Vampire Drain is (almost) dead

[Xenoilphobe]

I don't have a horse in this race as I don't own a Model S, but a Renault Zoe with a 22 kWh battery. I've been following this thread regularly and I have had mixed feelings about the vampire load. This morning it came to me to compare the vampire load of the Model S with other electric devices to see how it holds up.

When I see a desk top computer uses 21W while in sleep mode, 42W for the Model S is nothing short of amazing to me. We are talking about an electric car here, which is as big as an electric device as I own privately.

http://standby.lbl.gov/summary-table.html

Amen! I charge with solar panels and this equals to one solar panel for 5 hours to support the Tesla. One time cost for the panel was $400 (AUO250MA) of which Uncle Sam paid for $100. So for a $300 device I have negated the vampire loss for the lifetime of the vehicle.

Even if it is two panels (which is possible due to weather and standard PTC losses). I can deal with this while Tesla further enhances through software updates. Power costs here in Northern Virginia are .10 so either way it costs next to nothing.

Other note. I am sure Tesla loves feedback from all consumers. Not just Tesla owners. In fact the street is more interested in the gen III strategy and not so much in the rare air premium car segment that the P85 resides in. As a freshly minted P85 owner I would personally love a 300 mile RAV4 or Highlander BEV. I own a FJ cruiser that I love that is a gas pig, which I wish was more efficient. Only time it has moved since purchasing the P85 was for a firewood run.

 

[J1mbo]

I don't have a horse in this race as I don't own a Model S, but a Renault Zoe with a 22 kWh battery. I've been following this thread regularly and I have had mixed feelings about the vampire load. This morning it came to me to compare the vampire load of the Model S with other electric devices to see how it holds up.

When I see a desk top computer uses 21W while in sleep mode, 42W for the Model S is nothing short of amazing to me. We are talking about an electric car here, which is as big as an electric device as I own privately.

http://standby.lbl.gov/summary-table.html

Perhaps a better comparison would be the EeePad Transformer.

This tablet was based on the same Tegra2 chip that the MS uses, and ran the same kind of OS (Linux).

The EeePad came with a 24.4Wh battery and could standby on that for just 30 hours.

The Sony S Tablet had the same chipset, and the same problem.

If we assume that the MS is running both Tegra2 boards in deep sleep, rather than shutting one down completely, then the vampire drain looks pretty close to that seen on the EeePad.

At the time, Android 3.1 was used in these tablets, and later software upgrades helped improve things, but IIRC it wasn't until the Tegra3 came out that the problem was properly nailed, with something like 50 days of standby possible from a similar sized-battery.

I would imagine that physically swapping out the Tegra2 boards for Tegra3 (or better) would be a fairly cheap exercise for Tesla, however, the quality assurance needed in order to do this without introducing other problems is a different ball game. Maybe something that could be retrofitted to S from the MX development programme, assuming the MX doesn't continue to use the Tegra2...

 

[ggr]

I'm somewhat skeptical of this. But if it's true, I expect Tesla to justify every idle watt in great technical detail.

I not only don't expect them to justify this, I don't want them to. As an investor, I want them to to make money and spur further research by others, rather than just giving away their proprietary secrets of battery management and communication protocols (which I assume account for much of the drain).

 

[markb1]

I not only don't expect them to justify this, I don't want them to. As an investor, I want them to to make money and spur further research by others, rather than just giving away their proprietary secrets of battery management and communication protocols (which I assume account for much of the drain).

I'd much prefer they just eliminate the idle watts.

 

[jerry33]

I'd much prefer they just eliminate the idle watts.

Even if it means reducing functionality and/or battery life?

Not trying to pick on you here, but a certain amount of vampire drain may be necessary for long term car health. No one wants a car that loses 25% of it's original range in the first year if it's used in less-than-perfect conditions. Agreed, vampire load should be minimized but I don't believe zero at the expense of everything else should be the exclusive-of-everything-else goal.

