Capacity Loss on 2011-2012 LEAFs

[smkettner]

Interesting that we seem to refer to the last two bars of the charge level as the red zone when reality is the only thing marked red is the battery capacity indicator on the right.

So is the first year the worst of it? Will capacity loss accelerate from here? Or have we just taken off the top edge and the middle will hold up better?

What is a good ratio to evaluate relative loss? GIDS/Miles?

 

[edatoakrun]

It's official.. Lost the bar today.

I find it incredibly hard to believe that so many people would loose the first capacity bar within what, 2 weeks? With such a vast range of mileage. Just doesn't make sense...

Recent battery temperature somehow involved in the bar display, perhaps?

Maybe Spring will be the season for bars to go away?

Please give your best estimate of actual capacity loss in kWh, at 11 bars, by whatever methods you choose.

As usual, I would suggest you all use CW reports, of daily kWh use from 100% to low level, whether you have a gid/SOC meter or not.

 

[TonyWilliams]

What is a good ratio to evaluate relative loss? GIDS/Miles?

Gids seem to be getting the job done. We've been alerted to loss by Gid, only to be confirmed when that first 15% loss of capacity bar disappears at 85% remaining capacity.

18500 watts (231 Gid * 80 wattHours) is 82% of 22500 watts (281 Gid).

Sure, you could drive it around and prove it, but why?

 

[TRONZ]

Loss of a bar among very different mileage packs just means its something else that accelerates the loss. The usual suspects are heat and sustained hi/low charges. It would be interesting for people with SOC meters to have curious owners come by for an unofficial check-up. Mr Gid himself is closest to me in fact. Bringing some of the persons favorite beverage and/or food while topping off might be a nice move. There are a lot of well respected owners with SOC devices on MNL. These folks would be a safe conduit for the data into a spreadsheet.

 

[LEAFfan]

I wonder if anyone in Phoenix has been tracking Gids over the past year.

My LEAF ScangaugeII only reads out SoC%, but they based it on the 281 raw number. When I first got the gauge a few months after I got my car (June), I would consistently see 80-82% when I charged to 80% and 94-95% when charging to 100%. Now, it is around 73% at 80% and only 83-85% when charging to 100%. These new figures are with using the DCQC. I haven't used L2 since May 2. I will probably lose a capacity bar in a month or two.

 

[vegastar]

I can say that I'm very happy that today my charge to 80% yielded 230gids (24000km/ 15k miles). There must be something that is making all those cars lose 15% capacity in just one year. BTW, did TickTock allready lose the first capacity bar?

 

[Boomer23]

I'm also seeing an unusual and abrupt capacity loss, though only about 3%, actually 9 Gids, and of course I haven't lost a capacity bar.

I usually charge to 100% and I've been able to get 281 Gids routinely, with drops down to 278 or so occurring often. But I got a couple of 281 readings early this month. Now, suddenly, I'm only able to get 272 Gids, which reads as 96.7%. I tried charging to 80% for one night, then back to 100% the next night, but still got only 272 at 100%.

I always set a start timer only and leave the J plug in for hours after the charge completion, so there's ample time for balancing.

 

[turbo2ltr]

I don't think anyone is doing it.. I just have to see this visualized.. I'll make a spreadsheet

Form: https://docs.google.com/spreadsheet/viewform?formkey=dHMyRTVOcGRfWUFkc1A0WUtmbUd6UEE6MQ#gid=0" onclick="window.open(this.href);return false;

 

[KJD]

I'm also seeing an unusual and abrupt capacity loss, though only about 3%, actually 9 Gids, and of course I haven't lost a capacity bar.

I usually charge to 100% and I've been able to get 281 Gids routinely, with drops down to 278 or so occurring often. But I got a couple of 281 readings early this month. Now, suddenly, I'm only able to get 272 Gids, which reads as 96.7%. I tried charging to 80% for one night, then back to 100% the next night, but still got only 272 at 100%.

I always set a start timer only and leave the J plug in for hours after the charge completion, so there's ample time for balancing.

You really do not need to balance the pack every night. I only do mine once every month or two. Your pack will last longer if you remove the start time and enter an "End time" just before you leave in the morning.

