Decreasing rated range.

[bigsmooth125]

Yes, very useful. I have been charging to 70% and ending the day at 30 to 40% thinking I was doing my pack a favor by playing in the middle of it's range (which I guess I am). I have also been experiencing very noticeable drops in my Rated Range numbers. Even my 70% number has dropped from 217 to around 201 miles now. The reduced rated range hasn't been a "problem" as such, but is a "concern".

Your 70% charge is greater than my 80% which gives me 194 rated miles. I usually charge to 70-80% and drive down to 50-60%, rarely to 90%, and very rarely 100%. I'm not concerned but do pay close attention to the rated miles out of curiosity.

 

[qwk]

Your 70% charge is greater than my 80% which gives me 194 rated miles. I usually charge to 70-80% and drive down to 50-60%, rarely to 90%, and very rarely 100%. I'm not concerned but do pay close attention to the rated miles out of curiosity.

His 70% number has to be a mistake, as it's not possible unless he has a 300 mile pack. :wink:

 

[scaesare]

His 70% number has to be a mistake, as it's not possible unless he has a 300 mile pack. :wink:

Agreed. That sounds like a 90% range #...

 

[gaswalla]

might be ideal range numbers

 

[Gear]

I think it's worth highlighting that there are two separate (but related) issues:

- What allows the algorithm to be most accurate

- What's best for the battery pack longevity


First- The algorithm:

It must estimate overall capacity of the pack based on some direct measurements (overall min/max voltages, module min/max voltages, charge energy delivered, temp, etc...), as well as some things that can't be measured at rest state, but must be observed as the pack depletes: amount of current delivered, voltage drop over time, etc...

Some of those items (specifically voltage limits) can only be truly measured if the pack is as close to possible to 0% and 100% respectively. It is also at the upper limit of pack charge that it has a chance to most effectively balance the modules, which also eliminates any capacity loss due to a module not having a chance to balance up.

Thus, for the algorithm, full range charges and driving till shutdown, however impractical, would allow for the greatest accuracy and least range loss due to imbalance.

Secondly- The pack:

The health of the pack is best with fewer "full-equivalent" charge cycles, fewer max charges, less excursion in to low charge states, and cool temps. In other words, operate it "shallowly" in the middle of it's range as much as possible.

Although this can lead to pack imbalance, that's not harmful to the battery, just inconvenient to us. The battery management system uses the lower limits of the lowest brick, and the upper limits of the highest, to determine what to set the upper and lower discharge and charge limits, so the pack is always protected.

As can be seen, the two operational schemes are at odds with one another: Pushing the pack to it's high and low limits often is best for the algorithm accuracy and slightly improves capacity due to balancing. It's also the hardest on the pack health. This is a bit frustrating for owners (and likely gives Tesla headaches in trying to tune the display behavior).

For me: the pack health is a priority. I'm not gonna sweat a few miles of variance. My daily driving requires only a fraction of my capacity, so I normally charge to 60-70% and drive it down to about 30-35% on weekdays. On weekends I charge to 90% and may drive it down only to 70-80% at some times, or all the way down in to the 20's at others. For the occasional road trip I'll range charge, but that's becoming rarer with more superchargers sprouting up.

I likely have some inaccuracy in my range displays. I may also have some imbalance. I'm OK with that if it means my (expensive) pack is happier. My 60% charge is right at 147 rated miles. I can often drive a couple of miles before losing any estimated range, so I'm pretty close to 25 miles per 10% of range charge. (my 90% charges are at about 221, so again close). That would put me at just shy of 250 miles for a range charge (which I haven't done in months).

I'd guess that if I did a series of range charges and deep discharges, I'd gain several miles back due to balancing.. and also some due to accuracy as the algorithm learned from the greater sampling extremes... but I don't need it and if my trips are that "close to the edge", I'd probably plan alternate charging stops anyway. The number on the dash isn't enough to get worked up over...

Playing devil's advocate, if you're charging to 90%+ on a daily basis and are showing several miles higher than others who only rarely charge to 90%+, and you're only losing minimal actual mileage because of it (Islandbay only lost 1 or 2 miles after 34,000 on a 60kWh), then aren't you kind of getting more for your money? During trips where range is tight, your presumably can make it more comfortably since your pack is better balanced and displays higher, more accurate range. Having a lower, less accurate rated range reading (say that 10 times fast) wouldn't be a problem if you still were able to achieve the same actual range, but we don't believe it does, do we? I think it's something we all have to decide for ourselves, but there are merits to both sides.

