Do you know that you must keep your battery charged?

[Norbert]

Did you even read what I wrote?

Yes, and I responded to the import of your description multiple times, including in that message, in the part that you didn't quote. You tried to establish a binding formal requirement that such a letter must logically specify all relevant state changes. My answer was that in terms of the letter, the "pump stops operating" event is not a relevant part of what happens, as the letter only describes events in so far as necessary to show that the Roadster behaved according to its specifications as described in the user manual. The user manual does not make any promises about what happens or doesn't happen at low SOC, and when, and so it is not relevant to the letter's intent. The letter does not even try to give all the information that we would need to understand all the details of how it works exactly. It only gives the information that is relevant to the question of whether the warranty applies, or not, and that is independent of when exactly the pump stops operating. However it mentions the pump working in the area around SOC 21% since that is normal operation and part of what the Roadster's thermal management is supposed to do even in its idle state.

 

[TEG]

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

I think that is correct.

Tesla Initiates Voluntary Recall After Single Customer Incident | Press Releases | Tesla Motors

...Roadster 1.5 vehicles (VIN ending with 500 or before) ... do not include the 12V auxiliary cable...

 

[Doug_G]

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.

If the Volt's 12V battery goes flat, you can't start the car even if it has a good charge in the traction pack. (I've seen it happen.)

 

[JRP3]

That's interesting since the 12V battery should be kept up by the DC/DC converter connected to the pack. I wonder if that was from a converter failure that let the 12V battery drain and die? As I remember the Tesla uses a dual output DC/DC, one that powers the vehicle accessories and one that keeps the 12V battery charged up.

 

[dpeilow]

Greenie Weenies at Autoblog Butt Hurt About Tesla Bricking News

 

[Doug_G]

That's interesting since the 12V battery should be kept up by the DC/DC converter connected to the pack. I wonder if that was from a converter failure that let the 12V battery drain and die? As I remember the Tesla uses a dual output DC/DC, one that powers the vehicle accessories and one that keeps the 12V battery charged up.

No, it was caused by having the door left open for a week. The cabin light drained it. Nothing wrong with the car.

 

[doug]

Greenie Weenies at Autoblog Butt Hurt About Tesla Bricking News

This guy misattributes Tesla's PR response to the Roadster owner's manual.

 

[dsm363]

This guy misattributes Tesla's PR response to the Roadster owner's manual.

That guy is obviously is not objective and I don't agree with his choice of words in the title (Greenie Weenies at Autoblog Butt Hurt About Tesla Bricking News).

 

[JRP3]

No, it was caused by having the door left open for a week. The cabin light drained it. Nothing wrong with the car.

If the DC/DC is stepping down pack voltage to 12V and sending it to the battery as it should, and the pack had charge, how did the 12V battery drain? Unless the DC/DC disconnects from the 12V battery when the car is shut down. I guess it does make some sense, that way a 12V drain, such as a dome light, can't kill the main pack.

 

[Doug_G]

If the DC/DC is stepping down pack voltage to 12V and sending it to the battery as it should, and the pack had charge, how did the 12V battery drain? Unless the DC/DC disconnects from the 12V battery when the car is shut down. I guess it does make some sense, that way a 12V drain, such as a dome light, can't kill the main pack.

The car was not on. In fact the first day they accidentally left it on, and many hours later it decided to start the engine! Indoors! Sitting on a carpet! After that they made sure it was turned off, and plugged it in. But the hood and doors were kept open pretty much a whole week, and the 12V battery went dead. Once the car was boosted we could drive it out using the traction battery. Kinda strange that it had all this juice in the pack, but we had to get it boosted.

 

[eledille]

My answer was that in terms of the letter, the "pump stops operating" event is not a relevant part of what happens, as the letter only describes events in so far as necessary to show that the Roadster behaved according to its specifications as described in the user manual. The user manual does not make any promises about what happens or doesn't happen at low SOC, and when, and so it is not relevant to the letter's intent.

Ah, of course. It's now blindingly obvious even to me that whether or not the car did everything possible to prevent the death of the battery is completely irrelevant to the letter's intent, so Tesla chose not to waste 30 characters worth of paper and toner to include this unnecessary detail. The only question remaining is why they included so many other details about what happened at low SoC, even though the user manual says nothing about those either.

Frankly, this is absurd. I think you know that too.

