Vampire drain on standby

[Zeppos]

I have a 2022 MSLR. All runs well but it has a wicked high battery drain if you park the car for an hour. No issues when i go to work and leave it for a few hours but if i stop for lunch or other quick 1-2 hour stop - the car seems like it’s been running and wil love 4-6% of the battery in 1 hour when i get bwxn


No issues when i leave it alone for a few days - but the battery drain for a 1 hour lunch appointment is horrendous. I suspect perhaps that I’m too close the car in the quick stopovers and the car runs on an aggressive standby mode?

I do not run sentry mode or any other dog mode etc …..

Any suggestions are appreciated

 

[zivac87]

when was last time you charged to 100% and discharged to 10% or lower?

my guess is that you keep car between 40% and 70% and BMS has problem in calculating your true state of charge,

 

[ATPMSD]

Also, the battery capacity drops after being driven as the battery cools. And it will drop even more if the car determines it needs to cool the battery, and does so.

 

[zivac87]

Usually car is dead silent after parking and 2-4% drain happens almost instantly, within 10 min of being parked after being charged. There is nothing that could drain that amount of energy and its impossible to cool battery that fast at 60F ambient. After researching this problem on multiple threads / reddit / other forums, problem dissapeared once BMS was properly calibrated.

 

[dzeppos]

I typically charge to 75%. I've only charged to 100% once ever. its the quick drain above that 2-4%) in the first twenty minutes.
Never an issue when I come home from work or leave it at work all day. Or when I leave it at the airport for a week (usually 1% drop a day)
More like it when I am close to the car - at my buddy's house for an hour, that I come back and it loses 4% - maybe because i didn't walk away far enough and its picking up my phone.
What's BMS?

 

[zivac87]

Its Battery management system. Usually drop happens shortly after you completed charge and made your 1st trip.

From my understanding you have 7920 individual cells in your car. If you havent balanced cells for long time and you charge it to something like 70% not every cell voltage will be at that state, some will be lower and your BMS will have hard time to determinate exact state of charge, sometimes it will compensate and lower your SoC because it miscalculated it (energy app - "vehicle standby"). When you charge at 100% BMS will make sure all 7920 cells get full voltage, and its probably what is called cell balancing. When you reach low SoC BMS will now learn how big is your cars range from high SoC and low SoC and it will make accurate estimates.

 

[ATPMSD]

I typically charge to 75%. I've only charged to 100% once ever. its the quick drain above that 2-4%) in the first twenty minutes.

Here is the most likely reason for the loss: “The batteries are heated and cooled to stay in a healthy temperature range without you ever knowing, even if the car is off.”

BTW, you should charge the car to 100% every now and then. I do it quarterly on a day when I can drive the car on the next morning.

If you want to read up on the BMS read this: Tesla battery management system (BMS) calibration

 

[dzeppos]

Everyone has been saying its the 'kiss of death' to charge to full capacity often. I'll do that over so often going forward and see what happens.
Thanks for the advice.

 

[vcor]

"Kiss of death" is an extreme exaggeration. While no one has solid numbers, think of a 100% charge reducing the life of your battery by a few days. Yes, it's not great, but over a 15-year design life, a few days are nothing to worry about. Do it if you need to, but don't do it every day. The car will even warn you if you do it more than a couple of days in a row.

That said, I'm not sure a recalibration will help, but worth a try. I assume Sentry mode and Summon standby are off. Here are more ideas about Vampire drain that may help that I wrote up: Vampire Drain – TeslaTap