Large Drop in Charge When Parked in the Cold

[montgom626]

What will cause my EV range to vary?

If you want a primer on range for an EV, look at Chevy Volt Electric Car | FAQ | Chevrolet Chevrolet has a number of very good videos explaining temperature, terrain and technique, also known as the three Ts. Take a look halfway down the page, on the left side, for their FAQ on Range. The electric range of Model S may be higher or lower than expected due to the driver's technique, the terrain, and/or the outdoor temperature. In other words, driving and braking aggressively, driving in areas with large elevation changes, or driving in extreme outdoor temperatures will impact the electric range capability. Electric range may vary based on these factors.

 

[cinergi]

Observed last night the car started charging at 229-230 rated miles. This happened around midnight or 1am last night .. which is about 26 hours since the previous topoff. So about 10 miles in 26 hours (again, with the setting to turn the displays off turned off - so always on / no sleep). It's currently sitting at 235 (down from 241 or 242).
Ambient is approximately 55F (sits in a garage).

 

[brianman]

BTW, I've never seen a rated range under 230 miles or over 241 miles (standard charge mode) when plugged in continuously.

Same. This lead me to conclude that it tops off more than once a day.

 

[surfingslovak]

Same. This lead me to conclude that it tops off more than once a day.

Interesting, thank you for posting that. Has anyone been able to measure how much energy is drawn from the wall to keep the vehicle at a state of full charge during a 24-hour period? It would be good to note the ambient temp also.

 

[PRJIM]

Observed last night the car started charging at 229-230 rated miles. This happened around midnight or 1am last night .. which is about 26 hours since the previous topoff. So about 10 miles in 26 hours (again, with the setting to turn the displays off turned off - so always on / no sleep). It's currently sitting at 235 (down from 241 or 242).
Ambient is approximately 55F (sits in a garage).

It takes at least 4 consecutive days of not touching the car for the ideal miles to drop to <195 miles while plugged in. If you unlock/open the doors or re-insert the charge cable, it will immediately start charging.

 

[Larry Chanin]

It takes at least 4 consecutive days of not touching the car for the ideal miles to drop to <195 miles while plugged in. If you unlock/open the doors or re-insert the charge cable, it will immediately start charging.

Did this information come from direct observation, or do you have an authoritative source?

Thanks.

Larry

 

[tezco]

Stevezzzz reported the following in the "Time from Standard to Range" thread. (He has a whole house energy monitoring system as part of his solar array package). I believe he was on software v4.1 at the time of his post:

In early software revs the S never re-initiated charging if you left it plugged in. By 'never' I mean that I never saw it, though to be fair, I never let it sit more than a week or so without driving. More recently, the car wakes up every 24 hours or so to top off the charge. It's not very consistent, though (I've seen anything from 22 to 24 hours) so I wonder if it's on an SOC trigger rather than a timer. But that's not likely since the timing of reinitiation hasn't changed since Sleep mode was enabled.

Thanks, that is the most definitive info yet. Can you tell from your logs how many kwh it uses to top off and from that back into what the SOC was at the time it re-initiated charging?

Looks like it spent about ten minutes at 10kW during the top-off yesterday, so roughly 1.6 kWhr, or about 4 miles of rated range, taking into account the inefficiencies of charging. That's one data point, though, so I'd use it only as a rough guide.

It's been quote cold lately; the garage is probably hovering in the upper 30s. I don't know how much of that top-off charge is due to battery heating, if any.

 

[PRJIM]

Did this information come from direct observation, or do you have an authoritative source?

Thanks.

Larry

This is from my own observation. I usually travel during the week and I am back home on the weekends, so this ends up being 4-5 days away from the car. I also recall reading something about the car waiting 60 hours before going into a storage type of mode but I am not sure where I saw that.

 

[M_Mike]

It takes at least 4 consecutive days of not touching the car for the ideal miles to drop to <195 miles while plugged in. If you unlock/open the doors or re-insert the charge cable, it will immediately start charging.

That is what I was talking about - it appears a plugged in car will eventually get to an optimal storage SOC if left alone for a long enough period of time. The car doesn't know when you are going to need it again and holding the battery at a 85-90% SOC will reduce battery life. The question is what is the optimal storage SOC and how long will it take a plugged in car to get to that level - if ever? We haven't had production vehicles sitting around long enough to figure it out and I don't think it is in the manual - I am sure someone in engineering at Tesla could answer the questions.

 

[ModelS1079]

Observed last night the car started charging at 229-230 rated miles. This happened around midnight or 1am last night .. which is about 26 hours since the previous topoff. So about 10 miles in 26 hours (again, with the setting to turn the displays off turned off - so always on / no sleep). It's currently sitting at 235 (down from 241 or 242).
Ambient is approximately 55F (sits in a garage).

