Dec 27, 2012
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.�
Dec 27, 2012
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).�
Dec 27, 2012
brianman Same. This lead me to conclude that it tops off more than once a day.�
Dec 27, 2012
surfingslovak 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.�
Dec 27, 2012
PRJIM 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.�
Dec 27, 2012
Larry Chanin Did this information come from direct observation, or do you have an authoritative source?
Thanks.
Larry�
Dec 27, 2012
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:
�
Dec 27, 2012
PRJIM 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.�
Dec 27, 2012
M_Mike 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.�
Dec 27, 2012
ModelS1079 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...�
Dec 27, 2012
brianman Projected: Yes.
Rated, Ideal: No.�
Dec 28, 2012
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?�
Dec 28, 2012
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.�
Dec 28, 2012
stevezzzz 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.�
Dec 28, 2012
MikeK 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.�
Dec 28, 2012
PRJIM I am using the UMC plugged into a 14-50 outlet running v 4.0. How many days?�
Dec 28, 2012
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.�
Dec 28, 2012
stevezzzz 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.�
Dec 28, 2012
jerry33 What's not clear is whether it's a real drop or just an SOC measuring artifact caused by low temperature.�
Dec 28, 2012
Al Sherman Exactly. That seems to be the question.�
Dec 29, 2012
jkirkebo A range drop in the cold is not a problem, that is to be expected. Winter tires, snow/ice, cold air with higher density, heating requirements etc.
But if the battery SOC continually drops in cold weather when parked and not plugged in because the car tries to keep the battery temperature up continously, that is a problem. We do however not yet if this is happening.
If I can park my car with 60% SOC for 5 days in 0F weather, then fire up the generator for an hour before leaving to heat up the cabin and battery, and then have say 55% SOC remaining, that is fine. If I instead have 10% SOC remaining that is no good since I then have to charge for 8 hours on generator and my wife will be pissed at me:crying:
We will find out as soon as the app is released and someone parks their car in the cold for a few days without plugging in. Heating the battery & cabin from the grid should restore any SOC points missing from a cold battery.�
Dec 29, 2012
tezco Same problem with the Leaf. When it's below 20 F the heater draws up to 4500 W which is more than the engine is pulling on level ground. Typically I live with a little less comfort and get a third less range. The "calculated" projected range is more like what you expect at 45 F, and the figure isn't reduced as the heater draw increases at low temp. I don't think the LiIon battery output really falls off that badly in the cold, but whatever it is just adds a little more insult to what the heater use causes. I suspect Nissan didn't tie the actual heater draw into the calculation of projected range since otherwise "range" would plummet when the heater first came on (since it runs full blast for a while). I don't know how the S calculates the projected remaining range, but it is less variable than the Leaf's , which bounces all over the place (the Leaf's seems to mostly be based on your last couple minutes of engine current draw).�
Dec 29, 2012
JRP3 This is about the loss of charge while the car is parked, not reduced range from driving conditions. There is a difference as jkirkebo describes.�
Dec 29, 2012
MikeK Howdy!
I'm back from a weeklong trip, during which my Model S sat unplugged. It was parked in the San Mateo area, in a parking garage that is at roughly the ambient outdoor temperature. I believe the high temps during the past week were in the 50's and the lows were in the mid-40's, but somebody who was actually here can probably give better figures.
In any event, I parked the car last Saturday morning with between 220 and 230 miles of range showing. I'm sorry I neglected to write down an actual figure, but it had been on a standard charge overnight and then I drove 4.4 miles on city streets to my friends' place to leave the car in their protected garage.
Upon my return this evening (Saturday, so 7.5 days later), the car was showing 191 miles of range available. The handles extended when I walked up, and everything worked normally. The regen was limited to a bit over 15kWh and that limit climbed to about 30kWh by the time I got home. It's the same 4.4 miles, but with a hill climb at the end, and I had the heat on. The car was showing 180 miles of range available when I shut it down.
So, I don't think it was as cold during my trip as it was the one night that I saw the large range drop in near-freezing temperatures. But, I wanted to share this experience of a prolonged stay unplugged in chilly weather. The loss of indicated range is more than is called for in the manual (which says that the car should lose 1% per day, which would have been about 20 miles lost). I may have lost as much as twice that, but it was not drastic and I will look forward to hearing others' reports of how the car behaves in differing conditions.�
Dec 30, 2012
nolngrgrsngslde I don't guess the S comes with a cover. If you did cover it though when parked outside, that should reduce battery drop by keeping the heat in the battery longer.
Should I order one, guys?
http://shop.teslamotors.com/collections/model-s-functional/products/model-s-outdoor-car-cover
The Tesla S cover looks good but it should have a skirt all the way to the ground to keep cold air away from bottom of the car. Also, the front wheel is open, that let's air through as well.�
Dec 30, 2012
jerry33 I doubt the cover will do much for keeping the battery warm--even if it went all the way to the ground. I'll likely get one as mine will be parked outside. Whether I will use it after the first couple of weeks is the big question
�
Dec 30, 2012
JRP3 That cover won't help one bit. You'd need something heavier with at least an inch of insulation and completely covering all openings, as well as touching the ground, and even then it would have a limited effect.�
Dec 30, 2012
stevezzzz I don't favor a car cover for the purpose you propose, for two reasons:
1. It doesn't do much to slow battery cooling since the entire bottom of the battery pack is still exposed to ambient air.
