Understanding the origin and nature of Vampire Drain.

[fbitz777]

I am skeptical that you lose zero. I think I have seen discussions that indicate that Bolts or I3s may have SoC update issues that make it look like you lose zero, when you really lose more than zero.

Why are you so worried about the Bolt? I have left it out weeks and I did not loose range and got the same 60kwh out of battery at end of trip. I had same behavior with Focus EV

Now on Tesla I left it once at airport for 10 days and maybe lost 30 miles which I was "happy" but that was 2 years ago...These days it would be much more...my car is the same just software updated so many times (vs only one on Bolt in 2 years)

 

[MaryAnning3]

Bolts have way less "vampire" drain than Tesla's.

yes, less than model3, and more than zero. I agree.

 

[seattlite2004]

yes, less than model3, and more than zero. I agree.

Negative....not my Bolt...drain is zero .

What's the drain on your Bolt ?

 

[MaryAnning3]

Now on Tesla I left it once at airport for 10 days and maybe lost 30 miles which I was "happy" but that was 2 years ago...These days it would be much more.

Hmm? That is almost exactly what I got three weeks ago. Left model 3 for 10 days and lost 30 miles. I haven't seen any change. It is still 3 miles per day.

 

[mobil-ai]

I see what you mean. There is some pretty broad ranging discussion of the origin of ordinary drain as well as variation and anomalies. Still I would love to see a more focused explanation of the origin of ordinary (1%, 800 W-hour per day) power usage.

I was losing about a mile an hour on my parked new model 3. All it took was a visit to the service desk at Tesla. They advised me to configure Sentry Mode to off when at home, and voila! It worked like magic! Idle discharge is now only 0.5% in 24 hours.

Sentry mode is a battery hog. Expect discharge of a mile an hour and charge accordingly if planning to leave it on for long periods.

 

[FrankPuettbach]

It is only 1% = 3 miles = 0.75 kwh for a model 3 with no third party apps. It is not really a problem. Park at an airport, or anywhere, at 70%, come back a month later at 38%. Drive 60 miles and/or stop at a supercharger. Not a problem. Best battery I have heard of. Would not trade it for the world.

1%/day is ok? I beg your pardon! If you drive 12000km = 7500miles/year, thats nearly 15% of your consumption! In other words, compared to cars with no drain, you have to add 15% to your 100km consumtion if you be honest.

 

[fbitz777]

1%/day is ok? I beg your pardon! If you drive 12000km = 7500miles/year, thats nearly 15% of your consumption! In other words, compared to cars with no drain, you have to add 15% to your 100km consumtion if you be honest.

Yes my vampire is 1000kwh per year (2-3 percent per day) or one month of production on my solar panel. Lucky I have free superchager nearby.

I have even turned to data sharing to Tesla and Mobile Access with not much improvement.

Note that originally 2 years ago I was loosing much less but that was many versions of software ago.

 

[MaryAnning3]

1%/day is ok? I beg your pardon! If you drive 12000km = 7500miles/year, thats nearly 15% of your consumption! In other words, compared to cars with no drain, you have to add 15% to your 100km consumtion if you be honest.

I guess Tesla agreed with you because they reduced the daily power consumption of a parked car to 0.25% per day. So it is 4x less than before and really no longer an issue. To put the whole thing in perspective, the model 3 has an exceptionally great battery and what makes it great is the architecture and the BMS. Presumably it was the BMS that was using most of that power and now Tesla has figured out how to maintain the battery with less power. The 2170 cells are state-of-the-art, but how Tesla put them together and managed them was what put them way ahead of the competition. Gotta take the bitter with the sweet sometime.

 

[MaryAnning3]

Yes my vampire is 1000kwh per year (2-3 percent per day) or one month of production on my solar panel. Lucky I have free superchager nearby.

I have even turned to data sharing to Tesla and Mobile Access with not much improvement.

Note that originally 2 years ago I was loosing much less but that was many versions of software ago.

Things aren't set up correctly with your car I would guess; or are you using sentry mode? Normal draw for a model 3 is now 0.25% (200 Watt hours) per day. Negligible.