Simple question: If I drive more efficiently, will the Model S estimate more range for the same charge? I noticed 230 miles for my first charge range (none max), but now typically 239...

 

[brianman]

Simple question: If I drive more efficiently, will the Model S estimate more range for the same charge?

Projected: Yes.
Rated, Ideal: No.

 

[teddyg]

I don't know if it's because we are here all the time but the Tesla website does do a pretty good job of letting people know about its estimated performance in cold/hot weather on this page:
http://www.teslamotors.com/goelectric#range

Too bad it doesn't let you go below 32 degrees or above 90 degrees though...however at least Tesla is letting people know that temperature will affect their range even if it appears that some people who have already received their car's didn't seem to know about it. Tesla should really clarify this with new owners when delivering the car at least.

They should also put a chart specifically showing what sort of vampire load can be expected to warm/cool the batteries when the car is not plugged in at specific temperature ranges (ie. an average loss of 10 miles per hour at 50 degrees or an average of 25 miles per hour loss in 32 degrees)...this would let people know that they can't just leave the car unplugged out in the cold for a week while they are on holiday, as they may come back to a bricked Tesla! I know Tesla has the "plug it in" mantra but this really isn't good enough...people will assume if they have a 250 mile charge in the car that they could leave for a holiday and leave the car unplugged...hopefully this is also something the delivery specialists really focus on...especially in very cold/hot climates!

They really need a chart showing people how much power the car uses up on average, when parked and not plugged in, in certain temperatures. Especially if people are starting to order in Canada and Norway.

On the flip side how are Tesla owners fairing in hot places like Phoenix? If you leave the car outside in the heat, unplugged, in the heart of summer, how much of a battery drain is occuring to keep the batteries cool?

 

[JRP3]

You won't come back to a "bricked" Tesla. You might come back to a car that has shut itself down and might need to be started back up by Tesla.

 

[stevezzzz]

Stevezzzz reported the following in the "Time from Standard to Range" thread. (He has a whole house energy monitoring system as part of his solar array package). I believe he was on software v4.1 at the time of his post:

That's correct: the top-off charge time of 10 minutes at 10kWh was with 4.1 software. I just went back and checked the logs for the period before 4.0 came out, but after the update that first enabled periodic top-off charging: back then (mid-November) a top-off charge lasted about 20 minutes. So my real-world data suggest that Sleep mode has cut vampire loads roughly in half. The variable I can't control is ambient temperature in my garage, which is insulated but not heated. Since it's colder now than it was in November, it's probable that Sleep mode actually cuts vampire loads at moderate ambient temps by a factor of three or four, as Tesla has claimed, but I can't prove it without reverting to a pre-4.0 software version.

@PRJIM: My experience is that even when the car isn't touched for a period of days, when plugged into a 14-50 outlet the Rated range never falls below about 239 miles because of the daily top-off charges. Are you running an older software version, or maybe plugged into 120V instead of 240V? There was at least one rev before 4.0 that implemented daily top-off charging.

 

[MikeK]

this would let people know that they can't just leave the car unplugged out in the cold for a week while they are on holiday

In fact the manual describes leaving the car parked for a week at the airport, and makes no mention of ambient temperatures when it describes how much charge the driver should expect to lose. Right now the car is losing more than that amount, it seems, especially if it's cold. So, the manual is either wrong, or there's an issue with the car using more energy than it's supposed to.

 

[PRJIM]

@PRJIM: My experience is that even when the car isn't touched for a period of days, when plugged into a 14-50 outlet the Rated range never falls below about 239 miles because of the daily top-off charges. Are you running an older software version, or maybe plugged into 120V instead of 240V? There was at least one rev before 4.0 that implemented daily top-off charging.

I am using the UMC plugged into a 14-50 outlet running v 4.0. How many days?

 

[Shorty]

Teddyg

The Tesla website shows that the range drops from 300 miles to 287 miles at 32 degrees. I think that the point people are making here is that the range shows as dropping far more than that when parked for a short duration in cold weather.

 

[stevezzzz]

I am using the UMC plugged into a 14-50 outlet running v 4.0. How many days?

I've got the same setup for home charging. The longest I've left the car untouched is about six days, I think. Since it started topping off the charge every day, the rated range while plugged in has never dipped below 230-231.

 

[jerry33]

The Tesla website shows that the range drops from 300 miles to 287 miles at 32 degrees. I think that the point people are making here is that the range shows as dropping far more than that when parked for a short duration in cold weather.

What's not clear is whether it's a real drop or just an SOC measuring artifact caused by low temperature.

 

[Al Sherman]

What's not clear is whether it's a real drop or just an SOC measuring artifact caused by low temperature.

Exactly. That seems to be the question.