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Trying to see if our CPO Roadster ideal mile range loss/CAC value decrease is real...

Discussion in 'Roadster' started by AEdennis, Jul 7, 2014.

  1. AEdennis

    AEdennis Active Member

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    So, we picked up my wife's 2008 1.5 in September and it had about 187 Ideal Miles in Standard Mode and around 240 in Range Mode (don't remember exactly how much.).

    She's been pretty much driving it on a daily 60 mile roundtrip and plugging in and charging overnight. Since we got it in September it was (until I started fiddling with it last week) at 171 Ideal Miles in Standard Mode.

    So, I asked the Service Center if there is something that can be done, so I did as they suggested and did two days of Range Mode charging and drawing the battery down to between 20-30% SOC (thanks to OVMS it's pretty good with that.) I actually overshot the charge the first day (down to 10%) and was pretty good the second day (around 20%). And then per a suggestion in my blog comments from MPT, I plugged it in on Storage mode overnight and drew the battery back down to 21% SOC (OVMS again) until I charged it at Standard mode last night.

    This morning, my wife had 174 miles in Standard mode...

    I'm wondering whether or not the capacity loss is "real" or "perceived" and the other thing that I was suggested to do was have her plug in every other day. (Or at least in storage mode overnight in-between full-standard charges.) It's getting hotter, so the car and it's loud fan racket will start draining more in the heat of the garage.

    Any suggestions? It's a bit of a hassle either way, not sure how to react to a range loss from 15 miles to 12 miles of loss in less than a year from CPO is "normal" or not.

    Just thought to post OVMS values (I probably should update my blog with this information too)

    Values from October 2013, when I first started to use OVMS.
    Standard - Charging Done SOC: 96% Ideal Range: 183 mi Est. Range: 173 mi ODO: 3,578.8 mi CAC: 154.38

    Values from today overnight charged in Standard mode and 174 miles (the CAC value is the same from the evening before it started to charge.) (unfortunately after my wife drove about 30 miles)

    Not charging SOC: 82% Ideal Range: 147 mi Est. Range: 144 mi ODO: 10,901.2 mi CAC: 145.44.

    Thoughts?
     
  2. wiztecy

    wiztecy Active Member

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    If your CAC has dropped from 154 to 145, dump your logs and run it through the VMSparser to see if you have a battery sheet that's pulling the rest down. Tesla has a graphical parser that shows the Ah capacity of each individual brick as well as sheet. The VMSparser, ran with the right flags, will show you which brick is low as well as the Ah capacity.
     
  3. AEdennis

    AEdennis Active Member

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    Thanks for the advice. Something to look forward to when the wife gets home today (I get visiting privileges to her Roadster). The Service Center is scheduling something called a "bleed" test when they get some parts that we're waiting on to fix some minor things with the car.
     
  4. wiztecy

    wiztecy Active Member

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    To me the bleedtest is useless, it won't flag one or two sheets that are pulled down low.
     
  5. slcasner

    slcasner Member

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    The change you are seeing may not be real. In a comment at the end of your blog article that you reference, you mentioned that when you first got the car you would charge at 12A/120V and noticed that it would charge to a higher IM than at 30A/240V. Several of us have observed this phenomenon, but I don't think anyone has a definite answer as to why the charging keeps going longer when at the lower rate. Your 187 number may reflect the battery being charged to a higher fill level like 100% rather than the typical 95%. It's not valid to compare the IM when charged to 100% with the IM when charged to 95% since the IM is proportional to the charge level. If you charge again at 12A/120V it will probably again fill to a higher level.

    The second factor is that the estimate of battery capacity loses accuracy when the bottom of the battery has not been tested for a while. That's what you were addressing in your experiments. For my own car (VIN #33 2008 Roadster 1.5 with 32K miles), the typical driving pattern was a 13-mile round trip commute with charging only every 3-5 days after the battery level dropped to the 50-60% range. The CAC was down to 140.12 and the typical Standard Mode Ideal Miles was 168. Then we drove from home in Sunnyvale to Vancouver, BC in early April, followed by a trip down to Santa Barbara later in April and another trip to LA in mid-June. On those trips we would charge in Range Mode overnight and drive in Standard Mode up to 150-160 miles in one leg, with the deepest discharge to 11% and 19 IM. I anticipated that this exercise for the battery would increase the range estimates, and indeed it did. After the Vancouver trip the CAC was 145.01 and now it is 149.15. The IM increased to 179. So, I don't think the change you have seen is cause for alarm.
     
  6. AEdennis

    AEdennis Active Member

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    slcasner,

    Thanks... That's what I was wondering. Figure the algorithm for miles on the 1.5 is the first attempt with numerous adjustments...

    12A/120V actually charged greater than 187 when I used to do that a few times in September. But, will try to do that when I have space to do that test. (I have 120V on the other side of the garage from the Roadster (where the Model S parks) and the S doesn't fit in the space we have set aside for the Roadster.) I figure the wait for parts with the SC is "a while"....
     
  7. AEdennis

    AEdennis Active Member

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    OK... Tried plugging in a 1GB FAT, 1GB FAT32, 2GB FAT, and 2GB FAT32 drives to the USB port of the Roadster. I got a Memory Stick Transfer Failure message on all four formats in the VDI. I created a folder in each of these drives called VehicleLogs.

    Same failure in all four drives with the diag port.

    Any hints will be welcome.
     
  8. slcasner

    slcasner Member

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    The official "TESLA"-labeled flash drive is 1.03GB capacity in MS-DOS (FAT16) format. It was provided with the root directory containing a file named "Log file instructions.pdf" and a directory named "VehicleLogs". The file is not required, so it sounds like at least one of your setups should have worked. The only guesses I can make are that you mistyped the directory (folder) name or perhaps made it write-protected?

