Capacity Loss on 2011-2012 LEAFs

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mwalsh said:
thankyouOB said:
maybe its mike's meter.

I think my car's capacity reporting is acting up, if anything - GOM was 74 miles this morning.


pure speculation, but perhaps a bad cell module instead of capacity loss. This would explain the GOM going wild over the past few months as well as the GID irregularities. Perhaps it has a bad connection on one module, or just plain bad. Might be worth purchasing the Leafscan to see what is being reported by the on board computer.
 
edatoakrun said:
tbleakne said:
My data:
I used cool recent weather (65 deg F evening, 62 deg F overnight low), to do a rare test of my 100% charge. Result:
271 gids, or 3.6% loss...

When I first finished my SOC meter in late Aug 2011, I never saw more than 274 gids, but with the onset of cooler Fall weather the readings went up, and I hit 281 for most of my winter once-per-month 100% checks. Last 281 was probably February...

RE "3.6% loss", wouldn't it be a good idea to calculate percentage losses, from gid readings, taken at similar temperatures?

You only have a about a 1% gid loss since your highest gid count in late August 2011, right?

Were all those nights significantly warmer, than during your recent 271 result?

Do you have a similar charge temperature gid count recorded from that time (or later) to compare to the present?

Are the 11 bar LEAFs also seeing gid counts variable by temperature?
1. Yes, I am now setup to record garage temperatures, including morning, maximum afternoon (if car present), and minimum over-night.
2. Yes, 271 is about 1% less than the best I achieved last August.
3. Yes, Aug nights are all at least 5-6 degrees F warmer than the highest recent night temperatures, and most of the recent temperatures since my last 281 were an additional 3-4 degrees cooler than the highest recent night temperatures.
4. No, I do not have recorded temperatures from last Aug.
5. (11 bar LEAFs) I don't know. It is a reasonable question, but I would expect that temporary temperature loss would continue to add to permanent capacity loss.

My main concern about the coming summer is possible permanent loss from high daytime temperatures while the car is in the garage with most of a full charge, ready for a planned evening out. My garage gets quite hot in the afternoon, despite its insulated door and solar panels on its roof. The same conditions last summer didn't cost any immediate loss, but it seems possible that the loss effect could be cumulative.
 
Mike's latest readings concerned me and piqued my interest enough that I'm recording my 'Gids', voltage and temp much more frequently.
I really want the battery temp at the beginning and end of charge though, ambient seems less relevant.
Anybody get that CAN code yet?
Mike's LEAF and mine are days apart in age, live in similar climates and are close in miles driven but I'm only at 14k.
Since Jan 2011:
507 charges; Usually 80% but 135 to 100%
Nearly all the 100% charges have been the night before.
Car sits in shade at both home and work. Color: Black
Been to LBW less than 10 times and VLBW once.
I've been checking the 'gid' number off an on since last July.
I've only rarely seen above 275 and never 281.
80% charges have always been 227-233; Yesterday was 231.
100% charges in the last 8 weeks have been 258 to 276 averaging about 269.
So, I'm figuring about 3% loss so far. I'll be looking closely this summer to see if it falls off a cliff.
If I didn't have the measurement tools I'd never have any suspicion that there was any loss. On the same drives ( 25 mi and 50-70 mi) I see very consistent gauge readings. So, perhaps I'll see some more loss over the summer followed by recovery in the Fall. If I get to 2 yrs with 90% capacity I'll be happy as long as it does some leveling off after that.
 
mwalsh said:
palmermd said:
Might be worth purchasing the Leafscan to see what is being reported by the on board computer.

Would if I could. Maybe Ingineer will bump me up to the top of the list in consideration for helping out on getting the EVSE Upgrade business started!

That sounds good. And imagine what it would do to sales of Leafscan if the first unit shipped actually diagnosed a battery problem.
 
