Discuss data from the LEAF Battery app, and Comparisons

[jguenst]

I just had a huge jump in may Ahr, was down to 58.48 now above 61 Ahr. I had mobileye installed. could it be when 12v battery disconnected and the battery management system started balancing all the batteries at once. all lines in red. I had never seen before.!! mileage still the same so far but have not been doing any hypermiling lately

 

[ttweed]

As far as I can tell, I am about to lose the second capacity bar any day now, with my AHr readings dropping into the high 51s for the first time.

As I suspected might happen, I lost my second bar today at 38,685 miles after almost 33 months in service. Readings from Leaf Spy Lite this morning showed 51.77 AHr, SOH=78%, Hx=60.85%, battery temps from 63.4F-66.4F, 17mV spread between high and low cells.

TT

 

[mwalsh]

6/22: AHr=54.07 CAP=81.61%
6/24: AHr=54.01 CAP=81.52%
6/25: AHr=54.12 CAP=81.68%
7/11: AHr=53.16 CAP=80.23%
7/12: AHr=53.30 CAP=80.45% Hlth=76.57%
8/26: AHr=52.54 CAP=79.30% Hlth=75.16%
9/11: AHr=51.49 CAP=78.49% Hlth=73.22%
10/2: AHr=51.81 CAP=78.98% Hlth=73.82%
10/8: AHr=51.58 CAP=78.63% Hlth=73.39%
10/23: AHr=52.12 CAP=79.51% Hlth=74.46%
11/5: AHr=52.68 CAP=80.31% Hlth=75.43%
11/12: AHr=52.47 CAP=79.98% Hlth=74.80%
11/22: AHr=52.74 CAP=80.40% Hlth=75.53%
11/25: AHr=52.89 CAP=80.63% Hlth=75.81%

12/21: AHr=52.74 CAP=80.40% Hlth=75.53%

 

[JeremyW]

12/21: AHr=52.74 CAP=80.40% Hlth=75.53%

Interesting, I'm at 55 Ah and 70% Hlth (which we think is related to internal resistance). Probably related to how much hard city driving I do...

 

[DaveEV]

12/21: AHr=52.74 CAP=80.40% Hlth=75.53%

Interesting, I'm at 55 Ah and 70% Hlth (which we think is related to internal resistance). Probably related to how much hard city driving I do...

My Hx value is even lower. This morning I had 54.24 Ah / 66.93 Hx. Most of my driving is on high speed (45-55 mph) city streets.

 

[mwalsh]

6/22: AHr=54.07 CAP=81.61%
6/24: AHr=54.01 CAP=81.52%
6/25: AHr=54.12 CAP=81.68%
7/11: AHr=53.16 CAP=80.23%
7/12: AHr=53.30 CAP=80.45% Hlth=76.57%
8/26: AHr=52.54 CAP=79.30% Hlth=75.16%
9/11: AHr=51.49 CAP=78.49% Hlth=73.22%
10/2: AHr=51.81 CAP=78.98% Hlth=73.82%
10/8: AHr=51.58 CAP=78.63% Hlth=73.39%
10/23: AHr=52.12 CAP=79.51% Hlth=74.46%
11/5: AHr=52.68 CAP=80.31% Hlth=75.43%
11/12: AHr=52.47 CAP=79.98% Hlth=74.80%
11/22: AHr=52.74 CAP=80.40% Hlth=75.53%
11/25: AHr=52.89 CAP=80.63% Hlth=75.81%
12/21: AHr=52.74 CAP=80.40% Hlth=75.53%

1/21: AHr=51.38 CAP=78.32% Hlth=73.02%

Back to September/October numbers. Perhaps the hot spell we've just endured?

 

[DaveEV]

1/21: AHr=51.38 CAP=78.32% Hlth=73.02%

Back to September/October numbers. Perhaps the hot spell we've just endured?

Do you have the P3227 update? I haven't seen any changes in AHr, but then my battery temps might have reached 60F perhaps only a couple times this winter, 65F is more typical compared to 75F in the summer.

I'm still curious about how your AHr is higher than mine (and Jeremy's), but our Hx values are lower.

