Reset Capacity Bars

SurfHawk said:

I used Leaf Spy to buy a 12 bar 2013 a month ago. SOH was 91% and AHR was 59, so I bought it. Now a month later im 87% SOH and 56 AHR. Not sure what's going on, but I didn't think it was reset based on AHR.

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not reset. its just you. your driving habits can easily sway the numbers +/- 2-3 ahr

http://daveinolywa.blogspot.com/2016/05/april-2016-drive-report-after-36000.html

http://daveinolywa.blogspot.com/2014/09/manipulating-battery-stats.html

http://daveinolywa.blogspot.com/2014/10/battery-stats-part-two.html

AntronX said:

baustin said:

The charge cycle has to completely finish for the cells to be balanced...

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I keep seeing this posted here, and it does not make sense. Look at first leafspy page. All those red lines are cells being bled off via balancing resistors in BMS. It happens all the time, regardless of the SOC. I think you are perpetuating the myth that you need to charge to full in order for balancing to occur.

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balancing happens all the time but there is a benefit to top end balancing and that is more range.

The issue we have is that even slight amount of overcharging will degrade your cells MUCH faster so the charging profile insures that does not happen but cutting off charging when the fullest cell hits a certain voltage. in a perfect world, all the cells would be at that same voltage but no... not happening. Some will get left behind. this is why the charge cycle will kick back on for 3-4 short charge cycles after the main charging has been completed.

there is also a factor on the discharge curve because Li likes to give its all until its nearly exhausted which means SOC tends to fall off a cliff at a certain point. this means weaker cells get weaker at a faster rate. This explains why voltage delta is so small when SOC is high but grows considerably as SOC drops

so what happens when you to top end balance? You will have the cells that fell behind will potentially continue to fall behind. they won't get that far behind because they will be in a perpetual state of 24/7 trickle charge. (ok not quite that bad!) so is this bad? not really if

1) you don't spend a lot of time at real low SOC (if you are then you need to tell me why you are not charging to full...)
2) you don't need that extra few miles of range

so top end balancing is important... if you need it.

Thanks for directing me to your blog posts, Dave. Super helpful. I think I shouldn't look at AHR daily as it will drive me crazy. Hopefully my driving/charging habits have it at this number and it won't get worse

SurfHawk said:

Thanks for directing me to your blog posts, Dave. Super helpful. I think I shouldn't look at AHR daily as it will drive me crazy. Hopefully my driving/charging habits have it at this number and it won't get worse

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TY TY
well thinking daily fluctuations matter will drive you crazy. As you probably read, I had my batt stats in the 57 ahr 87% Hx range was still able to bring both up to near 100% by changing driving/charging habits. I record my stats daily but only really look at the numbers on a monthly basis.

I am over 44,000 on a 45,000 mile lease so soon will have a new set of numbers to play with if I stick with Nissan and will be going stir crazy with wonder if I dont! :shock:

SurfHawk said:

Thanks for directing me to your blog posts, Dave. Super helpful. I think I shouldn't look at AHR daily as it will drive me crazy. Hopefully my driving/charging habits have it at this number and it won't get worse

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Keep us posted.

If you could answer my questions at http://www.mynissanleaf.com/viewtopic.php?p=473832#p473832, that would help us in better guessing whether you were a reset victim, or not.

A big red flag is if the vehicle previously had resided in a hot climate.

Build month was 4/13. The former owner bought it in Santa Monica and lived in Malibu, two coastal climates I'd expect to average in the mid 70s. I bought it from an independent dealer in Tarzana who got it at auction the week before.

SurfHawk said:

Build month was 4/13. The former owner bought it in Santa Monica and lived in Malibu, two coastal climates I'd expect to average in the mid 70s. I bought it from an independent dealer in Tarzana who got it at auction the week before.

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I think part (most?) of what you are seeing is due to degradation that occurred while the car sat on car lots. Unfortunately, the BMS cannot know about this degradation until the car is driven and charged for a while. As a result, your first LeafSpy measurement likely recorded the capacity of the battery as it was when the original owner sold it while what you are measuring now is closer to what it ACTUALLY had when you purchased it.

RegGuheert said:

SurfHawk said:

Build month was 4/13. The former owner bought it in Santa Monica and lived in Malibu, two coastal climates I'd expect to average in the mid 70s. I bought it from an independent dealer in Tarzana who got it at auction the week before.

