"Verifiable" Normal Battery Degradation

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DaveinOlyWA

Well-known member
Joined
Apr 24, 2010
Messages
16,265
Location
Olympia, WA
Starting this because the other one is so long and this is something really completely different but does allow data to be used to determine a "general" rate of degradation.

**for this we need to include your degradation, how you figured it. now, there is no real reliable "check it once" measurement so please only post if you are certain your pack is balanced and your #'s are repeatable

** we need details on ANY situation you think might have added to this degradation. we know the basics, temp, time, etc. but we dont know you. so if you have seen 7 TBs, mention that. if you have seen Turtle, mention that. if you have QC'd, lived thru a heat wave hitting 90+, etc.

** charging habits. if you charge to 100%, how long after you are done until you take off in the morning and how far do you drive before parking it and do you have covered/shaded parking

1) LEAF delivered 1/18/2011

2) Miles; 19,500 when degradation started

3) SOC 98% (275 GID) measured with GIDmeter on 4 consecutive days charging to 100%.

4)Turtle; 3-4 times

5)QC ~ 20 times. but only 3 times to over 80%.

6) 4-6 TBs never seen 7 yet.

**charging habits; only charge manually, plugging in 3-6 days a week. charge to 100% on average 2-4 days a week in Summer, 1-2 days a week in winter. am a big fan of opportunity charging taking advantage of the multitude of L2's in town. not unusual to plug in 4-6 times in a day and not get more than 2-3 hours of total charge time.

weather is upper 30's to mid 40's for winter. occasional dips into high 20's. Summer, average high for hottest month of July is 78º (we hit that or better like 4 times this year...) We do get jumps into the 90's occasionally but before our 2 week heatwave in 2009, The Olympia area record for consecutive 90º days was 3. most days in 90's for a year; 5 so our heatwaves generally means the mid 80's. Now, after saying all that. it was 82 on Friday. 90 yesterday and expected to be 93 today. 84 tomorrow before going back to the mid 70's. (average high for August is 76)

Last Summer was very mild as well with zero days in the 90's. in fact, our hottest and longest "heatwave" last year was end of Sept where it hit the 80's for like 5 of 6 days.

as far as parking, neither of us have shaded or covered parking so even mild temps in the mid 70's can create high ambient temps on asphalt parking lots
 
That pretty much sums it up. I charged to 100% for 5 consecutive days to insure a good reading and it was 275 or 276. Now its conceivable that its temperature related but I doubt it. At 20,000 miles I have to say I am very pleased at the performance ihave seen so far and withthe announcement of 9new DCFCs soon to be running I feel that EVs have got a fighting chance to thrive here
 
mwalsh said:
SteveInSeattle said:
Do I interpret this correctly that you have 2% degradation at 18 months? That bodes pretty spectacularly for the longevity of the Leaf, or am I missing something?

Overlooking something...PNW location.

actually the thing overlooked is when does heat become critical. i contend it to be 30C or 86F. look at Tony's car. 5,000 more miles and slightly warmer temps. even if 5% is temporary loss due to temps, he still had another 10% loss to deal with verses my 2%. so am i to lose another 8 % in the next 5,000 miles then have the loss taper to 2% a year? that might happen.

but i think Tony can attribute his loss to more trips to Turtle. i dont think that any other level including VLB is something to worry about. His case is a perfect example that temperature is only part of it. considering the fragility of the pack; Nissan may be marketing a car nationwide that is only viable to less than half the population. Only time can tell with others in his neighborhood.

i have lost track of them which is why i started this thread. is there ANYONE from San Diego who has had their car at least 15 months, has 15,000 miles or more and has any loss to report no matter how small?
 
Given that you'll lose more capacity in the first cycles than in later cycles, your 2% degradation at 20K or 260 cycles implies something like 20% degradation at 10,000 cycles and an EOL at 400,000 miles. That would be great but doesn't seem realistic. Even half that doesn't seem realistic. 2000 cycles to 70% would be outstanding!
 
DaveinOlyWA said:
is there ANYONE from San Diego who has had their car at least 15 months, has 15,000 miles or more and has any loss to report no matter how small?

Yes. But they wisely don't advertise the fact until they can potentially unload their car(s).
 
