I want my 281!

[TomT]

Clearly the Leaf is best used in a cave where it is a constant temperate temperature. :lol:
Any warmer or cooler than that, and you have capacity issues...

It sounds to me that what you have actually observed is that gid count is limited by higher temperatures, just as TickTock has been reporting for almost a year

 

[TickTock]

with the temperature relationship in full swing beginning to wonder if this 281 is due to a relatively large termperature swing. was camping yesterday, got home around 6 PM and ambient temps were near 90º. i did not plug in car until 11 PM and garage was still 81º

get up this morning and temps are in mid 50's and charge was completed at 4:35 AM.

now supposing i actually charged to my normal 276-280 and the temperature rise to the upper 60's was the reason it read 281?

Yup. See page MWI-27 in the SM - explains how the number of bars can increase when temp drops (in the box at the bottom). Assuming this is based on gid count, stands to reason gid count increases, too.

(and, I would add, explains why we see large recoverable apparent degradation in the AZ summer heat. Don't flame me, I'm not saying we aren't seeing degradation, I know we are - just saying some should be recoverable)

 

[palmermd]

Except that that page shows capacity dropping as temperature drops and all the empirical data shows capacity dropping as temperature rises. Perhaps both are true and there is a bell curve where there is an optimum temperature with maximum capacity and it drops off above and below.

 

[edatoakrun]

with the temperature relationship in full swing beginning to wonder if this 281 is due to a relatively large termperature swing. was camping yesterday, got home around 6 PM and ambient temps were near 90º. i did not plug in car until 11 PM and garage was still 81º

get up this morning and temps are in mid 50's and charge was completed at 4:35 AM.

now supposing i actually charged to my normal 276-280 and the temperature rise to the upper 60's was the reason it read 281?

Yup. See page MWI-27 in the SM - explains how the number of bars can increase when temp drops (in the box at the bottom). Assuming this is based on gid count, stands to reason gid count increases, too.

(and, I would add, explains why we see large recoverable apparent degradation in the AZ summer heat. Don't flame me, I'm not saying we aren't seeing degradation, I know we are - just saying some should be recoverable)

"Assuming this is based on gid count, stands to reason gid count increases, too."

Have you tried this, TickTock, which could confirm your assumption?

Has anyone with considerable variability in their daily ambient temperatures watched the gid count following a charge, while remaining parked, and neither charging nor discharging the battery, to see if the gid count changes (declines, presumably) as the ambient temperature warms during the day? (8/29 edit- Or watched to see if the gid count increases, as the battery cools overnight?)

I've had my car parked at following a "80%" timer charge for a few days, with nighttime lows around 60 F, and daytime highs around 90 F.

The charge bars increase from 9 to 10 in the early morning, and decline back to 9 late in the afternoon, shortly after the battery temp bars increase from 5 to 6.

(8/28 edit- On the last test cycle, it went back up to 10 bars by one AM the next morning, completing a 10 bar to 9 bar to 10 bar cycle, without any charging or significant battery discharge.)

Just wondering if this charge bar variability by temperature, is reflecting gid count variability, or if something else is causing it.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=9776&start=20" onclick="window.open(this.href);return false;

 

[KJD]

It begs the question:
"What will the highest mileage/age to see 281. I'll see 18 months in just a few weeks and we're still good to go. But on the other hand, no one would NOT want to baby their traction packs the way we have

Hill, are you saying that your car is still seeing 281 ?
How many miles does the car have on it now and what exactly are you doing to baby that pack ?
Sounds like it is working what ever you are doing.

 

[TickTock]

Except that that page shows capacity dropping as temperature drops and all the empirical data shows capacity dropping as temperature rises. Perhaps both are true and there is a bell curve where there is an optimum temperature with maximum capacity and it drops off above and below.

Perceived available charge drops with higher temperature (as measured via gids or bars). This is different than actual capacity which increases with higher temperature. These both are different than the irreversible aging-related degradation (which increases with higher temperature). "The candle that burns twice as bright lasts half as long" - Bladerunner.

 

[edatoakrun]

Except that that page shows capacity dropping as temperature drops and all the empirical data shows capacity dropping as temperature rises. Perhaps both are true and there is a bell curve where there is an optimum temperature with maximum capacity and it drops off above and below.

Perceived available charge drops with higher temperature (as measured via gids or bars). This is different than actual capacity which increases with higher temperature. These both are different then aging-related degradation (which increases with higher temperature).

And how much of the loss of one, two, or three capacity bars is actually aging-related degradation is highly uncertain, IMO.

BTW TickTock, does your LEAF still have all 12 capacity bars?