    I have also successfully used the 1GB flash drive that was given by the Blink folks to each of the participants in TESLIVE last year. All I did was to delete the unnecessary Blink advertising files and add the VehicleLogs directory.
     
  9. richkae

    richkae VIN587

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    I don't think you left it plugged in long enough in range mode.
    I recently had my battery replaced. When I got the car back, the car charged to the ~150s in standard mode.
    After a little less than 3 weeks of low SOC + range mode cycling it charges to 184 in standard mode.
    During those 3 weeks I charged in range mode several times - leaving it plugged in and full for more than 24 hours for some of those.
    It took me a few days each time to drive it down to low SOC between each charge.
    I think it needed time plugged in and near full to balance.

    ( it was not easy for me, the car spent more time at full range mode during those 3 weeks than it did in my previous 5 years )
     
  10. wiztecy

    wiztecy Active Member

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    #10 wiztecy, Jul 8, 2014
    Last edited: Jul 8, 2014

    Ask Tesla to reboot the VDS when you stop by next time. I've had my VDS fail to dump logs and what it took was an unplug/plug of the computer which triggers the reboot.

    - - - Updated - - -

    Balancing the pack will occur greater or equal to 82% which is the standard mode SOC of the pack. I had two replacement packs, the first one never climbed up to my original SOC / ideal miles after balancing and Tesla replaced it. I did the Range mode balancing. The second one I was easier on it, did all the balancing via std. mode and it balanced fine. Both balancing paths worked, Range mode will balance it a little faster but I didn't think it was worth it since its sitting at a higher SOC doing nothing useful and I had time... no long trips planned. Once the pack was balanced I did a full range mode charge, quickly unplugged when done, then pulled the SOC down to 30% or more on one key turn drive and charged it back up to recalibrate the CAC / ideal miles.

    The CAC will drop and same with ideal miles. I've found CAC will drop the most in the winter. If it drops in the summer it usually comes back up after a long drive. My ideal miles will fluctuate between 182-188. CAC from 154 - 157.
     
  11. AEdennis

    AEdennis Active Member

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    Thanks Wiztecy... I'll do that.
     
  12. wiztecy

    wiztecy Active Member

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    #12 wiztecy, Jul 8, 2014
    Last edited: Jul 8, 2014
    You're welcome. Also mention to your service center that you're concerned about the drop in range and CAC. Giving Tesla feedback helps them have a bigger picture down the road as well as for them to do what they're pretty good at, customer service. My original pack had its range dive as well as the CAC after it hit 6500 miles, I picked up my roadster used with 3k on it a few years back. I let Tesla know that it seemed rather odd that my range was steady but then started declining slowly down. A hardware engineer ran the logs against their graphical parser and found two sheets pulled down low. Both sheets side by side. The hardware engineer had a theory that since the BMB manages 2 sheets at a time, except for the 11th odd sheet, that this might be the case of a bad/flaky BMB. They ended up changing out the BMB that managed those two low sheets and the the CAC / ideal miles thereafter stabilized. I later had my Aux. Power Supply go out which was in the battery pack. Roadster just went out of warranty. They fixed that issue, but also replaced the battery pack since they indicated I was concerned with my pack and the lower range I was getting. Both were done under GoodWill.

    So my point is always keep them in the loop on how your Roadster's holding up. I also give them feedback saying how well and awesome the car is, that I have no complaints. Positive feedback is just as important so they know they'd doing a good job and keeping the customers happy.

    So after having 3 battery packs (original, replaced one that never reached orig SOC, and the one I have now that reached 160 CAC) I've found they each exhibit a slightly different behavior with the ideal miles and CAC. So you have to learn your pack's behavior and gauge best what its trying to tell you.
     
  13. Mark77a

    Mark77a Member

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    Fascinating discussion on CAC values, guys .. I always thought the 160 CAC is 'as new.. theoretical' so good 1 Wiztecy !

    A UK high miler (Alexander Sims) 50,000 mikes in a 2012 2.5 (must be one of the latest ?) has posted a very interesting thread in the UK >
    Roadster Battery performance after approx. 50,000 miles
    Alexander was quizzed about his charging habits.

    There are some gems of info amongst the 'Limy banter' :smile: including the meaning of life (hint: its not 42, its 1050 )
     
  14. AEdennis

    AEdennis Active Member

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    Thanks for the thread Mark77a... Need to bookmark that and read it closer when I'm not "at work."
     
  15. brianman

    brianman Burrito Founder

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    Picture?
     
  16. slcasner

    slcasner Member

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    As requested, here are pictures of the front and back of the 1GB flash drive that Tesla provided to Roadster owners early on.

    flash-drive-front.jpg flash-drive-back.jpg
     
  17. brianman

    brianman Burrito Founder

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    Neat! Except for the China part.
     
  18. Doug_G

    Doug_G Lead Moderator

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    My Roadster stick (came with the car) died. I tried several sticks that were lying around and eventually found an old one that worked. Oddly it was the same design as the original stick, and also red though not quite the same hue. I popped off the Tesla branded black bracket and put it on the replacement stick.
     
  19. AEdennis

    AEdennis Active Member

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    Ok, tried to run VMSParser, couldn't figure out the "right" flags to get the battery status...

    Did find Doug_G's TeslaGLoP and saw the lowest brick command, but don't know how to read it. Using TeslaGLop, I see the same numbers repeating a lot, but it does change... Don't know if it goes newest to oldest or vice versa, nor can I tell how long the periods in between commas are.

    Thanks for the help so far, I have the car at the SC, but want to be able to read this myself.

    Any additional advice?
     
  20. wiztecy

    wiztecy Active Member

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