Model 3 Performance Battery Degradation One Month (Story)

[D3xDt3Reaction]

This morning, after charging to exactly 75% (as I have done for the past several days, and driving about 35 miles per day), I was at 216 miles, which works out to 288 miles calculated full range (216 / .75 = 288). Just two days ago, it was at 293, and four or so days before that, it was up at 300.

Last time I got down to a calculated 291 range, I did the 10-100% charge cycle (well, not exactly 10%, I think I got it down to 15%, and based on my use/needs I just couldn't have it go lower without *really* going lower). After about 24 hrs from doing that cycle, my range popped to 300. And now it's drifted down again, past 291, down to 288. I do not have V9 software yet.

Conventional wisdom is that "displayed range = Rated Range" and is not adversely affected by driving habits, up/down kwh/mi numbers, *or* cold weather. So a displayed range of 288, and falling, starts to look odd when it's a number that should not *at all* be affected by temperature or how hard/soft I'm driving the vehicle (ave 254 wh/mi btw).

I'm not going to do another re-balancing at this stage (seems one shouldn't have to rebalance once every two weeks, after all). I want to do just how Low my car can Go, in terms of calculated full range, when I use the car in a manner that at least is supposed to be the best for the battery (70-75-ish%, daily charging). If it plummets into the 270's under this regime, then I'll go back to Tesla SC and complain.

I’m in almost exactly the same boat: now at 288 miles extrapolated from 80% SOC. Similar charging habits and have never charged to 100%.

 

[D3xDt3Reaction]

OK, thanks. I'm still trying to get a handle on this, and I've run across posts that say cold weather shouldn't affect rated range displayed, though obviously it affects actual range significantly. So, based on your reply I'll adjust my assessment of the CW to reflect that in cold weather the displayed rated range can be lower.

But . . . How cold are we talking? In my area, the highs have been around 75-85 for the past few months. Evening temps can dip down to the high 40's only very lately (as in 48, 49); otherwise lows have been mostly in the mid-50's to upper 60's over the life of my car.

In other words, this isn't exactly Fargo, ND weather here in Nor Cal. You can indeed find a million (literally I think a million) posts about folks in Minnesota, etc. where they're wondering why their range has dropped when it's 15 degrees outside, but those posts carry little relevance to my situation.

So bottom line then, how cold should it get before I can start attributing any part of my current 22 mile range reduction to temperature? If it goes from 85-75 degrees, is that at all meaningful in terms of range you should see displayed? Because that's exactly the temperature band my car has been in its entire life so far.

As a last data point, I did a 10-100% cycle to achieve only 291 miles full range, I did that cycling when my days averaged highs in the low 80's, and yet Tesla Dublin said that my 310-291 drop probably was all due to temperature decrease.

Does this sound right to you?

PS - I see in some searches of cold-related range issues, that S's and X's will actually tell you that the cold is affecting range, and will even tell you how much. I also understand Model 3's will show a little blue snowflake next to the range when the car senses that temperature is affecting range. I have never seen the blue snowflake on my display. Ever.

I don’t think cold weather is at play here. I’m in the Phoenix area anyway and for comparison my wife’s S has been rock solid on extrapolated *rated* range regardless of the time of year. My 3, on the other hand, is declining in extrapolated rated range just like yours. Temperature definitely affects actual/predicted range in nav but I have not seen it affect rated range.

 

[Vines]

You were doing well until you said “cold weather”. Battery capacity is lower in cold weather, and the rated miles displayed has always reflected that. A 100% charge in cold weather will show fewer miles of range than in warm weather. There has never been any dispute about this. Search the hundreds of posts on this topic over the years for details.

I did a search and did not find that answer, can you point me to a thread where this is posted? Are you saying that it is normal for cars in colder climates to show less miles for a similar charge state percentage?

I thought the displayed range was basically the EPA range, and it didn't care about temperature or driving habits.

 

[FSKT]

I did a search and did not find that answer, can you point me to a thread where this is posted? Are you saying that it is normal for cars in colder climates to show less miles for a similar charge state percentage?

I thought the displayed range was basically the EPA range, and it didn't care about temperature or driving habits.

Here's something I found on the net with a google search. It's an Insideevs.com article, and it depicts some battery/range info from an S, and it clearly is showing a very graphic indication of range loss due to cold. It's a nifty looking display. It's a three-year old article, but it supports the idea that displayed range might be lower if it's super-cold. But I'm still wondering how going from 85's to 75's in temperature is really "getting colder" in terms of battery capacity / range.

I understand that the 3 will at least display a little blue snowflake if it senses it's cold enough for range to be notably affected. I for one have never seen the snowflake displayed.

