Power drain while idle (Vampire Load)

[mknox]

Still, the vampire load can easily be offset just by plugging into a 120v outlet, which are much easier to come by than 240v.

My concern in all of this is the additional cost of electricity for power that won't be used to operate the car. Kind of like spilling gas at the gas station - you've still paid for the gas, and it makes the operating (fuel) costs higher than anticipated.

I'm wiring in a separate meter on the NEMA 14-50 outlet so I can keep track. On the other hand, I'll probably make up for it by picking up free charges at work and such :wink:

 

[Robert.Boston]

@mknox: wasting power isn't good, but it's not very costly in this case. I think the highest reported loss has been ~10 miles of range/day, which equates to about 3.5kWh/day, or about $0.50/day (depending, of course, on your electricity rate). Still, that's ~$200/year, which could pay for a fine dinner for my wife and me. Still, this is an order of magnitude lower than the savings in gasoline.

 

[mknox]

@mknox: wasting power isn't good, but it's not very costly in this case. I think the highest reported loss has been ~10 miles of range/day, which equates to about 3.5kWh/day, or about $0.50/day (depending, of course, on your electricity rate). Still, that's ~$200/year, which could pay for a fine dinner for my wife and me. Still, this is an order of magnitude lower than the savings in gasoline.

I don't disagree, but it is funny when you think we're telling people to unplug cell phone chargers and coffee makers when not in use to cut down on "vampire" (standby) loads at home!

 

[Rodolfo Paiz]

I'm too hard-headed to buy a completely unreasonable car even if it looks pretty. My calculations were predicated on the Model S having a reasonably low vampire load; if the vampire load is too high, it actually costs more to *maintain* the Model S than it does to fuel a gasoline car, which makes it completely unreasonable. It's not clear to me yet exactly how much the vampire load currently is. If it's around 3 kWh/day, that's high, but still tolerable. If it's as much as 10 kWh per day, it's more expensive than buying gasoline (at the rate I drive).

3 kWh per day is roughly $10/month in most of the USA. I charge up my Roadster (good for about 150 miles the way I drive) on only $5, so that's 30 mpd (miles per dollar). My wife's BMW 535, a direct Model S competitor with less power, and our Honda Odyssey, both get only 16 mpg (4 mpd). For every 100 miles of travel, our ICE cars spend $25 on gas, and I spend $3.33 in electrons. Or, to put it a different way, it takes only 40 miles of driving each month to offset the cost of electricity taken up by those vampire loads.

I drive a bit less than average, about 7000 miles a year. Based on the paragraph above, I expect the purchase of a Model S to save at least $1520 in fuel each year (@ $4/gal). I'd break even on the Model S maintenance plan with my fuel savings if I drove only 2200 miles a year. Both those numbers assume $4/gallon gas prices, and become more favorable when (not if) gas gets more expensive.

I have no idea how you've run your numbers, nor do I know whether your math is correct. All I can see is that your definition of a "deal-breaker" is a lot different from mine, and so is your expectation of the benefits of the car: even just the economic ones. To each his own, I guess.

 

[dsm363]

On top of that, Tesla has already said they would address this with a software update I believe to should be even less of an issue.

 

[SCW-Greg]

So you drive say 50 miles to the airport, park, go on vacation for 10 to 15 days... will you make it home?

 

[Martini]

I am reminded of the Nest learning thermostat. With the right software, the car could eventually "learn" when you are likely to use it and power itself up during those periods. It could also in principle learn what % of charge you need on different days or times. User-defined settings are so 20th century. If they open the system to independent app developers, imagine the possibilities.

Nest | The LearningNest

 

[stevezzzz]

Where do you find these? Thanks.

My solar PV system sends data to a central repository that allows me to go online and see time plots of both the electricity generated by the solar panels and the electricity used throughout my home. See Currently Connected Devices and click through to see any of the connected devices (anonymously, of course).

 

[brianman]

My solar PV system sends data to a central repository that allows me to go online and see time plots of both the electricity generated by the solar panels and the electricity used throughout my home. See Currently Connected Devices and click through to see any of the connected devices (anonymously, of course).

Ah, ok. Silly me, I thought it might be in a log in the car itself. Can't get that SDK fast enough...

 

[neroden]

Handles are way cool. As you approach they now automatically extend.

New Features...
Vehicle Sleep

Is this going to solve the vampire load issues? :smile::smile::smile:

 

[dsm363]

Is this going to solve the vampire load issues? :smile::smile::smile:

Yes it will or it will at least significantly decrease the drain.

 

[neroden]

I have no idea how you've run your numbers, nor do I know whether your math is correct.

4000 miles/year, 40 mpg. I already know the Model S is in some sense uneconomic for me. :-( Apparently the vampire load is only 3 kWh/day, which is an amount I can justify, however, as I said.

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So you drive say 50 miles to the airport, park, go on vacation for 10 to 15 days... will you make it home?

Let's use my numbers. I expect to get 300 miles out of the big battery due to speed limits here. 60 miles to the airport, 15 days away @ 10 miles per day is 150 miles, 300 - 60 - 150 = 90 miles. So yes, I'd make it home.... unless cold-weather losses ate up those last 30 miles of charge. I'd be doing this in February, mind...