I wonder if this reflects a difference in usage patterns - you do a lot of freeway miles (more steady state discharges at 60-65 mph with more large cycles of the pack) while Jeremy and I appear to do more city miles (bursty discharge (20-40 kW) with more regen spikes for stop lights). Perhaps it's mainly the additional regen spikes that do it?

Has anyone tried collecting the various bits of data and comparing?

 

[vrwl]

1/21: AHr=51.38 CAP=78.32% Hlth=73.02%

I'm still curious about how your AHr is higher than mine (and Jeremy's), but our Hx values are lower.

I wonder if this reflects a difference in usage patterns - you do a lot of freeway miles (more steady state discharges at 60-65 mph with more large cycles of the pack) while Jeremy and I appear to do more city miles (bursty discharge (20-40 kW) with more regen spikes for stop lights). Perhaps it's mainly the additional regen spikes that do it?

Has anyone tried collecting the various bits of data and comparing?

Drees, I also have the same situation. My AHrs are higher than mwalsh's (53.xx), but my Hx reading is considerably lower (66.xx). I do almost exclusively street driving at speeds around 45-55, RARELY get on the highway.

 

[jguenst]

Drees, I also have the same situation. My AHrs are higher than mwalsh's (53.xx), but my Hx reading is considerably lower (66.xx). I do almost exclusively street driving at speeds around 45-55, RARELY get on the highway.[/quote]


how many miles on your leaf? is it 9K?

 

[TickTock]

1/21: AHr=51.38 CAP=78.32% Hlth=73.02%

I'm still curious about how your AHr is higher than mine (and Jeremy's), but our Hx values are lower.

I wonder if this reflects a difference in usage patterns - you do a lot of freeway miles (more steady state discharges at 60-65 mph with more large cycles of the pack) while Jeremy and I appear to do more city miles (bursty discharge (20-40 kW) with more regen spikes for stop lights). Perhaps it's mainly the additional regen spikes that do it?

Has anyone tried collecting the various bits of data and comparing?

Drees, I also have the same situation. My AHrs are higher than mwalsh's (53.xx), but my Hx reading is considerably lower (66.xx). I do almost exclusively street driving at speeds around 45-55, RARELY get on the highway.

In Garden Grove, CA, the average daily temperature swings from 59F to 75F throughout the year (59 now) whereas in Frisco, TX the range is 41F to 82F (41 now). Since Hx appears to be related to pack resistance perhaps the cooler temperatures this time of the year is impacting it. If so, in the summer your Hx should be higher.

 

[vrwl]

I'm still curious about how your AHr is higher than mine (and Jeremy's), but our Hx values are lower.

I wonder if this reflects a difference in usage patterns - you do a lot of freeway miles (more steady state discharges at 60-65 mph with more large cycles of the pack) while Jeremy and I appear to do more city miles (bursty discharge (20-40 kW) with more regen spikes for stop lights). Perhaps it's mainly the additional regen spikes that do it?

Has anyone tried collecting the various bits of data and comparing?

Drees, I also have the same situation. My AHrs are higher than mwalsh's (53.xx), but my Hx reading is considerably lower (66.xx). I do almost exclusively street driving at speeds around 45-55, RARELY get on the highway.

In Garden Grove, CA, the average daily temperature swings from 59F to 75F throughout the year (59 now) whereas in Frisco, TX the range is 41F to 82F (41 now). Since Hx appears to be related to pack resistance perhaps the cooler temperatures this time of the year is impacting it. If so, in the summer your Hx should be higher.

That's an interesting theory. Since we didn't have the ability to see this data last winter, we won't really know for sure until this coming spring/summer. I can confirm that the Hx value had gone lower since starting the readings of my pack last summer. When it was added to the app in July, my first Hx reading was 78.93, so I've had a pretty big drop.

 

[GregH]

In Garden Grove, CA, the average daily temperature swings from 59F to 75F throughout the year (59 now) whereas in Frisco, TX the range is 41F to 82F (41 now). Since Hx appears to be related to pack resistance perhaps the cooler temperatures this time of the year is impacting it. If so, in the summer your Hx should be higher.

Hmmm if Hx is measuring impedance there must be some sort of temperature compensation. My Hx still more or less tracks capacity (post p3227). I don't see big swings with Hx over the course of the day when my pack swings from 20C (110-120mohm) to 30C (90-100mohm).

