Just what is 'vampire drain' energy been used for?

4874 Views 25 Replies 12 Participants Last post by donald, Apr 12, 2018

gzoom

Discussion Starter · Mar 14, 2018

Last two nights we've been away from home so not plugging in the car.

Monday night parked up with 50% SOC, in the morning it was down to 45% - followed by an option to 'update' the software even though the car had no access to Wifi.

Last night parked up with 30% SOC - turned off 'always on', passive entry, turned on energy save, in the morning 29%.

So clearly when you 'turn off' some of the options the vampire drain drops dramatically, which makes wonder what on earth the car is doing to use so much energy in 'normal' mode. Is it something to do with it constantly reporting back to base , and software updates etc been pushed??

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JWilde

· #2 · Mar 14, 2018

I've always assumed it runs some power hungry X86 set up, essentially it's running a PC in there all the time. People seem to have confirmed it's running a build of Debian.

I think they are stuck with that and it would be tricky to move to something more economical. Not sure what the 3 runs but I'd have assumed something lighter.

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DBMandrake

· #3 · Mar 14, 2018

10 miles range (5% of 200) lost just because you parked the car for two days is pretty bad really. That's around 3.5kWh ?

I really hope they've addressed this on the Model 3, but I'm not sure that they will have. I haven't seen any reports one way or the other about vampire drain on the Model 3 yet.

Simon Mac

· #4 · Mar 14, 2018

@JWilde I'm pretty sure it's NVIDIA Tegra based, not x86, so the processor power should be fairly modest on that front.

As for the drain, I'm sure it's more likely radio comms. 3G / fob scanning / WiFi and generally poor power management because Debian isn't really optimised for power consumption in the way iOS / Android are.

Anecdotally I noticed it seemed to be more pronounced the higher the SOC was. So it could also have something to do with the BMS and/or how the car decides how frequently the car talks to mothership based on SOC.

arg

· #5 · Mar 14, 2018

It's not an X86, but in normal mode it does leave the processor for the entertainment/displays fully active.

IMO, there's not any reason ever to use the car in 'normal' mode: 'energy saving' mode saves a lot of energy at almost no cost in functionality: it can take a few seconds longer to power up the car when you get in, but usually it's done almost within the time it takes to put your seatbelt on. Turning off 'always connected' saves a modest amount more, but at a huge cost in inconvenience if you use the app for remote access.

I don't know for sure whether turning off passive entry has an effect: passive entry is certainly one of the legitimate contributors to vampire drain (ie. not down to poor implementation), since passive entry has to transmit a continuous radio signal to 'wake up' the keyfob when it comes into range. However, it appears that the system already turns this off after a couple of days - probably the explanation for the fact that leaving the car long-term has less observed vampire drain than if you took the figures for 1 day and scale up. Possibly disabling passive entry turns it off altogether.

Even with 'always connected' turned off, the embedded cellular modem is still active and signed in to the mobile network, and the car can be turned on remotely - when you want to use the app, or if Tesla want to push a software update. So if a software update happens to get pushed, you will lose some energy regardless of the energy saving settings (it will be equivalent to the 'non-saving' setting or possibly even more for the length of time it takes to download the upgrade image). The difference between 'always connected' and not is that in 'always connected' it has an open IP connection through to Tesla's servers, while otherwise it can go to a deeper sleep where the on-board computers are not doing anything, just the cellular modem waiting for 'the phone to ring' (actually, I think it's a SMS that triggers the wakeup, but I don't have evidence of that).

JWilde said:
I think they are stuck with that and it would be tricky to move to something more economical. Not sure what the 3 runs but I'd have assumed something lighter.

The processors they have are capable of running in much lower power states (being derived from ones commonly used in tablets and achieving long standby life there), but it is almost certainly their software/system architecture that prevents them getting into low power states effectively. That in turn is undoubtedly a legacy of the rush to get Model S out of the door - where the original software builds had no power management at all and significantly worse vampire drain than we see today. It's almost impossible to retro-fit a good power architecture on a system designed without one. Whether they've learned the lesson for Model 3 remains to be seen.

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gzoom

Discussion Starter · #6 · Mar 14, 2018

DBMandrake said:
10 miles range (5% of 200) lost just because you parked the car for two days is pretty bad really. That's around 3.5kWh ?

That was over one night, so 10 hrs not 2 days!!

The strange thing is when you turn off the various bits the vampire drain really does drop ALOT. Temperature also seems to have some effect, back in the summer I left a 90D X at Heathrow for 10 days, turned off all the bits didn't check the app, it only lost 2% in that time period. Ideally yes you want to see 0% loss in 10 days, but 2% loss over 10 days is light years away from 5% in 10 hrs!!!

Just trying to understand what on earth is using up all the power, surely the 4G/data connection cannot be that active....that must be ALOT of data Tesla is sending/receiving from the cars to increase energy drain from a few % over a few days to 5% overnight.

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ebyard

· #7 · Mar 14, 2018

gzoom said:
Just trying to understand what on earth is using up all the power

Do you have dashcams fitted?

I lose ~3 miles per day, by and large, more if it gets very cold. I recently left my car for 5 weeks, and lost around 100 miles in range I think.

arg

· #8 · Mar 14, 2018

ebyard said:
more if it gets very cold

Are you actually losing more vampire drain, or is there an element that the reported range is lower when the battery is cold and would theoretically come back if you could warm the battery up again?

The vampire drain itself shouldn't vary with temperature, though one possible factor would be that all the energy gets cycled in/out of the 12V battery which may be less efficient at lower temperatures; if that were the cause, it should go away with the recent cars that have the direct 12V output from the main pack (and probably @gzoom 's car is one of those).