2. After you drive to the airport parking garage you'll be putting a cover on a dirty car, which won't do the finish any good.
A better plan IMHO would be to spend the same money on upgrades to covered airport parking with an EV plug-in.
Or did I misunderstand your question: are you not able to garage your S at home?�
Dec 30, 2012
nolngrgrsngslde On the cover question:
I thought the same as you guys. I just wanted to hear some opinions.
On a normal basis, I will garage the S. Actually, it will be very happy with my well insulated garage.�
Dec 30, 2012
bluetinc Hey all,
I have to say I've only made it through about 8 pages of this and I'm about to pack up and head back into the car for the next leg or my trip but I wanted to through my two cents in.
I'm running 4.0, and had a few occasions to leave the car overnight now when it is cold out (sub 35 degrees F). When coming back to the car the mileage is significantly reduced, say 48 miles down to 26 miles. After driving then for a few minutes, I've watched the mileage then climb back up the about where I expected it as the pack warms up. It seemed to me to simply be voltage sag due to temperature being displayed.
Peter�
Dec 30, 2012
MikeK Interesting datapoint, Peter!
Perhaps the mods might want to split the Volt discussion elsewhere?�
Dec 30, 2012
FlasherZ I think I may have seen the same thing too... there have been times when I leave the garage with 240 miles displayed and it just simply "hangs" there for a few miles as things warm up. There have been times when I have pre-heated the car, gotten in, and it shows more (say, 245 mi or 250 mi) than a "normal" charge should show.�
Dec 30, 2012
tezco Actually, what I really care about is loss of available energy in the cold, to which is added the insult of increased heating loads. This directly relates to true available range. The SOC may be unchanged from yesterday, but when I hop into the car when it is now 60 degrees cooler, is my "fuel" gauge still accurate?
The problem is that we are looking at a very imperfect energy gauge in the S when we look at the "range" meter. I don't know if the S energy gauge factors in battery temperature, battery age/permanent loss of capacity and whether it even keeps track of 100% of the current draw from all devices. Is some of the "lost" range recoverable when the battery heats back to normal operating temperature? How much of the "lost" range is due to a true loss of electrons from vampire loads, how much from a calculated subtraction to account for less extractable energy from a cold battery, and how much is the computer subtracting from the range for the increased heating and battery warming loads that now have become active when I ulock the door?
I think it is folly to look at a change in the range meter in any EV and assume that the difference means that xxxx coulombs have been irrevocably used.
From Battery University: "Users of electric vehicles need to understand that the driving distance specified per charge is given under normal temperature; frigid cold will sharply reduce the available mileage. Using electricity for cabin heating is not the only cause for the shorter driving distance between charging; the battery performance is reduced when cold." [Would sure like to see a graph of the S LiIon battery capacity vs temp.]
See also: How to Improve the Battery Fuel Gauge - Battery University�
Dec 30, 2012
jerry33 What that misses is the difference between batteries that are thermally managed and ones that are not. Having a thermally managed battery reduces the effects of both hot and cold weather. Also, determining the SOC of the battery is more an art form than it is a science because there are a number of variables. So even if you had a graph, it wouldn't necessarily reflect what happens in a Model S.�
Dec 30, 2012
JRP3 There are a few separate issues. If the car uses some energy while parked to manage the pack, that energy is gone. Additionally a cold pack will have a lower voltage reading, which the range gauge may interpret as reduced range even though the pack may not have lost any energy. However the lower voltage and likely higher voltage sag under load means the pack will have to use more current to produce the same power, so less actual available energy. As you drive the pack warms up some which reduces voltage sag. Then on top of that you have heating loads, plus cold air is more dense, also affecting range. Current sensors may also be affected by temperature. There is a lot going on and it's going to take a lot to get it right every time.�
Dec 30, 2012
tezco I agree. There are so many variables to take into consideration when you try to design a truly accurate "fuel" meter. It's even more difficult looking backwards from a change read at the "fuel" meter, and trying to figure out what has changed for a single variable.�
Dec 30, 2012
Todd Burch As others have said, and some of the stories here seem to imply, I do think a lot of the lost range is just virtual, and when the pack warms back up some of that indicated mileage comes back. After all, the pack doesn't need to be maintained to a very warm temperature--just enough to put it over its minimum limit.
Speaking of which, why is there a minimum limit? I can understand if conditions are really cold, but if temps are 32 deg F for example, what is the harm in just letting the battery get cold? Sure, you have very limited power when you first start up again, but the battery wouldn't really be harmed, right?
We need a technical blog post from JB to cover a lot of these issues and put customer minds at ease. What happened to the blog posts? Seems like there were tons for the Roadster and very few for the Model S.
