Power drain while idle (Vampire Load)

[JRP3]

Seems as if the 12V lead acid battery is not the proper technology for this application. Lithium titanate, (Altairnano, Toshiba Scib), would probably be perfect, though somewhat costly. Maybe the new A123 EXT nano phosphate as well. High cycle life, low self discharge, no need for temperature management, and lighter than lead acid.

 

[tezco]

I think the LEAF has a larger 12V battery than the S, and the S has larger idle loads since the LEAF has no active battery management, so the LEAF design makes sense for the LEAF, but not the S.

Or perhaps the S wasn't designed to have as large an idle load as it does. It could be that the design was to have most of the electronics sleep like the Leaf's, but so far Tesla hasn't gotten that process to work well. I think the Leaf has some sort of active management since there is a current measuring clamp on one of the cables. Maybe it is used to adjust the output of the DC/DC converter such that the 12V isn't discharging when the car is powered up (or maybe it measures recharge current when idle so that it can warn of a failing 12V)?

 

[JRP3]

By active management I'm talking about temperature management. The LEAF has none. As for the S I do hope they lower the idle loads, but when temperatures get extreme the load will be higher.

 

[tezco]

By active management I'm talking about temperature management. The LEAF has none. As for the S I do hope they lower the idle loads, but when temperatures get extreme the load will be higher.

Actually the Leaf has a 300 W battery heater that turns on at -14 F, just to keep the cells from freezing, but that apparently can drain the battery in as little as a week. Unfortunately, there is no active cooling (apparently prototype packs had an eqalizing fan, but this was left out of the production packs). Recently this is appearing to be problematic in the desert Southwest. Do we have any authenticated data from Tesla or other sources regarding at what setpoints thermal management of the Tesla battery turns on when the car is idle?

Updated: (See post #270)

 

[TonyWilliams]

Actually the Leaf has a 300 W battery heater that turns on at -14 F, just to keep the cells from freezing, but that apparently can drain the battery in as little as a week. Unfortunately, there is no active cooling (apparently prototype packs had an eqalizing fan, but this was left out of the production packs). Recently this is appearing to be problematic in the desert Southwest. Do we have any authenticated data from Tesla or other sources regarding at what setpoints thermal management of the Tesla battery turns on when the car is idle?

Virtually all USA delivered LEAFs for 2011 model year do NOT have this. Also, the activation temperature of the battery heater for LEAFs so equipped is -4F, and continues heating until 14F (-20C to -10C).

 

[JRP3]

I forgot about the updated LEAF heating in cold weather. Do we know if that goes through the DC/DC and uses 12V or is it pack voltage?

 

[Hans (Amsterdam)]

Owners Manual page 25:

Even when you’re not driving Model S, the 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 travelling).
In these situations, keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level.
For example, over a twoweek period (14 days), the Battery discharges by approximately 14%.


February 24, 2012

Plug It In

By Tesla Motors
Full article: http://www.teslamotors.com/blog/plug-it

Model S and Model X will have batteries that can sit unplugged for over a year when parked with only a 50 percent charge. And when that year is up, all you need to do is plug it in.

Now I am getting a bit confused. Why plug it in all the time when discharge is on average only 1% per day (SOC > 50%) or 4% per month (SOC < 50% ) ????

 

[donauker]

Model S and Model X will have batteries that can sit unplugged for over a year when parked with only a 50 percent charge. And when that year is up, all you need to do is plug it in.

Now I am getting a bit confused. Why plug it in all the time when discharge is on average only 1% per day (SOC > 50%) or 4% per month (SOC < 50% ) ????

Because those numbers are really only wishful thinking!

My actual numbers show that while parked at the airport for 12 days in moderate temperatures I will loose 145 miles of charge and when parked there for only 5 days in colder conditions I will loose 95 miles.

 

[Hans (Amsterdam)]

Because those numbers are really only wishful thinking!

My actual numbers show that while parked at the airport for 12 days in moderate temperatures I will loose 145 miles of charge and when parked there for only 5 days in colder conditions I will loose 95 miles.

So basically the product is not according the specifications that were promised to you. Did you send in a complaint about this to Tesla Motors ?
Did Tesla Motors inform you in any way about this problem and the way they are going to deal with it ?