Jon G

· #9 · Mar 14, 2018

So over one night you lose 5% but its suggesting you need to do a software update, and after a bit of fiddling another night you lose 1% which could be anything from 0.1% to maybe 1.5% depending on how close you are to the thresholds (ie you may have started at 29.6% which rounded up and ended at 29.4% which rounded down)

Anyway... I think the clue is probably in the fact it was downloading and preparing a software update. If it happens repeatedly then it might be something else.

Phil W

· #10 · Mar 14, 2018

I think Elon is using our cars to mine crypto currency.

Edit: Glad to see you are still on the nursery rhymes

Reactions: 1

gzoom

Discussion Starter · #11 · Mar 15, 2018

Phil W said:
Edit: Glad to see you are still on the nursery rhymes

I think I'v forgotten what proper music sounds like

.

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gzoom

Discussion Starter · #12 · Mar 15, 2018

20% when parked up last night at 530pm, 20% this morning at 8am, but dropped quickly to 19%. Arrived home with 11% tonight, in theroy enough charge to make it to the weekend but Im a chicken so plugged in just now.

Might actually leave the car in the setting as it is, might turn on passive entry but 1% vampire drain overnight seems much better than 5%. Hardly any difference in start up speed. I do wonder how much juice the 4G/LTE connection is using when plugged in charging.

Phil W

· #13 · Mar 19, 2018

I left my loaner 2017 S 90D for 36 hours at -1c. I had everything switched off, including passive entry. Only lost 1%.

Admittedly the Leaf would not have lost anything.

gzoom

Discussion Starter · #14 · Mar 19, 2018

Am pretty sure the vast majority of Vampire drain is the car calling back to base and uploading/downloding data.

I turned everything back on at the weekend expect for the 'Data sharing' option. Wife parked up on Saturday night with 47%, -1/0 overnight, next day 47% still!! Tesla must be doing some serious data gathering from the fleet to be consuming 4-5% a night from the LTE/3G data link.

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arg

· #15 · Mar 19, 2018

gzoom said:
I turned everything back on at the weekend expect for the 'Data sharing' option. Wife parked up on Saturday night with 47%, -1/0 overnight, next day 47% still!! Tesla must be doing some serious data gathering from the fleet to be consuming 4-5% a night from the LTE/3G data link.

Did you just turn on 'always connected', or did you switch it to "energy saving = off"?

Either way, the difference made by those controls is mostly about which of the various on-board computers goes to a sleep state, rather than volumes of data being exchanged - although your original data point where there happened to be a software update downloaded is obviously an exception.

When working normally, 'always connected' and "energy saving = off" transfer exactly the same amount of data (ie. not much, but connection remains open) - you can see that by snooping on WiFi traffic if connected that way. The difference between those modes can be seen by the time to boot up when you get in the car.

gzoom

Discussion Starter · #16 · Mar 19, 2018

arg said:
Did you just turn on 'always connected', or did you switch it to "energy saving = off"?

Energy saving off, always connected NOT ticked. But there is a separate option called 'Data sharing' I unticked consent for Tesla to access data, which seemed to drop vampire drain to below 1% a night.

cah197

· #17 · Mar 19, 2018

gzoom said:
Energy saving off, always connected NOT ticked. But there is a separate option called 'Data sharing' I unticked consent for Tesla to access data, which seemed to drop vampire drain to below 1% a night.

That’s the price for letting the machines learn our ways.

Reactions: 1

gzoom

Discussion Starter · #18 · Mar 22, 2018

So left all options on last night, energy saving off, always connected ticked, passive entry on, only thing disabled was 'data sharing' with Tesla.

Vampire drain was at most 0.9%, seems like a huge amount of reported energy usage by the car is nothing to do with electronics and more to do with Tesla hoarding data, which is understandable.

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arg

· #19 · Mar 22, 2018

gzoom said:
Vampire drain was at most 0.9%, seems like a huge amount of reported energy usage by the car is nothing to do with electronics and more to do with Tesla hoarding data, which is understandable.

That's either new, or your results have been skewed by one-off factors.

People hacking the car have previously reported that it only sends a fairly limited amount of data - the AP data gathering has 'triggers' for interesting events which cause photos etc. to be captured if and when such an event occurs.

So on that basis, unless you happen to have been driving around a very 'interesting' neighbourhood for whatever they are looking for, that shouldn't be much data.

OTOH, it's quite possible there's a bug whereby data collection 'on' stops it going to sleep. You should be able to discover that by (with energy-saving=on, always-connected=no) noting the slow wakeup from sleep. This may be related to what @cah197 has been reporting of always having instant access from the app. Maybe the combination of AP2 and data-gathering=yes has a bug that prevents sleep, whereas those of us with pre-AP2 cars are seeing the expected behaviour that always-connected=no causes deep sleep.

A couple of years ago, my car was suffering from a software bug where it wouldn't sleep, and could be seen burning up my wifi connection downloading music even though the speakers were turned off and you couldn't hear what it was 'playing'.

Another factor in comparisons between your car and older ones is that yours is presumably new enough to have the new 12V output from the main battery pack, such that vampire loss doesn't cause wear on the 12V battery; possibly that modification also makes it more efficient overall so that the 'base level' of vampire drain in your car is less than older cars.

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gzoom

Discussion Starter · #20 · Mar 22, 2018

arg said:
Another factor in comparisons between your car and older ones is that yours is presumably new enough to have the new 12V output from the main battery pack, such that vampire loss doesn't cause wear on the 12V battery; possibly that modification also makes it more efficient overall so that the 'base level' of vampire drain in your car is less than older cars.

What am interested in the minimal energy loss. I've seen drops in 4-5% overnight before with everything turned on.

Will have a play with the setting some more, but <1% overnight with everything ticked expect for 'data sharing' is no that bad vampire drain.

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