In Cold Weather, Tesla Model S Vampire Drain Is Higher Than Tesla’s Claimed 1% Per Day

MAY 31 2015 BY MIKE ANTHONY 30

Tesla Model S.

Tesla Model S.

Our friends over at TESLARATI created a small guide, which includes a few tips for parking your Model S (unplugged) long-term.

The report mentions information on “vampire drain”, where the Model S’ battery pack will discharge 1% per day.

Per the Tesla Model S owner’s manual:

“Even when Model S is not being driven, its Battery discharges very slowly to power the onboard electronics. On average, the Battery discharges at a rate of 1% per day. Situations can arise in which you must leave Model S unplugged for an extended period of time (for example, at an airport when traveling). In these situations, keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level. For example, over a two week period (14 days), the Battery discharges by approximately 14%.”

Rob M from TESLARATI parked his Model S for approximately 2.6 days, and noticed he had lost 14 miles of range; 2.3% per day:

“when I parked and I had 186 miles of rated range left (71%). When I returned my Model S reported 172 miles of rated range left (65%).  I lost 14 rated miles over the 2.6 days at an average temperature of 16 degrees fahrenheit.”

Obviously, this is a little more than 1% per day.

A note that we would like to add for those who may not be aware: When the Model S is unplugged in cold weather conditions such as this, the battery pack will use some of its own charge (more than this 1% number) to keep itself at an optimum temperature, so the battery does not get damaged.

A few tips from TESLARATI would be to turn “Energy Saving” mode on when you have your Model S parked for multiple days, especially in these cold weather conditions.

Image Credit: Bob M. @ TESLARATI.

Image Credit: Bob M. @ TESLARATI.

Per Rob M at TESLARATI:

“Be smart and plan out your Model S long term parking strategy, especially if there isn’t going to be a charger on site or nearby. Be sure to have enough battery range upon return so that you can get to your destination or to the nearest charging location.”

“Tesla suggests a 1% battery discharge loss per day but you may want to consider a more conservative 3% number to ensure you have plenty of range left upon returning.”

Click here to read the full report from Teslarati.

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30 Comments on "In Cold Weather, Tesla Model S Vampire Drain Is Higher Than Tesla’s Claimed 1% Per Day"

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Doug (dhanson865)

If you turn off that “always connected” option in addition to turning on “energy saving” it’ll reduce the loss even more than just turning on “energy saving” only.

teslaliving

True but the startup from that mode is very user unfriendly

JakeY

If the goal is to save as much power as possible, then a less friendly startup is a certainly an acceptable trade-off.

Robert

What does “less friendly start up” mean to those of us that don`t have a Tesla?

Omar Sultan

I am also curious what the “less friendly startup” is, and I do have a Model and have used Energy Saving on occasion.

Doug (dhanson865)

It takes an extra minute or two to wake up.

rik

For clarification, the delay when “Energy saving” is on and “always connected” is off is about 30 seconds to wake up the Model S when connecting via the iPhone app. I just timed it with my own Model S.

The Model S starts up faster than that when the driver enters the car even at these maximum energy saving settings.

These are not user unfriendly at all, in my opinion as a Model S owner.

Tony Williams

i have a Chevy Volt and a Nissan Leaf and neither one has a drain of 1% per WEEK and the start up time for the Volt is about 2 seconds and for the Leaf 3 or 4 seconds. Surely Tesla could match these numbers.

Micke Larsson

Maybe there should be a “Flight mode” 😛 Or maybe Elon is saving that for when the car will actually leave the ground.

Bill Howland

Thanks for providing the info. It gives another hint at what is really happening.

MrEnergyCzar

Will it still brick if you leave it unplugged for a couple of months? What was the work around they did for that?

ItsNotAboutTheMoney

No, it doesn’t.

ItsNotAboutTheMoney

Given that Tesla gives an average, that’s not much of a headline.

If you want to say it’s significantly higher than the average, that’s a different matter.

Bikeandsail

2.6 days and 2.3% loss is less than 1 percent per day. Article totally wrong!!

Brian

approximately 2.6 days, and noticed he had lost 14 miles of range; 2.3% per day.

Just gonna go ahead and leave that one alone.

teslaliving

Don’t think you’re reading it right.

71% starting charge – 65% ending charge = 6% loss in 2.6 days.

6/2.6 = 2.3% loss per day.

Foo

Stick to biking and sailing.

Counter-Strike Cat

Shouldn’t the drive battery be completely disconnected from everything outside the battery pack, if the car is not turned on or on charge? All the stand-by electric uses the 12 V lead battery?

Eric Cote

Unfortunately that’s not the case with Teslas. It’s a pretty huge design flaw in an otherwise refined vehicle.

