Power drain while idle (Vampire Load)

[david]

Thought I'd quantify the idle power drain with 5.0. The car was left unplugged for 5 weeks. I checked the charge (using the iphone app) less and less frequently to see if it would go into some deeper sleep eventually. Overall vampire loss was 6.2 miles per day. Also, I'd say at first look, checking the car using the app wakes up systems to add approximately one additional mile of loss per day. Something to consider if you leave the car unplugged at an airport for a long trip.

Days/Rated Miles/Loss per day
0 240
3.8 211 7.6
3.4 184 7.8
9 125 7.0
18 15 6.2

 

[brianman]

Thought I'd quantify the idle power drain with 5.0. The car was left unplugged for 5 weeks

Thank you for sharing but 5 weeks? Please tell me you were on vacation rather than simply neglecting your racehorse.

 

[liuping]

Overall vampire loss was 6.2 miles per day.

Thanks for the numbers.

60 kwh per month still seems high for something that is supposed to be asleep.

 

[david]

That's for the numbers.

60 kwh per month still seems high for something that is supposed to be asleep.

Must be REM sleep - a cars gotta dream, right? I agree, though it is significantly better than 4.5. I was hoping after a week or so of no activity, it'd go from sleep to hibernate. Maybe that'll be a 5.1 upgrade.

brianman - it pained me also to leave it for so long, but business called. My luck it was only 5 weeks and I still had 15 rated miles to drive the 16 miles home from the airport garage...at a hyper-miling 40 mph, sweatin' bullets the whole way (literally, windows up, a/c off). Got home with 2 miles remaining. :scared:

 

[apacheguy]

Overall vampire loss was 6.2 miles per day. Also, I'd say at first look, checking the car using the app wakes up systems to add approximately one additional mile of loss per day. Something to consider if you leave the car unplugged at an airport for a long trip.

That does seem a bit higher than what others have reported. Currently, 4.5 daily loss is about 8 miles IIRC and 5.0 is supposed to cut it in half to no more than 4 miles. Waking it up just once per day from the mobile app should not alter these numbers much.

 

[brianman]

Napkin calculations on vampire load

17,000 mi - ~4,000 mi to/thru California => 13,000 mi

10.5 months, approximately 320 days
320 - 10 days in California => 310 days

trip meter average of 383 Wh/mi

(13,000 mi * 383 Wh/mi) / 310 days = 16.061 kWh/day


Using Tesla's calculator...
Tesla Charging | Tesla Motors

with 300 miles shows 99.0 kWh to refill the 85 kWh battery.



So from-wall consumption becomes...

16.061 kWh/day * (99 / 85) = 18.706 kWh / day



My monthly chart fairly consistently shows 25 - 30 kWh/day more usage than last year.

Using the smaller number (25), we can come up with a rough guess for the vampire load overhead:

((25-18.706) / 18.706) = 33.6% vampire overhead

Or put another way...

((25-18.706) / 25) = 25.2% of my power consumption is from vampire load


Now these numbers are even more generous than described above because I've used public chargers, superchargers, etc. which don't count towards my home power consumption.


So, yes, vampire load is pretty significant through at least 4.5 firmware.

 

[polyphase]

Thought I'd quantify the idle power drain with 5.0. The car was left unplugged for 5 weeks.

Did you enable sleep mode?

 

[liuping]

((25-18.706) / 25) = 25.2% of my power consumption is from vampire load

Vampire losses are usually considered the amount of energy used by a device when it's just sitting unused or off.

I think your calculations are including charging overhead, which is somewhat unavoidable (and is much worse at 110V and/or lower Amps settings)

Your calculations are usefully for seeing the true cost per mile, etc. but not for gauging vampire loss improvements from software updates.

 

[brianman]

I think your calculations are including charging overhead, which is somewhat unavoidable (and is much worse at 110V and/or lower Amps settings)

I think you missed this part:

Using Tesla's calculator...
Tesla Charging | Tesla Motors
with 300 miles shows 99.0 kWh to refill the 85 kWh battery.

So from-wall consumption becomes...
16.061 kWh/day * (99 / 85) = 18.706 kWh / day

 

[Zythryn]

17,000 mi - ~4,000 mi to/thru California => 13,000 mi
...
My monthly chart fairly consistently shows 25 - 30 kWh/day more usage than last year.

Using the smaller number (25), we can come up with a rough guess for the vampire load ...

Monthly chart? Is this based off of the increase in use of your entire house?
Did you use more or less electricity than last year due to weather changes?
New TV, computer, etc.

Did you independently measure the charge loss of your system?

If the car needed to cool or heat the battery pack prior to charging, at any point in that time, that energy is not Vampire Drain, however it would add to the electricity drawn.

The first factor is a huge one though. Oh, and did your rate structure change while you have had the MS?

 

[brianman]

Monthly chart? Is this based off of the increase in use of your entire house?
Did you use more or less electricity than last year due to weather changes?
New TV, computer, etc.

