Survey: Battery Temp Bars VS Battery Pack Degradation

Some of us have here been arguing about how hot is "too hot" when it comes to charging a Leaf, and we agree that the best way to find out is to get data from Leaf owners that will hopefully provide evidence that can help Leaf drivers decide when and how to charge, in order to improve battery pack capacity and longevity. Please copy and paste the following section into a reply, adding your info. You don't need the Leaf Spy app to participate! Just provide what information you can. All I ask is that if you don't know the answer to a question with some reasonable degree of confidence, don't answer it, or identify your answer as a rough guess.

The Survey Is Now, Finally, Active! Please feel free to answer it any time. Also, please ask any questions about the survey in the related topic I am about to start, not here. Thanks!

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1. What year and model is your Leaf? (Example: 2013 SV) ANSWER:

2. What is the car's "build date"? This info is located on the driver's side door jamb sticker. (Example: 4/2013) ANSWER:

3. Are you the original owner, or the second, third, etc? ANSWER:

4. Where (city, state, country) do you live? ANSWER:

5. What is your current odometer reading? ANSWER:

6. How many "capacity bars" (the short lines right next to the much larger "Fuel Bar" lines on the dashboard) are currently showing on your Leaf? ANSWER:

7. If you acquired your Leaf used, what were the odometer and capacity readings when you got it? ANSWER:

8. How would you describe your local climate? (see below)

"Cold"? ( Juneau, Alaska or the upper interior of Canada or Europe, for example, with high temps rarely exceeding 27C / 80F and lows well below 0F / -17C)

"Cool"? (Climates like the UK, Japan and Pacific Northwest where it is usually cool, but with mild Winters and occasional periods with temps in the 80s or 90s / 27+C )

"Temperate"? ( cities with cold Winters but Summer temps generally around 85F / 27C with occasional excursions into the 90s / 30+ C )

"Mild"? (Winter low temps usually well above 0 degrees Fahrenheit / -17C, Summer highs usually in the 80sF / 27C with occasional increases into the 90sF / 32+C)

"Warm"? (Summer highs in the 80sF / 27+C, with frequent readings in the 90s / 32s)

"Hot"? (Summer temps frequently in the 90s / 32s, and regularly above 100F / 38C)

ANSWER:


9. Does it usually cool below 75F / 24C at night in Summer where you live?
ANSWER:

10. Does it usually cool below 70F / 21C at night in Summer where you live?
ANSWER:

11. How many Temperature "Bars" do you usually see displayed on your dashboard in normal Summer weather? ANSWER:

12. How many temperature bars do you usually see displayed on your dashboard during the hottest Summer weather where you live? ANSWER:

13. What is the highest (in bars) temperature reading you have seen displayed on your dash while driving? ANSWER:

14. Have you seen this reading once or twice, occasionally, or often? ANSWER:

15. What is the highest (in bars) temperature reading you have seen displayed on your dash while charging? ANSWER:

16. Have you seen this reading once or twice, occasionally, or often? ANSWER:

17. Does your Leaf have Quick Charge (aka "Charge Package") ? ANSWER:

18. If your Leaf has Quick Charge, do you use it? (see below)

Never?

Rarely? (Less than once a month)

Regularly? (Once a month or more, but not daily or every week)

Weekly?

Daily?

Multiple times daily?

ANSWER:


19. Do you primarily use L-1 (120 volt) charging? ANSWER:

20. Do you primarily use L-2 (208-240 volt) charging? ANSWER:

21. Do you primarily use L-3 DCQC (aka "Fast Charge or "Quick Charge") charging?
ANSWER:

22. Do you normally charge to 100% SOC (state of charge)? ANSWER:

23. Do you normally charge to less than 95% with occasional charges to 100%?
ANSWER:

24. Do you regularly use the 80% charge option available on 2013 Leafs, or the similar 'charge to 80%' timer option if available? ANSWER:

25. Do you avoid leaving your Leaf at 100% charge for more than 3-5 hours?
ANSWER:

26. Do you regularly leave your Leaf at 100% charge for more than 3-5 hours?
ANSWER:

27. Would you rate your driving style as:

"Aggressive"?

