Large Drop in Charge When Parked in the Cold

[FalconNinetyD]

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.

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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.

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.

 

[RDoc]

I believe Logan charges you to park, but the charging is free.

 

[rclams]

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 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).

 

[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.

 

[jerry33]

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?

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.

 

[mknox]

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.

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.

 

[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.

 

[JRP3]

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.

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.

 

[mknox]

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.

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).

 

[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).

 

[Ampster]

From the Model S Owners Manual (also displayed when selecting the charging mode) :



Dennis posted:



Tesla is saying that repeated charging in Standard mode maximizes battery life so it does not necessarily follow that topping off would have an unduly negative effect on battery life since it is only charging to 90% of its full capacity.

Larry

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.

 

[mknox]

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.

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.

 

[sublimaze1]

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.

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 ....

 

[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?

 

[montgom626]

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?

Chevrolet does not share this information with Volt owners. Not sure why Tesla needs to if GM does cannot do it.

 

[stevezzzz]

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.

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.

 

[tezco]

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.

Wonder if the battery was too cold to charge at full force?

 

[lolachampcar]

Chevrolet does not share this information with Volt owners. Not sure why Tesla needs to if GM does cannot do it.

Ok, if Telsa = GM then I guess they do not.

 

[Jeeps17]

Chevrolet does not share this information with Volt owners. Not sure why Tesla needs to if GM does cannot do it.

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.

 

[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?