Leaf owners: Your thoughts on the battery pack?

Discussion in 'Nissan/Infiniti Hybrids and EVs' started by daniel, Jun 23, 2011.

  1. Zythryn

    Zythryn Senior Member

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    That is what I am thinking. And Nissan does have a 'winter' package for heating the battery.
    The numbers geek in me would love to see some hard data though. Is the battery issue affecting only those in AZ, TX, etc, or is it affecting all LEAF owners, just to a lesser extent in other regions?
     
  2. Skoorbmax

    Skoorbmax Senior Member

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    It's got to be a sliding scale; we've always known all batteries would lose battery in time, but it's appearing to be accelerated in AZ.

    I read the letter from Nissan. They say this has affected only .3% of users so far (still quite high, IMO, for a vehicle released quite recently).

    However, did you know this? Tony W mentioned it and I googled further:
    Brrr. Cold details emerge on 2012 Nissan Leaf's standard battery heater

    Apparently the battery warmer is designed only prevent damage or non-start conditions to the car when it's below 14F; it's really got nothing to do with keeping it warm so it has better amp draw in cold temps and as such I don't see that it would positively impact cold-weather range at all (especially since as part of this, the 2012 Leafs are now giving more cold-weather features, which would pull even more from the battery).
     
  3. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    winter range loss is temporary as is part of the summer range loss for Phoenicians and that the winter loss is acceptable, well documented and expected. the summer loss is not. it has come on much faster and harder. is it due to record hot temps?

    maybe, but we dont know. a lot of evidence points to the BMS restricting capacity due to heat. what we dont know is how much capacity is gone for good, how much is coming back and what temperature parameters is causing the temporary and permanent loss
     
  4. Skoorbmax

    Skoorbmax Senior Member

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    Certainly a genuine loss in capacity will never come back. If this is a temporary computer restriction, though, have there been any reports of people losing a notch on their battery and it coming back? Parking in an underground garage at night or similar would let everything cool off.

    I personally have no problem predicting that these packs that have experienced such loss within a year or two will be rather useless indeed after another three years. Batteries' reduction in capacity AFAIK is always an accelerating thing. This is also why I find it strange that Nissan predicts 80% capacity after 5 years and 70% after 10. This is only possible if the reduction slows down. On the contrary I think it would accelerate, so if 80% after 5 years my money would be on 50% give or take, after 10. But that's a non-scorched pack. These ones losing capacity already so fast will be worthless 10 years from now.
     
  5. cwerdna

    cwerdna Senior Member

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    The "0.3%" figure is quite misleading. It's kinda like the crap that one denier/apologist on MNL would say. He doesn't live in AZ and TX and so far is unwilling to put his money where his mouth is by trading his no capacity bar loss Leaf w/an AZ or TX one that has lost 2+ bars.

    Thanks to My Nissan Leaf Forum • View topic - Early Capacity Losses-Was(Lost a bar...down to 11), the pointer to the wiki (Battery, Charging System - MyNissanLeaf) currently states
    MNLers were tallying the capacity bar loss people for awhile and Nissan did later mention there are ~400 Leafs in Phoenix (or was it AZ?). So, that'd put the figure at 9% and that's just of the ones we know of. There have GOT to be more than just those 36 as some folks have no clue, aren't on MNL, etc.
     
  6. Zythryn

    Zythryn Senior Member

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    Yes, much of the winter range loss should be temporary. Which is exactly why I am curious about range/battery capacity loss in those areas. Is it indeed temporary, or are they also getting a battery capacity loss. From what we have seen, I would guess if there is any, it is less than the 15% needed to loose the first battery bar.
    We should expect some loss. But is it 1% a year, 2%, 5%?
     
  7. Skoorbmax

    Skoorbmax Senior Member

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    Ah, right, I would expect that the stress on a battery running in the winter is harder--demanding the same watt draw when it's cold will stress it more, but that the actual innate capacity of the pack is unchanged; if it's got a 70 mile range in 70F and this all drops low in cold conditions/when using heaters, etc. it's going to go up again when it warms up.

    --

    cwerdna brings up an obvious point I missed which of course is that even if we are to believe a number like .3% or perhaps .5% (if not all have been reported), given the high preponderance of these being in a couple of states, when taken as a percentage of sales in those states the loss of capacity is nothing less than alarming.
     
