Discuss data from the LEAF Battery app, and Comparisons

[mwalsh]

If it took Mike about a month, and Joe about two weeks, we're looking at between 50 and 100 starts. Sound about right guys? How often were you guys starting the car per day?

Twice a day to actually drive, on average, plus another "start" daily (double push of the start button without using the footbrake) to check stats after charging.

 

[fooljoe]

I'd say about 20-25 starts per week.

 

[mwalsh]

Don't forget to post AHr if you want to be added to the list of 4 bar losers. Master list here:

http://www.mynissanleaf.com/viewtopic.php?f=44&t=12789&start=593

 

[Stanton]

:!: :!: :!: :!: :!: Lost my bar today! :!: :!: :!: :!: :!:

46,730 miles, 42.75 Ah, 64.53% SOH, 44.02% Hx, Purchase: 6/11, Manufacture: 5/11.

This is exactly where I'm at as of this morning (except I'm full @184 GIDs). Only problem is temps have cooled here in TX. I've been trading messages with Karl (and he's still ahead of me), but I've got to think I'm right on the cusp of losing that 4th bar.

 

[kolmstead]

I'm predicting November 20. For whatever reason, I've always run a month behind Mike. It's just the way things are.

Forecast is for another week of 80 degree weather, so I could see 42.1s some time in November. 42.50 Ahr and 43.61% Hx Friday evening.

As long as battery gets above 85F each day, it should continue degrading. Not a lot; maybe 0.01 to 0.02 Ahr per day. But if my postulated "cold battery bar loss inhibitor" algorithm kicks in, I'm out of luck. Another reason to keep battery warm!

 

[fooljoe]

As long as battery gets above 85F each day, it should continue degrading. Not a lot; maybe 0.01 to 0.02 Ahr per day. But if my postulated "cold battery bar loss inhibitor" algorithm kicks in, I'm out of luck. Another reason to keep battery warm!

I'm thinking maybe it's the opposite - there could be a "hot battery bar loss inhibitor" that keeps the bar from dropping during periods of rapid degradation / high heat. In my case the bar loss came after things had cooled down a bit and Ah had been pretty stable at 42.7-42.8 for a week or so.

 

[kolmstead]

Good point, fooljoe. It makes sense that Nissan would want to filter out sudden transients. As someone pointed out recently, the engineers undoubtedly have a mathematical model of the battery, and they probably calculate "real capacity" based on that model instead of short-term conditions. We're just guessing what the inputs to that model might be.

-Karl

 

[Stanton]

As long as battery gets above 85F each day, it should continue degrading. Not a lot; maybe 0.01 to 0.02 Ahr per day. But if my postulated "cold battery bar loss inhibitor" algorithm kicks in, I'm out of luck. Another reason to keep battery warm!

I'm thinking maybe it's the opposite - there could be a "hot battery bar loss inhibitor" that keeps the bar from dropping during periods of rapid degradation / high heat. In my case the bar loss came after things had cooled down a bit and Ah had been pretty stable at 42.7-42.8 for a week or so.

I should be a good test of your theory; if I drop my 4th bar in the next week or two, you may be on to something.

 

[mxp]

I have about 8 more months till July 2016 to lose 1 more bars in order to get a new battery on warranty.
Will I make it??


Updated 10/26/2015.

2011 Blue Leaf (all updates applied, QC=2, L1/L2=1718), 47,077 miles
09/23/13: AHr=57.03 CAP=86.07%. Hlth=83.67%
05/11/14: AHr=55.10 CAP=79.89%. Hlth=85.33% (lost 12th bar somewhere in Mar, 2014)
10/13/14: AHr=51.61 CAP=77.89%. Hlth=60.45% (lost 11th bar on 10/13/14)
02/16/15: AHr=50.70 CAP=76.60%. Hlth=58.47%
07/25/15: AHr=49.17 CAP=74.22%. Hlth=54.76%
10/26/15: AHr=47.55 CAP=71.76%). Hlth=51.88%, GIDS=191 (lost 10th bar on 10/26/15)