I think they do this to keep some electronics powered on always, so the vehicle boots up quickly when a driver enters.

If I were the engineer, I would have found a way to design their door handles to react very much like today’s passive keyless entry buttons do (without need for a high voltage battery supplying power all the time).

Then I would then use that cue to boot systems prior to driver entry.

I think that would be a better way to accomplish their desired behavior.

Tech01x

The battery management system is active the entire time in order to protect the pack. That’s the primary power draw when the car is asleep. It’s powered by the 12 volt lead acid battery at that point. When the charge on the lead acid battery drops to a certain point, it has to wake the high voltage system to charge it.

There’s no design flaw. Would you rather the pack suffer catastrophic temperature damage instead?

Jeff N

What was the temperature of the battery pack when he turned off the car and what was the cold-soaked temperature when he turned it back on 2.5 days later?

I’m betting that much of the alleged battery range loss was simply due to having a colder battery rather than any actual power loss. If he checked the battery at the same temperature as when he checked it 2.5 days earlier the reported range loss might be closer to 1%.

Batteries can appear to show lower charge levels when they are colder.

Jeff N

To clarify, the article says he dropped off the car when it was 11 degrees outside but what matters is the battery pack temperature. Driving the car before he parked it would normally warm the battery but 2.5 days later it would have dropped to match the average recent ambiant temperature.

Bone

+1

I had same thoughts when reading the article. We don’t know how model S software deals with variables like temperature in range estimation, so it’s practically impossible to say if it’s real energy loss or merely a change in range estimate.

This is very common. People report range loss based on range estimate on the display, without understanding that there is a lot of variables and fuzzy logic behind that estimate.

Li-ion battery is not like a fuel tank. You can easily measure how much fuel there is in the tank, but it’s very difficult to measure the energy left in the battery.

David N

One of the enduring Tesla myths is that the car keeps its battery at some optimum temperature when the car is shut down and unplugged.

This is simply not true. The battery goes to whatever the ambient temperature is and stays there. This was confirmed by Elon Musk in a talk in Europe a couple of years ago. In fact,he said, when it comes to long-term inactivity and battery health, the colder the better.

My own Model S, with the energy-saving option enabled (which slightly delays the start-up process) typically loses about three miles a day of range–roughly one percent.

Still, it’s odd that, as far as I know, no other electric car loses any range whatsoever when shut down. I once let my Volt sit unplugged for two weeks, and the range was unaffected.

Jeff N

Yes, I consider the amount of Model S default vampire loss to be a design flaw that needs improvement. The Volt has a small vampire loss so that OnStar can check for incoming remote commands for the first 2-3 days and then it shuts down almost completely and has very little loss. It’s good that Tesla added some configurable controls on energy use when parked but I wonder how many owners bother to enable them. I’m curious to see this evolves for the Model 3.

Bone

Correct. Cold temperature is good for long term storage of li-ion cells. You only get problems if the electrolyte starts to freeze, but the freezing point is typically around -40 F. Maybe even lower for automotive cells.

Speculawyer

Vampire drain has long been an issue with the Model S. And I’m not sure if this is good or bad news but this current vampire drain rate is after a significant software update to address the issue.

Hopefully the Model 3 does better.

Bill Howland
Yeah as I’ve stated before, the only article I’ve seen where the issue was attempted to be fully addressed other than bits and pieces was David Noland writing for Green Car Reports. I’m not worried about ‘pseudo capacity loss’ due to a cold battery, that recovers its capacity later when warmed to room temperature. I’m worried about real usage. But as I say, for a few years I was thinking my next car was going to be an S, but it is so hard to get information on how the car really performs in actual life. If I say I don’t trust the mileage figures, someone will post that the S gets 200 wh/mile. Well, with an 85 kwh battery discharged 95% that would be well over 400 miles in everyday driving. And if THAT were really true, then there’d be ads all over place saying that not only does the Tesla get a fictional 300 miles real world , but an extra 100 besides. There is a great reluctance to say anything even mediocre about the car let alone say that something is inefficient. Now with my ELR, I hate the cutesy stuff and I say so, and I… Read more »
Andrew Rivers

It also depends on if the Tesla manual is talking about 1% of driving range or 1% of battery capacity.

If it a capacity drain:
0.01*85e3 = 850wh/day lost
at 200wh/mi that would be 4.25mi/day
for 2.6 days at this rate, the range loss would be ~11mi.

If the car uses a value other than 200wh/mi to estimate range (which is very likely) then I can see an estimated loss of 14mi while remaining close to a 1% capacity drain per day as the manual claims.

rik

I measured slightly less than 1% per day vampire loss when I left my Model S unplugged for several weeks during January.