Not something you want to experience often....

[NigelM]

Coming home after midnight last night (on a trip I've done many times before and usually make it home with about 10miles to spare) and about 5 miles from home I'm showing 19 miles of ideal range...Out of nowhere I hit an area of very cold fog and then shortly afterwards I get a message saying that ESS state is not able to give an accurate range estimate. Pic of the VDS when I stopped at a traffic signal....

Trusting in almost 7 years of Roadster experience (and realizing I had little choice, with no charging options anywhere nearby) I figured there was enough juice to get me home as usual. Eventually pulled in to my garage and plugged in....

Phew!

This morning all is well again in Roadster Land, but I admit to feeling a lot more sanguine about the experience today than I did on the country roads in dense fog in the middle of the night.

 

[bonnie]

I saw that screen a LOT ... obviously I cut things closer than you, my friend.

 

[NigelM]

I saw that screen a LOT ... obviously I cut things closer than you, my friend.

You're a brave person Bonnie. I've been on many trips where I've arrived with just a handful of miles to spare, this was my first time 'blind' on zero miles....I think it was caused by the sudden drop in outside temperature and thankfully 46F is a rare occurrence here. Being on country roads with fog and in the middle of the night was the less-than-fun-perfect-storm.

 

[supersnoop]

That message pops up when the battery hits 10% in range mode.

 

[ChadS]

It also makes a very loud BEEP! BEEP! BEEP! when it comes up.

Very disconcerting the first time you encounter it...

 

[ecarfan]

Thanks for your post Nigel. I don’t ever want to see that screen! Before I got my 3.0 battery I occasionally did a drive for work that typically resulted in my arriving home with about 18-20 miles of range left with the car in Range Mode. That’s as low as I care to go.

I appreciate that your post says you had 19 miles or range showing when suddenly it went to “- - -“. You seem to be guessing that a sudden drop in temperature dramatically changed the range calculation, is that correct?

 

[hcsharp]

I've run into that screen several times. I'm surprised it waited until you were at 19 mi range. My experience is like supersnoop - it happens when you go below 10% in range mode. People who have the 3.0 battery experience the same message at about 10%. I think dhrivnak saw it on a recent trip and had to be towed after going only a few miles after it popped up. Tesla changed the firmware about 5 or 6 years ago to add that message. It kind of annoyed me because the original firmware would count every mile down to 0 in range mode.

 

[ecarfan]

My experience is like supersnoop - it happens when you go below 10% in range mode.

Interesting. I’m surprised I have never seen what Nigel posted a photo of even though I have gone down to 18-20 miles in Range Mode on my original battery.

 

[supersnoop]

Maybe these are estimated instead of ideal miles? 10% should be around 24 miles of ideal range, but the estimated range could be lower when you hit that threahold.

I’ve hit it a couple times on hot days when I had to use the a/c on an Austin/Dallas trip.

 

[hurd300403]

Am I right to assume that the car will keep driving until the batteries are fully depleted beyond 0% if calibration is wonky? or will the car stop at a certain point no matter what to protect from bricking?

 

[supersnoop]

Am I right to assume that the car will keep driving until the batteries are fully depleted beyond 0% if calibration is wonky? or will the car stop at a certain point no matter what to protect from bricking?

The car will brick itself at some point. There is no protection, as far as I know; at least in Range mode.

 

[DeedWest]

I too experienced this last week, but noticed something even more peculiar. Not only did I confirm that the range turns to “uncertain” at 10% like @supersnoop said, but my “RR” (Rated Range) on this diagnostic screen turned into 65,535 Miles.

If only...

 

[CSPHD]

View attachment 266833 “RR” (Rated Range) on this diagnostic screen turned into 65,535 Miles. If only...

Evidence of an integer underflow error in the software. Seems like an obvious case to cover during testing.

 

[hcsharp]

I too experienced this last week, but noticed something even more peculiar. Not only did I confirm that the range turns to “uncertain” at 10% like @supersnoop said, but my “RR” (Rated Range) on this diagnostic screen turned into 65,535 Miles.

If only...

That's the highest 16-bit number, or one less than zero, which is a common integer underflow, but it may not be an error as CSPHD suggested. They might be using that number as a code that means "The system can no longer predict ideal miles."

Then again maybe it means your rated range is one less than 0.

 

[hcsharp]

Am I right to assume that the car will keep driving until the batteries are fully depleted beyond 0% if calibration is wonky? or will the car stop at a certain point no matter what to protect from bricking?

The car will stop to protect from bricking. However, it assumes you will plug it in shortly after it stops. If you wait a couple days it might brick in the meantime.

 

[NigelM]

That message pops up when the battery hits 10% in range mode.

Although I've never had the numbers drop to precipitously to zero before.

 

[NigelM]

I appreciate that your post says you had 19 miles or range showing when suddenly it went to “- - -“. You seem to be guessing that a sudden drop in temperature dramatically changed the range calculation, is that correct?

Correct. I hadn't been watching the temperature up to that point but it was in the high 50's so I'm guessing the temp drop was more than 10 degrees. Also it was just after I turned off the Interstate and headed home on the country roads, so may have been related to a drop in speed (thinking cold effect). I've never experienced cold as a range limiting factor before because, well, Florida.

 

[dhrivnak]

I believe there is a significant difference between the Roadster and the Model S. On the Roadster 0 is 0. And actually the you never see close to 0 as the Roadster goes to indeterminate for the last 10% so with the 3.0 that is about 35 miles. And when the Roadster stops it stops. No buffer no second chance. And shortly after 0 you will be bricked. Not sure if it is hours, days or weeks but I for one will not try to find out.

 

[Indian Steve]

I have yet to make mine go that far low and it scares me!

Random question, is it worse for the battery to drive in range mode or to drive in standard and let the battery get down to say 10 miles left of ideal range? It has been a little bit colder so my daily commute has been taking more charge and a couple of days I have gotten low on ideal and not wanting to use my range I leave it there but I am not sure which has more harm in the longterm?

 

[gregd]

Standard mode hides the bottom 10% or so of the battery capacity from the VDS calculations, so Standard mode's "0" miles is about 20-ish miles in Range mode. Standard mode also considers the battery full at about 83%, where Range mode lets you take it all the way to about 94% and disables regen to keep it from going any higher. This is different than the Models S & X where I believe you always see the actual battery charge, and Range mode changes other aspects of the car's operating behavior in an effort to save power.

The reason that Standard mode hides the top and bottom of the actual capacity is that running the battery in those end zones is harder on the battery than in the center. Range mode also limits power to 50%, which also helps a bit with battery stress, especially at the low end.