a few specific cells from getting power -- so effectively, its as if you literally have a 60 kWh battery with a few (disabled) extra cells stapled on. Your battery range starts decreasing over time, and a mechanic breaks the DRM, which restores most of the failed capacity, which puts you back up to close to your original range.

Problem? Have you violated your contract if the car battery never got above 60 kWh?

And of course, finally you have obvious question, which is, 'if you buy a Tesla car and immediately break the DRM as soon as you get it home to get extra capacity, is that a problem?' Which, yeah, that's a problem. Tesla will not be happy with you.

The difficulty of looking at Tesla's policy as if it's a pure contract is that the physical constraints get in the way -- in other words, it's not a completely encapsulated system. If you look at something like being charged per-mile in a taxi, it's easy to completely divorce that from the physical process. You're charged per-mile that the taxi drove. Doesn't matter how it drove, doesn't matter what the actual cost of driving it is, doesn't matter what the implementation details are -- you're being charged for a result.

Similarly, if you buy something physical, then the physicality provides a reasonable set of consistent restraints and rules. Doesn't matter if it breaks later, doesn't matter why you bought it. In that case, only the physical reality matters and very few contractual things get in the way.

But with Tesla, you've got both systems clashing with each other. It makes sense to say, "okay, you payed for a 60 kWh battery and got a 60 kWh battery." But you didn't really get a 60 kWh battery. You got a 75 kWh battery that has extra restrictions. So you can't completely ignore implementation details, because you're still buying a physical battery, but neither can you take the entire system apart or universally mess with those implementation details.