SageBrush
Posts: 1481
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Thu Jun 01, 2017 7:21 am

DaveinOlyWA wrote:It is not recovery you are seeing with improved numbers. Its better top end pack balancing

What does this mean ?

I look at my pack in LeafSpy and see a maximum delta of 0 - 15 mv between modules. That is not enough to explain any significant Ahr differences.

On a related note, how are the Ahr and kWh rating calculated ?
There is some basic physics here I don't understand where the LEAF is concerned since I usually think of a battery capacity being determined during a controlled voltage charging cycle but that cannot be the method in a LEAF.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

rmorgansd
Posts: 10
Joined: Sat May 27, 2017 4:50 pm
Delivery Date: 14 May 2017
Leaf Number: 305326
Location: San Diego, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Thu Jun 01, 2017 6:05 pm

DaveinOlyWA wrote:
It is not recovery you are seeing with improved numbers. Its better top end pack balancing

What does this mean ?


I think he might mean the Nissan algorithm that determines the SOH might favor cells that are very close in voltage, which happens during the balancing process. Balancing happens most significantly when the pack is topping off the charge when near full. Although the SOH reading might not be a super-accurate indicator of a battery's true health, it IS useful in relative comparisons between batteries that we all own, which is what this thread is about.

Speaking of which, here is another data point on my new 2017 SV:

Another 50 miles, another SOH % decline. I now have 320 miles on the car, SOH down to 94%, Hx 89%. Every 50 miles I'm losing a % SOH like clockwork. I've done a L2 6kW charge, let the cells balance and did some freeway driving and it didn't help. I can't believe the battery health is going to continue to decline at this rate because I'd lose my first capacity bar before I hit 1000 miles. But who knows? Every time I connect Leaf Spy I cringe.......then take a screen shot.

At this point my new car's battery stats have dropped below the used 2016 I was looking at. With 11,000 miles it was reporting higher GOM mileage, GIDs, SOH and Hx. Super lame.
Carmel Mtn Ranch
Northern San Diego, CA

DaveinOlyWA
Posts: 12310
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Fri Jun 02, 2017 7:05 am

SageBrush wrote:
DaveinOlyWA wrote:It is not recovery you are seeing with improved numbers. Its better top end pack balancing

What does this mean ?

I look at my pack in LeafSpy and see a maximum delta of 0 - 15 mv between modules. That is not enough to explain any significant Ahr differences.

On a related note, how are the Ahr and kWh rating calculated ?
There is some basic physics here I don't understand where the LEAF is concerned since I usually think of a battery capacity being determined during a controlled voltage charging cycle but that cannot be the method in a LEAF.


First off we need to understand that the #1 parameter is poor Nissan instrumentation that gives us these wild fluctuations.

The other thing we need to understand is EVERYTHING we do is a trade off. There is no action that does not have consequences.

The other thing is that there is HUGE disparity from one car to another INCLUDING one in similar areas. It is this we need to understand. So the conjecture of this and that mattering or not mattering is only that. Because no matter what one person says is the cause of their degradation, we have another who is doing the same thing and they are fine.

So what is the key differences here? Is it weather, Driving style, time on the lot, charging patterns? Or is it simply the newer the pack, the better?

I am betting its a combination of all of that. I have a leased 2016 S 30 build date 10/16 picked up 11/11/16. Time on lot probably as close to zero as you can get. Right now I am in the process of experimenting with the car centering on "heat abuse" I hope to be able to see some results within the next 2 months (which means signs of degradation) that likely won't clear up a lot but will be another step towards having more insight.

as far as how important is top end pack balancing? Its vital, its ALL vital. Why would Nissan go thru the motions of creating the SW that takes up to an hour to run at the end of every charging cycle if it meant nothing?
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

edatoakrun
Posts: 4745
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Fri Jun 02, 2017 8:00 am

DaveinOlyWA wrote:
...First off we need to understand that the #1 parameter is poor Nissan instrumentation that gives us these wild fluctuations...

Neither Nissan or any other responsible BEV manufacturer has claimed that the on-board instrumentation can accurately gauge either remaining available energy capacity, or total battery capacity losses over time.

Nissan's solution to this limitation was to provide the highly inaccurate LBC (BMS) data to the driver only using the two twelve-bar displays, without ever attempting to specify any specific energy values per bar.

You really can't blame Nissan for the foolishness of those who choose to access their LBCs and try to use that data for purposes it is so obviously incapable of accurately providing.

Until a few decades ago (when gas gauges were dampened, achieving an effect similar to what Nissan did with the LEAF's 12 bar displays) fuel gauges in ICEVs changed every time you accelerated or decelerated or took a turn, as the float measuring the gasoline level bobbed up and down.

I can't recall any driver believing the actual amount of gasoline remaining was increasing or decreasing when this occurred, but If they had, I don't think you would have held the ICEV manufacturer responsible for "poor instrumentation"...
no condition is permanent

rmorgansd
Posts: 10
Joined: Sat May 27, 2017 4:50 pm
Delivery Date: 14 May 2017
Leaf Number: 305326
Location: San Diego, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Fri Jun 02, 2017 10:43 am

Inaccurate as the battery status readings may be, there are two real-world implications of the imperfect Nissan software:

1. Declining resale value of the car as capacity bars go away.
2. If the car 'thinks' its battery is in poor shape or low charge then it will limit your driving range.