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I think part (most?) of what you are seeing is due to degradation that occurred while the car sat on car lots. Unfortunately, the BMS cannot know about this degradation until the car is driven and charged for a while. As a result, your first LeafSpy measurement likely recorded the capacity of the battery as it was when the original owner sold it while what you are measuring now is closer to what it ACTUALLY had when you purchased it.

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While not great news, seems a very logical explanation...

Does seem logical. It has stabilized around 57Ahr and 87% SOH so maybe that's what happened. The previous owner's paperwork was in glove box, he bought late May of 2013, and if he turned it in May of 2016, so it could have been sitting around for 4 months before being auctioned. I guess if you are in the market to buy an off-lease 2013, try to get one as close as possible to 3 years old so it might be fresh off lease.

SurfHawk said:

Does seem logical. It has stabilized around 57Ahr and 87% SOH so maybe that's what happened.

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Out of curiosity, is it still at about this level or has it gotten significantly worse?

I posted some of my stats earlier at http://www.mynissanleaf.com/viewtopic.php?p=473832#p473832, but as of tonight, mine have improved from ~3 weeks ago.

Readings of my car taken a few hours ago are:
AHr: 57.60
SOH: 88%
Hx: 86.78%
odo: 39,507 miles

cwerdna said:

SurfHawk said:

Does seem logical. It has stabilized around 57Ahr and 87% SOH so maybe that's what happened.

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Out of curiosity, is it still at about this level or has it gotten significantly worse?

I posted some of my stats earlier at http://www.mynissanleaf.com/viewtopic.php?p=473832#p473832, but as of tonight, mine have improved from ~3 weeks ago.

Readings of my car taken a few hours ago are:
AHr: 57.60
SOH: 88%
Hx: 86.78%
odo: 39,507 miles

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your numbers are just below my 2013 in a somewhat worse climate so I would say you are ok.

^^^
To be clear, I'm quite confident my vehicle hadn't been a victim of reset given my observations of the various values from July 2015 (when I checked the vehicle before purchase) and now. And, I know what my former leased '13 Leaf's numbers looked like, near the end. I'm just wondering about SurfHawk's number.

My climate for battery degradation I believe is much worse than yours. I live in a hotter part of the South Bay and am working in a city that's even slightly hotter.

Still at 56.45 AHR and 86% SOH, so I don't believe it was reset, just sat on lot

SurfHawk said:

Still at 56.45 AHR and 86% SOH, so I don't believe it was reset, just sat on lot

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Any update on your stats? Just curious.

cwerdna said:

Any update on your stats? Just curious.

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Hadn't checked since that post probably, just checked this morning and I'm at 57.20Ahr and 87% SOH so it definitely has stabilized.

@SurfHawk

What is you QCs history on your car?

7 QCs when I bought it in October. I've added 3-4 since then.

I am looking at a used 2016 S in SD, and am curious if anyone might think the battery was reset. The car was built in Nov 15, and not sold until Mar 17, with 68 miles on it. Sold in Dec 17 with 8500, and then again in Feb 19 with 21800. 71 quickcharges and 1077 L1/L2.

AHr: 55.99
SOH: 90.16
Hx: 82.85
odo: 21,851 miles
https://www.carfax.com/VehicleHistory/p/Report.cfx?partner=AFS_0&vin=1N4AZ0CP1GC302009
Thanks for any input.

I am looking at a used 2016 S in SD, and am curious if anyone might think the battery was reset. The car was built in Nov 15, and not sold until Mar 17, with 68 miles on it. Sold in Dec 17 with 8500, and then again in Feb 19 with 21800. 71 quickcharges and 1077 L1/L2.

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Since it shows a reasonable amount of degradation (10%) it probably hasn't been reset.

I don't know...that's a pretty big delta between the SOH and the Hx, isn't it? If Hx recalibrates faster than SOH as stated above in this thread, wouldn't this be a sign of a reset? Mine bounce around a bit, but the biggest difference I can find is < 6%. It's usually about 5% over the last six months, up from a couple % when I first got the car.

Anyone have a prediction of what the SOH *should* be after sitting on the lot (probably at 100% SOC) for over a year, then two years of normal service in that climate?