Understanding the origin and nature of Vampire Drain.

[chinnam3]

I am thinking one of the factor may be, Tesla using main computer(ECU) which is much more powerful but high power consumer is the one of the reasons for vampire drain(Keeping the battery conditioning aside for now). I am not sure, but my guess is Tesla main CPU does all the processing even while the car is off to support various remote functions and some monitoring functions (like Battery or Cabin conditioning). Probably it is not very power efficient under low work loads.

For example if we assume while car is off mode it uses 50w with all the modules together, like Battery Monitoring (BMS), Bluetooth, RFID monitoring, LTE monitoring, scheduled functions, and remote functions.

It does not sound like much, but if you calculate 50w x 24hr= 1200Whr. That is equivalent to 1200/250wh= 4.8 miles range. May be it takes power from 12v battery, but calls for 12v charge function from main battery(reason for clicking noises while sleeping?).

May be Bolt strictly using 12v Battery for most of these functions with very low power processor(like 1 or 2 Watts)?

But in summer, and even in September and October time frame, what I observed is, if I do not ping the car from the app, I was losing 1 mile to 1.5 miles per day. I watched it over 8 days, and average with pings from Mobile App once in 2 days came out about 1.5 Miles loss per day.

That is about 15w of power consumption to the total system while Car is off, and car is not processing any external commands. But during this time, LTE interface is still up, Bluetooth, BMS all are actively running/monitoring.

Winter is all together different story. I think Battery monitoring and conditioning is aggressive, and taking lot of energy keep it in good shape. May be Tesla battery chemistry is more sensitive to temperature compared to GM/LG Battery hence it needs more precise/tight temperature control?.

May be someone with Bolt can comment on how Bolt behaves with Cold soaked battery. is the consumption is very high with cold soaked battery compared to M3?

 

[Saghost]

Interesting. Do you think they would be "normalized closed" type or "normally open". I wonder how much power they draw?

Pretty sure they have to be normally open types for safety reasons - you always want a system failure to isolate the dangerous high voltage rather than leaving it active with no way to kill it.

No idea on power required. I think some of the contactor failure/replacement threads from a couple years ago have images and part numbers that might lead to an answer with enough research...

 

[CCIE]

Beg to differ. GM does provide a surprising amount of remote functions, compared to cars in the past - remote start, lock/unlock, map location, send destination to car, current electric/gas range, odometer, tire pressures.

(It's been a while since I gave up my Volt, so I might be missing one or two? My experience a few years back was it was unreliable to use and always took several minutes to work, but that might have gotten better.)

It's not even in the same league as what Tesla gives - Tesla has all of that (except gas range, of course, and I don't think it can do tire pressure,) and so much more - real time location, speed and power use. Locked/unlocked status, status of every door on the car. Real time voltage, amperage and power while charging. Interior and exterior temperatures in real time, and fan speed when climate control is active. Set a temperature for climate control. Individual control of the seat heaters for every seat and the steering wheel. Set a charge level. Start/stop charging. Keyless start (not just climate control - drive the car without a key.) Trigger homelink/garage doors and gates. Open and close rear hatch and sunroof, open Frunk. Set valet mode and speed limits. Even Summoning the car.

And it's consistent, reliable, and typically takes a few seconds to go through.

Meant what I said.

Volt 12V battery, 60 Ah AGM. Tesla model S/X battery, 12V 33 Ah Deep Cycle. Technically not exactly twice the size, but pretty close. For reference, my gasoline powered car before the Volt was of similar size to the Volt, and also had a 60Ah battery, though not AGM. Not sure what's in the Spark EV, but I'd expect it to be similar to the Volt.

My model 3 does show some cool info in the app, but I only really use it to turn on the climate system and track the car, both of which the onstar app could do for the Volt/Spark-EV. Setting valet mode with speed is pretty cool, and if the app can trigger my garage door that would be cool (though I don't see how to do it). The Tesla app is no faster than the onstar app (maybe you had a Volt with the old 2G cell modem?). In any case, I'd like the option of having reduced app functionality if it would keep my M3 from wasting $1-2/day on vampire loads.

I can't comment on the size of the Model S/X 12V batteries, but the 12V battery in the Model 3 is physically the same size, or slightly larger, than the 12V batteries in the Volt or Spark-EV.

