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Decreasing rated range.

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I did not drive the car below 50% during these three max charges. I simply charged to 100% for three days in a row and drove whatever miles I drove those days. My bet is on balancing.

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Yes, range went from 223 to 228 at 90% and from 248 to 253 at 100%.

Sweet. It gives me hope because I lost 7 miles at both 90 and 100 on a new 90D in 6 weeks.

wk057 mentioned something upthread about Tesla being able to do the same thing (reset) which I took to mean they do something at the SC that we can't at home. Is my understanding correct?
 
wk057 mentioned something upthread about Tesla being able to do the same thing (reset) which I took to mean they do something at the SC that we can't at home. Is my understanding correct?

Take this for what it's worth because not everything the service advisors say is actually true, but their intentions are good. I was told by my service advisor that there is a battery "reset" only available to service that will reset the range counter. He said they do this on their loaners after I asked why their loaners, with higher mileage, seem to show no degradation. I asked if they could reset my car in the same fashion, to which he said no.

This is the only time I had heard of anything like this, so take it with a grain of salt.
 
I tested some of this the last few days.

I've been 90% charging to 234mi rated for awhile now (2014 P85, ~20k miles).

A few days ago I range charged to ~97% to trigger a balance cycle, then over the course of a few days drove all the way down to 14mi remaining. Today I charged back up to 90% and the charge stopped at a smidge above 234...it dropped to 233 right after I left my driveway. So not an improvement, but actually slightly worse than it's been. Might try a few consecutive 100% charges later, just out of curiosity.
 
This is very confusing.

1. Why, if the pack was able to balance at 90% on previous firmware, did Tesla opt to change this feature to only be effective during constant voltage charging? Especially when they recommend 90% charging, they should not incentive folks to range charge in order to balance.

2. Why, if the pack can indeed balance at 90%, does it not balance at 80, 70, etc.?

3. Repeated 100% charges should accomplish nothing. Given what we know, balancing only needs one go to get it right. It should not take any more than 1 range charge.

If someone at Tesla is reading this and feels like writing up a blog post addressing these points I think all owners who have ever spent time wondering about range numbers would be enormously appreciative - and there are quite a few, especially with the new 90 kWh customers who are wondering about this.
 
This is very confusing.

1. Why, if the pack was able to balance at 90% on previous firmware, did Tesla opt to change this feature to only be effective during constant voltage charging? Especially when they recommend 90% charging, they should not incentive folks to range charge in order to balance.

2. Why, if the pack can indeed balance at 90%, does it not balance at 80, 70, etc.?

3. Repeated 100% charges should accomplish nothing. Given what we know, balancing only needs one go to get it right. It should not take any more than 1 range charge.

If someone at Tesla is reading this and feels like writing up a blog post addressing these points I think all owners who have ever spent time wondering about range numbers would be enormously appreciative - and there are quite a few, especially with the new 90 kWh customers who are wondering about this.

Agree. I think an easily understood explanation from TM would indeed be helpful. Right now people are uncertain whether it's an issue of a changed or inaccurate algorithm or a battery issue.
 
This is very confusing.

1. Why, if the pack was able to balance at 90% on previous firmware, did Tesla opt to change this feature to only be effective during constant voltage charging? Especially when they recommend 90% charging, they should not incentive folks to range charge in order to balance.

2. Why, if the pack can indeed balance at 90%, does it not balance at 80, 70, etc.?

3. Repeated 100% charges should accomplish nothing. Given what we know, balancing only needs one go to get it right. It should not take any more than 1 range charge.