 

[Dave EV]

Perhaps a better comparison would be the EeePad Transformer.

This tablet was based on the same Tegra2 chip that the MS uses, and ran the same kind of OS (Linux).

The EeePad came with a 24.4Wh battery and could standby on that for just 30 hours.

I have that exact EeePad and it will standby for weeks before it needs to be recharged...

 

[J1mbo]

I have that exact EeePad and it will standby for weeks before it needs to be recharged...

You have the original, or one of the subsequent models? The Prime lasted for almost 2 months on Standby.

 

[Dave EV]

You have the original, or one of the subsequent models? The Prime lasted for almost 2 months on Standby.

TF101, the one you linked to. It might go longer, I haven't really tested it, just know it will go a least 2 weeks without having to charge which puts it's standby power draw at well under a watt.

 

[J1mbo]

TF101, the one you linked to. It might go longer, I haven't really tested it, just know it will go a least 2 weeks without having to charge which puts it's standby power draw at well under a watt.

The excessive drain happened when the external battery/keyboard accessory was attached. This was linked to a specific chipset, more info here.

 

[markb1]

Even if it means reducing functionality and/or battery life?

Not trying to pick on you here, but a certain amount of vampire drain may be necessary for long term car health. No one wants a car that loses 25% of it's original range in the first year if it's used in less-than-perfect conditions. Agreed, vampire load should be minimized but I don't believe zero at the expense of everything else should be the exclusive-of-everything-else goal.

I just need a good technical explanation for me to believe that.

 

[chickensevil]

This whole thing goes back to what Elon was saying about the car fires. People are holding this car to a really high standard (which is fine to some degree, keeps them honest and gives them pressure to keep pushing to make a better product) but lets compare to what we are REALLY fighting against here which is an ICE.

Chalk up the vampire drain to "inefficiency" and lets add that cost into your overall operating costs of the vehicle. You are still leaps and bounds ahead of your average ICE that gets 20-30 MPG running at 20% efficiency.

Also keep in mind that this car far more electronic than it is mechanical. Of course other cars do not compare to the vampire losses because they have a lot of mechanical parts to them... their version of "vampire loss" is keeping the parts oiled... so you slowly lose oil over time... some lose more oil than others.

Am I saying they shouldn't fix this? no. By all means, if you know your product has room for improvement then make it better, but I find it depressing to hear that someone would NOT buy this car just because out of 300 miles if you let it sit for a while you lose a handful here or there. On a percentage of miles lost if your 80 mile LEAF was losing 4 miles a day which would kill you more? You will still easily get your 80 miles of range and then some, and when you actually need the full distance, vampire loss is a non-issue because you are actually USING the car.

The only people I see who have a real case here is long term airport parking. But if New York ends up being the standard, we might be getting more and more superchargers near airports.

 

[liuping]

Of course other cars do not compare to the vampire losses because they have a lot of mechanical parts to them... their version of "vampire loss" is keeping the parts oiled... so you slowly lose oil over time... some lose more oil than others.

I think the biggest vampire loss for ICE cars is the gas used for idling. Even newer cars and hybrids that kill the engine during long stops waste gas before the engine is kill and when it's started it back up.

 

[Kalud]

I think the biggest vampire loss for ICE cars is the gas used for idling. Even newer cars and hybrids that kill the engine during long stops waste gas before the engine is kill and when it's started it back up.

From an overall 20% efficiency when making the car moves point of view, then yes, idling is like 100% waste, but driving is still a huge "vampire" loss by itself...

 

[neroden]

The only people I see who have a real case here is long term airport parking.

And similar things. Thankfully, the recent changes (12V battery replacement and sleep mode) have brought vampire loss down to where it's not a big deal for most such scenarios.... except in the cccooolllddd for battery heating, and that may not be fixable.

---

I seem to have used 15 miles of rated range overnight in my garage last night. The car claimed "Charging Finished" but was 15 miles below the target, and I was able to unplug, replug, and get back up.