Yeah, I would be a lot more comfortable with a smaller vampire load. Perhaps the new "sleep mode" will provide that?

- - - Updated - - -

That's the charge point map. Stations only show up when the software is active, which means that the stations are live.

Well, that's good news. I'll go check again!

Edit: looks like the replacement of the ficticious stations was successful. That is very much good news.

Further edit: OK, still none at the train station, but there are some across the street at Carousel Mall. I doubt they'd let me park there for 15 days, though. So worst case, my model S just needs enough battery to drive from the train station to the chargers at the mall (and then I can wait in the mall until I have enough charge to get home). The access card thing (why are most the charging station companies doing this?) is probably kind of a waste given how infrequently I'd use it, but for $25 it's probably worth it. So that solves my problem. Thanks for pointing it out; Syracuse has been claiming to have chargers for several years without actually having them available, so it's very nice to see that they finally got it working. Makes trip planning a *lot* easier, since it fills in the biggest gap.

 

[contaygious]

It says it saves 8 miles a day. Is that the vamp Load? I'll probably leave sleep off as I don't really need those miles and don't want to add a delay to driving the car (unless there is virtually no difference).

 

[Todd Burch]

It says it saves 8 miles a day. Is that the vamp drain? I'll probably leave sleep off as I don't really need those miles and don't want to add a delay to driving the car (unless there is virtually no difference).

Sounds like it means the vampire usage went from 10 miles/day to 2 miles/day, meaning the Model S now draws about 700 Wh/day in standby mode. Not terrible, but not yet excellent . 700 Wh/day still seems like more than it should be with some sleeping electronics.

For comparison, vampire load for a modern LCD TV is about 20-24 Wh/day.

 

[Vexar]

Ah, ok. Silly me, I thought it might be in a log in the car itself. Can't get that SDK fast enough...

What SDK? Oh, do not tease me, brianman!

 

[Rodolfo Paiz]

4000 miles/year, 40 mpg. I already know the Model S is in some sense uneconomic for me. :-(

It may be small comfort, but then isn't every other sedan which competes with the Model S even worse? I don't believe that the BMW 5-series, Mercedes E-series, nor any car in that class or price range will get 40 mpg. (Someone will post one in 10 seconds to prove my ignorance, I'll bet.) So you can either get a smaller car, which is more economical and cheaper, or you can get a similar car, which will obviate your range concerns but cost you more in fuel. Or, I'm missing something.

 

[dtich]

OP has links...

ah so.. thx.

- - - Updated - - -

Sounds like it means the vampire usage went from 10 miles/day to 2 miles/day, meaning the Model S now draws about 700 Wh/day in standby mode. Not terrible, but not yet excellent . 700 Wh/day still seems like more than it should be with some sleeping electronics.

For comparison, vampire load for a modern LCD TV is about 20-24 Wh/day.

with respect, think you're being a bit over simplistic with this and maybe your expectations are unrealistic. your tv doesn't have to keep a $20k battery conditioned whether it's on or not.. and would you like the car to not respond to pings for fw auto-updates or your smart phone app? this is not a tv. it has many other things to monitor and log and respond to whether it's in sleep or not. the tv only has to respond to an IR ping. one tiny little IC and relay. the rest can snooze. the car on the other hand has many subsystems that can't simply not pay any attention at all. IR receivers are passive. broadband cellular chips are not, they are necessarily transceivers. they must transmit in order to stay linked. the battery must be monitored for temp and charge. and if necessary it must heat/cool. this takes a bit more than 24W. i understand the drive to efficiency.. but let's not get carried away... imho.

 

[DrComputer]

Sounds like it means the vampire usage went from 10 miles/day to 2 miles/day, meaning the Model S now draws about 700 Wh/day in standby mode. Not terrible, but not yet excellent . 700 Wh/day still seems like more than it should be with some sleeping electronics.

For comparison, vampire load for a modern LCD TV is about 20-24 Wh/day.

Yes, but your average LCD TV isn't running cooling pumps to keep a very large battery at ideal temperature.

 

[Todd Burch]

First, I never said I expected the Model S to have a draw anywhere near 24 Wh/day. I just put that number up to provide a relative value for those non-technical folks to get an idea of how much the Model S is using. If it seemed otherwise, than I was unclear in my writing. Sorry...long day (and a long night to come).

Second, I would hope that active cooling is not necessary with a non-charging car sitting in relatively comfortable temperatures. Many of the reports of 10 mile/day vampire loads have occurred with cars parked at the airport for a few days...not charging, and in relatively temperate conditions which should not require active cooling based on my understanding of the Model S battery system.

Do I expect anywhere near 24 Wh/day? Of course not. Do I think Tesla can beat 700 Wh/day? Absolutely.

Having said that, this stuff probably belongs in the Vampire load thread. Regardless, glad to see this next firmware update is improving things significantly.

 

[brianman]

What SDK? Oh, do not tease me, brianman!

Heh. No teasing. There's was some discussion about them making an SDK available at some point. AFAIK, we don't know any more details than "sometime before the sun explodes, they might give us a Model S SDK".