Do you know that you must keep your battery charged?

[efusco]

It's not unfair when the question was (and I paraphrase) "Why don't Tesla tell you what to do?". I'm just saying that the manuals and warnings are clear.



No Doc, I have done that. That's not a problem. You and I both know that we wouldn't leave our cars at the airport with a minimal charge in any case...how we would get to a chargepoint on our return? So much of this hysteria is based on the false premise that owners will drive somewhere, leave their car with a minimal charge and then come back months later to find a major problem.

What I'm saying is, that does it say in the manual that that is OK? If not, then there is some vagueness there. Unless they give you specific amounts of time to leave the car uncharged at various SOC levels then it is somewhat vague. As pointed out, you can't both "always leave it plugged in" and "leave it partially discharged at the airport for 10 days". We can both agree that there are extremes that anyone with a bit of common sense can appreciate. But the rub, and the vagueness, are the gray areas...you say 10 days is OK. Is 14? Is 21? Is 30? What if the SOC is 70%? What if it's 30%?
There is vagueness here and unless/until Tesla builds in some tools to automatically protect the car and notify the owners that vagueness will create some element of anxiety, particularly for us new buyers. I'm not paralyzed by that anxiety, mind you, but I'd sure like to know a bit more and know that Tesla's got my back on this if I should make a mistake. What if I'm hospitalized and my wife doesn't think about charging the car? I can imagine a ton of unintentional neglect situations that are highly likely to occur even to well informed owners that could potentially result in problems unless some added protections are added.

[onlinespending]

I give up....

as you should because you must not have read what I wrote after that.

[Lloyd]

They did give you pretty good rule of thumb. Up to 50% first week, and 5% every week thereafter for a total of 11 weeks.

[efusco]

I don't think Tesla can specify exact rules other than give guidelines and estimates of SOC going down by about x percent a day. The only hard rule is not to let your SOC get to zero. If you do, you need to plug in right away or you risk needing to buy a new battery out of warranty. With the Model S and mobile phones, you should be able to keep an eye on your car of you think you're
cutting it close.

Do those numbers exist? Either officially from Tesla or unofficially from owners--the % drop in SOC per day at various temps?

[loganss]

They did give you pretty good rule of thumb. Up to 50% first week, and 5% every week thereafter for a total of 11 weeks.

People are refusing to listen to that fact.

[NigelM]

as you should because you must not have read what I wrote after that.

Oh I did...but it made my head hurt.....

[NigelM]

They did give you pretty good rule of thumb. Up to 50% first week, and 5% every week thereafter for a total of 11 weeks.

I swear people are refusing to listen to that fact.

Amen.

[efusco]

They did give you pretty good rule of thumb. Up to 50% first week, and 5% every week thereafter for a total of 11 weeks.

honestly just trying to learn here. Is that 50% in the first week (which seems freaking huge IMO!) from 90-100% SOC or is that 50% from whatever the SOC was? IOW, if I take my airport example above, I have a 85kWh pack, drive 100 miles to the airport leaving me with let's call it 60% SOC, then I park the car for 20 weeks. Do I return to find the SOC at 25% (50% of 60% + 5% of 30%) or 50% (5%/wk)?

And why the heck does it drop so much that first week?

[dsm363]

Do those numbers exist? Either officially from Tesla or unofficially from owners--the % drop in SOC per day at various temps?

Look a few pages back. I copied the relevant section of the Roadster manual and a link the the PDF of the manual. Lloyd summarized it above too.
Tesla does stand by their battery. If leaving your can unplugged for days on end is going happen, you need to do the rough calculation to see how close you'll get. Again, the actual decrease can vary so Tesla provides just an estimate. You'll also be able to monitor your car via the mobile app.

Are they worst case scenarios where everything could go wrong? Sure but that can happen with anything. Tesla can't design away every problem.

[dsm363]

honestly just trying to learn here. Is that 50% in the first week (which seems freaking huge IMO!) from 90-100% SOC or is that 50% from whatever the SOC was? IOW, if I take my airport example above, I have a 85kWh pack, drive 100 miles to the airport leaving me with let's call it 60% SOC, then I park the car for 20 weeks. Do I return to find the SOC at 25% (50% of 60% + 5% of 30%) or 50% (5%/wk)?

And why the heck does it drop so much that first week?

Someone else can speak to why this happens but parking your car and not charging for 20 weeks probably a bad idea.