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Roaster owners have the ability to access internal logs and diagnostics that provide info on the battery pack. Does the MS log the same info? Absolutely and probably more. Are we allowed to see them? No, I've tried asking.
Providing owners with simple diagnostic info seems like a no brainer to me especially since Tesla has already demonstrated a willingness to do so with Roadster owners.
Providing owners with simple diagnostic info seems like a no brainer to me especially since Tesla has already demonstrated a willingness to do so with Roadster owners.
Tesla has changed the firmware so much, that comparing numbers is very difficult. My car charges to 258 rated at 100%, and 233 rated at 90% consistently. Yesterday I took a trip from a max charge to 11 rated miles and the car showed right at 70kwh used, and 208 miles traveled. If a new car range charges to 265 rated, but can use 74kwh, something is way off in some my displayed numbers above.
Absolutely true that firmware changes negate validity of many comparisons. Your numbers do not seem that far off. If 265 mi and 74 kWh capacity is correct for a "new car" full charge, -- you used 70 kWh and had, say, 3 left for the remaining 11 miles, for total of 73 kWh... then your rated at 100% should have been ~261.5 vs. 258 you showed. That's actually about a 1% difference. Pretty darned accurate!
If your issue is that you only got 208 + 11 miles, then maybe the problem is you exceeded 283 wh/mi average during your trip, which would be rated per mile "par" for a battery with 73 kWh capacity and 258 rated range!
kevincwelch
Active Member
So, I max charged to 252 miles this morning. I have 8500 miles on the odometer. Other than battery error, manner in which the firmware calculates rated miles (per previous few discussions), and possibly temperature (it's 34 degrees in my garage), what could be an explanation for this decrease in max range? The last time I charged fully was in September, and I got 263 miles. The car is 2/2013 vintage. VIN 4xxx.
1) There's nothing to indicate temp is in algorithm directly, tho temp could affect the BMS perception of battery capacity when cold. So, in that way it could be a factor.
2) Battery degradation over first year is typically about 5%, after which it levels off. You are right at that, so could be factor.
3) You didn't note your charging and discharging habits. If you don't regularly charge to 90, and occasionally discharge to some low number, the BMS loses track of the endpoints... and possibly does not effectively balance pack.
Well the issue is that a new car charges to 265 rated, and can use 74kwh. There is no way that 11 rated plus 7(the difference between 265 and my 258) is equal to 4kwh, because I was at 67 kwh used with around 72 rated remaining. Things just dont scale. In my opinion, Tesla is somehow compensating for battery degredation in the older cars with the newer firmwares.
Probably about 100 or more on this thread... unfortunately nobody has compiled into database, and thread is becoming unwieldy, so could take some browsing/searching.
In my experience, if one doesn't charge to at least 90% on the slider, range drops, possibly due to the module groups varying max voltage, and rated range drops. This is very hard or maybe impossible to get back into whack. All of my drops are a result of many consecutive partial charges without a chance to balance.
Wow.... only 8500 miles in 21 months of ownership? That's only about 276 miles a month. Was your last range charge September of 2014, or 2013, and hopw many of those miles were since that last range charge?
The difference is ~4% of capacity, and you may still be in the "steep" part of the battery degradation curve with that few miles on the car. That having been said, I also wonder if there's more than average error as well, as it would seem likely that the frequency and/or depth of charge cycle are probably much less than average as well...
I do have many other data points to compare to, but most of them are with older firmware. It just seems like there is either less energy available for use now, or the pack really has some degredation/is out of balance, but doesn't show it in the rated range numbers. I'm not even sure if the kwh used display hasn't changed to some degree. So many questions, with few to no answers.
kevincwelch
Active Member
I regularly charge to 80% and typically put on 20 miles or leas per day. I used to charge to 90% but changed to 80% maybe 6 months ago.
My last range charge was sept of 2014.
I wonder if I should keep it at 90% and not charge as frequently. This seems to go against what Tesla recommends - keeping it plugged at all times when possible.
My main problem is at work: unplugged for 12-14 hours per day, and in the winter around 20-30F. Loses quite a bit of range....
My last range charge was sept of 2014.
I wonder if I should keep it at 90% and not charge as frequently. This seems to go against what Tesla recommends - keeping it plugged at all times when possible.
My main problem is at work: unplugged for 12-14 hours per day, and in the winter around 20-30F. Loses quite a bit of range....
The battery degredation difference between charging to 80% or 90% is going to be pretty small, while the rated range shown difference is going to get bigger. This we know. What we don't know with absolute certainty, is whether one can get this range back with either new software or different charging methods. In my opinion, it is going to be very difficult if not impossible to get ALL of it back.
50000 Mile Report. B Pack (as a Sig not sure why because never replaced). 90% charge is 223-225. 100% is 249-250. The car will be two years old December 2nd. I am very pleased with the slight degradation. My secret has been to charge to 90% every day. However I set the current to the lowest it will allow to be ready in the morning. I rarely have to change past 25 amps to get the job done. most nights its 15. My theory (and keep in mind I know nothing about batteries) is that a slower charge is better because it keeps the battery cool.
But still it is 100% guaranteed that this "estimated range loss" has 0 (zero, none, nada, zilch) effect on actual range you can get out of the car i.e. distance driven before shut down.
Stop obsessing about numbers. DRIVE!
kevincwelch
Active Member
And you know this how? "100% guaranteed"? Battery degradation is real and a fact. You have no clue how much is lost in actual range and how much is just calculation inaccuracy.
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