Maybe having access to the internal battery readings is a little TMI, but even though we look at SOH, Hx and the like with one eye closed there are valid reasons to be concerned, and try to understand them better because they really do affect us. Trading experiences is helping us all learn how to use this car better, and giving us a few things to look out for as well.
Carmel Mtn Ranch
Northern San Diego, CA

edatoakrun
Posts: 4745
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sat Jun 03, 2017 3:08 pm

rmorgansd wrote:Inaccurate as the battery status readings may be, there are two real-world implications of the imperfect Nissan software:

1. Declining resale value of the car as capacity bars go away.
2. If the car 'thinks' its battery is in poor shape or low charge then it will limit your driving range...

1. The average retail value of a ~six year old "24 kWh" LEAF showing 12 capacity bars seems to only be ~$2k higher than one with eight bars, from what I can tell.

2. That does not seem to be the case for early "24 kWh" packs.

I and other 2011-12 LEAF owners experienced an apparent miraculous healing of their packs after a Nissan provided an LBC software update:

Had the P3227 reprogram done today: interesting results.


viewtopic.php?f=27&t=13273

I can personally report my observations of no real increase in available capacity or range, just a temporary increase in gids, and corresponding decrease in wh/gid, which remained highly variable.

That update did not in any way effect the more useful kWh use reports from CW/NC reflected in the dash and nav screen m/kWh displays, BTW.
no condition is permanent

Scaramanga
Posts: 111
Joined: Fri Apr 28, 2017 9:31 pm
Delivery Date: 23 Dec 2016
Leaf Number: 308884
Location: Tacoma, WA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Jun 11, 2017 12:21 am

rmorgansd wrote:From my experience with Li-Ion they don't tend to self-recover a lot. A little here and there but you can't regain capacity similar to when you cycle an old Ni-Cad or Ni-MH. In fact, one of the worst things you can do to Li-Ion is deep discharge then charge to full. You'll get the longest life by keeping it between about 40 to 80%, although we all recognize that doesn't work well in an EV where you want to go on a long trip.

Very interesting report from Battery University on the Nissan Leaf battery where they were studying early capacity loss. They disassembled some batteries and found the problem. They found what I surmised an an earlier post.....that sitting around at full charge prematurely ages the battery. A quote from the report:

An interesting discovery was made by NASA in that Li-ion dwelling above 4.10V/cell tend to decompose due to electrolyte oxidation on the cathode


Entire report can be found here: http://batteryuniversity.com/learn/article/bu_808b_what_causes_li_ion_to_die


I found that my 2016 had drifted as low as 92% SOH when I was only driving it 5 - 8 miles per day to the train station and just by taking a couple of long drives (80 miles round trip on a single charge) then recharging fully, my SOH has climbed back up to 95%. So I don't know if that's just instrumentation, or if I've just balanced the pack better by giving it a good long pull on the battery. I drove it once to Bellevue from Tacoma and once to Olympia (up a long steep hill on the way back) and returned home with about 20% each trip, and my SOH climbed after each drive. Odd, but encouraging perhaps? Sounds like I need to go do something fair to midland far away a couple times a month on a Saturday.
2016 SL Premium - Gunmetal Grey, built 2/2016
2014 S w/ QC - Cayenne Red, built 1/2014
EVSE: ChargePoint 25 32A Plug-In w/ 18' Cord
ELM 327 / LeafSpy Pro
'06 Sentra Compact Spare / Jack
Renault Tow Hook

2016 Murano SL AWD
VW / Audi / Volvo ex-aficionado

rmorgansd
Posts: 10
Joined: Sat May 27, 2017 4:50 pm
Delivery Date: 14 May 2017
Leaf Number: 305326
Location: San Diego, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Jun 11, 2017 11:33 pm

Maybe it's more to do with their algorithm than the true state of the battery, not sure. Over the last week I've put another 100 miles on my new 2017 SV , the car now has 399 miles on it and the SOH has gone down another notch to 93%. Hx is now 87%. We had a heat spell, and now it's cold and raining. Some freeway driving, some in-town driving. A few L2 charges and more L1 and so far my readings have only declined. It is losing reported capacity faster than I ever imagined it would. I have seen 3 yr old cars with 20,000 miles with better reported battery health. Takes some of the fun out of it.

I'd like to see the battery health readings pop back up like some have reported. I'll let you know what happens as I check back here every so often.
Carmel Mtn Ranch
Northern San Diego, CA

cwerdna
Gold Member
Posts: 7252
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Sun Jun 11, 2017 11:38 pm

rmorgansd: Thanks for the update.

Can you update your location info via your user name in the upper right > User Control Panel > Profile tab? That way, we don't need to ask in future posts/threads or do sleuthing to deduce it.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

Scaramanga
Posts: 111
Joined: Fri Apr 28, 2017 9:31 pm
Delivery Date: 23 Dec 2016
Leaf Number: 308884
Location: Tacoma, WA

Re: 2016-2017 model year 30 kWh bar losers and capacity losses

Mon Jun 12, 2017 4:31 am

rmorgansd wrote:Maybe it's more to do with their algorithm than the true state of the battery, not sure. Over the last week I've put another 100 miles on my new 2017 SV , the car now has 399 miles on it and the SOH has gone down another notch to 93%. Hx is now 87%.


I think what you're experiencing is what I did in December / January. My 2016 SL car came off the lot @ 98% SOH, promptly plunged to 92% over the first 1000 miles and now has rebounded to 96% SOH and I haven't quite hit 3k yet. I can't tell how much of this behavior is real performance change or just a combination of all the slop in all the variables.
2016 SL Premium - Gunmetal Grey, built 2/2016
2014 S w/ QC - Cayenne Red, built 1/2014
EVSE: ChargePoint 25 32A Plug-In w/ 18' Cord
ELM 327 / LeafSpy Pro
'06 Sentra Compact Spare / Jack
Renault Tow Hook

2016 Murano SL AWD
VW / Audi / Volvo ex-aficionado

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