If you want a psychological boost by seeing a slightly higher number, switch your settings to range mode and you should see 2 or 3 additional rated miles at 90% SOC and probably the same at 100%. I'm at 14,500 miles, and my numbers are basically identical to yours.
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If you want a psychological boost by seeing a slightly higher number, switch your settings to range mode and you should see 2 or 3 additional rated miles at 90% SOC and probably the same at 100%. I'm at 14,500 miles, and my numbers are basically identical to yours.
Kipernicus
Model S Res#P1440
My battery's about the same as hans and SFOTurtle. 4 mile gain from all that range charging hardly seems worth it. I'll use it when I need it, and hopefully the degradation/out-of-balance will slow down in coming years. At least there continue to be more superchargers coming out!
dennis
Model S Plaid
According to this graphic there are 75.9 kWh available for range driving. This weekend I did a range charge and immediately drove to where there were 7 miles left and 69.2kWh used. 7 miles equals approximately 2 kWh, so my usable capacity is now 71.2 kWh, representing lost capacity of 4.7 kWh, or approximately 16 miles of range. My current range charge shows 245 miles of rated range. So the "algorithm problem" appears to understate my battery capacity by 4 miles (265-16=249).
The real question is whether the lost 4.7kWh is recoverable by improved pack balancing with some future software release (as opposed to better range estimation).
'A' battery, 11,000 miles in 16 months. Normally charge 40%->80%, approximately 10 range charges total.
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Kipernicus
Model S Res#P1440
I wonder what this chart looks like for a 60. Would the protections at the bottom be a similar %, or a fixed # of kWh?
I'm wondering the same.
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I wonder how accurate this chart is when the total of the 4 segments shown is actually 84.9kWh. Do we know where this chart originated from exactly?
my observation is that the less frequent one does a range charge, the larger the "degradation" appears when the range charge is finally done. In my opinion, this leads more credibility to the fact that the range loss is from balancing issues, and can be recoverable by repeated range charges.
Maybe, but at any rate it is NOT healthy for the pack to be imbalanced. Reason is that some cells will be cycled to lower SOC than others which can be detrimental. So we shouldn't just say, "Oh well, my pack is out of balance so it's not a big deal. I'll recoup those miles when I range charge next time."
> Did my first range charge in quite a long while and got 250. I'm at 14 months and 18,000 miles. A bit disappointing. I was at 272 when I got the car, so very close to 10% loss in a little over 1 year. [ckessel]
So you got 272 @14 months ago under (ancient) firmware, and 250 today under latest firmware. Due to the firmware differences your best today might be around 255, based on what others have concluded, I believe.
In the next few weeks if you can do a couple of range charges for long trips down to ~20 miles remaining each time, you might see that number improve somewhat.
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So you got 272 @14 months ago under (ancient) firmware, and 250 today under latest firmware. Due to the firmware differences your best today might be around 255, based on what others have concluded, I believe.
In the next few weeks if you can do a couple of range charges for long trips down to ~20 miles remaining each time, you might see that number improve somewhat.
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Thumper
Active Member
My experience is identical to wycolo. A pack battery, 11K miles, first max charge for months, 250 miles. Is the loss real? It is hard for me to think that with all the other sophistication that Tesla has put in our packs, that they don't balance cells automatically. I will not be undertaking any max charge regimens unless directed by Tesla.
I don't believe this is true. As I understand it, the high and low of the pack is determined by the most out of balance cell. That is why your capacity is reduced.
Yes, that's true, but not what I was saying. I was merely arguing that it is detrimental to battery health to run an out of balance pack due to the fact that some cells will inherently be cycling to lower SOCs (bad) than other cells. This is why Tesla really ought to do the best they can to have the BMS continuously balance the pack, not just when charging to 100%.
stopcrazypp
Well-Known Member
I believe the range buffer on the bottom (both the "reserve" range after "0" miles left is shown and also the buffer that prevents battery bricking) prevents that from happening, however, you are correct that in general it raises the risk of a over-discharge. The Roadster does continuously balance the pack, but Tesla appears to have disabled or greatly reduced that for the Model S.
