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Battery losing 1 mile per hour when parked

I searched the forum and cannot find a discussion that matches this one so here goes:

I have had my Model S for just over two weeks now and it consistently loses 1 mile of range per hour when it is not plugged in. Considering that at full charge it is rated for 188 miles that is a 12.8% loss per day. At this rate of loss my car would be at zero miles in less than eight days. The owners manual says that the loss of range should be around 1% per day. When I called the Tesla service representative I was told that 1 mile per hour loss was normal and not to worry.

I am curious what losses other people are seeing. If there is already a discussion with this information I would appreciate being pointed to it.

there is a thread that I started about losing charge while parked at Philly Airport.

It's got the explanations Tesla customer service has given.

Which thread is that, exactly?

I guess that when it loses 1 mile of range per hour when it is not plugged, it loses 1 mile per hour as well when it IS plugged in (on-board systems need energy all the time). So in one year your will loose 365 x 24 = 8.760 miles. This seems like a lot, not to worry ?

I have been driving a Nissan Leaf for almost 2 years now, and it didn't loose miles when not plugged in, simply because it was switched off.

Also I have a couple of Lithium Batteries (total 8 kWh) at SOC of 40% doing nothing now for almost 4 months. Energy loss after 4 months was near to zero, simply because they were switched off.

Airport thread:

http://www.teslamotors.com/forum/forums/car-sitting-philly-airport-bricking

Pay NO attention to the title - it's pure hyperbole, IMHO...

I read through the Philly Airport thread from start to finish. It sounds as if the loss slows down after a while, something like a logarithmic curve. This does not address my main question, however, which is what is "normal"? If the Tesla manual says 1% per day and I am getting almost 13 times that loss, how is this considered normal? What are other Tesla owners seeing with their cars?

yea, I am also very concerned about losing charge during the day especially when Model S Facts page (http://www.teslamotors.com/en_EU/models/facts) says exactly:
"The Model S battery will not lose a significant amount of charge when parked for long periods of time. For example, Model S owners can park at the airport for extended vacations without plugging in."
And if I remember correct owners manual says something about 1% lose per day, not 1 mile per hour.
Tesla should do some official statement about that...

The loss does appear to be logarithmic. Sort of. But I can't be sure. They are telling me 4-5% a day in charge. But the mileage loss is different.

The experience very much makes me think that cold weather has surprised the California design team.

Roadside Experience was shocked to learn that Philadelphia Intl. didn't have charging stations.

Welcome to the Northeast.

When I parked the car it said I had 140 miles to go. That was Thursday. 4 days later it tells me I have 74. I've got a 45 mile drive back home.

Hopefully this is something that will be addressed when sleep mode is re-enabled. On the bright side, the monthly electricity savings will probably pay for the 3G data plan.

I think looking at the projected range is conflating the actual state of charge in the battery with the projections of how many miles can be obtained from that charge. Tesla has already acknowledged that the calculations on range take into account how much energy can be extracted from the battery at its current temperature, and do not take into account the fact that the battery will warm up from being used.

A more useful value would be the battery_level field in the charge_state API used by the mobile app (unfortunately you can't get that easily without writing code yourself at the moment), which should be just the battery's state of charge.

You can switch from miles to kwh, that should be more accurate.

Though frustrating, I wouldn't be too worried. When they issued Software Version 4.0, loss dropped to 3-4 miles per day when not plugged in by using what TM calls 'sleep mode'. There were concerns that under certain scenarios the car might not come out of sleep mode 'gracefully' and so it was pulled in the 4.2 release. Based on conversations with TM it is definitely coming back; the only question is whether it will be days, weeks or months before it reappears.

Usually on the drive home from work averaging about 400kWh/mi the battery recovers about 15 miles of ideal range from a cold start, sub freezing temperatures. I use 5 miles of range for a 20 mile trip. Of course I wouldn't set out on a 100mi trek with a cold battery showing 85mi left. We will still have to deal with this uncertainty in cold weather specially after deep sleep is re-enabled. It is just a fact of life with cold Li-ion chemistry.

Get the ideal range and divide by 3. That's your SOC. Honest.

