Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[thebigbobowski]

I'm in the same boat (have posted about this in other threads) and feel your pain. My 2018 AWD charges to 280 at 100%. Just had it in to service on Thursday for a few minor things and asked them about resetting the BMS. They ran diagnostics and said the battery was functioning "normally." Not really much that can be done about it, then. I love my car but this situation is pretty disappointing.

 

[namikun]

Mine is pretty whacky looking. Had a chat with a Tesla service rep after I submitted a service request via the app and was told that the rated range recalculates periodical based on driving style to approximate real range over time. I can confirm that during the two months or so I drove the car like a slowpoke, the rates range actually crept up from under 300 to 318.

 

[VT_EE]

I charge my LR AWD to between 70-90% at my work, where I can charge for free every day, but the car might go 3-4 days without being plugged in.... due to my schedule or how occupied the charging stalls are.

The reason for the inconsistent charging is that the charging stalls are free for use for four hours and the charging is only @ 30 amps.

I charged up to 90% the other day and, since the car is almost exactly 1 year old (has only 8,100 miles) I decided to check the range in miles.

I was rather surprised to see that the range is down to 254 miles.

Actually rather surprised is an understatement, I was somewhat shocked by this much range reduction after only one year and 8,100 miles of ownership.

This would work out to a range @ a 100% full charge of only 279 miles for a range loss of 31 miles which is exactly 10% of the range of the car when new.

It has been suggested in other threads that the range might not be gone but might simply be hidden due to the cells being imbalanced due to my imperfect charging habits.

I've seen conflicting information on how to get this shown range back. Would charging nightly to 90% for a few weeks suffice or would I need to first discharge the battery and do a 100% charge?

If I can't get a portion of this range to display I will probably contact Tesla to see what they have to say since this seems like a lot of range loss in one year of ownership.

VOIP, did you notice the consumption that correlates to the "rated" range line in the Energy graph change? I have a LR RWD. When I first bought the car, it had 310 miles of rated range, which correlates to ~240Wh/mi consumption. Last spring they "gave" the LR RWD and additional 15 miles. This adjustment actually changed the rated line in the Energy graph to ~230Wh/mi. In a recent update, that line moved back up to ~240Wh/mi and I lost 15 miles of range overnight. I don't know if they are messing with the range calculation in the AWD cars, but they did on my RWD. Of course, none of this actually affects real range, just the display. Also, you definitely need to drain the battery down to 20% and charge it back up to 100%. I did this over the weekend and got 5 miles back. If you haven't cycled the battery recently, then the estimate might be pretty far off.

 

[VT_EE]

Mine is pretty whacky looking. Had a chat with a Tesla service rep after I submitted a service request via the app and was told that the rated range recalculates periodical based on driving style to approximate real range over time. I can confirm that during the two months or so I drove the car like a slowpoke, the rates range actually crept up from under 300 to 318. View attachment 458659

There are many examples on TMC of people quoting service managers as stating the displayed range changes based on driving style. In most cases, the poster thinks the manager is lying or uninformed. You have provided the first evidence I've seen that Tesla is no longer using a fixed multiplier for the range display. This is very informative. Thanks!

 

[bedoig]

Wait, so correlation does equal causation?

 

[mike123abc]

I just passed 32k miles in just over a year of ownership. While I keep it on % all the time, I charge it up to 100% on occasion. I happened to do it on Monday I slid it over to distance and it reported 300 miles. I have seen 298 on occasion, but the most common result of 100% charge is 300. Note that summer driving has lowered my Wh/mi down to 291. It hit 305 at peak over the winter. I keep it on % and only budget 250 mile range or 25 miles for each 10%.

It is an AWD with 19" wheels.