 

[rrolsbe]

I measured the current draw using a DC current clamp while my Model 3 was sleeping and every time I checked it, many times, the current draw was between 0.5-0.6A or approx 6-7.2W. This was measured while the 12V AGM battery was NOT being topped off. Since I was not logging the current draw, I can not say for sure it did not draw more current at some point. I did turn off WIFI and remote access during my testing. When the car tops off the 12V battery, it does NOT use shore power. Would be nice if it did but I have read speculation that the on board charger is not efficient with the fairly low power requirements to top off the battery (fair enough). To top off the 12V battery, which appears could be 3 or 4 times a day while parked, requires the car to wake up, close the contactors, use the DC-to-DC converter to top off the 12V battery and run the cooling pump(s) to cool the converter. It appears this could take several hours each time? The power required for all the components, required to top off the battery, could be significant? My current probe could not measure the power required for all of these components because the DC-to-DC converter is charging the 12V battery (current flowing into the battery). Power is used from the traction battery during the 12V battery top of which must replaced at some point via the UMC2 charger via shore power. It appears the car may not actually draw that much power during deep sleep, but the act of topping off the 12V battery and replenishing the traction battery might be a large part of approx 1KW power usage, 42W average, per day. If you drive the car two or three times a day this power consumption would probably not be significant, because the 12V battery is being topped off while driving. I have read forum posts where Model S owners have attached smart battery chargers to the 12V battery posts, while parked for months, and the car apparently never topped off the battery (the battery charger probably did many times) and the traction battery had the exact same level of charge at the end. Unfortunately, no one monitored the wall power draw of the Smart Battery charger using something like a Kill-O-Watt meter. Eliminating the requirement to charge the traction battery, while parked, should not decrease the battery life because less or no discharge/charge cycles would be required. I have not read of anyone having success attaching a Smart battery charger to a Model 3?

I know just drive the car an be happy but to a curios techie engineer that is boring. I bought the car partly to learn what makes it tick.

 

[chinnam3]

I measured the current draw using a DC current clamp while my Model 3 was sleeping and every time I checked it, many times, the current draw was between 0.5-0.6A or approx 6-7.2W. This was measured while the 12V AGM battery was NOT being topped off. Since I was not logging the current draw, I can not say for sure it did not draw more current at some point. I did turn off WIFI and remote access during my testing. When the car tops off the 12V battery, it does NOT use shore power. Would be nice if it did but I have read speculation that the on board charger is not efficient with the fairly low power requirements to top off the battery (fair enough). To top off the 12V battery, which appears could be 3 or 4 times a day while parked, requires the car to wake up, close the contactors, use the DC-to-DC converter to top off the 12V battery and run the cooling pump(s) to cool the converter. It appears this could take several hours each time? The power required for all the components, required to top off the battery, could be significant? My current probe could not measure the power required for all of these components because the DC-to-DC converter is charging the 12V battery (current flowing into the battery). Power is used from the traction battery during the 12V battery top of which must replaced at some point via the UMC2 charger via shore power. It appears the car may not actually draw that much power during deep sleep, but the act of topping off the 12V battery and replenishing the traction battery might be a large part of approx 1KW power usage, 42W average, per day. If you drive the car two or three times a day this power consumption would probably not be significant, because the 12V battery is being topped off while driving. I have read forum posts where Model S owners have attached smart battery chargers to the 12V battery posts, while parked for months, and the car apparently never topped off the battery (the battery charger probably did many times) and the traction battery had the exact same level of charge at the end. Unfortunately, no one monitored the wall power draw of the Smart Battery charger using something like a Kill-O-Watt meter. Eliminating the requirement to charge the traction battery, while parked, should not decrease the battery life because less or no discharge/charge cycles would be required. I have not read of anyone having success attaching a Smart battery charger to a Model 3?

I know just drive the car an be happy but to a curios techie engineer that is boring. I bought the car partly to learn what makes it tick.

Very good analysis. I think it should be fairly easy to connect battery charger and measure total power used by charger for whole day. But we need to account for Charger losses/efficiency.

I agree most loss is happening when main battery brought online to charge 12v via DC to DC converter. I doubt it is issue with DC-DC converter efficiency issue, rather all electronics, relays related to Main battery. Typically these relays itself consume 10+watts.