 

[fbitz777]

Things aren't set up correctly with your car I would guess; or are you using sentry mode? Normal draw for a model 3 is now 0.25% (200 Watt hours) per day. Negligible.

I have an X and yes I am aware off all parameters to turn off including mobile access. As per Sentry my X does not have dashcam functionality so no use for Sentry.
For some reason my vampire has been less in the last 5 days like 2-3 miles a day...there is no rhyme or reason over the 3 years )anywhere from 2 miles a day to 12 miles a day) but when I look at the Stat App it looks like the average Model 3 users loose that much anyhow.

 

[MaryAnning3]

I have an X and yes I am aware off all parameters to turn off including mobile access. As per Sentry my X does not have dashcam functionality so no use for Sentry.
For some reason my vampire has been less in the last 5 days like 2-3 miles a day...there is no rhyme or reason over the 3 years )anywhere from 2 miles a day to 12 miles a day) but when I look at the Stat App it looks like the average Model 3 users loose that much anyhow.

I think around July 1 the model 3 drain rate dropped from 1% per day to about 0.3% per day. From Nov 2018 to July 2019 it was 1% per day. Since early July it has been 0.3%. Seems pretty systematic and reproducible for the model 3.

 

[darth_vad3r]

I guess Tesla agreed with you because they reduced the daily power consumption of a parked car to 0.25% per day. So it is 4x less than before and really no longer an issue. To put the whole thing in perspective, the model 3 has an exceptionally great battery and what makes it great is the architecture and the BMS. Presumably it was the BMS that was using most of that power and now Tesla has figured out how to maintain the battery with less power. The 2170 cells are state-of-the-art, but how Tesla put them together and managed them was what put them way ahead of the competition. Gotta take the bitter with the sweet sometime.

The manual still says 1%

 

[MaryAnning3]

The manual still says 1%

Interesting. This could be an experiment to see if the battery can be well-managed with this lower power consumption level? I hope it sticks (though i guess I would be okay either way).

 

[Magnets!]

Interesting. This could be an experiment to see if the battery can be well-managed with this lower power consumption level? I hope it sticks (though i guess I would be okay either way).

You might be right. If we see a bunch of reports of dead 12v batteries, we'll know vampire is coming back

 

[AlanSubie4Life]

You might be right. If we see a bunch of reports of dead 12v batteries, we'll know vampire is coming back

They are probably just increasing the charge rate of the 12V battery so as to spend less time in idle mode. I assume this would be obvious to anyone tracking this time period with TeslaFi.

Or they are just spending less time in idle mode for other reasons, and 12V charging time was never the limiting factor on idle mode time.

In any case it seems to be getting close to the 7-10W sleep mode baseline consumption which seems to be required for all the car accessibility functions. Seems doubtful that we’ll ever get below that level for this car. Works out to somewhere around 1 mile per day. A little less but when you account for the idle mode overhead when recharging the 12V it will be about a mile.

 

[darth_vad3r]

You might be right. If we see a bunch of reports of dead 12v batteries, we'll know vampire is coming back

Heh, ya.

They may have reduced the minimum voltage that triggers 12V recharge, or just increased the time between periodic wake ups (or eliminated wake ups). Or maybe there were no periodic wake ups and it was always triggered by the 12V going low. What I’m noticing lately is the car seems offline a lot instead of asleep.

 

[AlanSubie4Life]

They may have reduced the minimum voltage that triggers 12V recharge, or just increased the time between periodic wake ups (or eliminated wake ups).

If they are more deeply discharging, it is possible that might improve charge time a bit, the reason being the 12V battery will charge faster when it is more heavily discharged, so overall charging times will be lower. But the deep cycle would reduce the number of allowed cycles on the AGM.

They need to add 170Wh-240Wh (this is based on what people have metered from the battery in sleep mode - it's around 7-10W as I recall) of energy to the battery every 24 hours. The battery is a 45Ah, 12V, so it only has ~540Wh of capacity. So it's going to need to be recharged every day to avoid deep discharges which will shorten the life.