2011 Silver Leaf (all updates applied, QC=29, L1/L2=1362), 47,057 miles
06/28/13: AHr=58.84 CAP=88.81%. Hlth= n/a
10/25/13: AHr=57.87 CAP=87.87%. Hlth=85.33%
03/10/14: AHr=56.05 CAP=81.61%. Hlth=81.75% (lost 12th bar somewhere in Mar, 2014)
05/18/14: AHr=55.10 CAP=83.16%. Hlth=79.88%
08/19/14: AHr=52.95 CAP=79.91%. Hlth=63.69% (SOC is 90.1%, 214 GIDs 76.2%)
10/14/14: AHr=51.97 CAP=78.45%. Hlth=61.36%
12/04/14: AHr=51.57 CAP=77.83%. Hlth=60.37% (lost 11th bar on 12/03/14)
02/16/15: AHr=50.64 CAP=76.44%. Hlth=58.21%
07/25/15: AHr=49.21 CAP=74.28%. Hlth=54.85%
10/26/15: AHr=47.61 CAP=71.85%). Hlth=51.98%, GIDS=202 (...very soon...)

(No new data from friend's car, as of 7/25, still 1 bar lost, charging only on L1 and occasional QC)
2011 Friend's Blue Leaf (QC=15, L1/L2=1664) * mostly L1 (120V charging)
05/20/14: AHr=58.00 CAP=87.54%. Hlth=85.57%
08/04/14: AHr=55.70 CAP=84.07%. Hlth=81.06% (lost 12th bar on 08/04/14)
09/28/14: AHr=55.75 CAP=84.15%. Hlth=81.16%

 

[mxp]

If you like to collect some observations....

We have been observing the use case of 3 Leafs:
All 3 Leafs all acquired back in July 2011 from the same dealer. 2 of which are ours and a friend's close-by to home. Our commute terrain is identical.

Friend's Leaf: Currently only have 1 bar lost. He only charges L1 exclusively.

For our 2 Leafs:
Blue Leaf lost the 3rd bar today (AHr=47.55). This vehicle is programmed for 100% charge 3 days per week. 80% for the rest. This vehicles has 2 QC cycles to date.
Silver Leaf haven't lost the 3rd bar yet, but we think close... (AHr=47.61). Vehicle is programmed for 80% charge unless requires 100%. This vehicle has QC= 29 times.

Our lesson learnt is:
L1 only charging preserves the battery best. (Or, perhaps just set the lowest amperage charging on a L2 Blink)
Keeping a battery charged-up and not driven is bad.
L2 and QC does not affect anything.

I've been tempted to start a new thread summarizing all our theories about bar loss algorithm instead of hogging this battery app data thread. I'd love to know the truth, but I doubt that we'll ever know it unless somebody decodes Nissan's BMS firmware.

Power cycles, battery temp, Ahr, Hx, full charge GIDs, available kWhr, number of charging cycles, how many cases you started with Nissan customer support, how many times you pressed Cancel instead of Accept...

 

[kolmstead]

mxp: It's going to be tough. Your cars are about a year behind mine in terms of degradation and mine hasn't dropped ninth bar yet, but you have, at best, three or four months of hot weather to work with. You do have one powerful tool, however... the QC ports. Put on lots of high-speed (or hill climbing) miles, and QC as much as possible. If you run through the battery and recharge at least twice a day routinely, you'll probably drop the ninth bar in time. If you just continue as you have, I'd bet against either car losing ninth bar. If you can't use both cars hard, pick one...

-Karl

 

[DaveEV]

10/26/15: AHr=47.55 CAP=71.76%). Hlth=51.88%, GIDS=191 (lost 10th bar on 10/26/15)

I also just lost my 10th bar, last Friday the 23rd.
Didn't grab the stats Friday or over the weekend, but here are my stats from this morning any my previous reading

10/21/15: AHr=47.47 Hx=51.75 202 GIDS 100%
10/26/15: AHr=47.38 Hx=51.59 203 GIDS 100%

I have until the first week of June 2016 to lose the 4th bar - doesn't look promising given that it took almost a year to lose the 3rd bar. Going to take a lot of driving, QCing and sitting at 100% to make that happen.

 

[mxp]

Yes, I think I'll have to drive/QC one of the cars more regularly. There isn't anymore hot days up here in SF Bay Area.

Question: Do I still need to perform that battery check-up at the dealer, as a requirement for battery warranty claims? it's like $100 which I am not keen on paying.