Did you independently measure the charge loss of your system?

If the car needed to cool or heat the battery pack prior to charging, at any point in that time, that energy is not Vampire Drain, however it would add to the electricity drawn.

The first factor is a huge one though. Oh, and did your rate structure change while you have had the MS?

Rate structure isn't really relevant when you're talking about kWh consumption rather than $ cost.

No new computers or appliances in the last year. (My attention has been occupied by my vehicle. )

Compared with last year's consumption. If anything, this year has been milder than last (or at least felt as such).

 

[david]

Did you enable sleep mode?

I was on 5.0 build 1.35.98 at the time. I don't recall being able to enable/disable sleep mode with that build. Also, others may have been seeing better results with 1.35.102.

 

[Owner]

I was away for a month and kept my Model S plugged in at 50% charge. Since I am on solar, I could accurately measure the vampire drain. In my case, it is 2.75kWh / day with 4.5. The car refreshes itself every other day. I did not include the house vampire drain, which runs less than .1kWh per 15 minutes as it was a bit noisy. So the number is probably more like 2.68kWh/day but it was not worth estimating that noise.

Gory details including energy charts:
Vampire Drain | Tesla Owner

I'm also estimating that to be about 2,700 miles of wasted energy per year.

 

[tezco]

My Leaf "wakes up" in a matter of seconds and uses almost no juice when parked. Hope Tesla can get this figured out soon since I'm sharing the J1772 with both cars. Hope to get a dedicated line in for the S soon, though. Still, can't park the S at the airport for more than a couple of days and still have enough juice left to get home.

 

[montgom626]

My Leaf "wakes up" in a matter of seconds and uses almost no juice when parked. Hope Tesla can get this figured out soon

Agreed.

 

[dennis]

A year and a day after I started this thread I can confirm that the issue is now resolved to my satisfaction. I received 5.6 last Thursday when my car was in for its annual service. When I parked the car yesterday evening it showed 143 miles rated range and now 20 hours later it shows 140. That loss of 3 miles compares to 10-12 miles loss per day pre 5.6 and is completely acceptable to me. Congratulations Tesla!

 

[yobigd20]

you know, I was googling around for various Tesla stuff and I came across this report http://uniteconomics.com/files/Tesla_Motors_Is_the_Model_S_Green.pdf 'Is the Model S Green?' which was written back in April. I found that this report referenced me and my posts in this thread directly regarding vampire losses.

Model S Idle Power Losses in Cold Weather
The primary problem behind the now-famous Tesla Supercharger review by John Broder of the New York Times was that he parked his borrowed Model S outside on a cold, February night in Connecticut without plugging it in to a charger. When he parked the sedan before dinner, it had 90 miles of remaining range. After sitting overnight in 10 degree F weather, the remaining range was just 25 miles - a loss of 5.4 miles of range per hour (2.03 kWh per hour). The car ultimately left him stranded, unable to drive the 45 miles to the next Tesla ‘Supercharger’ station. Was this a one-time problem or does the Model S have a major flaw?
Based on the Tesla Model S reservation map, we estimate that 46% of North American Model S owners live in areas where winter temperatures routinely fall below freezing. This makes the cold weather idle losses a significant problem. Forum member Yobigd20, from New Jersey, wrote that in March, his Model S was consuming 2.76 miles of range per hour when left in the cold, or 1.04 kWh per hour, prior to charging losses. On the lower end of the spectrum, forum user Kevincwelch of Chicago reports 1 to 2 miles of driving range is lost every hour when his Model S sits idle in the cold, or .38 to .75 kWh of charge per hour. Reports of excessive

Well, just as a response to this, if I haven't already noted in a more recent post in this thread, I no longer exhibit those vampire loses since v5.8. There are a few miles loss I think, but certainly orders of magnitude less than before. Its small enough now that it really has no adverse effect. It's negligible. Problem solved. Good job Tesla.

 

[gregincal]

I got 5.8 and then away for a week. With my car plugged in the whole time I still show the car drawing 2-3kWh every night. I need to double check my sleep settings, but is it possible it doesn't go to sleep if you are plugged in with a charge timer set?

 

[AEdennis]

I got 5.8 and then away for a week. With my car plugged in the whole time I still show the car drawing 2-3kWh every night. I need to double check my sleep settings, but is it possible it doesn't go to sleep if you are plugged in with a charge timer set?

I've been on 5.8 for a few weeks and it definitely sleeps.

 

[mknox]

Here are my results on 5.8 with Sleep Mode working:

I am at a conference and charged my car to 90% at a nearby charging station, then moved it into the hotel's indoor parking lot at 9:50 PM last night. It was at 215 Rated Miles. It was not plugged in.

This evening at 11:00 PM, I woke the car from my hotel room with the VisibleTesla app. It is reporting 208 Rated miles and 88% SOC.

That is a loss of 7 miles over 25 hours.