Personally, I don't charge to 90%+ normally because I live in the mountains and don't get enough regenerative braking when leaving my house at that charge level, so I end up having to use friction brakes to keep my speed down, which I don't like doing.

 

[mknox]

Agreed. That sounds like a 90% range #...

Yep, sorry I meant my 90% range :crying:

 

[glhs272]

Playing devil's advocate, if you're charging to 90%+ on a daily basis and are showing several miles higher than others who only rarely charge to 90%+, and you're only losing minimal actual mileage because of it (Islandbay only lost 1 or 2 miles after 34,000 on a 60kWh), then aren't you kind of getting more for your money? During trips where range is tight, your presumably can make it more comfortably since your pack is better balanced and displays higher, more accurate range. Having a lower, less accurate rated range reading (say that 10 times fast) wouldn't be a problem if you still were able to achieve the same actual range, but we don't believe it does, do we? I think it's something we all have to decide for ourselves, but there are merits to both sides.

Personally, I don't charge to 90%+ normally because I live in the mountains and don't get enough regenerative braking when leaving my house at that charge level, so I end up having to use friction brakes to keep my speed down, which I don't like doing.

This is more my situation. Until the charging situation gets better in my area, I need the most out my pack right now...all of it. I am hoping that in one or two more years more superchargers will be sprouting up in middle and northern Wisconsin that a little range loss will become less of an issue. So for me a well balanced pack is important, even if I might have a little more range loss when the car is at 100K+ miles.

 

[Benjamin Brooks]

Anyone on firmware 6.0 seeing any noticeable changes to their rated range numbers after 90% or 100% charge?

 

[AmpedRealtor]

I think it's worth highlighting that there are two separate (but related) issues:

- What allows the algorithm to be most accurate

- What's best for the battery pack longevity


First- The algorithm:

It must estimate overall capacity of the pack based on some direct measurements (overall min/max voltages, module min/max voltages, charge energy delivered, temp, etc...), as well as some things that can't be measured at rest state, but must be observed as the pack depletes: amount of current delivered, voltage drop over time, etc...

Some of those items (specifically voltage limits) can only be truly measured if the pack is as close to possible to 0% and 100% respectively. It is also at the upper limit of pack charge that it has a chance to most effectively balance the modules, which also eliminates any capacity loss due to a module not having a chance to balance up.

Thus, for the algorithm, full range charges and driving till shutdown, however impractical, would allow for the greatest accuracy and least range loss due to imbalance.

Secondly- The pack:

The health of the pack is best with fewer "full-equivalent" charge cycles, fewer max charges, less excursion in to low charge states, and cool temps. In other words, operate it "shallowly" in the middle of it's range as much as possible.

Although this can lead to pack imbalance, that's not harmful to the battery, just inconvenient to us. The battery management system uses the lower limits of the lowest brick, and the upper limits of the highest, to determine what to set the upper and lower discharge and charge limits, so the pack is always protected.

As can be seen, the two operational schemes are at odds with one another: Pushing the pack to it's high and low limits often is best for the algorithm accuracy and slightly improves capacity due to balancing. It's also the hardest on the pack health. This is a bit frustrating for owners (and likely gives Tesla headaches in trying to tune the display behavior).

For me: the pack health is a priority. I'm not gonna sweat a few miles of variance. My daily driving requires only a fraction of my capacity, so I normally charge to 60-70% and drive it down to about 30-35% on weekdays. On weekends I charge to 90% and may drive it down only to 70-80% at some times, or all the way down in to the 20's at others. For the occasional road trip I'll range charge, but that's becoming rarer with more superchargers sprouting up.

I likely have some inaccuracy in my range displays. I may also have some imbalance. I'm OK with that if it means my (expensive) pack is happier. My 60% charge is right at 147 rated miles. I can often drive a couple of miles before losing any estimated range, so I'm pretty close to 25 miles per 10% of range charge. (my 90% charges are at about 221, so again close). That would put me at just shy of 250 miles for a range charge (which I haven't done in months).

