Losing 9 miles of charge overnight.

[supernoman]

I noticed this again today. It isn't always happening but a few times now, I'm down 9 miles overnight. Well I park around 5PM and leave about 7AM so 14 hours. There are other times where range hasn't changed. What's the best way to track down what's going on?

I'm on the 2018.14.13 firmware.

 

[CO2CLEAN]

I noticed this again today. It isn't always happening but a few times now, I'm down 9 miles overnight. Well I park around 5PM and leave about 7AM so 14 hours. There are other times where range hasn't changed. What's the best way to track down what's going on?

I'm on the 2018.14.13 firmware.

Could it be related to (autopilot)data sent from the car to Tesla? This won't happen every day/night, but regularly. It will keep certain systems on while they would otherwise be in sleep/off.

 

[apacheguy]

Could it be related to (autopilot)data sent from the car to Tesla? This won't happen every day/night, but regularly. It will keep certain systems on while they would otherwise be in sleep/off.

How big are the AP logs? Maybe 100 MB at the large end? It shouldn’t take the vehicle more than 30 minutes to upload that data with modern internet speeds.

 

[365gtb4]

I did a test of my 85D. I let it set for 30 days unplugged. It lost an average of 5.6 miles per day. On the first day it lost about 9 miles and then after that it settled in at the 5.6 miles per day. The car was charged to 90% , 236 miles of range initially. I lost 168 miles of range leaving 68. The temperature in the garage was around 60°F.

 

[dhu1]

Go do a search for "vampire drain" in the forum. You'll see numerous threads regarding this topic. At the end of the day, nobody has a clear answer of why the car drains on certain days and not others. Having said that on my good days, I get 1-2 miles drain and others I get 6-7 miles on an overnight drain. The latest software dropped that drain down from 10-15 miles in a 24 cycle to 6-8 miles. I think we've exhausted all the plausible scenarios (weather, software, and sleep cycles). Have not been able to isolate out the culprit

The two remaining explanations exist at this time:
1) I read somewhere that Tesla engineering says this drain is typical for newer batteries and will stabilize over time (not sure I buy it)
2) Tesla is doing a ton of data collection and hence not allowing the car to sleep (not just AP)

With both these explanations, we kinda have to trust that Tesla knows what it is doing and that the drain will stabilize as it has with the S/X. I kinda have stopped worrying about it since there isn't much we can do or hope for

 

[supernoman]

I don't have AP so it's not that. And bonus...overnight I gained 2 miles. 234 -> 236. /shruggie
I think it may still be calibrating. It reminds me of my first gen leaf where updates kept changing the listed range. I do hope it settles down, but losing 9 miles just being parked seems like a flaw.

I did look at vampire drain threads. I also think it's they key fob shortcoming. They are not letting the car deep sleep in order to make the phone as key work better. I know mine has started working more reliably after the last 2 firmware updates.

 

[CameronB]

I periodically measure various options (semi-scientific like!) when I am on 2-4 day trips to see how they affect vampire drain. All measurements are taken inside a non-insulated but fairly stable (around 60 degrees F) garage in Northern California (i.e. not inclement weather!)

I haven't yet added trying to factor in software download speeds but may do that in the future.

Ignoring downloads, the biggest impact will be leaving on Smart Pre-Conditioning. Useful feature but it consumes a lot of energy. I leave it on most of the time because losing 5-7 miles overnight isn't a big deal for a day or even a few days at home with my short commute. But if I was to park in an airport and leave it for a while where cold(er) weather and a longer drive upon my return, I'd definitely turn it off. "Energy saving" option (in my few data points anyhow) also seems to have non-trivial impact.

FWIW. YMMV. All the other disclaimers . Here's my current data for my 2017 75D

 

[apacheguy]

I don't have AP so it's not that. And bonus...overnight I gained 2 miles. 234 -> 236. /shruggie
I think it may still be calibrating. It reminds me of my first gen leaf where updates kept changing the listed range. I do hope it settles down, but losing 9 miles just being parked seems like a flaw.

I did look at vampire drain threads. I also think it's they key fob shortcoming. They are not letting the car deep sleep in order to make the phone as key work better. I know mine has started working more reliably after the last 2 firmware updates.

Even if you don’t have AP enabled, that doesn’t mean it’s not there. All Model 3s have AP hardware and it is still collecting data in shadow mode.

 

[supernoman]

So today I charged up to 90%, 276 miles. Drove away from charging station to another parking spot. Checked about an hour later and car showed 270, and now 4 hours later, 268.

 

[supernoman]

Happened again yesterday. Charged to 90%, 278 miles this time. Drove home and parked at 260. I typically use 8 miles to drive home so I lost about 10 miles of range again after a charge.

 

[Brentt]

I wouldn't worry too much. The car is using a lot of different data points to determine your estimated range, which is just that, estimated.
If you charged at the top of a mountain, your car would still say 278 miles, but when you got to the bottom, it would obviously be wrong.

 

[keydiver]

See this thread:
2% Battery Degradation in 1 Month
Having driven an EV for almost 7 years, I can tell you one thing I have seen in the Forums: if you give people too much information, they just get a little too fixated on it. ;-)