Tesla hasn't released nearly enough technical info for the Model S--especially given that most of its customers are technical.�
Dec 30, 2012
JRP3 At freezing or below, depending on the battery chemistry, damage can occur during discharge and charge, (metallic lithium plating on the electrodes which can't be reversed). I'm sure Tesla wants some safety margin so they probably keep the pack above that.�
Dec 30, 2012
Todd Burch Ok...so some heating would be needed to keep the battery a bit above freezing...but overall that draw should be relatively small.�
Dec 30, 2012
napabill Being a Northern California/Arizona person, cold temps are typically not my concern. But in the transit from Napa to Tucson, I spent the night in Tehapachi at 4,000 ft. Was 36 when I arrived and 22 when I came out of the hotel the next morning. My rated range went from 185 miles to 145 miles. Tried to find a 110v outlet to keep things warm, but no luck. Fortunately, I only had 90 miles to a Supercharger. Arrived with 54 rated showing...no problem.�
Dec 30, 2012
mdh That is a big drop. Did you have "sleep" mode enabled?�
Dec 30, 2012
dtich leaving car undriven for 10 days
i have emailed ownership about this, but curious the thoughts here:
what is the best practice, vis a vis the battery, etc, with leaving the car undriven and garaged for 10 days? what about longer? two months?
i expect tm to say leave it plugged in, and i would assume that of course, but is there something else i can do? should it be driven every few days, would that be smarter? it would be tough, but i could arrange for it. i would like to do whatever the smartest thing for the battery would be.
roadster owners with any experience in long term storage? as far as i know there is no 'storage' mode on the model s. besides plugging it in, and potentially driving it semi regularly, any settings to tweak?
thanks for the thoughts.�
Dec 30, 2012
elecblue I'm in the middle of a 4-1/2 day trip and have left my Model S plugged in. I'll let everyone know what range has been lost when I get back.�
Dec 30, 2012
dtich yeah, actually, not too worried about that part of it all really.
my understanding is that the very best care for a Li ion battery pack is to charge it to 80 or 90% then discharge at a steady, not rapid, rate of discharge to not less than 30 - 20%, then recharge and not let it sit for days at a high SoC. after a lot of research and personal experience this is a formula i think is good for getting the most life from the battery. (i welcome other opinions.)
i am trying to do this with the car. the issue here being that while it sits in a garage it cannot really discharge to a useful degree, only bleed charge.. and i do not know at what level the charging system will recharge, but i assume it is somewhat higher than 50%... perhaps they let it get to 200 rated miles (~74% on a 85kWh pack) and then charge back to 240 rated (~90%)..? or maybe they let it drop to closer to 50%, 135 miles.. not sure. (be really nice to have this info.) [and this all assumes the actual full state of charge equals 270 rated miles. which, it might not really. they may call 270 rated miles 'full' but maybe it really represents 90% of the battery's actual physical capacity. this would actually be a smart 'derating' to do and prolong the life of the battery considerably, but would compromise the true full capacity of the pack, which is more about advertising and sales than anything else really..] but not having exact pack voltage and current info this the best i can do. using the 'ideal' scale, this would all slide up with 300 representing full SoC, 270 being 90%, 150 being 50%. but i don't use that scale as it's not close to my style of driving. (fast-ish.)
my basic daily plan is to drive down to not much lower than 100 miles rated (37%), standard recharge to 240 (90%), finishing charging as close to my drive-away time as possible to minimize sitting at high SoC. and i think i would actually not plug in every night if i thought that in the next day i wouldn't get close to using up my charge. so that rather than drive a light day down to 200 miles rated (~75%) then charge to 240 (~90%), i would skip a day and charge from, say, 140 miles (~50%) to 240 (~90%), with slower, steadier overall rate of discharge between.
obviously, this only suits my particular needs and driving habits. if i had 180 miles of driving to do everyday i'd obviously charge everyday, and that would work just fine. that would be 240-180=60, 22% (of 270 rated miles) charging to 90% (240 of 270 rated miles) everyday. reasonable care of the battery.
at any rate.. those are my thoughts. and the original question was about short term storage, and long term storage, and what to sensibly do with a car that won't be driven for a time.
thanks for the thoughts.
note: also, i'm fortunate enough to live in a warm climate and so low temperature concerns and plugging in each night for that reason isn't really an issue for me. it's one of the reasons i felt an electric car would be very appropriate for my situation.�
Dec 31, 2012
Johan This thread title should be changed soon before search engines pick up on it and index it. And why did you create that image. There is absolutely no reports of this happening. Extrapolating they way you are doing is just dumb: What's to say that the SOC will continue to drop in a linear fashion??? Very likely there could be an algorithm that tells the car that when there is plenty of charge it should use energy to keep up battery temp, when charge starts to run low however there are probably a number of lower power consumption modes the car can enter in to including a deep sleep mode that will kick in if SOC reaches dangerously low levels, that may prevent bricking for weeks even months even if SOC is low.
In fact, I vote to have this thread removed completely. It's one thing that anyone with a blog can publish anything, no matter how unsubstantiated, (as the Roadster "bricking" story) but TMC should not be the "source" of this kind of (mis)information.�
Dec 31, 2012
CanuckS#69 Wow, another crusader? Shouldn't you folks be out driving?�
Dec 31, 2012
Wattson I'm also concerned about the alarmist nature of Medved's brick post with title and graphic. I similarly hope moderators can steer this in a better direction.�
Dec 31, 2012
lolachampcar Very poor taste. Mods, please correct.�
Dec 31, 2012
dsm363 Medved:
What is your goal with that post? There is no evidence of that happening. A car being disabled due to a 12V problem is not what you are talking about.�
Dec 31, 2012
dhrivnak Just leave the car plugged in and all should be well. Weather you let it sit for 10 days or 100 days it is the same plug in at every opportunity and you will have nothing to worry about.