 

[Norbert]

Ah, of course. It's now blindingly obvious even to me that whether or not the car did everything possible to prevent the death of the battery is completely irrelevant to the letter's intent, so Tesla chose not to waste 30 characters worth of paper and toner to include this unnecessary detail.

The letter is in reply to someone asking for warranty coverage, not in reply to later accusations of design errors. The latter would probably require a much longer technical discussion of battery and EV technology.

The only question remaining is why they included so many other details about what happened at low SoC, even though the user manual say nothing about those either.

I read the whole letter again and found the following three points regarding low SOC. I don't see a single one of the supposedly "many other details".

- the date of reaching the SOC 4% "threshold" with subsequent alerts as specified by the manual
- the date of reaching SOC 0% exceeding the timeline specified by the manual
- the date and necessity of when logging stopped, as from this point it is technically impossible to provide further information about the battery (which however at least up to this point provided limited functionality).

All these events are relevant in terms of demonstrating the degree to which all specifications were met or exceeded.

Frankly, this is absurd. I think you know that too.

Not at all, the opposite. I'm getting tired of this.

 

[JRP3]

I think that is correct.

Tesla Initiates Voluntary Recall After Single Customer Incident | Press Releases | Tesla Motors

That specifically mentions "12V auxiliary cable" but doesn't say 12V battery. It's possible they did have a battery but setup differently without that specific cable. I'm inclined to think they didn't have a 12v battery but can't be positive from that statement.

 

[JRP3]

The car was not on. In fact the first day they accidentally left it on, and many hours later it decided to start the engine! Indoors! Sitting on a carpet!

You mean the electric traction motor started turning?

After that they made sure it was turned off, and plugged it in. But the hood and doors were kept open pretty much a whole week, and the 12V battery went dead. Once the car was boosted we could drive it out using the traction battery. Kinda strange that it had all this juice in the pack, but we had to get it boosted.

I'd say it's a design flaw, I can understand wanting to avoid the 12V battery draining the main pack, but you should be able to flip a switch or something to let the DC/DC send power to the 12V battery so you can drive it. An EV with usable range in the traction pack should not be stranded by a dead 12V battery.

 

[Doug_G]

You mean the electric traction motor started turning?

No, I mean the GAS engine turned on unexpectedly, while the car was just sitting there unattended and had been accidentally left turned on. This wouldn't have been a big deal except the car was indoors, and the conference center guys were kinda spooked by it. Once we investigated and found the car was turned on, we simply turned it off and that solved the problem.

The car was then plugged in to recharge the traction battery - it was pretty low and that could have been the reason the car started the engine.

I'd say it's a design flaw, I can understand wanting to avoid the 12V battery draining the main pack, but you should be able to flip a switch or something to let the DC/DC send power to the 12V battery so you can drive it. An EV with usable range in the traction pack should not be stranded by a dead 12V battery.

I suppose this was simply "(mis)use case" that hadn't been expected by the GM engineers. Or maybe it had been anticipated and they didn't want the traction battery to drain in this situation, to avoid a possible "bricking" issue.

In any case even though the 12V battery was flat, the traction battery had gobs of juice. All it took was a booster pack, and it drove away on electric power.

 

[JRP3]

I thought were were talking about a Roadster.....

Ah, I see your initial response was about GM, my bad. :redface:

 

[Doug_G]

I thought were were talking about a Roadster.....

Ah, I see your initial response was about GM, my bad. :redface:

Sorry for the confusion - I can see how you might be baffled if you jumped in mid-conversation.

 

[richkae]

I'd say it's a design flaw, I can understand wanting to avoid the 12V battery draining the main pack, but you should be able to flip a switch or something to let the DC/DC send power to the 12V battery so you can drive it. An EV with usable range in the traction pack should not be stranded by a dead 12V battery.

This happens to Prii/Priuses all the time. The good news is that you can "jump start" it with a 12v lantern battery because its not actually cranking anything, just running some electronics.

 

[DrTaras]

And the Nissan PR: 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".

Great pick up. In politics as in business, it doesn't seem that "words matter."
When someone says, "I guarantee" it that is worthless unless you find out what the ramifications are if they are wrong and what the fine print is that allows them wiggle room.
Usually you only find out the latter when you need to make a claim. :crying:

 

[Norbert]

This happens to Prii/Priuses all the time. The good news is that you can "jump start" it with a 12v lantern battery because its not actually cranking anything, just running some electronics.

I guess in the Model S it will help that the computer can turn off all lights (I think).