HV Battery Died with 7 miles range left showing on Range display

[Big Earl]

This happens, although it’s the first time I’ve heard of it on a Y. I try to keep my arrival above 9% whenever possible and have never run into an issue with the battery shutting down prematurely. I arrived home with 4% a few days ago, but I was taking it easy on rural back roads for the last few miles.

This is likely caused by one cell that’s a little weaker than the others at the bottom, making it difficult for the BMS to accurately predict the energy remaining at the very bottom of the pack. This can be compounded by high electrical loads like heat, battery conditioning, high load driving, and even temperature.

In my opinion, this isn’t something you’re going to get resolved under warranty. Tesla’s response about the calculation being an estimate is accurate, and you should avoid running to super low states of charge in any EV, just like you should avoid running a gas car down to one pint of fuel remaining.

 

[Evolutis]

Started the battery health test last night at 16% SOC, this morning I see the test completed but I got no result. Battery Health --%. Will reattempt soon.

 

[dhrivnak]

I've had 2 instances recently where the car died (forced to a stop) even though the battery showed a few miles of range left (7 miles and 4 miles). 2022 Model Y Performance, 38,000 miles. Current max range: 279mi, 6.4% degradation. Purchased new March 2022. Battery is usually set to charge to 80% but given I drive a lot for work I sometimes set it to 100%. 19% of my charging was done at Superchargers.

12/20: 7 miles left, 50°F, was en route to a supercharger that was about 1/4 mile away.
12/07: 4 miles left, 47°F, was 0.9 miles away from home on my freeway off-ramp exit. Had to get towed.

In both cases I had the car set to navigate to the supercharger or home and the car stated I could make it to my destination. In the first few months of ownership there were a handful of occasions where I arrived home with 1 mile or 0 miles left. The vehicle did not slow down dramatically or display messages that it was going to run out of range.

Has anyone else had this experience where the car is dying with 4+ to 7+ miles range left? Is there anything that can be done in a service appointment? For example, can a technician do a recalibration such that the estimated range shown is more accurate? I understand that taking the battery to a low SOC is not good for it's health however that's not my question. Since both instances, I've taken steps to ensure I arrive at my destination with more range but I'm losing a bit of trust / confidence in the stated range. Will it get worse over time? For example in the future is the car at risk of dying with 10 miles left, 15 miles left?

I have gone to 0 twice. No lower but I have seen 0 and yes my car ran. So something is off or wrong and should be checked by Tesla.

 

[Evolutis]

I have gone to 0 twice. No lower but I have seen 0 and yes my car ran. So something is off or wrong and should be checked by Tesla.

Thanks for the data point. I probably should have mentioned that in the first say 3 months of having the car when it also happened to be warmer I did take the battery down to roughly 2, 1, 0, and -2 (not my intention). The car ran fine and did not force me to go at very slow speed (30 mph or so), no warning messages about an impending forced shutdown. I'm making an effort now to not get that low again but the point is it let me before and now it doesn't. As I've mentioned before I'm now treating 10 miles of range left as effectively 0 miles for calculation purposes. I'm also spending more time at superchargers before heading home.

 

[ewoodrick]

Thanks for the data point. I probably should have mentioned that in the first say 3 months of having the car when it also happened to be warmer I did take the battery down to roughly 2, 1, 0, and -2 (not my intention). The car ran fine and did not force me to go at very slow speed (30 mph or so), no warning messages about an impending forced shutdown. I'm making an effort now to not get that low again but the point is it let me before and now it doesn't. As I've mentioned before I'm now treating 10 miles of range left as effectively 0 miles for calculation purposes. I'm also spending more time at superchargers before heading home.

Switch the display to percent and assume that 10% is empty.

If this was an ICE, 2 miles could be a teaspoon of gas.

 

[arbitrage000]

Did the car go through the various stages of power limitation seen in Bjorn's video linked below?
Sounds like it was much more abrupt in your cases.
Bjorn went 33km past 0% in the MYP.

 

[buckets0fun]

Started the battery health test last night at 16% SOC, this morning I see the test completed but I got no result. Battery Health --%. Will reattempt soon.

I had to do it twice to get anything to show up.

 

[GBMaryland]

It’s wild that an ecoflow got it to 7%!

 

[Evolutis]

I had to do it twice to get anything to show up.

Just finished the 3rd battery health test this morning and still no result! I guess I'll just try again but I'm losing hope. I want to get this test done before my March 8th service appointment.

 

[buckets0fun]

Just finished the 3rd battery health test this morning and still no result! I guess I'll just try again but I'm losing hope. I want to get this test done before my March 8th service appointment.

View attachment 914154

And you’re following the directions? Not charging from 110v, but from (iirc) 6kW+ lvl2?