What rational are you using to not plug in? Why would you consider this?�
Dec 31, 2012
JRP3 I assume his rational is that cells will last longer when stored at a lower SOC than higher. I am still surprised that Tesla did not provide a long term storage mode where the pack is kept around 50% SOC when plugged in, but maybe they feel the greater degradation from sitting at a higher SOC is minimal.�
Dec 31, 2012
NigelM Mod Note: The post is in moderation for now. Following complaints Moderators will temporarily remove a post and consider if it infringes ToS (e.g. is offensive, rude, harrassing etc.), at the same time Moderators try very hard not to be censors of valid arguments even if they are poorly argued. Due to the fact we have Moderators in all the different time zones any decision on the post will take a little while.
Personal Opinion: Medved has a valid point about temperature protection load in very cold climates although IMO the bricking comparison is one that does not hold up. I wouldn't leave my $100k car (EV or ICE!) sitting unplugged/unprotected in -10C weather for any length of time more than a few days. Anyone who does is literally asking for problems.�
Dec 31, 2012
mnx Did the ideal miles jump up at all after driving the car for a while?
Do you know if there are any 120V plugs anywhere at the Buffalo-Niagara Airport? I'm flying out of there for a week in March. I'm wondering if I can take the S (assuming it's been delivered) or if I'll have to take our van.�
Dec 31, 2012
FlasherZ Don't forget to try the off-site parking facilities - if there are any. In St. Louis, I found that several of the garages said they had 120V outlets available and would be happy to show me where they are.�
Dec 31, 2012
capt601 Left my car last night with 62 miles range showing on battery last night at 7:30 PM, just checked the car this morning at 8:45 AM, and it was showing 46 miles. Left it uncharged as we are driving somewhere local today where i will be able to charge it while we shop. It was a little cold in Socal last night but garage temp was only down to mid 50's. screens are set to power off. 16 miles in 12 hours is unacceptable.
We are not leaving until a couple of hours from now, so i will check to see if it comes back up a few miles.�
Dec 31, 2012
Al Sherman All well and good. However, Tesla is telling people that they CAN leave the car at the airport unplugged for a couple of weeks.�
Dec 31, 2012
RDoc IMHO this is exactly the issue. Whatever the characteristics of the car are, people probably can deal with it one way or another, but Tesla really needs to be up front about how the car behaves.�
Dec 31, 2012
NigelM Note that I said I wouldn't leave my car at -10C (14F) unplugged/unprotected. A good EV is going use power to try and keep it's essential elements warm enough to avoid damage so I'd expect some range degradation (the question would be what is acceptable and what do I need to factor in to my parking period); but even with an ICE I'd be concerned about oil viscosity after a car was standing for 10 days at those temperatures.
- - - Updated - - -
Thanks. The Volt discussion went to the sticky GM Chevy Volt thread.�
Dec 31, 2012
Al Sherman Again, all well and good. I'm not talking about TMC forum moderators, or even me for that matter. I'm considering the people that we need to sell these cars to in order for OUR investments to be secure. If the average consumer who isn't immersed in EV technology asks if he/she can leave it at the airport for 2 weeks and the stock answer from the product specialist is simply a yes, then this is somewhat misleading (apparently) and will not help sales going forward.�
Dec 31, 2012
NigelM ^^^ This where we cycle back to the need for a comprehensive manual (which I agree with BTW). Agree that there will be many new EV owners who don't understand the impact of temperature on vehicles/batteries although over time it should become second nature to "know" this stuff. I'm not an engineer or a mechanic but somewhere along the road I learned that starting ICE's can be difficult in cold weather, in more recent years I learned a great deal about EV's and many thanks to numerous members of this forum for that.�
Dec 31, 2012
montgom626
I have no doubt you can leave a fully charged MS unplugged. I would not do it, but I am sure it can be done.�
Dec 31, 2012
tezco I agree. The owner's manual that came with my Leaf is more complete and details how and when the battery heater comes on, and what to do if the heater causes the battery to run low (battery is allowed to freeze; you have to tow car to a warm garage to thaw out before charging).�
Dec 31, 2012
stopcrazypp I would not make the judgement that it's not possible to do that just based on the performance at the top end of the pack. What happens at lower SOCs may not necessarily be the same (it likely isn't). The BMS may certainly purposefully drain the top end of the pack because it's bad for long term battery life to be kept at high SOCs for extended periods of time. I know the Roadster's BMS did that (the top 50% SOC is purposefully drained MUCH faster than the bottom 50% SOC).
Another thing that needs to be understood is that the battery will not be damaged by cold weather if left alone (at worse, it needs external thawing, see tezco's example with the Leaf). It will only be damaged if you attempt to charge the battery while it is cold (which is why regen is disabled or reduced when the battery is cold and the onboard charger will not charge the battery before warming it up).
