Decreasing rated range.

[andrewket]

Just completed a 100% charge. 10,612 miles, 245 rated/283 ideal. "B" pack.

I've charged to 100% on ~10-12 occasions. Usually charge to 70%, and keep it at 50% when I'm traveling and the car is going to sit for awhile. The only thing I do that is somewhat "unusual" is I frequently charge at 80A.

 

[tomas]

Like everybody else, I've seen rated miles at end of <100% charges go up with 5.9. And, also increase over multiple charges. This implies that maybe the BMS was updated to improve balancing???

However, on the disturbing front, I've seen my "par" wh/mi go lower than I recall. Not sure this is conventional, but I compute by noting wh/mi used since last charge at the point where: miles since last charge + rated miles remaining = rated miles when I unplugged and departed. This only works on one "key turn", so if I don't reach that equilibrium on a single drive, I cannot compute.

Using that method, I'm now using between 285 and 290 wh/mi to achieve rated range. Problem is, I was not really tuned into this when the car was new, so I don't know what this number was previously. So, this may have always been "par" for my car, or maybe not! I was always under impression that "par" should be around 300 wh/mi, but a little difficult to compute when you know EPA 265 and 85 kWh, but don't know how much of 85 kWh battery was "hidden" (below zero + anti bricking + high charge cushion) when the car was EPA tested, and how that's been tinkered with over time.

So, don't know whether to be excited or not about apparent miles "returned" by 5.9. I know there are many on this site who know EE inside out, but y'all lose me when you get into coulombs. Any thoughts on whether the miles "returned" are likely real or memorex?

 

[gg_got_a_tesla]

Tomas, par Wh/mile has always been around 290. I've used your technique to verify that pre-5.9 and with 5.9 as well. It doesn't appear to have changed.

 

[Cottonwood]

However, on the disturbing front, I've seen my "par" wh/mi go lower than I recall. Not sure this is conventional, but I compute by noting wh/mi used since last charge at the point where: miles since last charge + rated miles remaining = rated miles when I unplugged and departed. This only works on one "key turn", so if I don't reach that equilibrium on a single drive, I cannot compute.

Using that method, I'm now using between 285 and 290 wh/mi to achieve rated range. Problem is, I was not really tuned into this when the car was new, so I don't know what this number was previously. So, this may have always been "par" for my car, or maybe not! I was always under impression that "par" should be around 300 wh/mi, but a little difficult to compute when you know EPA 265 and 85 kWh, but don't know how much of 85 kWh battery was "hidden" (below zero + anti bricking + high charge cushion) when the car was EPA tested, and how that's been tinkered with over time.

Your "par" Wh/mi is what I call Wh per Rated Mile. For my 19-month-old, 19,000-mile, P85, I have consistently measured 290 Wh per Rated Mile using your technique or normalizing the actual Wh/mi to 290 Wh/mi. This has been true for me since I have been keeping track of things (at least the last 10,000 miles) through 5.9.

To be more specific, for me, there appear to be 290 Wh per Rated Mile for use from the battery, 300 Wh per Rated Mile for DC Charging from a Supercharger, and 333 Wh per Rated Mile for AC charging. These all make sense to me because there is a little loss (3%) in the battery charge/discharge cycle, and 300 Wh per Rated Mile gives you 300 mph charging from a 90 kW Supercharger and 400 mph charging from a 120 kW Supercharger matching Tesla's claimed Supercharger charge rates. For AC charging, Tesla has always claimed about 90% charger efficiency. 40 Amps at 240 Volts is 9.6 kW AC. Divide that by 333 Wh per Rated Mile and you get a charge rate of 28.8 mph, very close to the accepted number of 28 mph charge rate for a 240 Volt 14-50.

To summarize, here are the various energies per Rated Mile depending on where you measure:

• 290 Wh/mi - Used From the Battery - Reported in the Car
• 300 Wh/mi - DC into the Battery - Supercharging - 3% Charge/Discharge Loss
• 333 Wh/mi - AC into the Charger - Day to Day AC Charging - 90% Efficient AC to DC Charger

 

[Kraken]

I've noticed my typical w/mile has gone down considerably this last couple of weeks. For quite some time, I was seeing 330-375. It would take going down a hill to see 300-310. Now I'm routinely seeing 290. I'm doing the same drive. It seems to be regardless of the weather.

 

[bigsmooth125]

Range charged for the first time in a while last night and got 247 rated miles. Strange (and pleasantly surprising) thing was that I drove 12 miles before the rated range budged. In my experience and the reported experiences of most others, typically after a range charge the car can be driven 4-6 miles before the rated range begins to drop.

