Do you know that you must keep your battery charged?

[JRP3]

Could they possibly be so confident about one cell not affecting the entire pack because of the battery management system?

Maybe, but if a cell goes into internal thermal runaway I don't think there is anything a BMS can do, unless it fires a mini fire extinguisher at it

[NigelM]

NYT article coming:

Of Bricks and Batteries: The Anatomy of a Controversy

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Garlic cloves! We need garlic cloves!!

[dsm363]

NYT article coming:

Of Bricks and Batteries: The Anatomy of a Controversy

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Garlic cloves! We need garlic cloves!!

This is news to me (the 36 days from 0% SOC to battery being ruined). That's much longer than I thought.

Q. Under what conditions would an electric vehicle battery become drained beyond saving?

A. An electric car’s battery will fail totally only under extreme circumstances, according to Tesla. This occurs if the battery has been discharged “for an extended amount of time.” Chemical changes that take place will make recharging impossible.

The electronic vehicle log from the Roadster with the failed battery recorded a span of 36 days from when the state of charge reached zero percent until Tesla said a complete replacement was needed.

[richkae]

This is news to me (the 36 days from 0% SOC to battery being ruined). That's much longer than I thought.

I think that was the time til it was confirmed to be ruined. It was ruined sometime before that, and not discovered until then.

[markwj]

WTF? An extra 12V battery can solve the bricking problem and allow a bricked battery to be recovered? In what universe?

[stopcrazypp]

This is news to me (the 36 days from 0% SOC to battery being ruined). That's much longer than I thought.

36 days was the time from 0% til the car reached Tesla. The battery was likely "bricked" before that. It's pretty clear though that it still wasn't over-discharged until 14 days after 0% (when logging stopped at 250V pack voltage). That means if he were to plug it in then, it probably would have still allowed him to charge.

WTF? An extra 12V battery can solve the bricking problem and allow a bricked battery to be recovered? In what universe?

The "Experts" seem to be talking about something else. For example the GM guy keeps talking about a "fail-safe" and "waking-up" system with the 12V battery. They are probably talking about resuming charging functionality after plugging in. That clearly isn't the issue in the Tesla case, since the technicians have direct access to the battery pack and can charge it directly with another charger if they wanted to.

And it seems like the experts are referring to other chemistries (for example the EV1 never had lithium batteries), in terms of recovering batteries. And it's unclear if it applies to a 6831 cell battery pack.

And the Nissan PR:

Nissan said in a statement that the Leaf’s battery pack “will never discharge completely, thanks to an advanced battery-management system designed to protect the battery from damage.”
And, said a Nissan spokeswoman, Katherine Zachary, “Never means never.”

I'd like them to explain then, why the battery warranty is voided after 14 days at or near 0% charge, if the battery "will never discharge completely". Unless they have a different meaning for "discharge completely".

[eledille]

There are many points where the pump etc could have stopped, points named in the letter are: SOC 4%, SOC 0%, end of logging, or even later than that.

It could have been any of those or some other point not mentioned (why not SOC 2% ?), the letter simply doesn't mention that. To think that the letter would imply SOC 0% (if that is what you think), or that it would imply 'later than SOC 4%', is merely based on your own expectation of what appears to make sense to you, but not based on anything written in the letter.

Did you even read what I wrote?

[JRP3]

I thought Roadsters do in fact have a 12V battery? There seems to be a lot of confusion in that article, by "experts" as well. If a cell is damaged by sitting at 0% SOC there is no "waking it up" as far as I know. I also don't buy the statement from Nissan that "never means never". Their pack is eternal? What is meant by the statement from Tesla that “less than 10” cars are “susceptible” to bricking? How does that fit with "Ms. Brooklyn of Tesla said there was “no facility to prevent this full discharge” in the more than 2,000 Roadsters produced since 2008." Sounds as if all Roadsters are susceptible. They need to be clearer than that and get on the same page.

[markwj]

I thought Roadsters do in fact have a 12V battery?

From first hand experience, that battery is used to power brake lights, hazard warning flashers, alarm, etc. The VMS, VDS, DIAG port connector, and other systems are powered directly from the ESS in the boot and NOT from the emergency battery.

I guess what the idiots (sorry, 'experts') in that article are saying is that if there was a separate 12volt battery that could power the VMS/VDS then you could still have enough control to start a charge even if the ESS power level was low enough not to be able to run the internal systems. This does nothing to address the 'brick' issue in that even if you could power up the VMS/VDS to start a charge, the batteries when 'bricked' are dead enough not to accept one.

Again, from first hand experience, even with a completely dead ESS (fuse blown), Tesla rangers can plug in a maintenance power source and bring up the VMS/VDS in order to get logs and do whatever else is necessary, just fine.

[ChargeIt!]

I thought Roadsters do in fact have a 12V battery?

AFAIK v1.x Roadsters don't. Probably started after VIN 500. Anyone can confirm ?