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VIN: P06092: Max charge rate drop from 266 miles down to 250 miles

I received my Model S in March 2013 (with now 15600 miles on the counter)

I used to be able to charge at 266 miles, I am now down to 250. (Service said it was software related)

Another tesla owner came to charge at my place (He got the car in November 2013) and max charged at 271 miles with the same software version!

I am very concerned about my max range drop. Is anyone experiencing the same drop?

Thanks

Software version: 5.8.4 (1.49.57)

I don't own one YET. Per my discussions with local service center, I was told that it is not uncommon to have small amount of range loss in the first year. That being said, i think your friends will also go down a little in the coming months and then level off.

@mlaureti

All batteries degrade and has a finite cycles. That means they will all have to die some day.

What different about your car's battery pack is it is guaranteed for 8 years with unlimited miles.

That's a long time, and many many cycles when compare with what are known with your flashlight and laptop batteries.

So you should expect degradation for the next 8 years.

Tom Saxton collected Roadster's battery history and found that the average at 100,000 miles is 80% of maximum capacity.

I would use that as a guideline and if Mode S degrades worse than Roadster's then I would worry.

A lot of it is software related after one of the more recent updates. 23,800 miles and 10 months. My usual charge Is 90 % which is 221 miles. My range charge is about 255

Recent owner data suggests that much of the current range difference that some owners are seeing is not degradation but rather cell imbalance.

Imbalance is where some cells in the pack are not charged to the same levels as others, and therefore don't get fully charged.

Rebalancing can be manually done now with a series of deeper charge / discharge cycles. Owners are reporting restoration of significant range from their experiments.

It's too early in the game, so it's hard to make definitive conclusions right now. Here are my intuitive predictions based on the engineering data available now -

1. The actual degradation is much smaller than currently suggested by the range estimation software.

2. Tesla will at some point provide a software procedure that automatically rebalances the pack to restore range.

3. Typical true capacity after 100K miles will be north of 90%

Those are just my guesses, but there is some early data that is consistent with them.

For now, I would not worry too much about range loss inferred from extrapolating these early changes to the estimated range calculations. The current range estimate method aliases the true capacity.

I have been able to keep my well-used battery balanced by doing a few successive full range charges back-to-back, and almost completely discharging the battery each time. I accidentally discovered that we recovered about six miles of range this way last November, while on a ten day trip that included using the full range nearly every day. We now have 21k miles on the car, 13k since battery replacement in August, still have 271 maximum range.

@sccrendo
Amazing or odd, however you want to look at it, but have 24,500 miles and my charging numbers are identical. I will admit to some degredation anxiety, but following the forums would usually ease that a bit. This particular topical seems to come up about every 2 to 3 months. After reading your charge numbers makes me think its software.

@mlaureti - if you have not been doing regular range charges and charging only to 50-70% routinely, then your pack may be out of balance. See the thread below for further info.

http://www.teslamotors.com/forum/forums/regaining-range-rebalancing-pack...

My bets are on nothing more than software. I'm really worried for the folks who are charging their cars to 100% constantly in order to "rebalance" their pack and regain a handful of miles on the display. Some of these folks are leaving their car at 100% charge for days or weeks to try to regain those miles. It seems to me that all you are doing is pulling the range algorithm in the opposite direction based upon usage, but you are also degrading your battery's long term performance in the process.

I'll wait for a software solution from Tesla. I've never range charged and have no interest in doing so simply to see what number I get on the speedo. If I don't need it, I don't do it.

I always assumed that the range number displayed was a prediction. One that was influenced by driving behavior. That is to say that the car takes in to account how you have been driving recently as a predictor of future range. Not unlike the way being heavy on the pedal reduces milage faster in the present.

Rebalancing is not simply gaining range on the display; it is a real increase in range. The evidence for out of balanced packs is widespread and most acute in the 40/60s who are limited to 70% charging and can never max charge. It is a very real loss of range that Tesla is aware of and trying to address. Elon was made aware of the issue this week at their Executive staff meeting (info from an email from Jerome Gullien to a 40/60 owner). This is not simply a software or driving style issue.

