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Help: Horrific battery draining while parked in long term parking structure - I've got 12 days to go

My battery drops 2% overnight sometimes, rises 1% overnight (not plugged in) other times. How do you know yours is true drain?
I've never had the percentage go up, only down. I don't know what you mean by true drain though. Anything that's using car battery is drain right? I've gotten some feedback from Tesla support that the battery is kept warm in cold temperatures and cool in hot temperatures. Also one time the fans ran while parked to dry out the air filters. The battery still takes a whack often. 2% in two quick 45 minute stops over the weekend.
 
I've never had the percentage go up, only down. I don't know what you mean by true drain though. Anything that's using car battery is drain right? I've gotten some feedback from Tesla support that the battery is kept warm in cold temperatures and cool in hot temperatures. Also one time the fans ran while parked to dry out the air filters. The battery still takes a whack often. 2% in two quick 45 minute stops over the weekend.
The % reading is the Battery Management System’s (BMS) best estimate of how much juice is in the battery. It’s an estimate because it can’t count the actual electrons.

When car is asleep, it will re-estimate % remaining.

This is why (for me at least) the % can go up a bit while not parked in.

So my “true drain” Q is how do you know if the loss is real (juice coming out of the battery) vs. a new, slightly lower estimate?
 
I've only had one month of data collection but the percentage has only gone down every time i look. Maybe I'm overdue to see it bump up. I am no expert but I thought battery life monitoring was a well known solution by now. For instance, phone battery over the last couple of decades.
There's also other corresponding data like in this last charge going from 80% to 70% over two days the driving ate 5kwh. At 81kwh capacity that's 3.1kwh unaccounted for. Even rounding up to 6kwh used that's 25% battery used not driving. This has been the pattern my entire time owning. A huge chunk of calculated capacity is unaccounted for. I'll look at the energy app to see what more I can gather. I know the phone app is using a chunk off that since I have several settings cranked so the phone key will work properly (which hasn't fixed the issue).
 
So over roughly a month that I've had the car I've driven 441 miles. At 273kwh/mi that should be 120.393 kWh used which matches the 120 it reports. I've charged it to 80 three times and it came filled at 80, with it at 62%. I charge it usually around 20% but to be conservative let's call it 25%. That's 1.93*84=148.23, or roughly 28kwh used up while parked. That's about 25% of the energy consumed driving, or 20% of total energy consumption over the last month. I had no idea this would be a factor when buying this car.
Looking at Tesla energy app I see standby is the major contributor in that consumption. Someone somewhere mentioned that the car can continue to keep the climate control on an hour after leaving it so I'll be turning it off when I get out to see if that makes a difference. Surprisingly the mobile app took very little. I expected a bigger chunk since I have it set to never sleep (again for another issue).
To be fair, I did have sentry mode on the first day or two, and there has been a few days my car was in cold mode (snowflake on monitor). It also ate 2% last night which probably is because of the update
 
Power off?

I've had really bad drain this week. Charged to 205 miles on Tuesday (6 year old S75D - 60k miles). Drove home (20 miles) and have done three short 2-3 mile trips since. I know it is cold (Cheltenham) and short trips are not ideal particularly in the cold but I'm down to 130 miles including losing 12 miles (6% since 1:30am today) without going anywhere.

I may be on the original 12V battery (I had it serviced just before the four years were up and, tbh, I don't know if the 12V battery was replaced so I assume not).

From this thread, I gather that it may be multiple recharges of the 12V battery causing the loss. Is it wise to power off the car or would that just about 'guarantee' that the 12V battery would go flat.

TIA for any tips
 
Power off?

I've had really bad drain this week. Charged to 205 miles on Tuesday (6 year old S75D - 60k miles). Drove home (20 miles) and have done three short 2-3 mile trips since. I know it is cold (Cheltenham) and short trips are not ideal particularly in the cold but I'm down to 130 miles including losing 12 miles (6% since 1:30am today) without going anywhere.

I may be on the original 12V battery (I had it serviced just before the four years were up and, tbh, I don't know if the 12V battery was replaced so I assume not).

From this thread, I gather that it may be multiple recharges of the 12V battery causing the loss. Is it wise to power off the car or would that just about 'guarantee' that the 12V battery would go flat.

TIA for any tips
I'm a new owner but fwiw given your description that seems about what I'm experiencing. I found the energy app on the car to be very insightful. Have you looked at it?
 
Power off?

I've had really bad drain this week. Charged to 205 miles on Tuesday (6 year old S75D - 60k miles). Drove home (20 miles) and have done three short 2-3 mile trips since. I know it is cold (Cheltenham) and short trips are not ideal particularly in the cold but I'm down to 130 miles including losing 12 miles (6% since 1:30am today) without going anywhere.

I may be on the original 12V battery (I had it serviced just before the four years were up and, tbh, I don't know if the 12V battery was replaced so I assume not).

From this thread, I gather that it may be multiple recharges of the 12V battery causing the loss. Is it wise to power off the car or would that just about 'guarantee' that the 12V battery would go flat.

TIA for any tips
I have seen similar behavior a few months back with the original battery but after I "preemptively" replaced the battery, I haven't seen anything like this.
 

brkaus

Well-Known Member
Jul 8, 2014
9,074
7,821
Austin, TX
From this thread, I gather that it may be multiple recharges of the 12V battery causing the loss. Is it wise to power off the car or would that just about 'guarantee' that the 12V battery would go flat.
Power off from the menu really doesn't power off based on my observation. The screen sure comes up quickly when opening the door to be in a full power down mode.
 

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