 

[voip-ninja]

VOIP, did you notice the consumption that correlates to the "rated" range line in the Energy graph change? I have a LR RWD. When I first bought the car, it had 310 miles of rated range, which correlates to ~240Wh/mi consumption. Last spring they "gave" the LR RWD and additional 15 miles. This adjustment actually changed the rated line in the Energy graph to ~230Wh/mi. In a recent update, that line moved back up to ~240Wh/mi and I lost 15 miles of range overnight. I don't know if they are messing with the range calculation in the AWD cars, but they did on my RWD. Of course, none of this actually affects real range, just the display. Also, you definitely need to drain the battery down to 20% and charge it back up to 100%. I did this over the weekend and got 5 miles back. If you haven't cycled the battery recently, then the estimate might be pretty far off.

I will need to investigate this. I did notice when driving home yesterday the car showed 240 miles of range and 235 kWh/m of energy consumption but the range estimate in the energy graph showed an estimate of 288 miles range.
Today the display tracked with what the main display was showing for range.

 

[Incredulocious]

If you look in this thread, there are some people sharing rated range graphs that show essentially no significant change in rated range (horizontal linear fit line) over many more miles:
LR RWD Battery Rebalance Success!

 

[voip-ninja]

If you look in this thread, there are some people sharing rated range graphs that show essentially no significant change in rated range (horizontal linear fit line) over many more miles:
LR RWD Battery Rebalance Success!

Interesting thread... however he doesn't have enough time following his "reset" to know if the recovery is "sticking" or not. I do think it's more likely that the low range is related to an unbalanced pack, lack of good measurement data, or firmware issue with BMS rather than that the battery has really degraded so quickly but right now there's no way to know.

 

[acoste]

Interesting thread... however he doesn't have enough time following his "reset" to know if the recovery is "sticking" or not. I do think it's more likely that the low range is related to an unbalanced pack, lack of good measurement data, or firmware issue with BMS rather than that the battery has really degraded so quickly but right now there's no way to know.

There is a way. Tesla Bjorn's capacity test I linked earlier.

 

[voip-ninja]

There is a way. Tesla Bjorn's capacity test I linked earlier.

I have zero interest in anything a Tesla basher like yourself has to say. Begone phantom!!

 

[acoste]

I have zero interest in anything a Tesla basher like yourself has to say. Begone phantom!!

Information is there. If you don't take it due to personal reasons, it is your loss.

 

[Swampgator]

Information is there. If you don't take it due to personal reasons, it is your loss.

Pretty sure he was joking.

 

[wrf2e]

What I don’t understand is why do you care what the screen says so long as the car has enough to get you where you need to go?

Because I would like to know how much range I have when I am driving somewhere. It is hard to rely on guessing.

 

[wrf2e]

Here is my chart. 12% loss since march, with the biggest drop between 7/8 and 8/8/19

 

[voip-ninja]

Here is my chart. 12% loss since march, with the biggest drop between 7/8 and 8/8/19

Is the source for these charts TeslaFi?

 

[voip-ninja]

Okay I'm going to attach my consumption graph. It seems like possibly my consumption has gone up a bit recently. I did notice a week or so ago that my drive home, which is ~9 miles of suburban traffic appeared to use over 6% of my battery which I thought pretty strange.

So, I can think of a few possibilities here other than the obvious "the car has less battery capacity".

One possibility is that the car is now basing range estimates on a faulty power consumption number, OR the power consumption has always been this high and Tesla has now modeled the range based on this... although this would seem to invalidate their original stated range values.

Also it seems that if this "we are now dynamically showing range based on driving habits, outside temps, etc." were true (I'm skeptical) then it should show a different range for a driver profile for example that almost never uses the car... I'm pretty sure that's not the case.

I know in the past it did not do this because it would show the same 280+ mile range at 90% charge in the fall that it did in the depths of winter when range was absolutely impacted.

Another possibility is that the value that Tesla is using to track consumption and predict range is simply wrong for some reason.... I don't quite buy that this is a widespread software bug because some users are reporting this big drop and others are not even if they have identical vehicle configurations.