 

[Gear]

Range charged for the first time in a while last night and got 247 rated miles. Strange (and pleasantly surprising) thing was that I drove 12 miles before the rated range budged. In my experience and the reported experiences of most others, typically after a range charge the car can be driven 4-6 miles before the rated range begins to drop.

It's probably more useful to know how many kWh were used before the rated range moves. For example, I can drive at least 20 miles before I'm below the range I started with because I start off driving downhill for 10-15 miles, plus different people drive differently in general.

 

[dave]

Range charged for the first time in a while last night and got 247 rated miles. Strange (and pleasantly surprising) thing was that I drove 12 miles before the rated range budged. In my experience and the reported experiences of most others, typically after a range charge the car can be driven 4-6 miles before the rated range begins to drop.

Very similar experience this week. Full charge was 249 and then I drove 12 miles without it moving...

 

[Mario Kadastik]

Odd, I've had one occurrence where I could drive 4km before it dropped, but in most cases the first few km consume far above the standard usage therefore dropping the range faster and not quite accounted for in kWh either. It seems even worse if there's been vampire drain after the range charge. I recently charged to 100% getting 396km typical range. Then it bled off overnight (was doing balancing to increase range as per Tesla instructions) 9km giving me 387km range when I started driving. Then after 3.8kWh and 15km I was at 359km remaining range (average usage 260Wh/km or ca 30% above typical range usage of 200Wh/km). The usage itself should have meant about 20km worth of range used, but instead I lost 28km of range. No clue where the 8km got to. Also, it seems the vampire drained 9km isn't accounted for in the kWh accounting that the car shows meaning that it's even more difficult to use the spent kWh as a way to estimate usable range as not all of it is accounted for.

In any case, for the statistics, I did get on 5.9 with the .94 flavor the ideal range of 505km @ 13500km about a week ago after multiple balancing charges (up from 496km before I did 3 balancing range charges). Then when .106 firmware came along the range max ideal charge dropped to 498km in an instant.

 

[AndreyATC]

I was wondering if i can get some answers on SOC
I daily charge my MS to 90% unless i take road trip
Summer weekends we pretty much out of town and i have to trip charge the car
So, in most cases i would time my departure and do 100% right before i leave
The question is: What's better for baterry,
100% and immediate drive
98-99% and immediate drive
Does it even matter since my car is not sitting with 100 SOC?

 

[Gear]

I was wondering if i can get some answers on SOC
I daily charge my MS to 90% unless i take road trip
Summer weekends we pretty much out of town and i have to trip charge the car
So, in most cases i would time my departure and do 100% right before i leave
The question is: What's better for baterry,
100% and immediate drive
98-99% and immediate drive
Does it even matter since my car is not sitting with 100 SOC?

The difference between the two is so minimal as to not matter. The most important thing to do is what you're already doing, not giving it time to sit at the high SOC. Keep doing what you're doing.

 

[jerry33]

I was wondering if i can get some answers on SOC
I daily charge my MS to 90% unless i take road trip
Summer weekends we pretty much out of town and i have to trip charge the car
So, in most cases i would time my departure and do 100% right before i leave
The question is: What's better for baterry,
100% and immediate drive
98-99% and immediate drive
Does it even matter since my car is not sitting with 100 SOC?

The only difference will be that the battery balances at 100%.

 

[Mario Kadastik]

I was wondering if i can get some answers on SOC
I daily charge my MS to 90% unless i take road trip
Summer weekends we pretty much out of town and i have to trip charge the car
So, in most cases i would time my departure and do 100% right before i leave
The question is: What's better for baterry,
100% and immediate drive
98-99% and immediate drive
Does it even matter since my car is not sitting with 100 SOC?

The difference will be in balancing as already mentioned. Also, if you rarely charge to 100% the balancing might take a while so expect the car to sit on 99% for a longish time. I charge at home at a rate of 10% / hour approximately and while going 70% to 80% will be 1h and 70% to 90% will be 2h, the actual 70% to 100% will take 3.5-4h. So anticipate some extra 30-60 minutes for the balancing of the battery pack. And unless it's really hot outside, the balancing does more good for the battery than the extended high SOC state does. A battery that isn't balanced will get different cells cycling at different depths of charge and that isn't that great. I personally would like to see Tesla introduce balancing to every charging, no matter if you charge to 80%, 90% or 100%, but I guess technically it's easier to do it at the top.