Power drain from 12v battery, if you turn off the Wifi and Remote access, then I am guessing, that will reduce power consumption by few watts. My guess is, keeping everything on like normal use case, it adds another 3-4 watts. Bringing it inline with 10-11watts because of monitoring. Additional 5W average because of occasional 12v Battery top off from main battery making it total 15-20W avg drain. This causes about 2 miles loss a day without battery conditioning, no software downloads etc.

 

[Del Schier]

I recently have been using the phone app TezLab which reports phantom drain. I wonder exactly what this is. The car never goes as far as it reports the range after a charge. I assume this is primarily using the heat, AC and lights; in that order. Of course the computers running is a factor.

Is phantom drain only considered what is lost when not driving the car while it sits? If that is the case what is the rest of the batter drain not used to propel the car called? I wonder what the TezLab app is actually reporting.

My Model S is HW1 early 2016 if that makes a difference. It does bother me that if I walk past the car in the garage with the key fob in my pocket the car operates the door handles and flashes the lights. Otherwise I am not sure what I can do to get more range per charge, except not to use the AC or heat. I am in Florida so I don't need the heat often.

I will look forward to the comments.

 

[AlanSubie4Life]

To top off the 12V battery, which appears could be 3 or 4 times a day while parked, requires the car to wake up, close the contactors, use the DC-to-DC converter to top off the 12V battery and run the cooling pump(s) to cool the converter. It appears this could take several hours each time? The power required for all the components, required to top off the battery, could be significant?

I think you've posted this useful info elsewhere. Someone else (?) put a battery maintainer on their 12V and I think they saw about 5W from that when the car was in sleep (it got overdriven when the car started charging the 12V). I wish I could find the post...

A question and a couple comments:

Question: Sounds like you measured the current delivered to the battery when the car goes to idle mode and starts charging the 12V battery? How many watts is that charging? I would think if there are a lot of parasitic loads in idle you'd want to charge that 12V AGM as quickly as possible and then get right back to sleep...I just wonder how fast the charging is. (It seems like it must be around 30-40W in order for the math to work out (3-4 hours per day to make up for 20 hours of 6-7W).)

Comments:
I've posted this elsewhere, but I've found that when the contactors are closed (idle mode), the following things are on (regardless of the temperature, at least when the temp is below 60 degrees which is when I checked):
1) Windshield heater for the cameras
2) Ultrasonic sensors
3) Cameras

I imaged all of these with my FLIR One. Hopefully they'll optimize this behavior over time. Note that these items are not needed for door opening, etc., as the door opening works fine in sleep mode, and these items are not on in sleep mode (at least when I have checked they have not been).

Second, regarding cooling of the DC-to-DC converter - it would be disappointing if a DC-DC converter from HV to 12V with <100W output needed active liquid cooling. (I guess it does have much higher peak capability than 100W, so maybe under some loads it would need liquid cooling.) Does anyone know whether or not the cooling loop actually runs near this DC-DC converter? I've seen pictures of the converter and it didn't look that large or appear to have obvious liquid cooling attachments. But I don't know. I hope that is not why they are running the cooling pumps. I assume it is because the contactors are on/closed that the battery sometimes decides it needs to cool itself. (Also is pretty disappointing that they can't be more intelligent about that, but I would expect them to tweak this behavior over time.)

 

[SoCalGuy]

I find the vampire drain very annoying. My Fiskers lose maybe 1 mile/2% of battery range every 30-45 days, while I lose 3.8 miles (1.2%) EVERY day here in SoCal. Seems super inefficient!

I wish Tesla has a “storage mode” where if you were going to be leaving your car for say a week or longer at a time, it would shut down all non-essential systems to preserve battery life.

 

[Richinwalla]

Does anyone have actual experience leaving their Tesla at an airport for 3 weeks or so in various weather conditions? I'd like to know if its feasible or not. Might have to keep one ICE after all.

 

[AlanSubie4Life]

Does anyone have actual experience leaving their Tesla at an airport for 3 weeks or so in various weather conditions? I'd like to know if its feasible or not. Might have to keep one ICE after all.

I would move this sort of inquiry to the vampire drain tracking thread. It has a fair number of documented experiences.