"Typical"?

"Economy-Minded"?

"Hyper-miling"? (Taking extreme economy measures to ensure maximum efficiency and range)

ANSWER:

28. Has your Leaf's battery pack been replaced under the 5 year / 60k mile capacity warranty? ANSWER:

29. Has your Leaf's battery pack been replaced due to a manufacturing defect? (If "yes" please include date & odometer reading when replaced, along with Leaf Spy readings if available.) ANSWER:

30. Has your Leaf's battery pack been repaired (not replaced) because of a manufacturing defect OR under the capacity warranty? (If "yes" please include date & odometer reading when repaired, along with Leaf Spy readings if available.)

ANSWER:

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THIS SECTION IS FOR LEAF DRIVERS WITH ACCESS TO LEAF SPY READINGS
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31. What is your Leaf's current SOH reading? ANSWER:

32. What is your Leaf's current AH reading? ANSWER:

33. What is your Leaf's current GID reading at full charge? ANSWER:

34. If known, what was your Leaf's SOH reading when you acquired it? ANSWER:

35. If known, what was your Leaf's AH reading when you acquired it? ANSWER:

36. If known, what was your Leaf's GID at full charge reading when you acquired it?
ANSWER:

37. How many QC charges has your Leaf recorded? ANSWER:

38. How many L-1 / L-2 charges has your Leaf recorded? (These are usually over-counted so don't be alarmed at the number.) ANSWER:

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QUESTIONS FOR LEAF DRIVERS IN "HOT" CLIMATES
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39. Do you keep your car parked mostly in a garage? (Including time parked at work. If about equally split, please answer "50/50".) ANSWER:

40. If your Leaf is garaged, is the garage air-conditioned? ANSWER:

41. Do you keep your car parked outdoors mostly in the shade? (Including time parked at work. If about equally split, please answer "50/50".) ANSWER:

42. Do you keep your car parked outdoors mostly in the sun? (Including time parked at work. If about equally split, please answer "50/50".) ANSWER:

43. In your hottest months, during the daytime, how many temperature bars typically show while driving? ANSWER:

44. In your hottest months, during the daytime, how many temperature bars typically show when charging is complete? (Assuming that you have this information) ANSWER:

45. Do you charge frequently in the daytime in Summer? ANSWER:

46. Do you charge primarily at night in the Summer? ANSWER:

47. Do you regularly Quick-Charge when 7 or more temperature bars are showing?
ANSWER:

48. Do you regularly charge with L-2 when 7 or more temperature bars are showing?
ANSWER:

49. Do you regularly charge with L-1 when 8 or more temperature bars are showing?
ANSWER:

50. Do you regularly Quick-Charge when 8 or more temperature bars are showing?
ANSWER:

51. Do you regularly charge with L-2 when 8 or more temperature bars are showing?
ANSWER:

52. Do you regularly charge with L-1 when 8 or more temperature bars are showing?
ANSWER:



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That looks like a good list, thanks for taking the time. I might be confused how to answer a couple of questions because of having batteries swapped out and also have more than one car.

Can there maybe also be a questions geared to be inclusive to battery(ies) replaced? Some of us have had to start over with our stats but may also want to reflect experience concerning former packs. Also when you get a new battery the onboard stats for number of charges doesn't reset so that could be confusing.

Some people may have issue with fast charging/quick charging being referred to as L3. It also may be easier to answer question 18 regarding "rarely" or "regularly" with a defined parameter example.

Also, since going this far... what about including a question about repairs. If the poll is not in essay form (which I prefer because it is easier to extract the data) it would have to be addressed as multiple choice. I was surprised to see in a recent post in this forum that, I think it was consumer reports that was referenced, said that the 2013 leaf was problematic/requiring a lot of repairs.

Good point. Done. Maybe a separate section is in order for cars with new packs...?