I do agree however, that the manual should be more clear on this. Right now it completely ignores what happens when the temperature management is on (giving only a 1% per day figure).�
Dec 31, 2012
dtich who said anything about not plugging it in?
of course plug it in. NO ONE, anywhere on this board i don't think, is debating the correctness of plugging the car in, for all intents and purposes, every night.
the question was, is there any sense/use/helpfulness-to-battery in not only plugging in, but also making sure it gets driven and doesn't just sit there week after week? in some cases it may not be possible, but where it is possible i assume this would be better for the battery, to have some drain every now and again. but, i don't know, no one here seems to know, what exactly the model s does to drain/recharge the battery over longer periods of idle time. so the questions are there, because we don't know how extensive the battery health algorithm is. that's why i posed the question, and asked for thoughts, hopefully from some roadster peeps who may have more experience with what tesla does to a battery when the car is sitting in storage...
thx�
Dec 31, 2012
dsm363 Some people actually have purposed not plugging in every night saying 'I only drive 20 miles a day and want to keep the SOC around 50% so I'll only plug in every few days' or something similar.
The Model S doesn't have a storage mode as well.�
Dec 31, 2012
montgom626 Why would I want to out think the TESLA engineers? And, what if I needed to travel another 100 miles, but I forgot to plug it in??????�
Dec 31, 2012
dsm363 That's exactly my argument. Just plug it in each night and wake up with a full standard charge and not try and outsmart the Tesla engineers.�
Dec 31, 2012
JRP3 I know. There is no benefit to cycling the battery. The way to make a cell last as long as possible is to discharge it to around 40-50%, take all loads off it, and store it in a cool place, probably a bit above freezing.
Now there are probably a number of reasons that Tesla doesn't do this, or something close to it. They have to balance extending calendar life with keeping the vehicle in a usable state, so they say keep it plugged in. It's the best thing they can recommend, but not necessarily the absolute best thing for the pack. Personally with my driving habits I would probably charge only after I used around 150 miles of range, but I don't drive much and I've never had to take an emergency long distance trip and can't imagine ever having to do so. I also have a second vehicle. There are plenty of test protocols that show extended cell cycling life by only using the middle portion of SOC. This keeps the cell voltage lower which preserves the electrolyte solvents. You do need to go above that once in a while to keep the cells balanced, since that only happens near the end of a charge cycle.
I'm not recommending anyone go against what Tesla is recommending, I'm just explaining some of the mechanisms of cell behavior.�
Dec 31, 2012
montgom626 Trust the engineers!�
Dec 31, 2012
Brian H Note also that if only 240 is available, you can emulate low voltage 'warming priority' behaviour by setting the max amperage low, like 6 amps or SLT.�
Jan 1, 2013
Robert.Boston Back to the "plugging in at the airport" point:
The good news is that my airport (Logan, Boston's primary airport) does indeed have J1772 chargers in all of the parking garages.
The bad news is that, once charging is complete, the Model S / ChargePoint handshake is broken. Consequently, the MS won't be able to draw additional power on subsequent days.
Any ideas of how to address this problem? Seems odd that, even though physically plugged in, I could still end up with a low SOC returning from a trip.�
Jan 1, 2013
Doug_G The obvious solution to airports is lots of 110V outlets. Unless you're on a single-day trip you'll get substantial additional range while you're away. There's no handshake required so the car can warm or top up itself as necessary. And they are dirt cheap to install.�
Jan 1, 2013
jomo25 This. The PHX airport has Blink stations. But the way they charge fees, it would only make sense for people to use if they are picking up or dropping off passengers. Cuz if you left your car plugged in to the station on a 3 day trip, you'd be charged $72 ($1/hr) at least. Even if it wasn't drawing any power from the station.�
Jan 1, 2013
ExhilR8 Just another data point here:
Left car at Albuquerque airport for 4 full days, Dec 22 - Dec 26, with temperatures averaging lows of mid-teens at night and high 30s to mid 40s during the days. Car had 217 miles of charge when left, 137 when I returned. Average loss: 20 miles/day.�
Jan 1, 2013
Johan Very interesting! What is your Firmware version? What happened after you had driven for a while or in other words did you get the feeling that the 137 miles shown when you started driving from the airport was correct, or was the SOC in reality higher and this became evident as the battery warmed up?�
Jan 1, 2013
ExhilR8 I don't know how to determine my Firmware version, but "About" says software 1.15.14
The 137 mile estimate seemed right, as it declined at a normal rate as I drove, never increasing, stopping, or slowing.�
Jan 1, 2013
JRP3 I wonder if Tesla could enable an "airport" charging mode, where current levels are very low so the car is always "charging" and never ends the charge? Or maybe a software change that keeps the handshake alive even when current flow stops?�
Jan 1, 2013
ChadS Completely agreed. Plug In America works hard to point out where 110V outlets work (places where you charge for a long time, like the workplace and airports), and has been working on getting the DOE to encourage this. Few EVSE makers even have a 110V product, so as you can imagine most sales efforts are for L2 charging, and many site hosts (who tend to contact EVSE makers rather than owners) don't even realize that 110V outlets are a possibility.