On a side note.. The upswing in capacity I saw last month preP3227 (from 58Ah to over 60!) has all been wiped out now.. Not sure if it's the warm spell or P3227.
1/10 58.9744Ah 78.80Hx
1/22 58.3708Ah 77.30Hx
Although Hx did drop precipitously with P3227..
11/24/13(preP3227) 60.7980Ah 91.03Hx
Whatever Hx is measuring, it seems to be much more so post P3227.

 

[Weatherman]

Just about at the 20%-loss point, now, after only a little over 18 months


July 11th: 57.45 Ahr
Aug 12th: 56.30 Ahr
Sept 10th: 55.46 Ahr
Oct 23rd: 54.61 Ahr
Nov 4th: 54.26 Ahr
Dec 10th: 53.86 Ahr
Jan 25th: 53.06 Ahr


With the cooler weather, I've been driving the Volt almost all the time. Even sitting idle, the LEAF's battery continues its relentless decay.

 

[ttweed]

I can confirm that the Hx value had gone lower since starting the readings of my pack last summer. When it was added to the app in July, my first Hx reading was 78.93, so I've had a pretty big drop.

When I started collecting the Hx value on 7/6/13, my AHr reading was 54.63 and Hx was 79.03%. Just before the 3227 update in mid-Aug., I was at 54.03 AHr and Hx was 78.17%. After that, Hx started dropping like a rock, although AHr went up temporarily (for 2 weeks only, dropping back below pre-update levels by the end of Aug. and continuing downward). When I lost the 2nd CB on 12/21, AHr was at 51.72 (a little higher than mwalsh) and Hx was at 60.72% (more than 12% lower than mwalsh). My "true" SOH reading was at 78%. We do maybe 20% freeway driving, 80% street. I don't understand how my Hx number can be so different than mwalsh.

TT

 

[Nuitari]

I've started looking at the logged data and I'm not sure how to interpret most values.

This is just after arriving at destination with turtle:

Ambient: -17C
Hx: 108.73
SOH: 100
Pack temp: 1.33,1.33,-1.78,1.33
gid: 5
max/min/avg/cp diff: 3361/243/3041/3118 (some cells were reading 0 for the first reading)
Judgment Value (what is that?) : 2561

(after 90 seconds)
Pack temp: 1.43, 1.43, -1.68, 1.43
gid: 6
max/min/avg/cp diff: 3371/2813/3185/558
Judgment Value : 2906


As for the Hx reading I've seen the following:
110.39 when pack temp was between -0.68 C and 7.56 C
108.73 when pack temp was between -10.13 C and 1.43 C

 

[charge]

Just got the app and ODBII a few days ago...

I have a question about gids vs. AH capacity. First, some background. Have a 2012, Got it 1/30/12. About 22k miles. I'm in CT, so high temps are not much of an issue here. Never QC'd. I'm using the latest version of the app v.26.

From the battery app - AH=60.44(91.22%), Health = 90.35%. Yesterday I charged to 80% and had a 213 gid reading.

If I understand the readings from the app properly, I'm down almost 9% capacity. However, if I compare to gids, a new batter should have about 281 gids when charged to 100% and about 225 when charged to 80%. When I compare my 80% charge gid (213) to the expected gid for for a new battery charged to 80% (225), then per gids I'm down about 5%.

Am I understanding this correctly? If so, why the discrepancy between AH cap and gids? Also, which is more accurate?

Thanks in advance for your help! This forum is great.

I posted this back in August. At that time my AH was at 60.44. Currently it is at 63.15. SOH was at 90.35 in August and is now over 96%. I do not have the most recent update (not sure if it's any benefit to me). Current mileage is almost 30k

The AH have been steadily increasing since August. I have read in other topics that GIDs increase as the weather gets cooler. Is what I'm seeing normal?

Another question - If I use the summer readings I'm down about 9-10% If I use the winter readings I'm down about 4%. Which one do I believe?

Thanks!

 

[Pipcecil]

So I finally got an ODBII connector and have been playing around with it and Leaf Spy (lite - I get the pro for valentines from my wife!). After reading the instructions and following this and other threads, the elusive Hx value still seems undetermined, but I got a theory that may hold (some) water:

The data I collected.

