Questions on battery percentage and mileage.

[kimwin]

My M3 SR has been quite straight forward when it comes to mileage and battery capacity.
Today, I can't figure the problem below:
1) a week ago, I charged the battery to 100% (at home)
2) after driving for 4 days, the Trips report shows: 101 miles using 20 kWh (about 5 miles/ kWh) which is what I have seen since I bought the car.
3) the battery percentage show only 50% remaining. Full capacity is 57 kWh, using 20 kWh should give (57-20) / 57 = 65% approx.

Question: Where do the 17 kWh (37-20) goes ?

I always have dashcam on while driving and sentry on when parking outside of home. No change in these settings
And I only used climate for about 10 miles, once.

By coincidence , my car got a software update a day or two before I do a full charge.
The new software version is V11.1 (to improve warning reading on screen with larger fonts) , whether this new version causes this problem is still a puzzle to me.

Anyone runs in to similar problem ?

 

[E90alex]

The trip computers only count the energy used while in drive. Energy usage when parked (eg sentry mode or preconditioning) is not counted.

 

[kimwin]

The trip computers only count the energy used while in drive. Energy usage when parked (eg sentry mode or preconditioning) is not counted.

I did not change anything the way I drive and use my car since I bought it 5 months ago. Going to same places every week, parking at home every night, etc... None of my habits change.
I like to see the car shows where these 17 kWh are used for. Will the energy screen shows this ?
I only see on the energy screen the graph AND the percentage deviation from expected) shown for each category (driving, climate, preconditioning, others, etc....).
Forgot to mention since my most recent full charge, the weather in my city becomes pretty cold compare to normal time (40 - 55 degree F). This is still not winter cold with snow.

 

[3sr+buyer]

Check the park tab on the energy screen. It will show how much was used while parked, including sentry mode.

 

[kimwin]

Here is the Energy, Park Tab.
It does show 15.5% energy loss.
Q: what time period the energy data is collected and shown here ? From most recent battery charging ?

 

[kimwin]

Even in standby mode, the car loses 2.9% battery capacity !!!
Q2: Preconditioning the battery when ? Before actual charging ?
I will look up the user manual rõ learn about this energy screen

 

[E90alex]

Yes it’s since last charged.

Preconditioning is climate preconditioning.

 

[kimwin]

Preconditioning is climate preconditioning

Even just for driving ? (for charging , I saw the car going thru conditioning at 12am then charging from 1am till 100% as scheduled.
For now, my guess is extra battery consumption is due to the cold weather in my area ( coldest season of the year ).
Learning something new today, I will keep track of energy usage to minimize energy wasted.
The app does recommend to keep the car plug-in when park at home to prevent energy loss BUT that means it will charge to maintain current SoC until it is told to charge as scheduled. I understand that plug in also ensures the battery never get down below 10%. So far, I never let it going down to 30%.

 

[KenC]

The Park tab has 2 choices, off to the right of your image, Since Last Drive, and Since Last Charge.

In my opinion the Vehicle Standby number on the bottom is the fudge number for ambient temperature change. If the temp drops, the BMS measures less battery capacity, and vice-versa.

It's confusing because the note tells people to stay plugged in, to reduce loss, but if it did reduce loss, then why doesn't it show zero, or tiny, loss when plugged in? And why doesn't it show more loss when not plugged in? I think like a lot of Tesla explanations, it just adds to the confusion.

Rather, I think it means, at some point, if the SOC level drops, it'll start charging again to bring you back up to your set point, like a thermostat's swing. Thus, it reduces loss, as most people want to start the day with their "full" set point. Just a different definition of "loss".

 

[kimwin]

Hi KenC,
Good thinking. However, "refill" to the setpoint costs us just like charging.
For my purpose, I just need to know where energy is wasted to cut it down if feasible.

 

[joebruin77]

Do you need Sentry mode engaged while parked at home? If possible, shut off Sentry mode and you will cut your energy loss nearly in half.

 

[kimwin]

Sentry has been verified to be OFF at home, location shows my home address. As I said, no settings changed so far, suddenly I noticed energy loss for many possible reasons: I drove out and parked more often (chinese new year parties) than previous months, weather got coldest in my city, software update from Tesla (unlikely reason).
I will charge to 100% this weekend and keep an eye on energy usage. Expect small loss, not 15 to 16%.

 

[kimwin]

After charging to 100%, driving for two days, energy usage goes back to normal, no "unexpected loss". The weather became a bit warmer so the energy for preconditioning is very low as expected. And sentry energy is also low as I only park outside once a day for 2 hours each.
I could say: cold weather increase preconditioning energy usage and same with high number of outside parking with sentry ON.
Another detail: my home is on a hill, not too steep for 2 miles. If I make frequent short trips (5 miles one way), then more energy is consumed for going up hill. Energy got from re-gen braking when going downhill is smaller than what is need to go up hill.

 

[kimwin]

10 days ago, I charged my car to 100%, drove about 130 mile since then.
The energy screen shows 42% for DRIVING and 10% for PARK (sentry is set to OFF)
On the PARK screen, I saw that preconditioning and vehicle standby consumes most of the 10%.
I like to understand what the "vehicle standby" does to consume energy while parking (at home mostly).
My guess the precondition consumes more energy due to many short trips (6 miles to 20 miles round trips daily).
If I drove 50 to 70 miles round trips a day, the 42/10 ratio could go way up to 70 or 90+/10.
I plan do drive a few long trips to verify my understanding about preconditioning energy.

 

[joebruin77]

Not sure if you already saw this post by someone with a similar question, but you might find some suggestions/ideas that apply to your situation.

One interesting suggestion was that excessive vehicle standby power consumption may be due to a faulty sensor that detects if someone is seated in the front seat or not. If the car detects that someone is in the front seat, it will keep the HVAC running and doing other things that use power. So you may want to have this sensor checked. And of course make sure you have not placed any objects on the front seat.

My Y has been losing 2-5% per day in "standby energy usage"

I recently noticed my stand by energy usage is much higher than 1%/day when I left the car unplugged at the airport for 7 days. During this time it lost 32.8% from just vehicle standby (4.5%/day). (attached file, very dusty; its mostly the lighting I swear!!) Sentry mode was off, no 3rd party...

teslamotorsclub.com

 

[kimwin]

Are seat covers treated as large object on front seat ? I do have seat covers.
I read thru the post above, got some ideas. Will try.

 

[joebruin77]

Are seat covers treated as large object on front seat ? I do have seat covers.
I read thru the post above, got some ideas. Will try.

I am not sure if this applies to you, but this is from the Model 3 Owner's Manual in the section about the airbags and front passenger detection senor:

"To make sure the sensing system can correctly detect occupancy status, eliminate the following:

• Aftermarket items attached to, or sitting on or between, the seat and occupant including but not limited to covers, mats, blankets, etc.

These conditions can interfere with the occupancy sensor. If you have eliminated the above possibilities, and the airbag status is still incorrect, ask passengers to ride in the rear seats and use the mobile app to schedule a service appointment to have the airbag system checked."