Power drain while idle (Vampire Load)

[EarlyAdopter]

I went out of town recently and left the car unplugged in the garage, which stays 50 - 55F. This was on v4.1 with sleep enabled.

Unplugged 2/3 9:00pm: 208
Returned 2/7 1:00pm: 195

13 miles of rated range lost over 3.67 days, or 3.5 miles per day.

The car keeps asking if I want to upgrade and I keep saying no.

 

[dennis]

I went away for 5 days and left both cars unplugged with garage temps 45-55F. The Model S lost 55 miles and the Karma lost...zero! Is this true for other EV's such as the Roadster/Leaf/Volt? In other words, is the Model S running that much more electronics than the other EV's?

 

[Lcaudle24]

We should probably start using a rate unit for such reports.

"12.57mi rated per day" or "22% over 3.5 days"

Temperature is the third factor that must be accounted for as it appears to be a significant factor.

- - - Updated - - -

I went away for 5 days and left both cars unplugged with garage temps 45-55F. The Model S lost 55 miles and the Karma lost...zero! Is this true for other EV's such as the Roadster/Leaf/Volt? In other words, is the Model S running that much more electronics than the other EV's?

I understand that the answer is a resounding, unequivocal YES.

 

[Zextraterrestrial]

The so called 'lost miles' aren't all really lost. If you charge for much less than what is shown that was lost you will have regained your miles, say ~ 1/2 of the power is needed for 'refilling' that many miles.

If I see 6-10 miles lost overnight in 12-14 hours, I can charge back to the spot I was at in a bit less than 6 minutes (~<1 kw tot). the 6-10 miles should be 2-3 kW of power

 

[RDoc]

I wonder how much of that is temperature, even at 50F?

 

[theganjaguru]

Vampire Draw - Sleep Mode - Physical Start Button

My buddy and I were discussing the fact that while the whole process of placing your keister in the seat is what starts the MS is cool, it does take away the power/decision of the driver, and people don't like to have their power taken away. I am almost inclined to agree with my buddy. Especially if this is the cause of the vampire draw you folks are experiencing.

Would a vehicle strart button (on future builds) be an easy fix for this issue? The MS can wait for the fob only to unlock doors and run accessories from the 12 V. Then when the driver is ready to turn on the car, they press the start button. Thus the option you folks have now could be part of the tech package (which would further increase the additional options the tech package includes) personally I'd rather have a start button as I've already had issues with airbag sensors (located in my seats) malfunction in my previous car. And I like the idea that "I am in control" (ya, I have control issues lol). I'd definitely prefer a push button startup if it would resolve the issue of vampire draw when idle

 

[JRP3]

I went away for 5 days and left both cars unplugged with garage temps 45-55F. The Model S lost 55 miles and the Karma lost...zero! Is this true for other EV's such as the Roadster/Leaf/Volt? In other words, is the Model S running that much more electronics than the other EV's?

Does the Karma have a temperature controlled pack? The pictures I've seen suggest not, at least no liquid cooling, and the A123 cells should need less temperature management anyway. When sleep mode is enabled again the S should use less power than it is now.

 

[strider]

My buddy and I were discussing the fact that while the whole process of placing your keister in the seat is what starts the MS is cool, it does take away the power/decision of the driver, and people don't like to have their power taken away. I am almost inclined to agree with my buddy. Especially if this is the cause of the vampire draw you folks are experiencing.

The start button would not affect Vampire draw. It would just move the start button from the seat sensor to a physical button. Vampire Draw is happening because Tesla was having trouble with some systems going to sleep and then waking back up again correctly. So they stopped putting anything to sleep. No more bugs but now we have vampire drain. It's a serious problem and I know Tesla is working hard to eliminate it. It will be solved in time.

 

[dennis]

Does the Karma have a temperature controlled pack? The pictures I've seen suggest not, at least no liquid cooling, and the A123 cells should need less temperature management anyway. When sleep mode is enabled again the S should use less power than it is now.