There is supposed to be a big announcement this month that will target some high-return charging issues, and this should be one of them.�
Jan 1, 2013
Al Sherman Apparently not. I freely stipulate that I'm more than likely not as smart or educated as at least 95% of the folks on this forum. However, and even after reading posts on SOC voraciously; I still don't see how I would risk this without a lot more data. I'm certain there will be more data. Right now it seems as though the answer to the question of whether or not you can park the S at the airport for 2 weeks should be no, maybe, it depends, I wouldn't risk it, we're not sure. Definitely not a blanket yes in my mind.
�
Jan 1, 2013
mdh I really hope TM answers this question....�
Jan 1, 2013
JRP3 Has anyone asked their specialist or anyone else directly what happens if you leave your car at the airport in the cold for X number of days?�
Jan 1, 2013
RDoc This makes a phenomenal amount of sense! Even at 2 miles/hour of charge after a few days it would really add up, not to mention keeping the car happy.�
Jan 1, 2013
MikeK I have not done that, but I did submit the question to the "bulletin board" over on the Tesla forums. Maybe they'll post an official answer there.�
Jan 1, 2013
woof <sarcasm comment="Just in case it isn't obvious...">
Now why would we do that? It takes all the fun out of speculating, extrapolating the worst from single datapoints based on early firmware, and then write scathing commentary on how this is a "deal breaker" and "Tesla Sux" as well as throwing virtual tantrums and stamping our virtual feet.
</sarcasm>�
Jan 1, 2013
bonnie /laughing�
Jan 1, 2013
jomo25 I was told by the Scottsdale rep to email the Ownership mailbox with my "use case scenario" questions I had that they couldnt definitively answer. I don't know if or how quickly they respond not having contacted them in the past. But I'm going to try it for a few of my questions, including this one too.�
Jan 1, 2013
Larry Chanin Comparing the Model S's BMS operation to Roadsters may prove to be misleading. I suppose it depends on what you consider high SoCs, but a number of Model S owners have reported in this thread that when plugged in in Standard mode the car repeatedly "tops off", never letting the rated range drop below about 230 miles or about 87% SoC and it tops off to about 240 rated miles or 90% SoC. Obviously Tesla doesn't consider this relatively "high" SoC to be problematic for the Model S because that is the preferred protocol that they recommend for the well being of the battery.
They do of course warn against repeated Range charging which takes the battery to 100% SoC.
Larry�
Jan 1, 2013
PRJIM Some cars must be behaving differently, my car routinely bleeds 40+ miles when left plugged in for 4+ days. If the Roadster is left in standard mode and left plugged in for the same amount of time, the ideal miles will stay constant. Some Model S vehicles do not behave this way-under the same circumstances.�
Jan 1, 2013
Larry Chanin It will be interesting to note if that is still the case when you are upgraded to version 4.1 of the software.
Do you believe that charging from an SoC of say 75% to 90% every four days or so, will be better for your battery than topping off from 87% to 90% daily over those same four days?
Larry�
Jan 1, 2013
FlasherZ We're going to have to get into the habit of posting our current version in our signature. My v4.1-enabled car has never shown less than 229 miles when I've gotten into it into my garage, after being plugged in for days.�
Jan 1, 2013
PRJIM I believe that keeping the SOC between 40-60% is better for the battery, long term. Furthermore, less cooling/heating is required to keep the pack at a lower SOC. Bottom line keeping your battery between 40%-60% will maximize your batteries useful life. There is a small amount of degradation that takes place charging to 90% daily. This is just my opinion based on people I have spoken with and the research I have done.
I am running 4.0. It is my understanding that the Model S starts a charge cycle anytime the doors are opened or it senses the key fob within range- even after it has been sitting for days. If there is no interaction at all with the vehicle for several days then- I believe- it starts to bleed miles. Of course it all depends on how many days we are talking about here?�
Jan 1, 2013
Larry Chanin Perhaps it is better to store the car at lower SoC, but what about if you plan to drive the car on a regular basis. Do you discount the fact that charging from a low SoC to a full charge might contribute to more battery degradation than merely topping off? Isn't it possible that you are merely trading one type of battery degradation for another?
Larry�
Jan 1, 2013
FlasherZ I'll watch more closely to make 100% sure, but short of me unplugging and replugging the charge cable, opening the door or bringing the key fob in range does not cause the car to begin a new charging cycle.
I've let the car go 5 days before without initiating a charge, and upon walking up to it, it had 235 miles of range on it. I haven't watched it like a hawk to see when it charges, but it does appear to "top-off" with v4.1.�
Jan 1, 2013
PRJIM This all depends on how many miles you drive- or plan on driving in a day. In my estimation if you have a solid handle on the amount of miles you drive in a day there is no reason to charge fully on a daily basis. I would be curious to look at your information that shows why charging from 40% to 60% to a full standard charge contributes more to battery degradation than topping off.�
Jan 1, 2013
Johan While it may be better in theory to keep the SOC around 50% (even accounting for the fact that drawing power from 50% SOC may be a little bit more harmful than from higher SOC's) one one could argue the following in short: For people who drive that car only a little or moderately it won't really matter if you charge the way you describe or with daily standard charges, as the battery will still be in good health after 5-8 years, and at some point "shelf life" or "calendar degradation" i.e. ageing becomes more of the issue. People who drive a very high number of miles per year (50k+ miles/year) might have something to benefit, but will at the same time not be able to do this in practice since all that driving will require frequent charging to high SOC's. For further discussion and arguments see these two threads:
http://www.teslamotorsclub.com/showthread.php/11700-Charging-Approach
http://www.teslamotorsclub.com/showthread.php/10708-What-does-the-battery-degradation-curve-look-like�
Jan 1, 2013
PRJIM How about this thread?