 

[Boomer23]

I'm also seeing an unusual and abrupt capacity loss, though only about 3%, actually 9 Gids, and of course I haven't lost a capacity bar.

I usually charge to 100% and I've been able to get 281 Gids routinely, with drops down to 278 or so occurring often. But I got a couple of 281 readings early this month. Now, suddenly, I'm only able to get 272 Gids, which reads as 96.7%. I tried charging to 80% for one night, then back to 100% the next night, but still got only 272 at 100%.

I always set a start timer only and leave the J plug in for hours after the charge completion, so there's ample time for balancing.

You really do not need to balance the pack every night. I only do mine once every month or two. Your pack will last longer if you remove the start time and enter an "End time" just before you leave in the morning.

Thanks for the comment. I'll try that. One complication is that I'm on a TOU plan with the best rates being between midnight and 6 am, so I want to get all of my charging done before that end time. And I'm retired, so I don't have an early drive time most mornings (I know, poor me). So If I set a 6 am end time, I'll probably still leave the car fully charged for a few hours each day before driving it.

I'll be very interested to see if I get a rebound back up close to 281 Gids or if this 272 is my new high. Temps have gotten warmer here in So Cal, but not so much overnight that I'd expect to see this much of a drop off.

 

[JPVLeaf]

While I have not (yet) lost a bar, I have also been experiencing an accelerated 'gradual' decrease over the past 30+ days in my no. of Gids at 100%. Prior to this, I would routinely reach 275-281 Gids on 100% charges, which I do 4-5x/wk. I've routinely recorded the Gids since Oct 2011 when I got my Gid-meter. Here's how my Gids have been tracking the past several weeks.

6/6/11 - 4/8/12, 275-281
Wk of 4/9/12, 271-280
Wk of 4/16/12, 263-276
Wk of 4/23/12, 263-269
Wk of 4/30/12 - 266-271
Wk of 5/7/12 - 262-267
Wk of 5/14/12, 260-265

My last 281 was on 3/26/12. I'm currently in mourning for My 281! It was nice while it lasted.

Some stats: After 11.5 mo., I have 16600 mi on the odo. I've QC'd 5-6x off Mitsubishi's Eaton DC QC. I received all 5 Stars on my Battery Inspection report at 15k mi. on 4/21/12.

 

[davewill]

... One complication is that I'm on a TOU plan with the best rates being between midnight and 6 am, so I want to get all of my charging done before that end time. And I'm retired, so I don't have an early drive time most mornings (I know, poor me). So If I set a 6 am end time, I'll probably still leave the car fully charged for a few hours each day before driving it. ...

You'll still be reducing the amount of time it sits fully charged. I'd set it for at least 7AM, maybe 7:30. It will still probably get done by 6AM, and even if does run past 6AM some mornings, it won't be by much.

 

[KJD]

Thanks for the comment. I'll try that. One complication is that I'm on a TOU plan with the best rates being between midnight and 6 am, so I want to get all of my charging done before that end time. And I'm retired, so I don't have an early drive time most mornings (I know, poor me).

OK if you are retired do you really need to charge to 100% every night or can you get by with 80% ?

With a Lithium battery the basic strategy is that you want to minimize the time at the very top SOC and the very bottom SOC as much as possible.

 

[edatoakrun]

While I have not (yet) lost a bar, I have also been experiencing an accelerated 'gradual' decrease over the past 30+ days in my no. of Gids at 100%. Prior to this, I would routinely reach 275-281 Gids on 100% charges, which I do 4-5x/wk. I've routinely recorded the Gids since Oct 2011 when I got my Gid-meter. Here's how my Gids have been tracking the past several weeks.

6/6/11 - 4/8/12, 275-281
Wk of 4/9/12, 271-280
Wk of 4/16/12, 263-276
Wk of 4/23/12, 263-269
Wk of 4/30/12 - 266-271
Wk of 5/7/12 - 262-267
Wk of 5/14/12, 260-265

My last 281 was on 3/26/12. I'm currently in mourning for My 281! It was nice while it lasted.


