Different Sentry Drain Based on Starting SoC

[Mark-YSR]

I've noticed this interesting behaviour from my Model Y SR since I've had it.

I charge up to 70% from 2 am to usually 4 am. I get to work just after 9 am and park with Sentry on.

On days I arrive at work with ~65% SoC, I see ~6% drain. TeslaMate shows ~500W average draw.

On days when I skip charging and arrive at lower SoC, say 50%, I see 2% drop or 100W draw.

This is pretty consistent. There's no reasonable way it is related to activity around the vehicle (unless people know my random charging schedule!).

What could account for such a discrepancy? I like 100W more than 500W, but only SoC when parked seems related.

 

[jcanoe]

Multiple Sentry Mode events do not affect the power used. What about temperature? Is the Model Y parked outdoors in sunlight (summer time.) The Tesla vehicle may run the fan and AC to cool the battery. Cabin Overheat Protection (if set On) can run the fan and the AC to maintain the passenger cabin below 105F (40.5C).

Neither 500W or 100W consumption while parked is typical. When The Tesla Model Y is parked, awake such as when Sentry Mode is active expect ~230W consumption. When the Tesla Model Y is in sleep mode expect ~25W consumption. Perhaps a third party app is controlling some of the settings, causing additional power to be used.

 

[Mark-YSR]

Vampire drain on October 21 started with SoC ~50% (at work) 2%

Vampire drain on October 24 started with SoC ~67% (at work) 6%

Vampire drain on October 25 started with SoC ~67% (at work) 7%

Vampire drain on October 26 started with SoC ~50% (at work) 2%

It makes absolutely no sense to me. No cabin overheat and weather has been in the 10 - 20C range.

 

[Empiro]

I've noticed that if I leave my car at around 60-65% charge, after a few hours it will often drop 3% or more. This is when parked in my garage with sentry mode and everything off. I think the issue is that the bms has some problems at this range. I've also found that I gain back this lost charge at around 50% or so.

If this is a systemic issue with all Tesla's, then it's likely you're seeing the same issue

 

[Mark-YSR]

I've noticed that if I leave my car at around 60-65% charge, after a few hours it will often drop 3% or more. This is when parked in my garage with sentry mode and everything off. I think the issue is that the bms has some problems at this range. I've also found that I gain back this lost charge at around 50% or so.

If this is a systemic issue with all Tesla's, then it's likely you're seeing the same issue

After doing some investigation, it appears that this is the explanation for what I am seeing. I have been charging to 65% (starts charging at 2:30 am) the last few days and even with the car plugged in, by 7:00 am the car is in the low 60's (61 - 62% or so). It shows that vehicle standby has consumed that energy. I thought maybe it was because my phone was connected to the car all night, however I turned Bluetooth off last night and the car is in the same state this morning.

Throughout the day while in that 55 - 65% range, it seems to not have a great grasp on an accurate level of charge. I can arrive at a destination and see SoC go up by 1 - 2% in some cases.

I'm guessing the reason I was seeing the big drop is because I'd arrive at work in the range of the miscalibrated BMS and it would show that significant drop whether Sentry is on or not because I see the drop at home and Sentry is off.

TeslaMate must just calculate the energy usage based on SoC reported and not actual energy used in these cases. It's probably a case of BMS issues rather than excess consumption.

Thank you for your response which seems to have guided me to the answer.

 

[Gray Man]

After doing some investigation, it appears that this is the explanation for what I am seeing. I have been charging to 65% (starts charging at 2:30 am) the last few days and even with the car plugged in, by 7:00 am the car is in the low 60's (61 - 62% or so). It shows that vehicle standby has consumed that energy. I thought maybe it was because my phone was connected to the car all night, however I turned Bluetooth off last night and the car is in the same state this morning.

Throughout the day while in that 55 - 65% range, it seems to not have a great grasp on an accurate level of charge. I can arrive at a destination and see SoC go up by 1 - 2% in some cases.

I'm guessing the reason I was seeing the big drop is because I'd arrive at work in the range of the miscalibrated BMS and it would show that significant drop whether Sentry is on or not because I see the drop at home and Sentry is off.

TeslaMate must just calculate the energy usage based on SoC reported and not actual energy used in these cases. It's probably a case of BMS issues rather than excess consumption.

Thank you for your response which seems to have guided me to the answer.

Not too surprising. Lithium battery State of Charge is notoriously difficult to reliably determine due to the very flat voltage curve.