Range loss from an unbalanced pack is as real as a loss from degradation. Unless you rebalance the pack it is lost forever. So either you rebalance or you live with the loss of range.

"Range loss from an unbalanced pack is as real as a loss from degradation. Unless you rebalance the pack it is lost forever."

Not to pick, but there does not appear to be any evidence to support this statement. However, Tesla has sent out a number of emails to limited 60 kW owners letting them know that this is a software issue and that it will be remedied in a future update. That's enough for me.

@amped, how do you know that people are "leaving their car at 100% charge for days or weeks"? I have followed the balancing threads here and at TMC closely and see no example of anyone charging and leaving the car fully charged for ANY length of time, except in the instances where the cars takes hours to complete charging the last few miles, which is apparently the best indicator of an ongoing balancing process.

I would never advocate leaving a car fully charged, but am positive that range charging and fully discharging back to back has helped maintain my range, and restore range when it was down. But that needs to be the cycle - only range charge before driving a long way in my opinion. We have lots of opportunity to do that as we must range charge twice per week and fully deplete the charge the next day. The other five days we charge to 90% or less. We did have some degradation, but with this pattern, we now have zero loss of range on a 13,000-mile battery.

We don't intentionally range charge and deplete for that purpose - it just happens to be our normal driving requirement, with a farm, and a house 190 miles away near the city, and an environment that gets a full dose of winter cold temps. I am in the camp that these batteries like being exercised and hate being stuck in perpetual middle-range of charge, with short daily commutes. Tesla says they can handle lots of cycles and we intend to prove it.

@amped, has any one posted examples of the "number of emails to limited 60kw owners letting them know this is a software issue..."?

There is plenty of evidence that rebalancing works to restore range. Everyone here who has tried it reports success. The deniers are not on board, perhaps for good reason, but they also haven't tested the process as far as I can tell from their comments here. I agree that no one has proven that lost range is permanent, although that can be implied from both battery theory and TM statements about range loss over time. Long term range loss may be unrelated to balancing, but we do know that balancing individual cells within a pack is logical from a chemistry and physics perspective.

The evidence is my car. My range was lost and was not coming back until I started higher level charging. There are also many other examples. Now, a software upgrade could rebalance the pack by other means, but it would still be addressing a real problem of an unbalanced pack and reduced SOC, not simply changing the number on the dashboard.

I remember reading a few posts from owners who claim to be leaving their car charged to 100% all the time in order to recover range. I'm just saying that's a bad idea to keep it charged at such a high state of charge for a long period of time (days or weeks). I'm an advocate of using the car as you need to use it, a little or a lot. In your case, PD, you need the range and are using the car appropriately. My concern is specific to those who are doing the full charge without really needing to drive that many miles. It's just my opinion that it may be doing more harm than good versus someone who is actually driving those miles and flexing the battery's muscles.

Anecdotal evidence seems to support your usage pattern, i.e., those who charge to max and then run the battery to low levels seem to show almost no degradation to the displayed range. I think this is a very important point to consider. You are using the full range of the battery versus just charging to 100% for the sake of recovering displayed range.

Apple has a recommended process for rebalancing its battery and making the remaining charge indicator more accurate. What does Apple recommend? Run the battery to zero, then plug in and charge to 100%. Performing this cycle recalibrates the software algorithm that estimates remaining charge. The Model S probably works in a similar fashion, but the key is to use the full range of the battery.

@amped, I just saw the posts about people leaving their cars at 100% charged for weeks! at Tesla's direction. Sorry to question. That would scare me too.

@Amped

"Performing this cycle recalibrates the software algorithm"

So, when "rebalancing", are we actually balancing the charge in the cells or merely causing the software to recalculate the range differently?

@ pbendo,

I suppose that's the million dollar question. Someone at TMC Forums who professes much knowledge about Li-Ion batteries has said or implied that not rebalancing a pack can lead to permanent range loss because the out of balance cells will be pushed further and further to extremes. However, he does not have specific knowledge of how the Tesla BMS (battery management system) functions and admits that his recommendations are based on previous experience with non-Tesla batteries.