I'd guess that if I did a series of range charges and deep discharges, I'd gain several miles back due to balancing.. and also some due to accuracy as the algorithm learned from the greater sampling extremes... but I don't need it and if my trips are that "close to the edge", I'd probably plan alternate charging stops anyway. The number on the dash isn't enough to get worked up over...

Awesome post, thank you!

I've already done a couple of 100% charges and my rated range estimate has increased by 8 miles. That's enough to tell me the battery is fine and I'll be going back to my regular routine of charging to 50%-70%, which is fine for my daily needs.

 

[islandbayy]

Anyone on firmware 6.0 seeing any noticeable changes to their rated range numbers after 90% or 100% charge?

Testing that right now, will report back in the 6.0 thread.

 

[islandbayy]

100% cane out to 206 rated compared to 205 yesterday. that's on my new battery pack that has 4,300 miles.

 

[mfrey]

My MS 60 has 12,000 miles and I only get 178Miles on a 90% charge and 198miles on a full charge. This is a bit disappointing. I tried to reduce the charge amps from 40 to 20 hoping it would gain me back some miles. Not luck still at 178.

Is this normal? I would love to know. This seemly happened overnight as I would normally get at least 185 on a standard 90% charge.

 

[Super Gizmo]

Interesting article regarding charging of li-ion batteries in PC World. Here is the link -
Want lithium-ion batteries to last? Slow charging may not be the answer | PCWorld

 

[Tacket]

Just another data point - MS60 32k miles - been charging to 90% past few days and range has increased from 166 to 171. Will likely continue doing this for a few more weeks then will go back to my normal regime (50%-70%).

 

[Dave EV]

Interesting article regarding charging of li-ion batteries in PC World. Here is the link -
Want lithium-ion batteries to last? Slow charging may not be the answer | PCWorld

This article is much more informative: Green Car Congress: Study finds rapid charging and draining doesn't damage lithium-ion electrode as much as thought

 

[hans]

My MS 60 has 12,000 miles and I only get 178Miles on a 90% charge and 198miles on a full charge. This is a bit disappointing. I tried to reduce the charge amps from 40 to 20 hoping it would gain me back some miles. Not luck still at 178.

Is this normal? I would love to know. This seemly happened overnight as I would normally get at least 185 on a standard 90% charge.

It's has been normal for my car for at least a year or more. My S60 has 18,000 miles and gets 176-177 miles on a 90% charge.

 

[gekkota]

Your experience is nearly identical to my 14,500 mile MS60. I think the car has shed approx 11 miles at 90% over the past few months on firmware 5.12. It's not a great feeling..

 

[Gear]

Your experience is nearly identical to my 14,500 mile MS60. I think the car has shed approx 11 miles at 90% over the past few months on firmware 5.12. It's not a great feeling..

My MS 60 has 12,000 miles and I only get 178Miles on a 90% charge and 198miles on a full charge. This is a bit disappointing. I tried to reduce the charge amps from 40 to 20 hoping it would gain me back some miles. Not luck still at 178.

Is this normal? I would love to know. This seemly happened overnight as I would normally get at least 185 on a standard 90% charge.

You guys will need to charge to 90% (or more) every day for awhile to get the miles back.

 

[efusco]

What about NOT decreasing rated range?
While my daily 90% charge level has dropped from the original 242ish that it started to around 231, and my "usual" range charge has dropped from 272 to ~258 miles, what I've found, at 39,500 miles, is that after a long trip and a full charge (allowed to range charge until the charging actually completed that hour-long last minute) that my range numbers improve dramatically, and they seem to be real. These photos are from this weekend. I range charged to 258 miles prior to a trip to St. Louis (about 225 miles all interstate), arrived with about 8 miles left, charged to about 80% overnight then topped up yesterday afternoon and hit 273 miles rated! Even my 90% rated range has increased back into the 240s it appears.

 

[mknox]

What about NOT decreasing rated range?

That's amazing! I never saw anything above 264 or 265 on a Range Charge even when the car was new. It sounds like your miles came back fairly quickly (i.e. no need for a month+ of 90% charges like others are suggesting). I assume you also have an A-pack battery???