 

[Evolutis]

And you’re following the directions? Not charging from 110v, but from (iirc) 6kW+ lvl2?

Yes, plugged into a Tesla wall charger with a 50 amp breaker so it's at the max kw possible.

 

[buckets0fun]

Yes, plugged into a Tesla wall charger with a 50 amp breaker so it's at the max kw possible.

verrrrrryyy odd. Wonder if this is SOP for cars with questionable battery health.

 

[avs007]

If you are under 10% and too far away from the charge, I don't think that I'd route to the Supercharger, I don't want the car to even think about using energy to condition the battery (I hope that it doesn't do it anyway)

If the arrival SoC is under 18%, it won't precondition the battery. I found this out by accident while driving back from canada in subfreezing temps. I was debating which charger to set the destination to, since I was planning on hitting an EA charger. When the arrival SoC dropped below 18%, it stopped preconditioning. I switched the supercharger that it was navigating to, and the arrival SoC was now 23%, and it started preconditioning again. It stopped again tho when it got to the same estimated SoC.

 

[RobDeBank]

I have a 2020 MY recently I have seen a drop in range, I am putting this down to temps really. I charge to 100% and can drive 128 miles to work, then have 40% left, I have to supercharge back to at least 85% to get home. It certainly seems I will only get around 200 miles from a 100% charge which has surprised me. On the app, it shows my battery has certainly lost power, from new it showed 320 miles now it says 220... I hope this is due to the current winter temps in the North east...

 

[arbitrage000]

I have a 2020 MY recently I have seen a drop in range, I am putting this down to temps really. I charge to 100% and can drive 128 miles to work, then have 40% left, I have to supercharge back to at least 85% to get home. It certainly seems I will only get around 200 miles from a 100% charge which has surprised me. On the app, it shows my battery has certainly lost power, from new it showed 320 miles now it says 220... I hope this is due to the current winter temps in the North east...

Certainly charging to 100% daily and SC daily are two of the the worst things you can do for the battery. If you can make it to work with 40% from 100% I'd start charging to only 80-90% to get to work with 20-30% and then SC just enough to get home. Do you really need 85% to get home if you only need 60% to get to work?

 

[Evolutis]

Initiated a 4th battery health test last night, and it failed again for the 4th time. This time I caught it before it charged to 100%. Service appointment tomorrow.

 

[avs007]

Maybe I'm just blind, but where does it say it failed? Just curious, becuase that looks like a really useful test...

 

[Evolutis]

After the test completes it should show a result such as Battery Health: 85%. For my car it shows Battery Health: --%.

 

[AlanSubie4Life]

This definitely should not happen, in a properly functioning vehicle. There is a large buffer so pushing to 7 miles should be ok (though should be avoided, to reduce stress if nothing else).

However, given that (usually) downwards BMS adjustments of several % are being observed on the new energy screen, recently, it is consistent.

I do wonder if there is a bug right now with the BMS estimation, because the consistency of negative adjustments seems more apparent than in the past.

Anyway if I were the OP I would look at the energy loss while parked after a charge and a sleep period, to see if at high SOC he typically is seeing an adjustment. I think that would be circumstantial evidence that his car is struggling to get the right estimate, or needs time to do so. Of course, it could also make no adjustment because it thinks all is well, which would also be problematic! So may be pointless but still would be curious. All readily available and easily observed and tabulated on the energy screen (ignore the categories, just shut everything off and be 100% sure the contactors are opening, and then observe the totals - the car has no idea how to categorize the losses - well documented that it puts BMS adjustment in random categories - like Sentry, for example).

Another question is was the car allowed to sit after the charge, before the problematic journeys occurred? Did it sleep and adjust? When I have seen the recent large (for me it isn’t that large, just 10 miles or so) adjustment right after a charge, I have occasionally wondered…”well, what would have happened if I had just started driving without letting it sit, and taken it to 5 miles?”

Anyway hopefully the appointment will resolve this but seems unlikely.

The whole point of the buffer is to avoid this, but if the BMS error is larger than 4.5%, you will be kind of screwed. Seems that the BMS error was more like 6-7% in this case. In my opinion that is too large an error to be acceptable.

Summary: right now we have observable evidence (at least on Model 3, though no reason for a difference on Model Y) that the BMS is kind of buggy. Well documented at this point. Has not always been that way.

That could be related here, or it could be a one-off issue with the vehicle.

 

[sabresd]

I’ve had the same thing happen to me and I made a post about it. I drive a 2025 p90d with ludicrous and 270,000 miles. Tesla service told me there was a CAC imbalance and that it’s not covered by my 8 year unlimited mile warranty