Another possibility in the "it really lost range" category is that Tesla is doing something with the range of certain cars with certain packs to try to prolong the battery life, like maybe there are problems with these packs and Tesla is trying to avoid eventual warranty replacement.

 

[qdeathstar]

View attachment 458910 Okay I'm going to attach my consumption graph. It seems like possibly my consumption has gone up a bit recently. I did notice a week or so ago that my drive home, which is ~9 miles of suburban traffic appeared to use over 6% of my battery which I thought pretty strange.

So, I can think of a few possibilities here other than the obvious "the car has less battery capacity".

One possibility is that the car is now basing range estimates on a faulty power consumption number, OR the power consumption has always been this high and Tesla has now modeled the range based on this... although this would seem to invalidate their original stated range values.

which are done under a very specific set of conditions. How do you imagine the car tests how much capacity there is in the battery? All it can do is measure current used and voltage level with a certain range. The more voltage drop for a given amount of current used, the less expected capacity (estimated range). The voltage drop as lithium cells drop isn’t linear or equal along different stages of discharge and so if you are charging and discharging over a small range of the cars capacity the discharge curve it gets to measure is small... so there is more likely to be error.


Also, you probably do have some battery degradation. That is the consequence of choosing to drive a car powered by batteries. Like your phone, the batteries will wear out.

But you never address what is an acceptable amount of degradation. Tesla says the acceptable amount is 30 percent over seven years. They are up front about that. What do you think a reasonable amount of degradation is?

Another possibility in the "it really lost range" category is that Tesla is doing something with the range of certain cars with certain packs to try to prolong the battery life, like maybe there are problems with these packs and Tesla is trying to avoid eventual warranty replacement.

which you have zero evidence to support. It’s equally as plausable aliens are siphoning your battery capacity.

 

[voip-ninja]

which are done under a very specific set of conditions. How do you imagine the car tests how much capacity there is in the battery? All it can do is measure current used and voltage level with a certain range. The more voltage drop for a given amount of current used, the less expected capacity (estimated range). The voltage drop as lithium cells drop isn’t linear or equal along different stages of discharge and so if you are charging and discharging over a small range of the cars capacity the discharge curve it gets to measure is small... so there is more likely to be error.


Also, you probably do have some battery degradation. That is the consequence of choosing to drive a car powered by batteries. Like your phone, the batteries will wear out.

But you never address what is an acceptable amount of degradation. Tesla says the acceptable amount is 30 percent over seven years. They are up front about that. What do you think a reasonable amount of degradation is?





which you have zero evidence to support. It’s equally as plausable aliens are siphoning your battery capacity.

Yes I'm sure it's aliens.

My expectation is that Tesla's newer battery chemistry would have superior degradation performance compared to the degradation curves seen on batteries in S and X vehicles, which typically suffer about 5% loss in the first year and then very slow degradation after that. Some high mileage estimates now indicate that those batteries might still have about 80% original charge/range after 500,000 miles and 10+ years of use.

And yeah, a Tesla battery is like the battery in your phone in the same way that an F-35 and the Wright brothers original prototype are both airplanes.

 

[qdeathstar]

Yes I'm sure it's aliens.

Could be... no evidence to show it’s not, right? Or just as much evidence as some conspiracy theory that Tesla is hoarding capacity to avoid warrantee claims

My expectation is that Tesla's newer battery chemistry would have superior degradation performance compared to the degradation curves seen on batteries in S and X vehicles, which typically suffer about 5% loss in the first year and then very slow degradation after that. Some high mileage estimates now indicate that those batteries might still have about 80% original charge/range after 500,000 miles and 10+ years of use.

Fair enough. And have you tested your actual range? (NO! QED)

And yeah, a Tesla battery is like the battery in your phone in the same way that an F-35 and the Wright brothers original prototype are both airplanes.

They both use lithium batteries brah... lithium chemistry is lithium chemistry. You don’t slap a T on it and change the laws of physics, yet.