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islandbayy
Active Member
YES! OMG! Corrected.
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And when I drove 20 miles today and charged back up, I was back up to 232 miles. This algorithm needs help!
islandbayy
Active Member
Not sure if I mentioned it in the past anywhere, but so far, to date, the absolute BEST MOST ACCURATE algorithem that projected the best rated range estimate was what my car was delivered with, I believe Firmware 4.1......
I think really it wasn't the algorithm in the older firmware was more accurate back then, just simply less aggregated battery pack measurement errors at mile 0... For example the initial conditions may have been accurately calculated at the factory, but over time without a recalibration the algorithm has less & less precise data to work from.
So my range has stayed up after my most recent service as previously discussed. My rated range at near full charge today was 263 (99%) and my 90% charge is 246.
I plan on asking my sc exactly what changed the range this weekend and post their response here very soon.
Havin now lost less than 1% of my range from 2012 is incredible. I hope again this lasts and is able to be replicated for others.
I plan on asking my sc exactly what changed the range this weekend and post their response here very soon.
Havin now lost less than 1% of my range from 2012 is incredible. I hope again this lasts and is able to be replicated for others.
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mknox
Well-Known Member
@walla - Please do post here once you know more. My car was in for annual service earlier this week and while it did have a temporary boost in range (likely due to FW update), this quickly disappeared and reverted to the old numbers.
SteveS0353
Member
I'd like to understand what the SC did for you. I have a 3 month old P85+ with 5,500 miles on it. For a few months, I was charging to 70% daily charge as I'd read somewhere that was best for the longevity of the pack, but my rated range was slowly sinking (see this post). On advice in this thread that it's a firmware calibration and balancing issue, I started to standard charge to 90%. But after 30 days of doing that, my rated ranges have only improved slightly. My standard (90%) charge is now 231, and 100% range charge pegs at 257. That's more range degradation than others are reporting after more miles on their vehicle. I suspect that there is a firmware variable which drifts over time with some packs and may need a manual calibration to correct the drift. Anyway, please post what you find out. I am planning to make a SC appointment.
Pilot_51
Member
I was holding steady at 147.44 rated miles (according to VisibleTesla) at 80%. I always charge to 80% and the lowest I've brought the rated miles is to the mid-70's, until yesterday when I drove it down to 37 (20%). After charging back up to 80%, VT shows an increase of 0.7 to 148.14. As expected, a low SoC is as important for calibration as a high SoC.
I have been charging at 60-70% daily for the past year in order to preserve the battery life. Since my daily commute is relatively short (~25 mi), I'm usually charging the car daily at ~50% SOC. Like many others, I have seen drops in the rated range using this charging strategy. While I understand that the battery life/range is unchanged and the calculated range is simply inaccurate due to lack of pack balance, etc., it is neverless disheartening to see the range drop on the car over time. This range drop also has real life implications when taking long trips, especially if the range charge reading is 20-30 miles short of 265. In reviewing this thread and others, it appears that many owners have had good success at charging daily at 90%.
Given these facts, I think 2 charging strategies seem reasonable in order to maintain accurate range calculation and still preserve long term battery life:
Any opinions?
Given these facts, I think 2 charging strategies seem reasonable in order to maintain accurate range calculation and still preserve long term battery life:
- Charge at 90% daily and plug in every night. (This strategy would have the benefit of maintaining accurate range calculations on the battery pack and see the least drop in range. However, I still wonder if maintaining 90% SOC over the long term can still degrade the overall battery life, especially in warmer climates like Florida.)
- Charge at 90%, but allow the battery to run down to about ~50% before charging back up to 90%. (This would keep the battery in the 50-90% range most of the time, which may(?) improve the overall battery life. However, one may see more range drop over time compared to charging at 90% daily.)
Any opinions?
I have been talking to the SC about my decreased rated range and they sent the logs to the engineers. The reply I got was "its the calculations in the firmware and should be corrected with next firmware update."
Right now I have about 17K miles on it, 1 year old and at 80% of daily charging, I get 202 miles. I will give the 90% method a shot and see what happens. Should I range charge now, or after a few weeks of charging to 90%?
Thanks
Right now I have about 17K miles on it, 1 year old and at 80% of daily charging, I get 202 miles. I will give the 90% method a shot and see what happens. Should I range charge now, or after a few weeks of charging to 90%?
Thanks
you should really not sweat. Your 80% is completely in normal territory for 17k miles. IMHO this thread causes a lot of undue concern and unnecessary charging routines. You should only range charge when you need it and will drive immediately on completion.
You have been doing the right thing. It is a fact (not rumors or speculations) that Lithium batteries will age slower when they are kept at a lower state of charge. So you have done the right thing to keep them healthy.
Seeing the range drop is a separate issue. It's annoying and a little frustrating, but of course Tesla wants to be on the safe side when it comes to predicting range. I had 270 on a range charge when I got my car, now I get about 10 miles less and the range drops about 3 miles almost right away when I start driving. Do I really have 5-6% less capacity on my battery than when it was new? I don't know for sure. I really wish there was a 'battery calibration cycle' or something similar to get the calculation current. There are all kinds of speculations on how to balance and recalibrate but truth is, we don't know. I have been tracking my battery with Visible Tesla to do a rates rage over battery percentage and it clearly shows a constant and linear drop over time. There is no indication that doing a full cycle to recalibrate would help regain range. I do remember Tesla saying that towards the end of the battery capacity the calculated range is based on current battery data rather than the calculation. IOW, they have a good idea based on that what is left in the battery. I think the mistake here in this discussion is that we charge and then look at the rated range which is a number mostly based on the algorithm.
The proper way to measure the capacity of a battery is to charge it to a specific voltage, then discharge it to a specific voltage and measure the amount of energy that was taken out. That's the only way to get an accurate measurement.
I understand your point. Since what you propose is not achievable by the owners, we are still left with our best guesses on the optimal way to preserve battery life while allowing the car software to calculate the most accurate range. As I stated above, I don't really think that my battery has lost as much range as the car displays. Nevertheless, it is still frustrating, particularly when it comes to long distance driving. I still adhere to the general principle that 0 means ZERO miles, which means that I would not count on any additional range than what the car displays. Although my current charging regimen preserves long term battery life, it has come at the cost of a progressively inaccurate range reading. I'm not sure it's a good trade off. Therefore, I will again propose two charging strategies for the community to consider:
- Charge at 90% daily and plug in every night. (This strategy would have the benefit of maintaining accurate range calculations on the battery pack and see the least drop in range. However, I still wonder if maintaining 90% SOC over the long term can still degrade the overall battery life, especially in warmer climates like Florida.)
- Charge at 90%, but allow the battery to run down to about ~50% before charging back up to 90%. (This would keep the battery in the 50-90% range most of the time, which may(?) improve the overall battery life. However, one may see more range drop over time compared to charging at 90% daily.)
Any opinions or suggestions?
It is. You charge the car 100%, you drive it to the end and look at the trip meter's energy consumption.
Perhaps. But I'm not willing to risk being stranded simply to get the number. It's certainly inconvenient at best. I would much rather tackle the issue via a sensible charging strategy. That is the reason why I posed the question.
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