Some stats: After 11.5 mo., I have 16600 mi on the odo. I've QC'd 5-6x off Mitsubishi's Eaton DC QC. I received all 5 Stars on my Battery Inspection report at 15k mi. on 4/21/12.

Seems odd that it would be so stable so long, and decline so relatively rapidly. For those who have owned LEAFs longer, (and had meters then?) how did your gid counts look during this time period last year, as ambient temperatures increased?

 

[Herm]

So If I set a 6 am end time, I'll probably still leave the car fully charged for a few hours each day before driving it.

Should be ok since its early morning and its cool out.. How cool is it usually at that time?

 

[TRONZ]

Your pack will last longer if you remove the start time and enter an "End time" just before you leave in the morning.

You are a Rockstar! I did not know you could leave the start time empty and LEAF will just adjust your charging window to an end time only. I thought you had to specify both and being L1 i am typically quick on the draw when I plug in for overnight. Thank you for this. I set for 8:10am since we always leave at the same time each day. This has no downside for me on L1 as if I am late plugging in I never get a full charge anyways. Now I am just guaranteed that the pack will only sit for about 20 minutes at 100% before being driven off.

 

[Herm]

Man I wish I was tracking capacity this whole time so we could of had a degradation curve.

Assume everyone started at 281, record miles, time in use, location and duration standing at 100% charge .. that should tell you a lot.

With 80 GID meters out in the field you could collect quite a bit of data if everyone cooperated.

 

[TickTock]

I've been since last October, but can't really draw conclusions until this coming October to be sure seasonal effects are removed. It'll be a while before we have a lot of people with > 1 year of data unfortunately.

Note to anyone who is a new owner or soon to be: I strongly recommend you get an SOC meter now and not wait until you suspect a problem before gathering data. In fact, ideally you would bring it with you when you pick your new Leaf up from the dealer and make sure it's at 281 before you take it home.

 

[tbleakne]

I'll try that. One complication is that I'm on a TOU plan with the best rates being between midnight and 6 am, so I want to get all of my charging done before that end time. And I'm retired, so I don't have an early drive time most mornings (I know, poor me). So If I set a 6 am end time, I'll probably still leave the car fully charged for a few hours each day before driving it.

You could use my special method to charge to a level you choose, say 88%, 90%, 92% by 6AM,
then top-off to "top" whatever that is, just before you leave on off-peak rates, before 10AM, if possible. If you are not heading out until weekday afternoon, and it is hot, top-off at peak rate could feel painful.

set timer1 to 80%, start 11:50pm, no end time, day = night before.
set timer2 to 100%, start time 5:00am, end time selected to get you from 80% to your target (40 min gets me to 92%), day = day of drive.
do final top-off with timer over-ride.

Once you get the hang of this, it is easy to setup for the next day.

I believe the very top of the battery, combined with elevated temperature, is where capacity loss occurs. Short times at full capacity are best.

 

[surfingslovak]

I believe the very top of the battery, combined with elevated temperature, is where capacity loss occurs. Short times at full capacity are best.

+1

You might want to revisit the excellent Tesla Roadster Battery Care guide by Dan Myggen. Before you delve into it, it's worth noting that the Roadster uses different cells (lithium-cobalt instead of lithium-manganese). What they call "range mode" is our 100% charge, and their "standard mode" is our 80%. In addition to that, they have a storage mode, which we don't have. Because of the difference in cell chemistry, our voltages that correspond to standard or range mode are different as well: 4.05V and 4.10V respectively. We can only speculate, but if some of the research reports we looked at apply to the Leaf, then the cell energy maximum should be around 4.17V.

Among other things, Dan says the following:

Think of battery degradation this way. It is very much a function of time spent at voltage and temperature. For instance, you do not want to charge a car all the way in performance mode, and then let it sit in the sun all day. Between the higher thermal limits and the high SOC, you are causing the battery a relatively high amount of degradation. In fact, the car will eventually allow itself to discharge to Standard levels if left in Performance mode to prevent inadvertent damage to the battery. If you start driving right away after charging in Performance or Range Mode, and don’t let it sit, you would minimize the damage incurred, as the time spent at these extremes is an important part of the calculation.