EDIT: I'll add a separate section for repairs tonight. That will also require renaming the survey, I think. "The Great Leaf Survey Novella"? ;-)

nr15 is not that important. Hot battery can cool down during low speed charging.
19-21 - the rest of the world doesn't have access to 120V, trickle for them is 2kW.
So maybe one question: "Main charging speed: 1kW (US trickle), 2kW (EU trickle), 3kW, 6kW, DC".
Those who charge 50% at home and 50% at work (3kW vs 1kW) should also answer 2kW as an average.
In EU some charge at home 3kW and work 2kW (answer 2,5kW). This will give excellent accuracy.

What would be interesting to acquire is information about DoD:
Do you often (more than 1/3 occurrence) discharge below LBW, or VLBW, or Turtle.

1 vs 2. Rest of the world doesn't have that parameter. Just the fact when/where was Leaf built and what
options does it have (24/30kWh, QC, Nav, UK/US/JP, color) - other data is not applicable (cameras, sound, wheels etc).
BTW white vs black Leaf might give interesting data points. Other colors will be weighted later from 5% up to 95%
solar absorption factor.

nr8 needs refining. Cool/Temperate are mixed up. Maybe split up nr8 into two question: first about winter low
end and second about summer high end.

Also very important data point: car is usually parked under: sky, shadow, cool garage (underground/AC).
And that should be split up into "parked at night" "parked at day" (work) as some do park at sun and AC garage.

Don't hurry with survey release. There are still some problems that need to be fixed. Ran out of time :mrgreen:

UPDATES:

L-1 charging will remain in the survey. That and anything else that doesn't apply to European drivers can simply be ignored by them. Euro Leaf drivers can also provide the option package names for European models. I've added a section for Hot climates, and adjusted the descriptions for Cool and Temperate climates.

I'm about done with writing this. I think a separate survey on reliability (written by someone else!) would be a good idea, but want to leave this one battery pack-oriented. Any last suggestions before we start responding to it? The idea is to have the info in one topic, available for collating or just 'mining' by others in the future - hopefully the near future.

In my lady's case. The car is parked in the parking garage for work but not garaged at home so maybe the question could be asked as a percentage. Also a home garage can be much hotter than a parking structure. Is this questionnaire going to remain set up as essay or something else with check boxes or yes or no, etc?

I added a "50/50" answer suggestion. If you or anyone else would like to rewrite this as multiple choice, try it and we'll see if it works that way. I planned to make it short-answer format. If we knew it would be converted into statistical data it would make more sense to have multiple choice, but that's a lot more work, and no one has volunteered to compile it...

Interesting survey.

Re: "24. Do you regularly use the 80% charge option available on 2013 Leafs, or the similar 'charge to 80%' timer option on pre-2013 Leafs?", apparently it remains in some (all?) 2014+ Leafs outside the US (North America?). See http://www.mynissanleaf.com/viewtopic.php?p=416013#p416013, for example.

I know I'd currently have a tough time answering some of the temp bar questions as I frankly don't pay much attention to it. I've only had this '13 Leaf since mid-July 2015. I couldn't tell you about the former '13 Leaf I had for 2 years.

For instance, I don't think I've ever seen either of my Leafs above 7 temp bars. I'm not sure either has gotten there even. But, I can't be positive. I know for sure I never came close to red.

I changed the timer option question. I've read about people who use QC often getting 8 bars, and I assume it happens in Hot Summer conditions without QC as well. We'll see, I guess. Again, any question to which the answer isn't known can be left unanswered.

I am concerned about the word "regularly" that maybe could be changed to 'typically" in much of the poll, especially questions 45-50. Or like question number 43 maybe ask if you frequently/sometimes/never...

So you really want us to post answers as a reply? How about email? This thread will grow to pages and pages very quickly.
You can post a summary down the road (for whatever you're trying to analyze).

The idea is to first erase the comments, the use the topic to "store" the information as replies. I really don't see a big issue with "regularly" vs "typically."