 

[tezco]

Actually the Leaf has a 300 W battery heater...

Virtually all USA delivered LEAFs for 2011 model year do NOT have this.

Fortunately those weren't originally sold in the colder climates. You were correct about the setpoints -- grabbed my info (including the 300 watt figure) out of a blog, at least some of which was incorrect. Here is the text from my Leaf Owner's Manual: The Li-ion battery heater helps to prevent the Liion battery from freezing and helps to prevent significant reductions in the Li-ion battery output when the temperature is cold. The Li-ion battery heater automatically turns on when the Li-ion battery temperature is approximately -4°F (-20°C) or colder. The Li-ion battery heater automatically turns off when the Li-ion battery temperture is approximately 14°F (-10°C) or higher. The Li-ion battery heater uses electrical power from an external source when a charger is connected to the vehicle. The Li-ion battery heater uses electrical power from the Li-ion battery when the charger is not connected to the vehicle.

 

[Cyberwelly]

Just another datapoint: my car is parked at the airport. The temperature is ranging from 50 at night to approx 73 during the day. It is in a covered parking structure. In the last 24 hours since I left it there it has gone from 197 to 184 rated miles. So approx 13 miles lost. I'll be picking it up in 3 days. I really want sleep mode back!

 

[strider]

So basically the product is not according the specifications that were promised to you. Did you send in a complaint about this to Tesla Motors ?
Did Tesla Motors inform you in any way about this problem and the way they are going to deal with it ?

It is because they disabled sleep mode in v4.2 of software. They had trouble with some systems not waking up properly so they turned it off. The intention is to re-enable this feature once they get the bugs worked out and deliver the advertised . They did inform owners that 4.2 had disabled sleep mode but no ETA has been given on when it will be restored.

 

[Hans (Amsterdam)]

It is because they disabled sleep mode in v4.2 of software. They had trouble with some systems not waking up properly so they turned it off. The intention is to re-enable this feature once they get the bugs worked out and deliver the advertised . They did inform owners that 4.2 had disabled sleep mode but no ETA has been given on when it will be restored.

I hope they do manage to get sleep mode working since here in the city of Amsterdam we only have public chargers available. I simply cannot plug in all the time and obstruct the charger for other EV's.
Besides the nearest chargers are 300 meters from my home, so I do not want to go there everyday.

 

[toto_48313]

I figure out that at 10 F, the car loose about 3 miles of rated range / hours, and the first 5 miles are very hard on the baterry as it's not warm enough.

 

[contaygious]

I parked my car in a garage in la and lost over 20 miles in 2 nights. Pretty crazy drain considering how slow the charging stations are.

 

[WarpedOne]

310Wh/mile * 20 miles = 6.2kWh
6.2kWh/48h = ~130W idle power

Yeah, it is much. Situation will improve when they re-enable Deep Sleep in future FW.

 

[donauker]

It is because they disabled sleep mode in v4.2 of software. They had trouble with some systems not waking up properly so they turned it off. The intention is to re-enable this feature once they get the bugs worked out and deliver the advertised . They did inform owners that 4.2 had disabled sleep mode but no ETA has been given on when it will be restored.

Actually the case I cited where the loss was 95 miles in 5 days was with v4.1 firmware with sleep mode active

 

[Trnsl8r]

I'd like to make the point that even though I don't need anywhere near the 232 rated miles that are left after a night of vampire load, that lost energy will at some point have to get recharged. Off my electricity. That I pay for. I don't mind paying for electricity that I use to drive to places, but replenish 10 miles that vanish into thin air every night is getting annoying.

That said, yes I know they are working on bringing sleep mode back. I also believe that the first miles vanish quicker off the battery than the later on, once the battery hits 50% or so. Little comfort, I know...

 

[Cyberwelly]

Left my car at the airport for 3.5 days (87 hours to be precise) and the rated miles went from 197 to 153: a loss of 44 miles in a covered parking structure in temp 73 during the day and 50 at night. Need sleep mode back.

 

[brianman]

Left my car at the airport for 3.5 days (87 hours to be precise) and the rated miles went from 197 to 153: a loss of 44 miles in a covered parking structure in temp 73 during the day and 50 at night. Need sleep mode back.

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

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