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range questions

Discussion in 'Roadster: Performance' started by chris22104, Mar 11, 2012.

  1. chris22104

    chris22104 Member

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    Just got an 08 roadster. It'll be a week or so before I get it on the road, so I can't really cycle it up and down yet (only up, by charging it.) It hadn't been charged in a long while, but was not totally dead. Using the 110 mobile connector (that's all I have right now,) it took a charge in standard mode, only to 139, then to 148 ideal miles, then in the range charge mode, to 172 ideal miles. From everything I've read, that's still very low. Scares me. But here's a few things I don't understand; the battery icon appears 7/8 full, and the range showed on the odometer display shows only 98 miles of standard mode range. I know the car figures in the way it was driven the last 40 miles (previous owner,) but that drastic of a difference between the 172 and 98? With use and charging, should these ranges come around? Anything I should do in the meantime other than just leaving it plugged in?
     
  2. bolosky

    bolosky Member

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    First: don't worry about the estimated range (the 98 mile thing). It depends very heavily on how it's been driven recently. I never look at it at all, I find that I do a better job of estimating by knowing how the car works and what kind of driving I'm planning on doing.

    The numbers you're quoting for full charge are very low. However, a car that's been sitting unplugged for a long time will be horribly out of balance (some of the cells will have more charge than others). I had the same problem when I had my battery replaced with one that had been unused for a while. The thing to do is to charge it to range mode full and let it sit plugged in for a long time. For my new battery it took 4 or 5 days to fully balance. Yours may take even longer. What you'll see is that as it balances if you start it charging again it will charge to higher and higher values until it's through balancing. It theoretically balances in standard mode, but I think it doesn't work that well.
     
  3. richkae

    richkae VIN587

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    You can't know how much energy the battery can hold unless you both deep discharge it and fully charge it.
    If you have a large container that you can not see inside, and you repeatedly pour 1 cup of water out and then back in - how much can it hold?

    I think you should do a few range mode charges and discharge it as deeply as you feel comfortable between each one.
    Until two range mode charges in a row top out at the same number of ideal miles - continue cycling it this way.
    Once that is done you should have a good idea of what the battery capacity is.

    The battery needs to
    1) balance the cells
    2) figure out where the bottom is
    3) figure out where the top is

    Please report your results.Take log files and use a log file parser to analyze them.
     
  4. markwj

    markwj Moderator, Asia Pacific

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    +1 Bolosky's advise

    Leave it plugged in (even if you can't drive it), and it should balance as best it can.

    It would be good to _exercise_ the battery, once you've got it on the road.
     
  5. markwj

    markwj Moderator, Asia Pacific

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    I would _love_ to see the log files on this car. It would tell us a lot about how the 2008 cars behave when not plugged in for extended periods. Given the recent 'bricking' news, this would be very useful. It would also let you know if the battery ever went to 0% SOC (or lower), and some more about the history of the vehicle.

    To get the logs use a USB stick (2GB or less would be best) and add a folder named “VehicleLogs” to the root, plug it in, turn the key on and off and watch the screen tell you it is downloading the logs. It takes about 15 minutes to get the logs from the vehicle onto the stick, and the car VDS will tell you when done. The logs are stored in a ".gz" file in the VIN subdirectory of VehicleLogs.

    Would you be willing to send me the log files? In return, I'll send you back the results of what we can see with the log file analysers. PM me if you manage to get them.

    Regards, Mark.
     
  6. richkae

    richkae VIN587

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    If you pull a log file from the car and use the analyzer from this thread: Roadster Owner Based Study of Battery Pack Capacity Over Time

    One of the sections of output is the estimated amp hours capacity of the bricks in the battery - it includes the average of all bricks, and the amp hours of the weakest brick.
    Those estimates are recorded every day - it would be very interesting if that estimate slowly becomes more conservative over time as the car sits unused.
     
  7. chris22104

    chris22104 Member

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    Thanks for the replies guys. I've initiated 3 standard charges over the last 5 days that I've had it (139 IR, up to 148 IR, as I'd indicated.) Then yesterday around 4pm, I hit it with the range charge (took about 6 hours more, and got up to 172 IR.) I guess I should have left it alone at that point, but right after the ring went to green, I unplugged it for 5 minutes to start it and look at all the driving screens to see what I could see. Then I plugged it back in, in the standard mode (ring still green,) and there it sits. I'll leave it plugged in and not start another charge cycle until I can drive it.
    And I'll see about getting the log files, and PM them to you Mark (thank you.) Give me a few days.
    I should have it on the road in a week or so. You guys mention discharging it fairly deeply. With an ideal range of only 172, how deep should I go, and should that be driven in standard mode? Then I'll do another range charge as you'd suggested, and see where it is at that point (and report back with the results.) Thanks again guys!
     
