Discuss data from the LEAF Battery app, and Comparisons

[Stoaty]

Based on the thermal time constant for battery pack cooling (estimated at 9-10 hours), I have changed my charging routine during the summer. I now get home about 7:00 PM, let the battery pack cool for 5-6 hours, charge back to 70% Gids (2-2.5 hours), then let the battery pack cool for another 4-5 hours before taking my Leaf out to the hot San Fernando Valley. I believe that my pack will be less likely to get above 86 degrees using this charging schedule (as long as ambient temp doesn't go much above 90 degrees). Somewhere between 90-95 degrees forecast maxium temp I will leave the Leaf at home and take the ICE.

 

[vrwl]

In the 6 weeks since I've started using this app, I have lost a little over 3% in my capacity reading. It was 89.9 to start off, now I'm down to 86.7. My car is garaged about 95% of the time in a garage that doesn't get above 80* inside, even in the most scorching part of the summer. Got our first L3 charge over the Memorial Day weekend, and I did notice that the battery temp jumped 10 degrees from low 80's to low 90's, but other than that, this car is babied beyond belief.

 

[klapauzius]

At 25.4 C it went from 67.57 Ah (@ 25 C) to 67.51 AH. Is it possible that this is some calculated value that has a constant 25 C in it somewhere?

 

[surfingslovak]

At 25.4 C it went from 67.57 Ah (@ 25 C) to 67.51 AH. Is it possible that this is some calculated value that has a constant 25 C in it somewhere?

Yes, it's definitely possible that the capacity is temperature-adjusted. This might explain the seasonality observed in Gid counts as well. The seasonal adjustment could be on the order of 5%, based on the data posted by TickTock and others.

 

[JPWhite]

At 25.4 C it went from 67.57 Ah (@ 25 C) to 67.51 AH. Is it possible that this is some calculated value that has a constant 25 C in it somewhere?

Yes, it's definitely possible that the capacity is temperature-adjusted. This might explain the seasonality observed in Gid counts as well. The seasonal adjustment could be on the order of 5%, based on the data posted by TickTock and others.

That matches my observations over the last 3 weeks. 4.5% of capacity has gone. Battery temp has been fairly consistent at low 80's with a few forays into the 90's. It seems the software shaves off a little capacity each day when battery temps get into the 80's until it settles around a new value.

We had a 2-3 day cool spell recently where the battery got down to the 70's constantly. 0.2% of capacity came back only to vanish a few days later when battery temps got back into the 80's

It's a real shame ambient temps aren't captured, apparently the data isn't available over the can bus. I am accumulating logfiles and will be able to concatenate them in the future into one big file to look at seasonal trends and other factors. The tool is going to provide us with much more data than we've ever had in the past.

 

[opencar]

Based on the thermal time constant for battery pack cooling (estimated at 9-10 hours), I have changed my charging routine during the summer. I now get home about 7:00 PM, let the battery pack cool for 5-6 hours, charge back to 70% Gids (2-2.5 hours), then let the battery pack cool for another 4-5 hours before taking my Leaf out to the hot San Fernando Valley. I believe that my pack will be less likely to get above 86 degrees using this charging schedule (as long as ambient temp doesn't go much above 90 degrees). Somewhere between 90-95 degrees forecast maxium temp I will leave the Leaf at home and take the ICE.

Stoaty, what are your 'gids from the battery app For 80 or 100%? Are they consistent with the values in your signature? I'm at 204 `gids for 80% in san diego.

 

[davewill]

Well, I just lost my first capacity bar, and I thought it would be helpful to post before and after data.

Here's the very first screenshot I took when I first got the app.

And one I took as soon as I noticed the bar missing.

It might have happened any time in the last couple of days. I've been doing a M-Th weekly commute (up on Monday, back on Thursday) about 85 miles away from home, the last two weeks, depending on DCQC to get up and back, as well as to get around while I'm away. You can see the raised temps, partially from QCing and partially from higher ambient temps. I got up into the lower nineties after a couple of the QCs. I'm hoping that a little capacity may return when I get back to my normal, cooler routine, but it's barely even a hope. I know the bar won't return. If I do get any capacity back, I will certainly report it.

The car is 24 months old, with 25,500 miles. It's survived two summers and is just getting started on it's third.



P.S. Please don't list my car in the bar loss list. If I decide to list my missing bar in the Wiki, I will do it myself.

 

[vrwl]

For those of you using the Kyocera eVent phone for this app, here's a pdf version of the owner's manual for that phone: http://www.virginmobileusa.com/resources/phones/prepaid/manual/kyoceraevent-en.pdf" onclick="window.open(this.href);return false;

Davewill: Sorry to see your post about your bar loss. Looks like it's going to be another busy summer of Leaf battery capacity losses and I'll probably join the group in a few weeks.

 

[Stoaty]

Stoaty, what are your 'gids from the battery app For 80 or 100%? Are they consistent with the values in your signature? I'm at 204 `gids for 80% in san diego.

I don't use 'gids for anything, they are too far off (especially for lower SOC%), and I have a Gid meter. I probably need to update my signature, but haven't had the need to charge to 100% for a while (take my brothers prius for the 100 mile round trip drives when it is hot--which it has been). I think my 100% gid count will probably be significantly lower, but probably not too much change in the 80% gid count (which was 212 about 3-4 weeks ago).

 

[TomT]

Really? My experience is they are the most accurate of all the various available data at low SOC, as long as you know what the numbers mean...