Vampire Drain/Loss Tracking

My brother left his in Seattle in 25-40 degree weather for 2 weeks and lost about 56 miles of range. He checked it once. No apps. It was actually closer to 66 miles but he had a cold battery. Very typical numbers. I’d expect you’ll lose about 65-80 miles in 3 weeks, maybe 10 miles more if you have a snowflake (but you get that back, assuming you can move).

 

[MaryAnning3]

Does anyone have actual experience leaving their Tesla at an airport for 3 weeks or so in various weather conditions? I'd like to know if its feasible or not. Might have to keep one ICE after all.

Definitely feasibly. In three weeks you will loose about 22%. Park at 70%, come back to 48%. I have done this a lot in CA. I don't use 3rd party apps and I don't check often, but I don't think checking once per day matters if you want to.

 

[MauiEVlover]

This drives me nuts. I lose 3-5 miles a day. My old Volt could sit for a month and not lose a mile. WTF is my S doing, just parked there?!?! (mining bitcoin for Musk I presume...haha) If you think about how much energy it takes to push that nearly 5000 lb car 30 miles, and then realize it loses that much JUST SITTING THERE for 10 days, it boggles the mind. Tesla needs to fix this. Agree with previous poster that they need to make an airport mode that minimizes losses. When you consider that most people power the Teslas from mostly dirty sources, you can see that this waste of energy causes a lot of co2 emissions.

 

[fbitz777]

I am loosing over 1000kwh per year on Vampire Drain and that is after shutting down every option that would require the car to be up.

Ridiculous as I loose zero on Bolt (except I think if you leave it plugged in in Winter when I saw a few times it kept battery pre-heated)

 

[AlanSubie4Life]

I am loosing over 1000kwh per year on Vampire Drain and that is after shutting down every option that would require the car to be up.

Ridiculous as I loose zero on Bolt (except I think if you leave it plugged in in Winter when I saw a few times it kept battery pre-heated)

Seems high. Is it higher on the X? I would expect less than 1kWh per day...which is bad, but not 1000kWh/yr.

 

[darth_vad3r]

I am loosing over 1000kwh per year on Vampire Drain and that is after shutting down every option that would require the car to be up.

Ridiculous as I loose zero on Bolt (except I think if you leave it plugged in in Winter when I saw a few times it kept battery pre-heated)

If you leave the Bolt unplugged for a year is the 12V dead?

How are you measuring per year loss? Are you taking a 12-hr measurement and extrapolating x365x2?
Or a 1 week measurement x52?
Or??

There can be a lot of extra battery usage after you first park as systems are still running and the car isn’t asleep yet. The shorter the measurement time the larger the error will be.

 

[fbitz777]

If you leave the Bolt unplugged for a year is the 12V dead?

How are you measuring per year loss? Are you taking a 12-hr measurement and extrapolating x365x2?
Or a 1 week measurement x52?
Or??

There can be a lot of extra battery usage after you first park as systems are still running and the car isn’t asleep yet. The shorter the measurement time the larger the error will be.

I have left Bolt off for a week and did not loose capacity..and I no the 12V would probably still be ok is you leae the Bolt unplugged as eh main battery would keep it up.

As for my X I use Stats App and it says I loose about 7-8 miles a day on Phantom Drain....it seems better now that the weather is warm.
That also matches what I see every morning when I check rated range versus the previous night.

 

[darth_vad3r]

I have left Bolt off for a week and did not loose capacity..and I no the 12V would probably still be ok is you leae the Bolt unplugged as eh main battery would keep it up.

As for my X I use Stats App and it says I loose about 7-8 miles a day on Phantom Drain....it seems better now that the weather is warm.
That also matches what I see every morning when I check rated range versus the previous night.

Seems really high, is X worse than 3? I thought people were complaining 3 was worse. Maybe try without stats app for a week and see if it’s interfering with sleep?

 

[MaryAnning3]

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.

 

[MaryAnning3]

Ridiculous as I loose zero on Bolt (

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.

 

[seattlite2004]

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.

I personally have left my garaged Bolt for 2.5 - 3 weeks and saw zero SOC change. I confirmed this with comparative data from my EVSE that shows me how much KWh I'm putting into the vehicle.

The Bolt doesn't have a liquid cooled computer... so zero systems are on when parked and "off". Bottomline... Bolts have way less "vampire" drain than Tesla's.