Oh, not quite. I forgot the ideal changed to max 265. So, ideal range divided by 3, plus about 1/8. Pretty close. E.g.: If ideal shows 210 miles, you're at 70+9= 79% charge. If ideal shows 90 miles, you're at 30+4=34%. To the nearest 1%.

Seems to me that if you need to leave your S unplugged for an extended period, you could power the car off. That is what I was told the transport people are supposed to do after loading up the cars for transport across the country.

@BrianH - ideal didn't change to 265, that is rated range. However, it isn't as simple as dividing since the software takes into account the battery temperature to calculate the range. So, you only get the battery capacity if the temperature was unchanged, not the capacity after it warmed up to normal operating temperature.

In that case, it's even simpler. SOC = Ideal/3. No calculation is done on ideal range to speak of, AFAIK. 300 miles = 100%. 210 miles = 70%. 60 miles = 20%. etc.

Above for the 85kWh, of course.

I charged last night on Standard mode to 190mi and charging self quit.
That charge ended about 9:45pm.

When I came out to the car in the morning, that same 190mi indication had dropped to 183mi. So I lost 7 miles overnight.

This seems like a lot to me. Any thoughts? It's realy just uder .5% but on line for about 1% for the day.

I don't know how you get 0.5%. If by over night you mean about 8 hours then that is about 7/8th of a mile per hour. In 24 hours that would be 21 miles, or 11% per day.

7/190 = 3.7%, and over how many hours?
I lose 8 ish miles over 10-12 hours starting at 240 rated miles.

Had ours parked for 14 days, unplugged.......started 195 mi and ended up with 66 mi left. In CA so were lucky to have good weather in the day time and lows around 30's at night.

@Scwins
I left my car plugged in for the weekend and it went from 190 to 182(or so) and then back up and then back down. I think the best bet is to follow the instructions and leave it plugged in (if possible).Hopefully a software update with either the sleep mode or charging scheduler or both would be nice. In the meantime, if your daily range allows it, just drive the hell out of it and enjoy the ride.

See this post for my results parked at Miami airport (70's during day, 50's over night). Net-net: settled down to c. 0.4 miles/hour after first 12 hours.

I'll preface this by saying I love the car. But the operating costs are much higher than implied / advertised. For example: Last weekend (President's Day) I went away for four days, left the car unplugged in my driveway with about 90 miles of range per the dashboard (rated range). When I came back (96 hours later) the car indicated 10 miles of range left, so that's 80 miles of range depleted in 96 hours, or just under 1 mile of range for every hour unplugged. That was in Berkeley with highs probably in the 50s / 60s, and lows last weekend in the low 40s. That's much higher than what was expected (the 1% per day, or about 3 miles per day of rated range - really it's 6x higher!).

I think Tesla needs to do a much better job explaining the details. It's an awesome care, but...

If it truly depletes at 20 miles per day, at my actual energy usage of 350 Wh/mile that's a consumption of 7kWh / day to go nowhere. At my *real* weighted average cost of electricity (PG&E E-6 rate, time of day metering) which is between $0.24 and $0.32 per kWh, it will cost me between $1.68 and $2.24 per day. Doesn't sound like much, but x 365 = $817 per year just to park in the driveway.

This will get fixed as soon as TM puts sleep mode back into the car. Hopefully in 4.3 Should be down to 2-3 miles per day.

Call service. I leave my car unplugged every night. The loss of miles is completely negligible. I don't even notice. Plug in once maybe twice a week.

@dschulner - which s/w version do you have? I assume not 4.2?

Bump. Does anyone have any new information?

My experience has been that in moderate weather, the average parasitic losses when not driving are about 13-15 rated miles/day. That comes out to about 180 watts. Powering down does not seem to help much. I suspect software updates will reduce that amount over time (and that a recent update might have made things worse). Also: when the battery gets down to a lower level, the car is supposed to go into "deep sleep mode" - see http://www.teslamotors.com/blog/plug-it

I have done calculations on monthly and by-the-mile fuel costs at http://EVTripPlanner.com/calcs.php - here is a snapshot (you can make your own adjustments if you download the spreadsheet):


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