I don't use 'gids for anything, they are too far off (especially for lower SOC%), and I have a Gid meter.

 

[LEAFfan]

Really? My experience is they are the most accurate of all the various available data at low SOC, as long as you know what the numbers mean...

I don't use 'gids for anything, they are too far off (especially for lower SOC%), and I have a Gid meter.

Tom, he's talking about 'Gids, which are simulated. But I found them to be rather close at low SoC. Turtle for actual Gids is at 4 I believe and my 'Gids hit 8 at Turtle.

 

[Stoaty]

Really? My experience is they are the most accurate of all the various available data at low SOC, as long as you know what the numbers mean...

I don't use 'gids for anything, they are too far off (especially for lower SOC%), and I have a Gid meter.

%'gids read about 2% higher than true Gids at 50% SOC, and by the time I get down to 25% SOC %'gids read 3-4% higher than true Gids

Do you have a Gid meter to compare? If so, are your results different?

 

[klapauzius]

Really? My experience is they are the most accurate of all the various available data at low SOC, as long as you know what the numbers mean...

I don't use 'gids for anything, they are too far off (especially for lower SOC%), and I have a Gid meter.

%'gids read about 2% higher than true Gids at 50% SOC, and by the time I get down to 25% SOC %'gids read 3-4% higher than true Gids

Do you have a Gid meter to compare? If so, are your results different?

Do you mean the simulated gids? Would be nice if we adopt a more identifiable nomenclature for those...

 

[Stoaty]

Do you mean the simulated gids? Would be nice if we adopt a more identifiable nomenclature for those...

Yes, I am using the nomenclature from Turbo3 in the Leaf Battery App. I agree that something like S-Gids would be a lot more obvious.

 

[GregH]

I've tested two different 2013 cars with the LeafDD and both came up with exactly 67.3620Ah capacity (0x0A4754)... Eh?

 

[opencar]

Well, I just lost my first capacity bar, and I thought it would be helpful to post before and after data.

Here's the very first screenshot I took when I first got the app.

And one I took as soon as I noticed the bar missing.

It might have happened any time in the last couple of days. I've been doing a M-Th weekly commute (up on Monday, back on Thursday) about 85 miles away from home, the last two weeks, depending on DCQC to get up and back, as well as to get around while I'm away. You can see the raised temps, partially from QCing and partially from higher ambient temps. I got up into the lower nineties after a couple of the QCs. I'm hoping that a little capacity may return when I get back to my normal, cooler routine, but it's barely even a hope. I know the bar won't return. If I do get any capacity back, I will certainly report it.

The car is 24 months old, with 25,500 miles. It's survived two summers and is just getting started on it's third.



P.S. Please don't list my car in the bar loss list. If I decide to list my missing bar in the Wiki, I will do it myself.

thanks for posting the info davewill. i'm in a situation close to your parameters: san diego, 21K miles, 24 months. seems like the bar is correlated with crossing the threshold of CAP somewhere very close to 85%.

 

[TomT]

Ahh, ok; my bad! I thought he was talking about real Gids... I missed the quote mark...

Tom, he's talking about 'Gids, which are simulated. But I found them to be rather close at low SoC. Turtle for actual Gids is at 4 I believe and my 'Gids hit 8 at Turtle.

 

[UkrainianKozak]

Actually I'm at loss with the capacity reported by app...
~2 weeks ago I was getting readings between 94 and 98%, today I noticed that it dropped to 89% at one point. Since then it climbed back to 91%... Feels like it is kind of temperature dependent, but not directly...
When it was colder overall I was getting higher readings. But if batt temp is going up as a result of charging for example, the capacity don't drop that much...
So, I'm kind of confused about the accuracy/usability of this number. I do see that lower number is worse, but what is actual meaning of it? to me the sway between 98% and 89% in 2 weeks is unreal, and it is not just going down, it goes up again...

So, anyone knows what this number is actually showing?

 

[TonyWilliams]

Tom, he's talking about 'Gids, which are simulated. But I found them to be rather close at low SoC. Turtle for actual Gids is at 4 I believe and my 'Gids hit 8 at Turtle.

Actual Turtle is lowest cell pair voltage threshold, which just happens to be in a variable mid single digit Gid value.

 

[DaveEV]

Well, I just lost my first capacity bar, and I thought it would be helpful to post before and after data.

Definitely helpful. Looks like your first screenshot was April 13th from the date in the picture?

Losing nearly 3Ah or 5% in two months is pretty extreme for a car which is already 2 years old - it really is more proof that suggests that the Ah / capacity readings are adjusted or normalized for temperature some how.

Coincidentally, the SOC is nearly the same in both pics and the pack voltages are basically the same, too - at least as expected the later pic has a slightly lower SOC% and also has slightly lower cell voltages.

In your 2nd pic, your pack is definitely pretty warm for San Diego, especially for mid-morning (mid-upper 80s) - out of curiosity, how much driving/charging was done before that? My car has been showing temps like in your first pic in the mornings - mid 70s - 5 temp bars. I have seen low 80s a few times after sitting in the sun all day before it cooled off the last week or so.

Edit: Just noting in this thread as well that it appears that the threshold for losing a bar is right around 55.25 Ah...

I'm going to go out on a limb and estimate that you will lose bars at these Ah readings:

11: 55.25
10: 52.00
9: 48.75
8: 45.50
7: 42.25
6: 39.00