Anyway, the weather outside was below 0 Farenheit last night (warmer this morning) and the garage is unheated, so I figured that was the reason. (I thought the car was supposed to pull directly from the wall under these circumstances, though.)

 

[chickensevil]

And similar things. Thankfully, the recent changes (12V battery replacement and sleep mode) have brought vampire loss down to where it's not a big deal for most such scenarios.... except in the cccooolllddd for battery heating, and that may not be fixable.

---

I seem to have used 15 miles of rated range overnight in my garage last night. The car claimed "Charging Finished" but was 15 miles below the target, and I was able to unplug, replug, and get back up.

Anyway, the weather outside was below 0 Farenheit last night (warmer this morning) and the garage is unheated, so I figured that was the reason. (I thought the car was supposed to pull directly from the wall under these circumstances, though.)

I think that only applies to using other things will just sitting there, like the touch screen. Unless you maybe don't have the latest update which provided this? I don't have a car (yet) to help test for you

But yeah, cold is the biggest thing to kill this car right now. It is a real concern, but I am willing to be over time they will improve this a lot more. I still consider us in the "early days" of R&D when it comes to the future potential of EVs, so I treat this like I do any "new" technology, a great first step. (better than the half/quarter step from the competition).

 

[jerry33]

But yeah, cold is the biggest thing to kill this car right now. It is a real concern, but I am willing to be over time they will improve this a lot more. I still consider us in the "early days" of R&D when it comes to the future potential of EVs, so I treat this like I do any "new" technology, a great first step. (better than the half/quarter step from the competition).

There are several things about cold that you can't fix:

Denser air.

More rolling resistance from snow and rain.

More rolling resistance because the tires are cooler.

Cabin heating is used.

At least we don't have the "winter fuel has lower energy content" problem.

Really, all cars have reduced range in cold but most ICE cars don't tell you, so you never know unless you keep a log book. In the Tesla, it's hard not to know.

 

[Merrill]

To put the vampire drain in perspective I just did my 6 month spread sheet for electricity cost to charge my Model S. Now granted I do have a small solar array and a second meter for the car. Factoring in all charging including 3 supercharger stops and 2 free charges at the service center and the fact that this 6 month period includes 3 summer months of good sun, my total cost to drive this car for 6 months is $50. So as much as I would like to see the vampire loss reduced, I feel that compared to my wife's ICE which would have cost around $900 that I cannot complain too much.

 

[chickensevil]

To put the vampire drain in perspective I just did my 6 month spread sheet for electricity cost to charge my Model S. Now granted I do have a small solar array and a second meter for the car. Factoring in all charging including 3 supercharger stops and 2 free charges at the service center and the fact that this 6 month period includes 3 summer months of good sun, my total cost to drive this car for 6 months is $50. So as much as I would like to see the vampire loss reduced, I feel that compared to my wife's ICE which would have cost around $900 that I cannot complain too much.

See this was my point, people are complaining about "wasted energy" from the cold, but when you put it into perspective, it is vastly better than what we have with ICE. Is there room to try to improve it? Sure, there is always. But I don't think it is a problem to the point where your car is going to be ruined and you are still saving money overall.

Here's to further improvements in the future!

 

[Robert.Boston]

I see two distinct issues about the on-going vampire losses:

1. It wastes power, which costs money and causes pollution
2. Cars left unplugged for several days lose range

#2 is a much bigger deal for me. At some airports there are simply no charging options, even 120v, so losing ~1kWh/day chips away at the remaining range. Combine that loss with ~doubled energy requirement to drive with a cold-soaked battery in winter, and you have the makings of a real problem for some owners.

 

[spentan]

The only people I see who have a real case here is long term airport parking. But if New York ends up being the standard, we might be getting more and more superchargers near airports.

Well, LAX already has EV charging in its parking garages, and Hawthorne supercharger is only 10 mins/6 miles away.

I wouldn't be surprised if lots of airports start getting ev charging in their parking garages.