Also, don't worry too much about sitting at 100%. It's not the true 100% of the battery anyway and Teslas own procedure to balance the pack is to let the car sit at 100% for 12+ hours. That was the recommendation I got from Tesla when they were investigating why I had lost range. And I did indeed gain back most of the range by doing a couple of days of range charging and letting the car sit overnight at 100%.

 

[glhs272]

As promised, another update on my decreasing rated range...or lack there of:

At 24,000 miles I am still getting 208/209 rated range miles at 100%. For this weekend's road trip, my first range charge on a cold battery yielded 208 miles rate range. The second range charge yielded 209 at the supercharger and with a warm battery. I did not let it complete the range charge at the supercharger, pulled away after it was showing 209. Sorry I forgot to check ideal range during the range charge.

Warm battery @supercharger

Cold battery @ home

 

[gg_got_a_tesla]

At nearly 25,500 miles, I'm at 203 miles rated, at 100%. 182 at 90%. Been at these numbers since 5.9.

As can be seen from our signatures, my car's about 7 months older than @glhs272's.

 

[Kraken]

Since the 5.9 changes that "increased" range estimations, I've lost a mile or two still. Nothing dramatic though as I'm hovering around where it's been since close to the start of the year. My drive length has increased dramatically, and I'm using most of the battery every day. I think that along with some other things is helping re-calibrate my range slowly over time. It appears that the car is slowly adapting. When I get home, I now have about 40 miles remaining. Initially when I started making this drive (on 5.8) I was getting home with 30. As time went by, that number dropped down towards 20. Then 5.9 came out and I was back up to 30 due to the 10 mile increase we all saw. Now though my remaining amount is raising up to 40.

I think it must be slowly wiping out the bad estimation numbers it learned over the first half year of ownership. It would be nice to see the 90% charge actually go up as well.

Also, the numbers (especially when my wife drives) for our Avg watt/mile have dropped quite a bit. There is a huge difference when my wife drives cruise control 75 and when I do. We drive opposite directions, so I'm not sure if it is a setting thing or a elevation/wind thing.

 

[mknox]

I noticed something odd the other day: As I was driving along, my Rated Range was counting down from triple digits to double digits. Somewhere in the 90's. I stopped at a Starbucks for a half hour to 45 minutes and when I got underway again the rated Range was back up over 100. I was not plugged in, and the weather was a nice sunny 72 degrees. I've never noticed anything like that before, but it was very obvious this time because of going from somewhere in the 90's to something a bit over 100.

I've also noticed that often the Rated Range number on the dashboard will be a mile or two different than the Charging screen on the 17". Both of these seem to have started after 5.9.

 

[Kraken]

I noticed something odd the other day: As I was driving along, my Rated Range was counting down from triple digits to double digits. Somewhere in the 90's. I stopped at a Starbucks for a half hour to 45 minutes and when I got underway again the rated Range was back up over 100. I was not plugged in, and the weather was a nice sunny 72 degrees. I've never noticed anything like that before, but it was very obvious this time because of going from somewhere in the 90's to something a bit over 100.

I've also noticed that often the Rated Range number on the dashboard will be a mile or two different than the Charging screen on the 17". Both of these seem to have started after 5.9.

I've seen both before on earlier versions of the firmware. I think parking for long enough causes it to re estimate the range left. The biggest thing I've learned in a year of ownership is that every number related to charging and current charge is an estimate and can vary a bit from day to day even under the exact same situation.

This goes for the displayed range, the energy graph, the charge rate, the used kWh display, the trip information, the amount charges display.. all of those are estimated and aren't 100 percent consistent.

 

[hans]

I've seen both before on earlier versions of the firmware. I think parking for long enough causes it to re estimate the range left. The biggest thing I've learned in a year of ownership is that every number related to charging and current charge is an estimate and can vary a bit from day to day even under the exact same situation.

This goes for the displayed range, the energy graph, the charge rate, the used kWh display, the trip information, the amount charges display.. all of those are estimated and aren't 100 percent consistent.

Estimating SOC is more accurate when the battery is not under load (i.e. charging or discharging).
That is why sometimes you will see the estimate drop after charging finishes, or rise when you stop driving.

 

[tiblot]

At nearly 25,500 miles, I'm at 203 miles rated, at 100%. 182 at 90%. Been at these numbers since 5.9.

As can be seen from our signatures, my car's about 7 months older than @glhs272's.

Just as a data point, My car is 1 week old. 90% daily charge goes to 190-191. I'm on 5.11.

Have not done a max charge yet.