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Could this really not be prevented by a $10 microcontroller and a big-ass relay to just disconnect the battery if it reaches a certain discharge state?

Not necessarily. This might help, but the battery will also have self-discharge, meaning that it can lose charge without being connected to any load at all. If you get the charge down low enough, and then wait long enough, then even a full disconnect from the system won't help.




You could add a $100 mobile phone, which auto-calls a service center. If 1% of cars get "bricked", that's $10,000 per car saved, not including intervention costs. Even with some false positives, it would be worth it. Of course, that cost is carried by Tesla, not the customer.

"The Tesla manager called me to warn that my car was in trouble" is a much better customer experience than "my Tesla broke down, and cost $40k to fix".

Cars used to have the same problems with oil changes. This got better, as customers were educated (at the cost of a lot of cooked engines), and cars were able to warn their owners, and run for longer without oil.


That's exactly what Tesla do, even once having gone so far as tracking the car down via GPS and charging it themselves when the owner was unresponsive.


According to the article they used to do that, but don't any longer.


Certainly that's going to peg some people's creepy meters.


As a Model S reservation holder, it pegs my pocketbook meter. If I'm about to lose $40K on my car because of a battery, I have no problem with them showing up in my driveway to charge the vehicle if necessary.

Creepy? I'm more worried about the app-of-the-day sucking down my iPhone contacts. THAT I find to be more personal than my vehicle location.


IMO they're both creepy, and using one to justify the other isn't helpful. Apple has already come out and admitted that was a mistake and they will be rectifying it, so it doesn't really help your case much.

In both cases though it's not the action so much as it is the fact that you weren't able to opt out of it, or in many cases you aren't even aware of the possibility of it happening.

It's the same violation, and in both cases it's equally creepy. Apple got called out and did something about it. What will Tesla do?


Tesla will have you sign a waiver: "We have the right to track your vehicle location in the event you're about to kill your $40K battery."

I don't know anybody in their right mind who would say no to that.


So set the cutoff higher?

Small portable gadgets using LiPoly batteries (which I assume the Tesla is using) can be left for months or years without charging, and then nursed back to life. If sufficient charge is left in them, and the circuitry is smart enough to recognise that the battery's about to die, the time before complete discharge could be extended to a much larger period of time.

The solution could even be a one-time use fuse, isolating the battery completely. Given the option, I think most owners would rather have to replace a fuse than a $40k battery.


Yes you woudl have though that this is not exactly rocket science. Or have a mechanical switch to isolate the batery coudl this be conected to the Parking Brake.

Jermy Clarkson must be pissing himself laughing over this


LiIon cells have virtually zero self-discharge. It is the battery management system that contributes nearly all of the self-discharge to a LiIon battery. You could have such a relay, but it would require some additional tools to recover from such a state (needs to get the BMS in a happy state, or the BMS itself must have the ability to charge the battery from an unknown state).

This all would seem to make sense to install though, it's far better to have a pack that needs a reset in the shop then a brick, esp. as the battery pack in the model S will make up nearly all of the resale value of the vehicle.




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