Dave, I can't help you with any verified numbers (sorry don't have GID-o-meter or Leaf Scan), but it is possible that SE WA state will generate some heat-related losses. It was 105 F for the past two days (normal for this time of year). So anyone in this area who drives >10,000 mi per year (not me) should show similar losses as CA, but not as significant as AZ, TX or OK. It's a two or three day drive to the nearest DC QC so I don't anticipate that being a problem.

Reddy
 
It is warm and will be near ya soon I am currently driving on the columbia gorge river scenic highway but it's also under construction which means I have plenty of time to cruise the web
 
DaveinOlyWA said:
is there ANYONE from San Diego who has had their car at least 15 months, has 15,000 miles or more and has any loss to report no matter how small?


I guess that would be me. Over 26K miles, 19 months 'ownership' on the lease. I haven't lost any of my high-voltage dots yet, but with 100% charge, in ECO, the GOM is showing 80-85ish miles available (it used to routinely show over 100)

When new, I could drive 65mph round-trip to work (62 miles) and have at least 2-3 bars left on the battery. Now, 65mph rt will have me pulling in with 1, maybe 2 bars, and occasionally under LBW (winds?!?)

So far, still useable for my original intentions. Will it last the remainder of my lease? Who knows...but I am noticing the reduced range now. :/

(FWIW, I ALWAYS charge to 100% since I got the car)
 
San Diego "inland" resident here, had LEAF since January 2011, about 12,500 miles, GID meter shows a few % loss (265-268 at 100%). Haven't really noticed much of a loss in real-world driving situations, but I'll start paying more attention. 80% charge most weeknights, 100% occasionally on weekends, never sits at 100%...
 
No GID meter readings, but I estimate my LEAF to be about 10% down on usable capacity based on 80% - LBW data and wall-to-car charge data. 14 months, 11k miles.

80% charge timer (used to always charge at midnight, but now use end-timer of 5:40am which typically stops charging around 5am to get a few more hours at lower SOC each day. Typically only charge to 100% once a month or so and do that as close to planned departure time as possible. Only other note is that I've always felt my LEAF to be down a bit in usable capacity since I got the car, but don't have any hard data to back it up.
 
Randy and Drees; both of u are making a new curve. How often have u parked in direct sun for more than a few hours and at what SOC?

I thjnk in all this we are using OAT to much. I think we need to examine ambient temp scenarios as well like asphalt, summer and full sunny days
 
I'm not so sure that GOM and/or real-world range are the best metrics for basing degradation assumptions as both rely heavily on driving style. Speaking from personal experience, I know that I've certainly gotten much more lax about being conservative with my driving style in the past 19 months of ownership. I'm still getting over 4 miles/kWh, but compare my former "grandmotherly" style of driving to my current "squirt-and-go" method and one couldn't help to realize that there will be a degradation in range and GOM readings.

Seems to me that we should stick to GIDs @ 100% charge as a basis of comparison. Obviously, this doesn't work if you don't have a GID meter (myself included), but everything else is too inaccurate. Heck, even the GID meter itself might be inaccurate as it seems that max-GIDs can vary with temp irregardless of battery condition.
 
DaveinOlyWA said:
3) SOC 98% (275 GID) measured with GIDmeter on 4 consecutive days charging to 100%.

I rarely got 281 in the first months after SOC meter was "invented" - usually got about 275. So, I wouldn't even count this as degradation.
 
DaveinOlyWA said:
Randy and Drees; both of u are making a new curve. How often have u parked in direct sun for more than a few hours and at what SOC?

I thjnk in all this we are using OAT to much. I think we need to examine ambient temp scenarios as well like asphalt, summer and full sunny days

I park mostly outside at work in the cooler months, but have been seeking shade lately in the last couple of summer months (Temp bars have always been 5 or 6, never any other number). SOC at work is mostly 70-75% when I leave home at 80% (slight downhill to work just a few miles away). And like EVNow, I never got near 281 since I got my GID meter....The earliest reading I got was in the mid 270s...So it has dropped about 9-10 counts after 18 months....
 
Randy your response makes me wish i had the GID meter when i first got my LEAF.
our Summer came late and does loosely correlate with my drop in SOC. its hard to pinpoint since i can go several days without going to a full charge. but wondering if i am seeing a "temperature adjustment because it is so small.

i think i am going to start playing with the 80% timer to see what results i get from it
 
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