  8. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    in the process of "sacrificing for the cause" we were "lucky" enough to have to heat here (thank you So. Cal!) from the south and i ran a few hot weather charging scenarios. unfortunately the heat did not hold up or get as hot as predicted so my goal of charging around 105 fell short. some background

    i do have a meter that displays GIDs which is equal to about 80 watt-hours of stored charge. what we can see is 281 watt-hours on a new battery. up until 19,000 miles i was reading 280-281 on full charges then dropped to 275-276 a few weeks ago (which also coincided with our "Summer") representing a 2% loss.

    now all these charging sessions were at night so ambient temps were around the low to mid 60's.

    as the temps increased i charged during the day to see what effect higher temps would have if any and did see a trend line develop results for a 100 % charging session along with temps
    66º/276
    86/268
    92/266
    99/265

    now 265 GID represents a 6% loss or 4% more than the 2% i had less than 2 weeks ago. assuming the less than 1000 miles i drove played no part, we are looking the loss solely a result of higher temps.

    so now the big question will be is my GIDs coming back when the temps go back down??

    more to follow tomorrow

    My Nissan Leaf Forum • TTID
    obtw; not a single shred of evidence that cold weather has any permanent effect of capacity​
     
  9. Jeff N

    Jeff N The answer is 0042

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    I have no idea what will happen with Nissan AZ packs but there are some Lithium cells that have a normal degradation curve that starts off at a steeper rate and then flattens off for awhile around 70-80%. I think some of Panasonic's cells do that. I recall that they publish the curves in their data sheets available online but it's been several months since I last looked.
     
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  10. dbcassidy

    dbcassidy Toyota Hybrid Nation, 8 Million Strong

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    Nissan should encourage all potential customers to ask all the questions they . Daniel being jerked around like that -that is BAD business relations. I don't blame Daniel for cancelling his order, I would too!

    DBCassidy
     
  11. cwerdna

    cwerdna Senior Member

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    Re: the AZ and TX capacity loss, unfortunately, Nissan's response has so far been disappointing, to say the least (updates in My Nissan Leaf Forum • View topic - Lost Battery Capacity and Range / Autonomy, Page 2). There's at least one Leaf that has lost 4 capacity bars, which is supposed to 33.75% (!) loss, after only 14 months.

    So, Tony's going to Phoenix and running a range test w/a whole bunch of Leafs this weekend. Thread at My Nissan Leaf Forum • View topic - Phoenix Range Test Sept 15 WE NEED YOUR 2,3,4 BAR LOSER LEAF.

    Since he's running them to turtle mode, it's likely most/many of the cars will need to be towed afterward.

    I hope it goes safely it and I'm very interested in the results. Some people are really dedicated. Tony's putting in a LOT of effort. At least one guy from the Bay Area is flying there to participate. I'm loaning them 2 GPS units for their efforts. Meeting w/that guy tomorrow.

    (I met Tony last year. He flew up to the Bay Area to be at the be meeting where the Leaf's Chief Vehicle Engineer and other senior Nissan folks and engineers were present.)
     
  12. Skoorbmax

    Skoorbmax Senior Member

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    Interesting, though it's surprising (to me). In any case, it seems not to be the case at least for the hot-hurt Leafs, which I think are losing capacity at an exponential rate.

    I'm intrigued by Tony Williams' plans on Sat. I can't believe Nissan is pretending that these pack issues are not pack issues at all but rather software problems. If his test goes well it's going to rather conclusively indicate what the real situation is, which is what I think most of us think it is: These small numbers of cars in AZ/TX/CA are suffering real loss of battery capacity.
     
  13. drinnovation

    drinnovation EREV for EVER!

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    Well Nissian has had two press releases.. one after their analysis, but before tony's results, suggesting it was an "instrument" problem, the most recent one saying its really just normal, though some "unique usage"

    Whole thread on it an MNL..
    My Nissan Leaf Forum • View topic - Open Letter from Nissan, September 22, 2012

    I think their handeling/denial will hurt them, but it also tarnishes all PEV a bit. But with nearly 100 people having lost > 15%, and more than 25 > 20%, I think TMS is looking like a necessity in hot areas.
     
  14. Skoorbmax

    Skoorbmax Senior Member

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    I haven't seen that yet...

    Tony's results at mynissanleaf.com in the charging/range section have some good insight. My original conclusion that there was a clear and obvious problem from them is challenged with some other views. Certainly there is an instrument problem and it may in fact be possible that the batteries are still fine but that the car is just not accepting a full pack charge (because of instruments), but I've not read in such detail as some of the people there.
     
  15. drinnovation

    drinnovation EREV for EVER!

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    In tony et al experiments they used a GID meter to insure full charges, though the GID meter does read stuff off the bus so a truly faulty sensor in 12 cars could be a cause, but then why only in AZ?
     
  16. cwerdna

    cwerdna Senior Member

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    BTW, Tony's test results are at My Nissan Leaf Forum • View topic - Phoenix Range Test Results, September 15, 2012. I think Tony's going to be doing some edits as there were some typos discovered, some people want more data (including me), and there were two results that should be tossed or separated out.
    Yes, I'm disappointed in Nissan's response (and I'm a Leaf fan). However, I'm not so surprised at them dismissing it as "normal". At My Nissan Leaf Forum • View topic - Open Letter from Nissan, September 22, 2012, I linked to a FB post of theirs where they "concluded that loss is consistent with usage".
     
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