Similar to when charging your car, the faster you can accomplish the charging, the less the idle mode overhead hurts you (but this time for vampire drain). But lead acid batteries are complicated on their charging - they have a constant current stage (where current is the highest), then a float charging state where current is decreasing. And I don't know what is typically the maximum charge rate and how much the current into the battery can be adjusted by modifying the voltage applied.

You'd probably need to keep charging time below an hour each day to get the reported 1-1.5mi per day of vampire drain (345Wh per day => 345Wh/day (total) -200Wh/day (sleep) = ~145Wh/day in idle mode => ~45 minutes/day in idle mode (idle mode is around 200W) )

So that would mean an average charge current of 18-19A or so over 45 minutes (0.75hr*19A*14V = 200Wh). I don't know whether that is achievable or not with an AGM battery.

There are at least three competing factors: depth of discharge (minimize), charge rate (maximize), time spent in idle mode (minimize). Also if it's possible for them to reduce idle mode consumption, that would help as well (not clear that they can).

Lack of knowledge about the exact details of AGM lead acid battery charging is a problem for me here.

Again, it's also possible they always had near-optimal 12V battery charging, and they've simply eliminated the other reasons that the car wakes up.

Would be interesting to see what people's TeslaFi stats say about time spent in idle mode now, as compared to a couple months ago - assuming that data can be trusted. If it hasn't changed that would suggest they've found a way to reduce idle mode power (unlikely).

 

[mobil-ai]

For model 3, has anyone noticed fans kicking in from time to time under the hood? It creates a distinctive whining sound. This happens during charging (I suspect to cool the batteries), but have also noticed this happening if the car is not charging but is parked in the hot sun or a hot garage. Perhaps these battery maintenance functions such as cooling fans kicking in, also contribute to the "vampire drain". This is different from the electrical discharge which happens to a battery via its internal resistance and the drain caused by apps that may be running even when the car is asleep.

 

[darth_vad3r]

For model 3, has anyone noticed fans kicking in from time to time under the hood? It creates a distinctive whining sound. This happens during charging (I suspect to cool the batteries), but have also noticed this happening if the car is not charging but is parked in the hot sun or a hot garage. Perhaps these battery maintenance functions such as cooling fans kicking in, also contribute to the "vampire drain". This is different from the electrical discharge which happens to a battery via its internal resistance and the drain caused by apps that may be running even when the car is asleep.

Do you have cabin overheat protection enabled (either “on” or “no a/c”)?

 

[FrankPuettbach]

I guess Tesla agreed with you because they reduced the daily power consumption of a parked car to 0.25% per day. So it is 4x less than before and really no longer an issue. To put the whole thing in perspective, the model 3 has an exceptionally great battery and what makes it great is the architecture and the BMS. Presumably it was the BMS that was using most of that power and now Tesla has figured out how to maintain the battery with less power. The 2170 cells are state-of-the-art, but how Tesla put them together and managed them was what put them way ahead of the competition. Gotta take the bitter with the sweet sometime.

I guess Tesla agreed with you because they reduced the daily power consumption of a parked car to 0.25% per day. So it is 4x less than before and really no longer an issue. To put the whole thing in perspective, the model 3 has an exceptionally great battery and what makes it great is the architecture and the BMS. Presumably it was the BMS that was using most of that power and now Tesla has figured out how to maintain the battery with less power. The 2170 cells are state-of-the-art, but how Tesla put them together and managed them was what put them way ahead of the competition. Gotta take the bitter with the sweet sometime.

I think around July 1 the model 3 drain rate dropped from 1% per day to about 0.3% per day. From Nov 2018 to July 2019 it was 1% per day. Since early July it has been 0.3%. Seems pretty systematic and reproducible for the model 3.

At mine, nothing changed: I can reproduce it. Enabling Online Access means over 4% a day, no matter where I stand or how temperature is. Disabling Online Access cuts the drain down to about 1-3miles = about 0,5%. And again: No sentry, no climatisation, nothing.