The A123 battery system in the Karma does have liquid cooling. If you recall, the first recall for the Karma (Jan. 2012) was for misaligned clamps in the battery cooling system. I have experienced the fans coming on while the car was charging, but don't know when/if it warms the battery.

I believe most/all of the 55 miles of range I lost in 5 days on the Model S was from running the electronics as opposed to conditioning the battery, given the mean 50F temperature in my garage.

- - - Updated - - -

The so called 'lost miles' aren't all really lost. If you charge for much less than what is shown that was lost you will have regained your miles, say ~ 1/2 of the power is needed for 'refilling' that many miles.

If I see 6-10 miles lost overnight in 12-14 hours, I can charge back to the spot I was at in a bit less than 6 minutes (~<1 kw tot). the 6-10 miles should be 2-3 kW of power

Is that when the battery is cold and regen is showing as limited? The 11 miles/day that I lose due to the electronics does not appear to be recovered when I first start driving the car, i.e. the remaining range ticks down rather than remaining steady for the first few miles of driving.

 

[JRP3]

The A123 battery system in the Karma does have liquid cooling. If you recall, the first recall for the Karma (Jan. 2012) was for misaligned clamps in the battery cooling system.

Of course, how could I have forgotten? I guess the cooling plates must run outside of the modules since I don't see them indicated in any pictures I've seen so far.

 

[dsmith2189]

The so called 'lost miles' aren't all really lost. If you charge for much less than what is shown that was lost you will have regained your miles, say ~ 1/2 of the power is needed for 'refilling' that many miles. If I see 6-10 miles lost overnight in 12-14 hours, I can charge back to the spot I was at in a bit less than 6 minutes (~<1 kw tot). the 6-10 miles should be 2-3 kW of power

Is that when the battery is cold and regen is showing as limited? The 11 miles/day that I lose due to the electronics does not appear to be recovered when I first start driving the car, i.e. the remaining range ticks down rather than remaining steady for the first few miles of driving.

My loss of 12-15 miles a day is not recovered.
When my car was delivered I had 4.0 (1.17.50) and had sleep mode enabled which was good since it took 3-4 weeks to ship it to me. It arrived with 3/4 charge. I did not notice any substantial loss for the first few days before upgrading to 4.2 (1.19.41) and then to 4.2 (1.19.42) 2 days later. After the upgrade is when I noticed the large loss overnight. I would fill to 242 miles and 24 hours later I would be down to 230 miles. I live in Hawaii so loss due to low temperature is not a consideration (average temperatures are 72F to 80F)

 

[tezco]

The so called 'lost miles' aren't all really lost. If you charge for much less than what is shown that was lost you will have regained your miles, say ~ 1/2 of the power is needed for 'refilling' that many miles.

If I see 6-10 miles lost overnight in 12-14 hours, I can charge back to the spot I was at in a bit less than 6 minutes (~<1 kw tot). the 6-10 miles should be 2-3 kW of power

My daily recharge for idle power losses and the ideal miles lost are plotted below for the past 10 days. The S was unplugged for 5 days while I was out of town and lost 71 ideal miles and took 4 hours for a 14.99 kWh recharge (@ 20A) which equates to 211 Wh/mile. (This is the data point farthest to the left.) If you are losing LT 1 kWh per 12 hours (or LT 2 kWh in 24 hours), you are lucky; my losses are about double that, at relatively moderate temperatures. 3 kWh delivered over a 6 minute interval at 240V requires a 125A charging rate, if I'm calculating it correctly.

 

[tezco]

There is the datafile at the end of February 2013. I was on vacation for a few days and the Leaf was outside and unplugged (mean outdoor temp approx 25°F). Over the 8.5 day period, the idle power loss was 0.4 kWh (took 9 minutes to top-off at about 11A average charging current), which equates to only 50 watt hours per day. It's the purple square on the graph. That car can really sleep, even in the cold!