 

[TickTock]

Dang it - tried to get my Bladerunner quote in before any responses (that was the edit above). Anyway, I still have all 12. I'm surprised - weather is still pretty hot. However, I have been cooling the garage with a swamp cooler since they reset it so maybe that is slowing it down.

 

[DaveinOlyWA]

i think the exit of AZ heat will bring back capacity but i see it not being as much as the losses reported here. i was able to generate about a 3.5% loss, so guessing that AZ "might" see 10% coming back with the winter but that is a bit of a stretch. my feeling is you will see no more than 6-7% but i could be wrong.

what i was able to reproduce on our hottest day during the hottest part of the day could easily be up to 30º lower than your normal stuff.

should be easy to find out. with that much coming back, bars will reappear. i think everyone will end of up only one bar gone which is still a lot

 

[WetEV]

Dang it - tried to get my Bladerunner quote in before any responses (that was the edit above). Anyway, I still have all 12. I'm surprised - weather is still pretty hot. However, I have been cooling the garage with a swamp cooler since they reset it so maybe that is slowing it down.

This sounds hopeful. What sort of temperature bars are you seeing during the day? Something like this:

Morning, before using the car?
After morning commute?
Afternoon, before using the car?
After evening commute?

 

[GregH]

Sadly my hopes of ever seeing 281 were dashed many moons ago. I'm in Irvine, 10 miles or so from the coast in O.C. and have charged mostly to 80% (finishing at 6am). During the few moderately cool days this past weekend I tried a few 100% charges after seeing my 80% gid slowly drop over the last few weeks (207, 206, 205 etc down to 202).
So the first charge took me to 241 and I hit the timer button again after a few hours and nudged it to 243.
The 2nd day it charged to 243 and I nudged it again up to 245.
The 3rd day it charged to 244 and I nudged it again to 245.
On the 4th and 5th days I charged back to 80% as was my norm, and just as before... it went to 202.

I still have all 12 "bars" and for a while I was getting 9 energy bars at 80% but it has since gone back to 10, even though the gid count had dropped.
I seem to recall Phil (Engineer? who seems to be the only one with active CAN data) saying somewhere on here that 80% was always 80% of rated capacity, but 100% could be something like 94%-99% (or something like that)... Which would seem to say that the 80% gid number is a BETTER way to assess pack capacity than the gid# at 100%...?
From my experience explained above, multiple 100% charges will indeed bump up the 100% gid count a bit presumably as some top end cell balancing is done, but it may not ultimately change the car's assessment of true capacity.

 

[palmermd]

During the few moderately cool days this past weekend I tried a few 100% charges after seeing my 80% gid slowly drop over the last few weeks (207, 206, 205 etc down to 202).

Seems like a pattern. Every one of these reports are with cars that are right around 1 year and then capacity starts plummeting. Strange, but it does seem to be a pattern.

 

[TonyWilliams]

During the few moderately cool days this past weekend I tried a few 100% charges after seeing my 80% gid slowly drop over the last few weeks (207, 206, 205 etc down to 202).

Seems like a pattern. Every one of these reports are with cars that are right around 1 year and then capacity starts plummeting. Strange, but it does seem to be a pattern.

My red car had a very similar pattern; everything good, then dropped like a rock. Folks were quick to point out that I "abused" my battery and that it had "high mileage", but I find that really had little effect in the grand scheme. Several have lost that first capacity bar here in SoCal without ever abusing it or racking up high miles, and to my knowledge, #2244 still has all 12.

Every one of these batteries will tank, in my opinion. The only thing to diminish the time factor is ambient temp. But, those will fall, too.

The few spin masters we have on the forum can never explain away the data that Nissan and the whole EV battery world knew; this battery was a really bad idea before they started production.

 

[mwalsh]

I only saw 281 twice in my car. I just looked at my spreadsheet and both times were around this very same time last year - 10/5 and 10/10 to be exact. These days I'm only seeing daily readings in the 230s-240s. Rest in peace, sweet 281.

 

[DaveinOlyWA]

my LEAF was over a year old when i saw 281 for the first time. seen 280 plenty (keep in mind, my car was just about a year old when i got the GID meter)

 

[ebill3]

The only way I ever saw 281 was to force it. That is, after a 100% charge completed, push the override button and get a bit more charge before shut down.

A few days ago, 277 by using the above "force" method. Normal is 274.

 

[GregH]

Now that I'm probably in the market for a new Leaf (still can't decide '12 or '13), I thought it would be cool to check the cars for battery health and am trying to come up with a simple SOC independent algorithm to do so. Seeing the Gids at "full" would be easiest but often the cars at the dealership (thankfully) are not at full. Now that we have access to SOC as well as Gids, there must be a way to measure capacity without regard to SOC.. Forgive me if this is covered elsewhere..