Tesla Roadster Battery Care�
Jan 1, 2013
Johan I'm not saying it's wrong, I'm saying for all practical purposes it doesn't really matter probably. The Model S battery is larger than the roadster battery, it's a newer somewhat different chemistry, it has more sophisticated temperature management etc. The Panasonic cells are one generation newer than in the Roadster, this too could mean that they tolerate better to a lot around SOC's up to 90% (and the Voltages this impilies).�
Jan 2, 2013
surfingslovak I think it would be better to let it discharge a bit, before charging back up. The difference in this particular case shouldn't be very significant though. The rationale is that the vast majority of the initial capacity fade will come from calender life degradation. Lower average voltage should help counter that somewhat, and that's why letting it discharge is helpful. Of course, cycling losses will increase by running a deeper cycle, but these losses will be negligible when compared to calender life degradation, especially at the beginning of the battery life cycle. That said, the most important factor will likely be cell conditioning or cooling. Battery temperature plays an important role when it comes to both types of losses. As others have noted, all these considerations are relative. Battery technology has been improving, and we are talking fractions of a percent per charge or drive event. To be clear, I'm basing the above statements on personal experience, and on the following NREL report: http://1.usa.gov/agingmodel
�
Jan 2, 2013
JRP3 Don't forget the balancing factor, which only happens with a full charge. If only running between 40-60% your pack could get out of balance, reducing effective range. As previously stated an occasional full charge should take care of that, but I think that's one of the main reasons Tesla want's the pack always plugged in for a full charge.�
Jan 2, 2013
CarlE_P439 Someone mentioned using a car cover to help deal with the cold temperature and the Model S' response to it. Does anyone think that would actually help???�
Jan 2, 2013
mcornwell A car cover would help very little. The battery has a large surface area on the bottom of the car, which is exposed to the cold or hot climate.
- - - Updated - - -
Robert, could you tell your car to only pull 5A or something slow, so the charge takes a few days? It might cost quite a bit for the ChargePoint fee though, if they charge by the hour.�
Jan 2, 2013
RDoc I believe Logan charges you to park, but the charging is free.�
Jan 2, 2013
rclams The airport J1772 EVSE's I have seen are in short term/Daily parking areas.
==> Would you not agree that Public EVSE etiquette implies disconnecting/moving your vehicle near the end of your charge, not days or a week later?
Pedestals with 120v outlets in Long Term lots would be nice, with payment keyed to your numbered spot to pick up the kWhr costs, if any (e.g., our LEAF has very low daily range degradation).�
Jan 2, 2013
RDoc At Logan they are with the hybrid car parking in the normal parking lots. I'm not sure what the point to a charging station at a short term parking area at an airport would be. When I meet someone, I'm only there for an hour or so at the most and I very rarely make same day return flights.�
Jan 2, 2013
jerry33 I think this will become moot once the iPhone App becomes available. After having it sit for a week or so (when presumably it drops to 50% or so based on the reports), you just wake it up a few hours before driving and you're up to a standard charge. That will allow the battery to "store" at a lower rate and still have full standard charge when you start to drive it.�
Jan 2, 2013
mknox So I'm thinking I don't want to set my alarm early just so that I can wake up to use an iPhone app. To me, I expect the car to charge the way my cell phone does; that is to say I plug it in when I go to bed and it's at 100% when I unplug it in the morning. The phone doesn't charge up, then at 2:00 am start bleeding off power.
When I plug my car in at night, I expect it to be fully charged and ready to go when I unplug it. I get the concept of "bleeding off power" to a more battery friendly SOC for longer periods of time, but I drive my car every day, usually several times a day. Why can't the car simply charge the battery to 80% (or whatever a "Normal" charge is), trickle charge it to keep it there, and maintain pack heating or cooling as necessary as long as it's plugged in to shore power? If it sits in this state for some pre-determined number of hours or days, then go into some sort of "storage" mode where the pack is run down to a friendlier SOC and pack heating/cooling is scaled back or shut down? If my car is parked for days or weeks on end, then I don't mind using an App to "wake it up", but not for day in, day out driving.�
Jan 2, 2013
stopcrazypp All this stuff can be solved with a simple "top-off" or "maintain SOC" setting. Or at the very least Tesla should have a chart of temperature/SOC thresholds where the discharge behavior changes (similar to the thermal management chart the Volt has), so we aren't just guessing.�
Jan 3, 2013
JRP3 Can't the car do a timed charge, so that it's fully charged only 30 min to an hour before you need to leave in the morning? That would reduce time at a higher SOC and still give you a full charge when you need it.�
Jan 3, 2013
mknox No, but they say that's coming.