I've had my car for almost six months, driven about 5,500 miles, and baby my pack like there's no tomorrow (charge to 50%-60%, increase as needed for daily driving, never go below 40-50 miles remaining, etc.). I just performed my first 100% "range" charge and at 99% I'm showing 301.2 miles (ideal range) and 265.4 miles (rated range).

I'll post a screen shot when I have a chance.

Looks like my battery is as good as new after six months and 5,500 miles.

I baby the pack and typically don't charge more than 50%-60%, don't run the car below 40-50 miles remaining... I just charged to 100% (you guys got the best of me) and here's what I see:

VIN 16XXX, P85, B revision battery

That I have an 85 I may not be as paranoiac as 40/60 owners. As I drive a fair amount most days I 90% charge generally going down to 40 %. the lowest mileage remaining has been 24. Range charged about a dozen times. My initial 90 % was 229 consistently and through 2 software updates went to 225 and now 221 where it has been absolutely consistent. With my recent 700 mile road trip did one range charge to 255 and some charges to 240. Lowest mileage was 45 remaining. My ideal miles was 288 at my range charge. The day after I returned from my road trip I went up to 224 at 90 % and since then am back down to 221. So It does remain possible I am rebalancing to a degree by using most of the charging range I am going to continue to charge like I am and range charge when needed and not worry about anything. At most I could have lost 4% with my range ideal miles at 288 but there has been no change in months. Frankly I am convinced the 4 % is mostly software change anyway.

@ampedrealtor. How do we get the visible tesla ap. Is it run off a smartphone, laptop or the cars computer screen

@amped - be forewarned, I was rock solid with zero range loss until ~8-9 months of ownership (~8-9,000 miles, A-pack). Then there was a relatively sudden loss. I think most of the range loss being seen is in older cars like mine. Now, this may be related to either 8-9 months of babying the pack, age of the pack, the type of pack or who knows what. It will be interesting to see what happens with your car at ~8-9 months.

BTW - up another mile today with rebalancing. My car keeps climbing, slowly but surely.

@SCCRENDO

Visible Tesla thread on TMC:

http://www.teslamotorsclub.com/showthread.php/19975-VisibleTesla

Runs on anything that runs real Java, but unfortunately, that doesn't seem to include my smartphone or the car.

Builds are available for Windows, Mac, and Linux, and the source code is available for enhancements and porting.

Perhaps the promised software solution is more effective rebalancing so a single, extended range charge does the trick.

The software solution for the 40/60s is most likely to simply allow them to max charge to rebalance the battery. Maybe this can be tweaked with software so that it only requires one max charge, but my experience and the comments on TMC threads suggest otherwise.

The fact that today's charging algorithm doesn't effectively rebalance doesn't mean that a software change couldn't implement repeated virtual max charges in a single charging cycle, greatly improving the rebalancing behavior. This assumes that rebalancing just requires exquisite control of the per-cell current and voltage and not repeated discharging below 20%. In other words, I'm assuming the rebalancing is primarily synchronization of the difficult-to-sense battery state and not actually reconditioning the cells like we used to do with NiCads.

@AnoneOne - IMO, this is a hardware issue, not software. A software fix would require sensors for every cell, which I doubt as it would be over 7,000 sensors. Only by measuring individual cells would you be able to find and correct unbalanced cells with a single max charge. Thus, I do not see how this can be fixed with software so only a single max charge is required.

Thank you all for your replies. I learned more in a day on this forum than in the last two weeks from my service centre.

AR;
That's one spectacular screenshot. Suggests the multi-000 cycle life expectancy is real.

I wanted to post a followup to my first 100% max charge and what happened next... As expected, regen was limited but not completely disabled. I had the dashed yellow line at about 30 kWh regen. What I didn't expect, however, was that I drove a full 10 miles on the freeway at 75 MPH before my range display dropped by a single mile. Moving the range display from 301 to 300 took effectively 10 miles of fast freeway driving. Where did these miles come from? The energy used to drive these 10 miles was not reflected in the range display, therefore they appear to have been hidden somewhere.

I'm sure there is a rational explanation, but on the surface it would appear that my 301 mile ideal range was really more like 311 miles because of the first 10 miles that seem to have come out of thin air. If I can get 10 miles with the range display moving only 1 mile, what's going on?


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