So I measured a friend's Leaf charging here at work and saw the following:
75 Gids at 30.0%
178 Gids at 67.0%
216 Gids at 80.0% (80% charge)
262 Gids at 95.8% ("Full")
Better than Joulee3, but certainly not 281...

Based on his car, I came up with Gids/(SOC-3.0) which more or less lines up the data..
75/27 = 2.78
178/64 = 2.78
216/77 = 2.80
262/92.8 = 2.82
Maybe a 3.1 or 3.2 offset would be a better offset...
but I don't know if this would be the same on other cars.

By this model a theoretical 281 gid car at say 97% would be 2.99
and a 231 Gid car at 80% would be 3 even.

So I tried a few cars at the dealer lot and saw this:
White SL car, just sold, didn't see vin: 249 Gids at 85.4% (3.02)
Blue SL vin26084 277 Gids at 94.1% (3.04)
Blue SL vin24735 233 Gids at 81.7% (2.96)
Black SL vin24652 180 Gids at 63.0% (3.00)
Black SL vin26967 273 Gids at 92.6% (3.05)

If the equation holds, then they all look pretty good (as one would expect for new cars with
potentially moderately imbalanced packs).. maybe the first blue and last black SL being strongest.

Does anyone else out there with a Gid meter and ability to see the car's
SOC% (on 0x55b) have data to contribute?

 

[TonyWilliams]

Does anyone else out there with a Gid meter and ability to see the car's
SOC% (on 0x55b) have data to contribute?

The following is not SOC% data in the sense that 95% SOC equals 100% charge and 2-3% SOC equals turtle, but hopefully it can shed light on comparing SOC to Gids and getting a degradation value.

For instance, using Gid2 % data compared to the 2013 LEAF SOC %, as those two diverge, the degradation can be calculated (assuming Gids are properly accounted for temperature changes):

I am used to the gids percentage, but I think that it would be good to have usable kW.h before turtle, like (gids - 7) x 0.08.

100 ((281 -7) / (281 - 7)) = 100% * 21 = 21kWh

100 ((144 -7) / (281 - 7)) = 50% * 21 = 10.5kWh

100 ((7 -7) / (281 - 7)) = 0% * 21 = 0kWh

The new 2013 will show 100% regardless of capacity, when fully charged, and show the following:

kWh----------Gid----Gid%---Gid2%---2013 dash % (2013 dash % data based on SOC %, not Gids)
21.0--Full----281---100%---100%----100% (non-degraded at 70F; 21kWh usable)
10.5--Half----144--51.2%----50%----50% (non-degraded at 70F; 10.5kWh usable)
10.5--Full***--144--51.2%----50%----100% (***used 50% degraded at 70F; 10.5kWh usable)
3.2---LBW----49---17.4%---15.3%----15% (2013 data on a new car, unknown for degraded)
1.3---VLB----24----8.6%-----6.2%----5% (2013 data on a new car, unknown for degraded)
0.0---Turtle --7-----2.5%-----0%-----0% (2013 data on a new car, unknown for degraded)

NOTE: LBW and VLB are indexed to Gids, therefore those values won't match the SOC derived data of the 2013 dash % with a degraded battery.

Turtle is not indexed to Gids, therefore under a high load, like freeway speed, expect turtle at 7 or 8 Gids, and at extremely low power, as low as 4 Gids to Turtle.

As SOC% and Gid2% diverge, the degradation of the battery can be calculated.

 

[GregH]

As SOC% and Gid2% diverge, the degradation of the battery can be calculated.

Yeah, that's what I hoped to do.. I wonder if 0x55b % is tied to turtle as Gids are not (?)

I'd basically like to predict the Gids at full charge (95-97% on 0x55b) without having to charge.
I wonder what's the highest 0x55b % anyone has seen? Could a really well balanced pack deliver 97%?

 

[TonyWilliams]

As SOC% and Gid2% diverge, the degradation of the battery can be calculated.

Yeah, that's what I hoped to do.. I wonder if 0x55b % is tied to turtle as Gids are not (?)

I'd basically like to predict the Gids at full charge (95-97% on 0x55b) without having to charge.
I wonder what's the highest 0x55b % anyone has seen? Could a really well balanced pack deliver 97%?

Well, first note that I'm comparing the 2013 LEAF SOC % specifically to the "Gid2" formula, while the straight Gid would be properly indexed to the SOC % of full = 24kWh = 100% = 300 Gid.

In that case, 281 Gid is 93.6% SOC (281/300)

Turtle is likely tied to voltage, per Phil, which makes sense to protect the cells from over discharge.