I don't keep up with the forums as much, therefore, I am not sure if anyone here managed to get a replacement even without the annual battery checkup.

mxp: It's going to be tough. Your cars are about a year behind mine in terms of degradation and mine hasn't dropped ninth bar yet, but you have, at best, three or four months of hot weather to work with. You do have one powerful tool, however... the QC ports. Put on lots of high-speed (or hill climbing) miles, and QC as much as possible. If you run through the battery and recharge at least twice a day routinely, you'll probably drop the ninth bar in time. If you just continue as you have, I'd bet against either car losing ninth bar. If you can't use both cars hard, pick one...

-Karl

 

[mxp]

Interesting, that your numbers are very similar. One of my Leafs has AHr=47.61 and it hasn't lost the 10th bar yet. I think when it gets to 47.5x, it will drop the 10th bar.

10/26/15: AHr=47.55 CAP=71.76%). Hlth=51.88%, GIDS=191 (lost 10th bar on 10/26/15)

I also just lost my 10th bar, last Friday the 23rd.
Didn't grab the stats Friday or over the weekend, but here are my stats from this morning any my previous reading

10/21/15: AHr=47.47 Hx=51.75 202 GIDS 100%
10/26/15: AHr=47.38 Hx=51.59 203 GIDS 100%

I have until the first week of June 2016 to lose the 4th bar - doesn't look promising given that it took almost a year to lose the 3rd bar. Going to take a lot of driving, QCing and sitting at 100% to make that happen.

 

[Evoforce]

Well, 9 bar car is at 42.29AHr and SOH=64%. I've got to be soo close to 8 bars. 183 GIDs at full charge. I have not seen any jumping around of stats. So sorry for your loss Mike... I mean happy! It's just a weird mix of emotions to want you to be an accomplished looser. Now, can I be a looser with ya?

 

[Stanton]

Question: Do I still need to perform that battery check-up at the dealer, as a requirement for battery warranty claims? it's like $100 which I am not keen on paying.

I don't keep up with the forums as much, therefore, I am not sure if anyone here managed to get a replacement even without the annual battery checkup.

The annual battery checks are crucial to the warranty process; however, it shouldn't cost $100 (I have never paid for one). Here's what I did: knowing I'm close to dropping the 4th bar, I went in to talk to my service advisor (@Nissan) and asked him if I needed to "go on record" with my annual battery check. He said I could wait and he will file that paper work when I bring my car in for the replacement battery. Two caveats here:
1) I have performed all Leaf maintenance at this dealer (which admittedly isn't much)
2) It is obvious that I will qualify for the capacity warranty (I have almost a year left and I'm ~42. 5 Ahr)

 

[kolmstead]

Well, I'm stuck. 42.50 Ahr, 43.60% Hx last two nights. I think that the days of significant losses are over for this year. Battery temps mid 80s when I park it. Pretty much a waiting game now. I was in the same situation last October, and the tenth bar didn't disappear until March, about 2 Ahr lower than it should have.

-Karl

 

[mwalsh]

^ I plateaued for quite a while. I wouldn't call "game over" just yet, especially since we've got at least one more good warm weekend ahead of us.

 

[kolmstead]

Found this info from Ingineer (Phil) in the "What is a GID" discussion. Quote is from 2012. We never heard any more than this, probably because Phil was operating under a NDA with Nissan:
---------------------
There is an actual number generated called "HV Batt Gradual Capacity Loss Display" and even a "Gradual Capacity Loss Segments" that is sent to the CM (Combination Meter).

The "Gids" (Stored Watt-Hours) aren't being scaled, they are being calculated. Another number that is tracked is total current capacity in amp-hours, along with many other interesting parameters, such as the "Gradual Capacity Loss Coefficient".

-Phil
--------------------

 

[NasGoreList]

Added mwalsh, schamberlin and fooljoe to my copy of mwalsh's list of losers. If Ahr is our best tool, then the range from 43.00 to 43.50 is the sweet spot. More than half the losers (winners!) are in that range; five between 43.00 and 43.25 and five between 43.25 and 43.50 Ahr.

Wondering if we should have paid more attention to Hx! Or maybe GIDs at full charge. Need a better predictor...

-Karl (42.55 Ahr, 43.75% Hx)

Well, my Hlth/Hx seemed to stick at around 44.0x for a while, and my Gids stuck at 182-184 for the longest time, and then I saw a drop to 181. So is 181 a magic number perhaps? I wish we knew!

just trying to catch up here. did you end up getting new battery from Nissan?