I suspect two factors for why Tesla did this: 1) Elon once mentioned they worked hard to get the charging efficiency numbers higher for the Model S in order to have good EPA numbers (and balancing is detrimental to this as you are essentially throwing energy away). 2) Vampire drain has been a big issue for the Model S and continuous balancing will only make it noticeably worse.
I also wonder how much of the balancing got screwed up when they implemented the charge slider.
Maybe I'm missing something, but how would it affect vampire drain if they just balanced at the end of each charge?
I have no idea if this information is correct, and I apologize if it has been posted before, but over at the teslamotors site
Range degradation remedy? | Forums | Tesla Motors
a poster is claiming that Tesla sent him the following email, which basically claims that the reason one might see a higher rated range after a full charge is that doing a full charge lets the car measure the battery's energy capacity more accurately than it can be estimated from their algorithm when the battery is not fully charged and that it doesn't have to do with balancing the pack:
"As far as your question about “pack balancing”, it is not really necessary. Fully charging your battery to the maximum several times may increase the estimated range that is displayed on your dash, but not necessarily because your battery packs need balancing. The algorithms used for estimating range are based on determining how much energy is stored in your battery. However, the only accurate way to measure the amount of energy a battery can store is to fully charge the battery, then completely discharge the battery to zero, then measure the amount of energy that was released. While this would give an accurate measurement, it would not be good for the battery. So the Model S uses algorithms to estimate the amount of energy a battery can store.
When a battery is fully charged, the algorithm is able “learn” the “upper limit” for the battery. But since you don’t fully charge your battery often (which is a good thing), the algorithm for your vehicle may no longer have an accurate value for the “upper limit”, causing your Estimated Range calculation to be slightly off. By fully charging your battery several times, your algorithm may relearn the “upper limit” of your battery, so it may start to show a different/higher number for your Estimated Range. It is important to understand, however, that fully charging your battery several times, is not going to actually help your battery. In fact, frequent full charging of your battery can actually accelerate battery degradation."
Range degradation remedy? | Forums | Tesla Motors
a poster is claiming that Tesla sent him the following email, which basically claims that the reason one might see a higher rated range after a full charge is that doing a full charge lets the car measure the battery's energy capacity more accurately than it can be estimated from their algorithm when the battery is not fully charged and that it doesn't have to do with balancing the pack:
"As far as your question about “pack balancing”, it is not really necessary. Fully charging your battery to the maximum several times may increase the estimated range that is displayed on your dash, but not necessarily because your battery packs need balancing. The algorithms used for estimating range are based on determining how much energy is stored in your battery. However, the only accurate way to measure the amount of energy a battery can store is to fully charge the battery, then completely discharge the battery to zero, then measure the amount of energy that was released. While this would give an accurate measurement, it would not be good for the battery. So the Model S uses algorithms to estimate the amount of energy a battery can store.
When a battery is fully charged, the algorithm is able “learn” the “upper limit” for the battery. But since you don’t fully charge your battery often (which is a good thing), the algorithm for your vehicle may no longer have an accurate value for the “upper limit”, causing your Estimated Range calculation to be slightly off. By fully charging your battery several times, your algorithm may relearn the “upper limit” of your battery, so it may start to show a different/higher number for your Estimated Range. It is important to understand, however, that fully charging your battery several times, is not going to actually help your battery. In fact, frequent full charging of your battery can actually accelerate battery degradation."
hans
P631
This description is consistent with the "Current integration method" and "Kalman Filtering" methods of estimating State of Charge (see State of charge - Wikipedia, the free encyclopedia ).
Kipernicus
Model S Res#P1440
Which do you mean?
(1) algorithmically (bug/design change)
(2) due to users picking values other than 90% (max Daily) and 100% (max Trip)
(3) the switch from 92-93% (Standard) to 90% (max Daily)
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