Here's that article:

Blue Bar Shows Impact Of Cold Weather On Tesla Model S Range - Video

 

[Vines]

Ah cool, thanks for that link. In walnut creek thats probably not an effect you will see at this time of the year.

Great question though. How cold does it need to be to start losing range as displayed by the battery bar?

 

[TexasEV]

The displayed range is the EPA range. But in cold weather, batteries have less capacity. Say for example you have a 100 kWh battery and the rated range is 200 miles. At some cold temperature, where the battery capacity is reduced by 10%, that effectively means you have a 90 kWh battery at 100% charge, and 180 miles of rated range. Cold weather reduces your range for other reasons, such as cold air is heavier and takes more energy for the car to push through it, and this isn't reflected in rated range any more than rain would be-- but the effect of cold on battery capacity affects the displayed range because it appears as if you have a smaller battery.

There are lots of cold weather threads, so just have to go through them I guess. But every Tesla owner who lives in an area where there is winter has had the experience of seeing a lower rated range displayed in the winter than in the summer.

 

[RyanT]

It probably doesn't hurt to do 100% charge sometimes. I noticed last weekend that my model 3 took more time to balance the pack then my model S ever did. It was sitting at over 300 miles for an hour or 2 and still charging/bleeding some cells. Maybe this new chemistry gets out of balance faster than the old 18650 cells. By charging to only 75% each night they might be getting really out of balance and you're not going to get as much range out of it. Usually the BMS balancing occurs when you get up in the higher ranges. It'd be nice if a pack/BMS expert chimes in.

I have 2,000 miles on the car P3D-. Last full charge was 308.

 

[brianman]

You were doing well until you said “cold weather”. Battery capacity is lower in cold weather, and the rated miles displayed has always reflected that. A 100% charge in cold weather will show fewer miles of range than in warm weather. There has never been any dispute about this. Search the hundreds of posts on this topic over the years for details.

Set a reminder in your calendar or June 2019. I predict there will be a handful of new threads (or just posts) touting that "firmware version __ that I just got now shows ___ more range for my car than the prior version".

 

[FSKT]

The displayed range is the EPA range. But in cold weather, batteries have less capacity. Say for example you have a 100 kWh battery and the rated range is 200 miles. At some cold temperature, where the battery capacity is reduced by 10%, that effectively means you have a 90 kWh battery at 100% charge, and 180 miles of rated range. Cold weather reduces your range for other reasons, such as cold air is heavier and takes more energy for the car to push through it, and this isn't reflected in rated range any more than rain would be-- but the effect of cold on battery capacity affects the displayed range because it appears as if you have a smaller battery.

There are lots of cold weather threads, so just have to go through them I guess. But every Tesla owner who lives in an area where there is winter has had the experience of seeing a lower rated range displayed in the winter than in the summer.

Would you expect the rated range displayed (or, by extension, the actual capacity of the battery pack) to go down (due to temperature) by any appreciable amount when ambient temperature highs start at mid-80's and then go down 6-8 degrees to mid/high 70's (with lows touching between low 60's down to mid 50's)? That's my temperature range for most of the time I've owned the car, and during that time displayed rated range has gone from 310 down to 288.

My guess is temperature cannot account for even a fraction of the observed loss for my vehicle in such weather. It must be something else.

 

[FSKT]

It probably doesn't hurt to do 100% charge sometimes. I noticed last weekend that my model 3 took more time to balance the pack then my model S ever did. It was sitting at over 300 miles for an hour or 2 and still charging/bleeding some cells. Maybe this new chemistry gets out of balance faster than the old 18650 cells. By charging to only 75% each night they might be getting really out of balance and you're not going to get as much range out of it. Usually the BMS balancing occurs when you get up in the higher ranges. It'd be nice if a pack/BMS expert chimes in.

I have 2,000 miles on the car P3D-. Last full charge was 308.

Thanks. It would be good to know if this is the case, more frequent rebalancing needed, more charges to 100% necessary with the new cells. It would also be a little disappointing, because as I understand it, it's good to keep 100% SOC to a minimum.

 

[Vines]

From what I have seen of brand new P3D reports, there is quite a bit of variation. Some folks have lost 2 or 3% (indicated) in the first couple thousand miles. Others like me are getting full or near full range still.

Funny data point, my car just now charged to 251 miles, with a visible pixel at least past the 80% SOC bar on my phone. I haven't changed it since the weekend and yesterday topped off at 248. It is sitting in the sun now, so could have this been a temperature change? Maybe a slight overcharge is allowed by the BMS? It seems unlikely as its parked in the same place today and with similar weather.

