Interesting battery behavior, just winter?

[verygreen]

So I was tracking my battery stats since I got my car (100D).

It started pretty well on Apr 5th

$ lv BMS_nominalFullPackEnergyRemaining
"98.100"

keep in mind there's additional 4kWh buffer on top of this.

This value held still until about Aug 15 or so - I charged my battery to 100% for the first time and the value was the same as when new.
Then on Aug 20th I noticed that it dropped to 97.800 and stayed steady there for some time
Then on Nov 21 I checked and it was already 96.800,
Dec 7th 96.600 and now today Dec 18th: 95.900 (everything with corresponding drop in reported rated range of course)

Of course battery capacity determination is not an exact science and colder winter temps might be affecting it too (I got some suggestions about it), so I wonder if others have noticed their battery capacity shrinking during winter and then comes back up as it becomes warmer?

4863 miles on my car now for those wondering.

 

[Cozjim]

I would like to hear from others on this too. I have 43,000 miles on my 2015 P85 Model S over the last 18 months living in Northern NJ. I noticed significnant reduction in distance per charge during the first winter last year but it’s worse this year. During the summer I can average 310 Wh/m so yes, I drive like an old man. Last winter I got +/-70% of the stated miles available, this year I am getting +/-55%!!! I keep a daily log when it’s below 50 degrees F, as an example I’ had 57 miles left the other night and drove 110 miles that day starting with a 232 mile charge. That’s 41% less miles than the car projected! It’s been worse. I will add, during summer months I’ve gotten a few miles more than the car projected due to my conservative driving habits. I absolutely get it that batteries do not like the cold, but these batteries are touted as "so smart" I expect they should be able to keep themselves warm without decimating the range. After charging just before I get in the car with 40amps @220v it’s still got the yellow lines and caution triangles on BOTH top and bottom of the usage meter. To me this means it’s not keeping itself warm which is not a "battery chemistry" thing!!

My position is the battery heating system is malfunctioning. After much review and analysis by T they are chalking it up to "that’s the way it is", I’ve asked if all or predominately all owners in this region experience over 40% less distance from their cars and don’t get straight answers. I find this astonishing and can’t get past the stock answers about using the heated seats more than the cabin heater, Pre-heat the car prior to driving, keep it in the garage, accelerate quickly once or twice to "heat up the battery", I do all that, the battery is just not maintaining its charge in the cold. I certainly accept you'll not get 100% out of the battery in cold weather but almost 50% less does not seem reasonable. I’ve driven from NJ to Boston, MD central PA, etc. in temps over 50 degrees F with NO range problem.

I have had nothing but good in my dealings with T. They have replaced a few items including my drive unit without batting an eye. If this is not a manufacturer default I don’t see how this car can become main stream. I absolutely LOVE my Tesla experience but this is a bit more than I am comfortable with

Does this sound like what’s happening to you? Are you getting most of the projected miles out of a charge in cold weather?

 

[verygreen]

I think you are having a different issue. For me the number of rated miles goes down at any particular SoC with reported capacity going down. If you have increased power draw-that's a totally different thing that is somewhat expected.

 

[apacheguy]

This behavior is well known

Displayed Range and Seasonality

 

[mspohr]

Tesla is working on a battery pre-heating feature to maximize efficiency in cold climates

 

[psbill]

A bit late to the conversation. My MX 90D consumed 3 miles of charge for every mile driven during a week of temps 10-19 degrees. Drive 7 miles, 21 miles of charge disappear. Car is parked in an unheated garage so not subject to the worst of the weather. This is all short, local trips, no highway miles. Trip gauge shows consumption of anywhere from 500-1100 Wh/mi during that week. Called Tesla and was told to preheat the car. Is this normal?

 

[mspohr]

A bit late to the conversation. My MX 90D consumed 3 miles of charge for every mile driven during a week of temps 10-19 degrees. Drive 7 miles, 21 miles of charge disappear. Car is parked in an unheated garage so not subject to the worst of the weather. This is all short, local trips, no highway miles. Trip gauge shows consumption of anywhere from 500-1100 Wh/mi during that week. Called Tesla and was told to preheat the car. Is this normal?

Operating any vehicle in cold weather will reduce "mileage". This is normal.

 

[scottf200]

10-19 degrees ... This is all short, local trips, no highway miles. Trip gauge shows consumption of anywhere from 500-1100 Wh/mi during that week. Called Tesla and was told to preheat the car. Is this normal?

I would think short trips in cold is one of the worse case scenarios for Wh/mi. Using a) watts for heating the cabin, b) for heating the battery, and c) for moving the vehicle. Like a ICE car you have all the grease and oil as part of the drivetrain and when they are cold they cause resistance and worse 'mileage'. Think bearings, gears, etc, and places like the 'hub' the wheels turn on.

Of course, "preheating" will do 'a' and 'b' still so I'd limit how long those were on (point of diminishing returns?). Food for thought.

 

[Rocky_H]

A bit late to the conversation. My MX 90D consumed 3 miles of charge for every mile driven during a week of temps 10-19 degrees. Drive 7 miles, 21 miles of charge disappear. Car is parked in an unheated garage so not subject to the worst of the weather. This is all short, local trips, no highway miles. Trip gauge shows consumption of anywhere from 500-1100 Wh/mi during that week. Called Tesla and was told to preheat the car. Is this normal?

People still get stuck in this thinking of just "miles". It's energy in the battery. All energy use has to come from it. There's barely any waste heat from an electric drive train, so you are not just using "miles" to drive miles. You're using up the energy in the battery for driving + heating.

 

[psbill]

Very helpful perspectives. Thanks to all of you.

 

[lymex2018]

The drop of 2.2kWh in 8.4 months seems a little beyond the seasonal effect (0.26% per month), especially the Aug. number is smaller than April's.

Mine is 97.6kWh now but was 98.4 in Oct, 0.20% per month. My car is 4700km/2921mi.

Any way, I hope we can come back here in summer to see the seasonality.