After preheating and running the app, I always started at a lower SOC than normal (it is really cold for DFW standards - low 30's or 20's), because of that, the battery pack never fully gets charged again after a preheat, even for about 30 minutes, leaving me with a SOC of ~88-89%. My current capacity from the AHr is stilling at 69% (sorry lite version doesn't show decimals). But my Hx number was in the upper 40's, ~48-49%. I noticed a direct correlation between my actual capacity (%) and the Hx number to my SOC. Being, 69(%) minus 48 to 49 gave me almost exact (remember no decimals on the capacity) % of SOC. This was repeated multiple times with the same result. Leading me to believe it was the difference (based on temperature and resistance) that would modify the % SOC.

This theory was quickly shot when I didn't preheat, hitting an SOC of 95% with the same Hx numbers. But it evolved into something else. Each time I preheated, the car had reached its target temperature and had just turned into the lower power draw for maintence heating (i.e. waiting for me to go). At that point, the required power to heat was minimal, but was dedicated to charging the car. Each time I preheated, regardless of temperature, I always got the ~88% SOC. So I am thinking the car hit a point to where it was such a high SOC it had to significantly lower the incoming electricity to not damage the pack (that last few % always takes so long, right?).

Well, if each time I hit that slow charging curve - what if the Hx number is somehow related to the the amount the battery can take before it needs to throttle the voltage down to a trickle. Usually on a brand new battery in moderate climates for any gadget this is only the last upper couple of %. But with a degrated battery with higher resistance and/or cold weather affecting it? We have seen pictures of Hx greater than the % capacity, I think this is showing that the batteries can accept full level 2 to full without damage. The over 100% just is a calculation it does to see how much capacity before it has to switch and in that case it would be greater than the capacity of the battery (so uber OK).

Even if its a corelation saying its directly related to resistence (its gets lower as battery gets used) and its affected by temperature that still pegs the Hx number as part of the resistence of the battery. The only way to prove my theory would be to get someone able to determine voltage input and see what happens after the capacity reaches the Hx number and see if voltage drops to a trickle amount.

 

[dhanson865]

so we know that a battery system reset will show 12 bars for several weeks.

What is the strategy when looking at a used car with this app to determine if the battery has degradation?

I walk up to a Leaf on a dealer lot that has 65,000 miles on it and no battery replacement is coming from Nissan, I fully suspect someone has reset the bars, I plug in my ODBII and boot up my Leaf battery app what number or numbers do I trust?

 

[vrwl]

so we know that a battery system reset will show 12 bars for several weeks.

What is the strategy when looking at a used car with this app to determine if the battery has degradation?

I walk up to a Leaf on a dealer lot that has 65,000 miles on it and no battery replacement is coming from Nissan, I fully suspect someone has reset the bars, I plug in my ODBII and boot up my Leaf battery app what number or numbers do I trust?

I'd think the Amp Hours on Screen 1 would be the one to look at. Or the GIDs on Screen 4.

 

[mwalsh]

6/22: AHr=54.07 CAP=81.61%
6/24: AHr=54.01 CAP=81.52%
6/25: AHr=54.12 CAP=81.68%
7/11: AHr=53.16 CAP=80.23%
7/12: AHr=53.30 CAP=80.45% Hlth=76.57%
8/26: AHr=52.54 CAP=79.30% Hlth=75.16%
9/11: AHr=51.49 CAP=78.49% Hlth=73.22%
10/2: AHr=51.81 CAP=78.98% Hlth=73.82%
10/8: AHr=51.58 CAP=78.63% Hlth=73.39%
10/23: AHr=52.12 CAP=79.51% Hlth=74.46%
11/5: AHr=52.68 CAP=80.31% Hlth=75.43%
11/12: AHr=52.47 CAP=79.98% Hlth=74.80%
11/22: AHr=52.74 CAP=80.40% Hlth=75.53%
11/25: AHr=52.89 CAP=80.63% Hlth=75.81%
12/21: AHr=52.74 CAP=80.40% Hlth=75.53%
1/21: AHr=51.38 CAP=78.32% Hlth=73.02%

2/25: AHr=51.37 CAP=78.31% Hlth=73%