If someone at Tesla is reading this and feels like writing up a blog post addressing these points I think all owners who have ever spent time wondering about range numbers would be enormously appreciative - and there are quite a few, especially with the new 90 kWh customers who are wondering about this.
This is not confusing at all. Tesla introduced the % slider only to avoid averaging the max EPA charge # with the standard EPA charge #. This would have forced them to advertise the lower EPA range sort of like the RAV 4 EV did. Since Tesla top balances the pack, it has to be at higher charge levels to be effective. This is why charging to anything below 90% used to get folks to see a lower rated range over time. I'm not doubting what Wk stated, because I have no concrete info on the newer firmwares, but it makes little sense that Tesla change the charging algo so much. It certainly is possible, as engineering has been making a ton bad decisions lately.

When a pack gets out of balance and is still being used, the weaker modules/cells get stressed more that the others, which causes them to degrade faster. Only Tesla knows how much though, and it could be too little to worry about.
 
This is very confusing.

1. Why, if the pack was able to balance at 90% on previous firmware, did Tesla opt to change this feature to only be effective during constant voltage charging? Especially when they recommend 90% charging, they should not incentive folks to range charge in order to balance.

2. Why, if the pack can indeed balance at 90%, does it not balance at 80, 70, etc.?

3. Repeated 100% charges should accomplish nothing. Given what we know, balancing only needs one go to get it right. It should not take any more than 1 range charge.

If someone at Tesla is reading this and feels like writing up a blog post addressing these points I think all owners who have ever spent time wondering about range numbers would be enormously appreciative - and there are quite a few, especially with the new 90 kWh customers who are wondering about this.

+1!
 
Yes, in fact it's increasing further. Two days ago I ran the car down to 4 miles of remaining range (that was fun), charging back up to 90% yielded 229 miles.

That is great! I tried a slight variation from your triple max charge method. I did a double max then discharged to 70% (that's all I had time for). Day one I picked up 3 rated miles to 254, day two lost one to 253, today is day three and it's still 253. Still need a few more days to call this a success but so far so good.
 
That is great! I tried a slight variation from your triple max charge method. I did a double max then discharged to 70% (that's all I had time for). Day one I picked up 3 rated miles to 254, day two lost one to 253, today is day three and it's still 253. Still need a few more days to call this a success but so far so good.
Y'all are just treating yourselves. I doubt you're doing the battery any good. If a few miles difference in estimated range, even if it's real and not a measurement artifact (which I doubt), is really that important to you then I would submit that you're cutting your trips too close between charging stops.
 
Y'all are just treating yourselves. I doubt you're doing the battery any good. If a few miles difference in estimated range, even if it's real and not a measurement artifact (which I doubt), is really that important to you then I would submit that you're cutting your trips too close between charging stops.

It's mostly important at the trip's destination when there are no easy charging options. An additional twenty miles can make the difference between being able to get back the previous SC (on the going home side) and having to spend a few hours charging to get there. While you're on the SC route there's currently no problem (although there might be in a few years--I'm hoping few becomes many)
 
Y'all are just treating yourselves. I doubt you're doing the battery any good. If a few miles difference in estimated range, even if it's real and not a measurement artifact (which I doubt), is really that important to you then I would submit that you're cutting your trips too close between charging stops.

I babied my battery for the first year, never charging above 60%-70% because I never needed more. So I don't see any harm in doing a few 100% charge cycles and running it down a few times. I also ran it down to 4 miles intentionally, and planned for it.
 
Just a data point. I just passed through 60k miles a few days ago at 2 years and 11 months since taking delivery.

90% charge is 228 miles (242 originally) = 6% loss
100% charge is 253 miles (272 originally) = 7% loss

While I only have minimal evidence to support this theory, I'm reasonably certain that the miles shown above 265 or so at 100% near the beginning of life are also a calibration artifact.
 
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Another data point...

I just had occasion to range charge and deplete a couple of times to support a road trip. This charge / discharge sequence has not changed the rated range, so I believe the rated range algorithm is calibrated and my pack is balanced.

18.8k miles in 16 months, 85kWh 'D' pack

90% charge is currently 231, originally 240
100% charge is currently 257, originally 267

Both of these results represent a 3.75% loss of rated range and is likely real degradation in the battery capacity.