I would use something like that, but I still like the idea (at least optionally) of having the car manintain a full (Normal) charge and maintain battery temperature for as long as it's plugged in to shore power (unless left that way for an extended period upon which it goes into some sort of storage mode).�
Jan 3, 2013
RDoc If there really is an optimum storage SOC which is worth using, I'd think the way to do it would be just tell the car when you'll be requiring it again and at what state of charge, same as what should be in the timed charge. Just include a date as well as a time. The car wouldn't have to guess when it should go into storage mode thereby avoiding the problem of it being down to a low SOC just when you get back and want to drive home through a blizzard. With the phone app it should also be possible to reprogam the car ready time if you were coming back early or decided to stay in Costa Rica for another week (or month).�
Jan 3, 2013
Ampster Unless the batteries have a finite life based on cycles. I believe that the do based on Panasonic's spec sheet. More agressive charging reduces the number of cycles. I don't know how much impact partial charging has on cycle life. I guess it matters what your interpretation if "unduly" is.
Driving a RAV4 EV since October 2012.
Converting a VW to electric since April 2012
Sent from my phone, using Tapatalk.�
Jan 3, 2013
mknox Problem is, I may not know when I want to use the car again, I just want it to be ready. For my normal drive to work day, that would be fine, but I have read a lot of comments here that folks come back to their plugged in cars and find reduced range and cold battery packs. We may decide, on the spur of the moment, to take a weekend drive out of town and find that the car doesn't have the range to get us there even though it's sitting plugged in.�
Jan 3, 2013
sublimaze1 For those who do not have their car, this statement has more value than you - to date - recognize.
For example, let's say you are banking on 235 miles in a standard charge, and you want only a standard charge for your own personal reasons (or recommended reasons, whatever). Drive to work is 21 miles each way, or let's use 50 roundtrip. 30 miles to get the kids to band/soccer/etc. twice a week ... add 45 for the grocery store and a dinner or movie. You do quick math and come up with under 150 miles. All is wonderful, right?
Well, not so much ...
The cold is going to deplete more miles than you expected, and throw in one run to Fry's or Best Buy or "fill in the blanks" and you run a pretty high risk of being 30 miles from home with 40 miles rated. Trust me, this is sphincter tightening the first time.
So I have now plugged in the car every time I get home, unless I still have 200+ on the green (e.g. only went to church on Sunday and nothing else) and I will deal with the battery cycles several years down the road.
Just my two ....�
Jan 3, 2013
lolachampcar I'm reasonably sure Tesla knows all the answers here. I find it odd that there has to be so much testing and speculation by customers on/about a very basic element of utility. The manufacturer should document exactly how much the car consumes when idle as a function of temperature. Tesla has provided very good information on what affects range (tire drag, wind, etc.) so they have obviously documented all engineering aspects of the design. Any idea why they are not sharing?�
Jan 3, 2013
montgom626 Chevrolet does not share this information with Volt owners. Not sure why Tesla needs to if GM does cannot do it.�
Jan 3, 2013
stevezzzz I'm in and out of my garage frequently and usually have the fob in my pocket. My car, running 4.0, doesn't start a charge if it senses my fob and presents the door handles. It doesn't start a charge if I get in the car with the charge cable still plugged in. It will start a charge if I unplug and replug the cable from the charge port. It will top off every 24 hours if left plugged in (I have a NEMA 14-50 in my garage that routinely delivers 240 volts at 10kW during a charge).
Until this week, that is: on Tuesday I drove about 50 miles and parked the car in my garage mid-afternoon, plugging in for a charge. Looking at my whole-house energy logs I can see that it initiated a charge (but, strangely, only at 5kW instead of the normal 10kW: what's up with that?). On Wednesday I did not drive the car and it did not do a top-off charge at all. I should point out that my car has been doing daily top-off charges since about November 1, on whatever software version came to us before 4.0. Today I went into the garage and saw a Rated range of 230 miles on the center console, which is consistent with about a 5 miles-per-day vampire load. Because I have a long drive later today I did the unplug-replug thing to force a top-off charge. It charged for about 15 minutes at 10kW.
Yesterday's 5kW charge (which lasted almost four hours and included a 10kW spike for a few minutes just before it stopped charging) is the only time I've ever caught the car charging at less than 10kW on my home charging outlet. Weird.�
Jan 3, 2013
tezco Wonder if the battery was too cold to charge at full force?�
Jan 3, 2013
lolachampcar Ok, if Telsa = GM then I guess they do not.�
Jan 3, 2013
Jeeps17 The problem with that argument is that you are comparing two different technologies. A Volt owner can always add gas to their tank and have a functioning vehicle in minutes, if for some reason their battery has drained.
Not so for the Tesla, which IMHO is why owners need at least some of this data.�
Jan 3, 2013
DocDog If I might, I would like to add a small point to this interesting discussion. Some of the more savvy electronics experts can also address this if they think it is worthwhile:
Much of this thread speaks as if the battery in the MS is a single entity, however, we all know that it is constituted of many small batteries. It seems to me that the engineers at Tesla have used this to their advantage with algorithms that assure that there is appropriate rotation of load and SOC for each individual element of the system in order to assure that they are achieving maximum usability and life. Does it really make sense to "outthink" this process with crude choices such as not plugging the car in every day?�
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