 

[FSKT]

Set a reminder in your calendar or June 2019. I predict there will be a handful of new threads (or just posts) touting that "firmware version __ that I just got now shows ___ more range for my car than the prior version".

Sorry, I don't get it . . . . I'm not saying that to be contentious, I sincerely just don't understand what your'e driving at here.

I will say, that whatever firmware it is, whenever it comes out, I'd just like the displayed range to be understandable - what affects it, what doesn't, so I can generally track the health of my battery, and know when to, and when not to, be concerned.

 

[TexasEV]

Would you expect the rated range displayed (or, by extension, the actual capacity of the battery pack) to go down (due to temperature) by any appreciable amount when ambient temperature highs start at mid-80's and then go down 6-8 degrees to mid/high 70's (with lows touching between low 60's down to mid 50's)? That's my temperature range for most of the time I've owned the car, and during that time displayed rated range has gone from 310 down to 288.

My guess is temperature cannot account for even a fraction of the observed loss for my vehicle in such weather. It must be something else.

I agree those aren’t cold temperatures. I was referring to near freezing temperatures.

 

[RyanT]

I don’t think temperature would have nearly that much effect. It never did on my model S. I would try a 10%-100% charge then another 100% charge the next day. When I did that it topped at 303 first day and 308 the second day(and still charging). If you time your drives to be right after 100% it’s not that bad, just don’t have it sitting at 100 all day.

I’m curious if other people are seeing the long balancing times I experienced too. Mine must have been balancing (above 300 miles) for 1.5 hours.

 

[brianman]

Sorry, I don't get it . . . . I'm not saying that to be contentious, I sincerely just don't understand what your'e driving at here.

When the weather changes (seasonally, or localized spike/dip), the capacity and reported capacity (in kWh or miles) tend to shift. When that happens in the negative, people complain and are often upset that the car "isn't as advertised". When it happens in the positive, people often attribute it to firmware that they recently got. That doesn't mean they aren't sometimes right that the firmware has changes that affect these things, just that the reporting of it outweighs significantly the real occurrences.

 

[FSKT]

When the weather changes (seasonally, or localized spike/dip), the capacity and reported capacity (in kWh or miles) tend to shift. When that happens in the negative, people complain and are often upset that the car "isn't as advertised". When it happens in the positive, people often attribute it to firmware that they recently got. That doesn't mean they aren't sometimes right that the firmware has changes that affect these things, just that the reporting of it outweighs significantly the real occurrences.

Ah, got it.

I don't think that's what I'm seeing currently with the reduction of my stated/rated range (which stands now at 288, down from 310 of course). The temps in my area have been within a band of 75-85 degrees for months now (with some spikes into the low 90's, but really, literally, nothing below mid-ish 70's). I don't think that sort of temperature history/variation can account for the observed 7% degradation (or capacity reduction) that I see.

So it's not temperature vis-a-vis my pack. And with rated range being calculated with a constant, it's not driving habits or kwh/mi variation. So that leaves two potential reasons: actual degradation, or un-balanced pack (though I recently rebalanced, got it back to 300, but then quickly within days drifted back down to 288).

It would be good to understand this better. I'd like to not have to worry about it, and just a reasonable reason/explanation for my non-temperature-related situation would be nice.

I'm on hold with Tesla SC as I type this . . . . .

 

[FSKT]

I don’t think temperature would have nearly that much effect. It never did on my model S. I would try a 10%-100% charge then another 100% charge the next day. When I did that it topped at 303 first day and 308 the second day(and still charging). If you time your drives to be right after 100% it’s not that bad, just don’t have it sitting at 100 all day.

I’m curious if other people are seeing the long balancing times I experienced too. Mine must have been balancing (above 300 miles) for 1.5 hours.

How long ago did you do that 10-100% cycle? I did that, a little over a week ago, and that got me back up to 300. I was ok - not thrilled but ok - with 300. But now, just about 8 or so days later, it's right back down again, to it's lowest so far - 288.

I'm just wondering if your re-balancing success has lasted. It hasn't lasted for me.

 

[brianman]

I'm on hold with Tesla SC as I type this . . . . .

Good plan. Hopefully they'll help you sort this out.

 

[FSKT]

Good plan. Hopefully they'll help you sort this out.

They're trying! Long hold, but eventually I talked to a human. Appointment set for next Friday for me to take the car in to the Dublin SC and have them look at the car/battery. Looking forward to some sort of resolution/understanding of what the hey is going on.

 

[FlyinDelorean]

I thought the displayed range was basically the EPA range, and it didn't care about temperature or driving habits.

This directly conflicts with something that I was told by the Tesla service hotline and, conversely, I believe now, confusion is the order of the day (or night).