Here is the reason why. I might not "regularly" Quick Charge" but when I do it is "typically" X bars in the Spring/Summer/Fall. Another question: We also have fewer hot months so are we to assume that regularly is only pertaining to the hottest months? See I would be answering (yes) to questions of 6 to red bars throughout different times of the year. Might it be better to ask the question: "In your hottest months and during the day, how many temperature bars typically show while Operating? Driving? Charging?"

Might it be better to ask the question: "In your hottest months and during the day, how many temperature bars typically show while Operating? Driving? Charging?"

Click to expand...

How is that substantially different from this?

11. How many Temperature "Bars" do you usually see displayed on your dashboard in normal Summer weather?

12. How many temperature bars do you usually see displayed on your dashboard during the hottest Summer weather where you live?

13. What is the highest (in bars) temperature reading you have seen displayed on your dash while driving?

14. Have you seen this reading once or twice, or often?

15. What is the highest (in bars) temperature reading you have seen displayed on your dash while charging?

16. Have you seen this reading once or twice, or often?

Click to expand...

LeftieBiker said:

Might it be better to ask the question: "In your hottest months and during the day, how many temperature bars typically show while Operating? Driving? Charging?"

Click to expand...

How is that substantially different from this?

11. How many Temperature "Bars" do you usually see displayed on your dashboard in normal Summer weather?

12. How many temperature bars do you usually see displayed on your dashboard during the hottest Summer weather where you live?

13. What is the highest (in bars) temperature reading you have seen displayed on your dash while driving?

14. Have you seen this reading once or twice, or often?

15. What is the highest (in bars) temperature reading you have seen displayed on your dash while charging?

16. Have you seen this reading once or twice, or often?

Click to expand...

Click to expand...

I am still mostly referring to questions 45-50. Yes 11-16 seem to cover related specifics.

And on another note, I believe the purpose of the pole is to provide an example of what Leaf owners can expect to see based on what region they reside in.

They may or may not be able to modify their behavior or modify their results using the information, but will hopefully gain some insight and possibly alleviate fears that their car is not performing well given the "Norm", of where they live. I am not sure that the poll will prove that 6-7-8-9 battery heat bars or more under redline substantially degrades the battery or even if it would somehow help it to be technically measurable. Everyone probably already knows to try not to redline and that the less heat the better. This will provide a good measuring stick to compare to each other. Thanks again, for taking the time to put it together.

Ok, this seems to be the best place to post these results as any (sorry, too many questions in that questionnaire for me).

I just finished tabulating and graphing my LeafSpy results since August 2014 for my May 2011 Leaf. The AHr and Hx numbers have been completely flat (zero degradation) from Oct 31, 2015 through Feb 20, 2016. I have four data points since 2/20/16 and the slope of the degradation curve is essentially IDENTICAL to last summer (4/15 to 10/15). Since I have better data now, I decided to look at the LeafSpy temps. Degradation re-started once the temps reached 60 F. :evil: :evil: :evil:

So, bottom line: Unless you keep your Leaf BELOW 60 F, degradation happens!

For those interested in the numbers: 52.13 AHr on 7/1/15 and 50.37 AHr on 10/31 = 1.0349 AHr difference in four months or about 0.00848 AHr per day when temps are above 60 F. Since I am such a low mileage, city driver and I baby the battery, I am assuming that this is all essentially "calendar" time-based degradation. I'll update my signature, but I'm around 31,500 mi and just dropped below 50 AHr (49.86). Assuming the current trend continues, I predict another 2.12 AHr loss until Oct 31, 2016 which will put me at 47.74 AHr (still just slightly above a 3-bar loser, which will probably drop in April 2017).

I have read that the BMS stops updating capacity at lower temps. You may be seeing exactly that.

LeftieBiker said:

I have read that the BMS stops updating capacity at lower temps. You may be seeing exactly that.

Click to expand...

Correct. Have not seen any SOH Hx update for half year. Never seen 5th bar during that time period (long winter).
In summer SOH and Hx just jumps around for very tiny amount: up and down, up and down.

ADMINs: if you can move the above comments on the survey (including mine) to the new 'Survey Questions' topic, I'd appreciate it.