  8. markwj

    markwj Moderator, Asia Pacific

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    I don't think anyone here will know exactly what to expect, but the real world experience is here.

    I would suggest you take it easy on the pack for the next few weeks, not taking it anywhere near zero until you know more about how it is, and keeping it plugged in whenever it is not driven. That should give the car the most opportunity to heal (and balance) itself. Then, start to exercise the battery across its SOC range.

    Jeez, that sounds like post-surgery advise! Don't forget plenty of fluids - actually, it may be worth checking fluid levels too :)
     
  9. dsm363

    dsm363 Roadster + Sig Model S

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    Have you had a chance for Tesla to service it and do a battery test? That does seem like a low number on the ideal range.
     
  10. Lancelac

    Lancelac 2010 Roadster Sport #690

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    A battery this out of balance could easily take a full month to balance, leaving it plugged in every second you aren't using it. When they replaced my battery (due to some defect found during a normal diagnostic), my standard charge was a good 40 miles less than my previous battery, despite assurances that the new battery had cells that were the same age or less as my old battery. Tesla's instructions were to leave it plugged in all the time, and the battery would balance itself at a rate of about 1 ideal mile per day. They were correct. Eventually, I got all those miles back and then a few more. Now it always charges up in the low 180s (standard). Tesla could tell you for sure by doing a test, but most likely you'll be able to remedy the problem over time.
     
  11. richkae

    richkae VIN587

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    I wouldn't ever try to drive down to zero, but I would think you would want to drive down to 10%
    Standard mode hides the bottom 10% of the battery from you - so when the ideal mode number gets low, just switch to range mode to see what the car really thinks it has left.
    Please also consider sending the log file summaries in Roadster Owner Based Study of Battery Pack Capacity Over Time
     
  12. richkae

    richkae VIN587

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    Would love to see your log files as well! As you prefer I can send back or post some charts of the change over time.
     
  13. chris22104

    chris22104 Member

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    So as far as settings (now that I did two standard charges and one range charge, and still can't drive the car for a week or so; all previously stated) and keeping in mind I only have the 110v mobile connector, if I'm going to keep it plugged in, should I set the mode to standard? (That's where I have it now, and the trim ring just stays green.) What sounds like the battery coolant pump has been on since last night; 22 hours after the range charge ended. It does not seem to want to shut off, no matter plugged in or unplugged. Is this normal? Furthermore, should I set the charge to initiate on plug in, or every night at, say 9pm?
     
  14. cinergi

    cinergi Active Member

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    Pump will stay on after a range mode charge for some time -- possibly until it reaches 90% SOC (AKA a "full" standard-mode charge).

    You don't need to initiate charge at a particular time unless it costs you less. Otherwise just keep it plugged in and set for standard mode.
     
  15. chris22104

    chris22104 Member

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    Thanks cinergi. So keeping it plugged in and set for standard mode and "charge at plug in," as opposed to setting a time, will it self initiate a charge once a day or something automatically?
     
  16. markwj

    markwj Moderator, Asia Pacific

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    Chris,

    Yes, it will wake up once a day and top-off its battery if it feels it needs to.
     
  17. user497

    user497 Member

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    I was told by someone on the forum that the battery does rebalance unless it is charging in range mode. So I am not sure why it keeping it charged all the time (I assume you were charging in standard mode) would help. But clearly it worked for you.

    Chris, what I found using the 110V charger was that I had to wait about 10 hours to fully rebalance after a full range mode charge. So don't unplug it for a while. It's annoying that you can't see what the car is doing and it doesn't give you an indicator that it is rebalancing but it is.
     
  18. dsm363

    dsm363 Roadster + Sig Model S

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    I thought the car balances after standard mode as well.
     
  19. Doug_G

    Doug_G Lead Moderator

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    The car does balance the pack in standard mode, although it does a bit more balancing in Range mode. BUT I would not charge in Range Mode unless you're planning to drive it. Leaving it charged that high degrades the batteries.

    Balancing happens immediately after the charging is done, and reportedly can go on for an hour or so.

    I would strongly recommend leaving your car in Standard mode. It will top up once a day, and over time it will show more range. Feel free to drive it - just not so much that it won't top all the way up again each night (since you're using 110V). Over a period of time the range should increase.

    Only once your car's pack is reasonably well balanced, it might benefit from a Range mode charge. Generally speaking it's a good idea to do a Range mode charge once in a while, as in a few times a year, to get that little extra bit of balancing. That said, don't leave the car sitting with a full Range mode charge indefinitely. You should drive it a few hours after it's fully charged, to drain it back down to Standard mode charge levels.

    And I'd recommend getting set up for 240V charging. You don't need an HPC, just get a 50 amp stove plug and the UMC (if it didn't come with one).
     
  20. richkae

    richkae VIN587

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    Definitely. My bad if any of my posts implied that you should charge in range mode and let it sit full. That certainly wasn't my intention.
     

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