In contrast, the Tesla lost 18.85 kWh over only 4.9 days, which equated to 5,630 watt hours per day. It took slightly over 4 hours to top off at 20A. If the Tesla had been unplugged for the same amount of time as the Leaf, it would have taken slightly over 7 hours to top off, using 32.63 kWh. At my cost (Windsource @ 16¢ / kWh) for an 8.5 day vacation the Leaf would cost 6.4¢ while idle, and the Tesla $5.22

It looks like the ideal miles lost per 24 hours average from around 12.5 to 16 at these temperatures:

 

[ckessel]

The vampire drain is actually my biggest worry with Tesla's technology when it comes to mainstream adoption. ICE cars don't leak fuel when they're parked (though gas can go bad after prolonged periods). Other battery powered devices lose extremely little power when "off" and the Leaf seems to behave similarly. Tesla's losses are far enough beyond either ICE or battery device comparisons that it's going to surprise most people. It also seems at odds with Tesla's blog post: Plug It In | Blog | Tesla Motors

I could not leave my Tesla at an airport for a 2 week trip. Between the 40 miles there and the drain, I wouldn't have the range left to get home.

 

[J in MN]

In contrast, the Tesla lost 18.85 kWh over only 4.9 days, which equated to 5,630 watt hours per day. It took slightly over 4 hours to top off at 20A.

So, this is the flaw in your methodology. The battery SOC was still way over 50% by the time you plugged in. It makes sense to me that MS will continue to heat the battery and power the electronics while SOC > some number, because it is such a big battery and you will still have lots of range left.

What I am looking for is someone willing to let it sit for as many days/weeks as is needed to let the battery run down to 0 miles (~5% SOC). Then we will be able to discover at what SOC it stops heating the battery or powering off some systems, and what the vampire drain is after that point.

But, time is quickly running out this winter.

 

[gregincal]

One thing that I do think that's confusing here is that there are multiple separate things going on. Drain due to electronics, which should be fixed with sleep mode. Apparent drain due to software not being able to correctly determine true SOC when the battery is cold. Finally, there may be some drain due to keeping the battery warm, but it's not clear to me due to the previous issue how significant this is. My understanding is that it's really only important to keep the battery warm if it's being drained or charged, but perhaps it wants to keep it somewhat warm so that it's ready to drive?

 

[RDoc]

Wouldn't it be a good idea for Tesla to simply publish what the characteristics of the car are in cold weather? I suspect they know.

 

[Zextraterrestrial]

Ok, my data , which includes 66 nights (or unplugged periods that were noted) shows that I 'see' 1.35 mph of average 'loss'.
This is at an average ambient of 45.5 F and the average time period is 12 hours. At the temps between 35 and 55 F I don't see a huge correlation but If it is closer to freezing I can drive ~ 10 miles w/out any rated change (If the car is cold to begin with)

...my temp source is what the car shows - highly inaccurate for this.

The longer Idle periods have much lower vampire draw than the short ones do. Most of the short rests actually would have kept the same rated shown after a few miles so accuracy of this is poor

How did I let her sit alone for 30 hours is my real question?

 

[strider]

Wouldn't it be a good idea for Tesla to simply publish what the characteristics of the car are in cold weather? I suspect they know.

They're not going to publish anything until Sleep mode is fixed. Once something is posted on the internet it NEVER goes away. So I'm sure they're just hoping they'll get it fixed in the next few weeks/months and it'll just go gently into this good night.

 

[tezco]

Ok, my data , which includes 66 nights (or unplugged periods that were noted) shows that I 'see' 1.35 mph of average 'loss'...This is at an average ambient of 45.5 F...The longer Idle periods have much lower vampire draw than the short ones do... How did I let her sit alone for 30 hours is my real question?

That's interesting. I haven't been able to document any lower rates of idle power loss after a long rest, even when the car sat for nearly a week. Your 1.35 miles per hour loss = 32 miles per 24 hrs. That's a bit more than double my rate at that temp. My car has been sitting a lot too, since I can't get in and out of my driveway right now without 4wd.