I am wondering if the scattered reports of capacity loss are due to a bad cell rather than the whole pack aging prematurely. If a cell was marginal, a year plus some heat might be enough to push it over the edge. Obviously Nissan would want to wait as long as possible to make any replacement of marginal cells since it costs them money to do so. It could be that they see a problem developing, but want to wait until the cell fails more severely and pack capacity starts plummeting before doing anything.
 
I wonder if Nissan actually knows there may be problems yet. I don't think any of us have actually reported it to them, or taken a car in for warranty work for the issue. I'm certainly waiting until I have more than a week of hard data and a month of supposition.
 
Recall the 15% degradation in 9 months is normal thread. I took mine in 3 months ago and got them to run the cell pair test. Despite confirming the loss in capacity/range, all the cells came back in good shape (only 60mV difference between the highest and the lowest cell pair). I go in again in the next few weeks for the mandatory 1 year check. Going to ask for it again since I have seen further degradation since then (am now down to 80%).
 
TickTock said:
Recall the 15% degradation in 9 months is normal thread. I took mine in 3 months ago and got them to run the cell pair test. Despite confirming the loss in capacity/range, all the cells came back in good shape (only 60mV difference between the highest and the lowest cell pair). I go in again in the next few weeks for the mandatory 1 year check. Going to ask for it again since I have seen further degradation since then (am now down to 80%).
Yes, but at that time you were still getting 255 Gids from a full charge (9.3% below "normal"). How many Gids are you getting from a full charge now?
 
Stoaty said:
TickTock said:
Recall the 15% degradation in 9 months is normal thread. I took mine in 3 months ago and got them to run the cell pair test. Despite confirming the loss in capacity/range, all the cells came back in good shape (only 60mV difference between the highest and the lowest cell pair). I go in again in the next few weeks for the mandatory 1 year check. Going to ask for it again since I have seen further degradation since then (am now down to 80%).
Yes, but at that time you were still getting 255 Gids from a full charge (9.3% below "normal"). How many Gids are you getting from a full charge now?

80% X 281=225 on my BCM. His is similar.
 
vegastar said:
The 80% voltage readings are taken how many time after the charge stop?
I notice that in my car the charge stops around 388.5V, but it always drops to 386 or 386.5V half hour later.

This morning I got 230 gids @ 386.5V with 6 temp bars.

My last reading of 388.0V was maybe an hour after charge stop. I went out again now, after the car has sat all night. Still 388.0V. Temp bars is at 5.
 
jkirkebo said:
vegastar said:
The 80% voltage readings are taken how many time after the charge stop?
I notice that in my car the charge stops around 388.5V, but it always drops to 386 or 386.5V half hour later.

This morning I got 230 gids @ 386.5V with 6 temp bars.

My last reading of 388.0V was maybe an hour after charge stop. I went out again now, after the car has sat all night. Still 388.0V. Temp bars is at 5.

It's a little strange that I only need 386,5V to get 230 gids and your car needs 388V. On the other hand at 100% I am getting 276-278 gids @ 393V and you get 281 gids...
 
Here's another data point.

Blue LEAF
14 months since delivery 3/31/11
Coastal Orange County, CA
I've charged about 26 times per month, almost always overnight with some public charging each month and two QCs. Home charging has been to 100% about 98% of the time. Car is mostly driven smoothly, with early average energy economy on the dash of 3.8 mi/kWh, now averaging 4.0 mi/kWh.
I have not lost a capacity bar. Nissan dealer battery report at 12 months, April 11, was 5 stars on all parameters at 11,600 miles.

80% charge overnight from 163 Gids on 5/29/12: 225 Gids, voltage 387.5, ambient temp at time of reading appx 65 F, overnight low temp 57 F.
100% charge overnight from 77 Gids on 5/30/12: 274 Gids, voltage 394, ambient temp at time of reading appx 64 F, overnight low temps range 59 to 61 F. Charge was done with timer override, beginning about 12:40 am, ending at 5:05 am, with car still plugged in until 8:30 am.

(Temp readings are from iPhone weather app, not recorded temps in garage. Garage is un-insulated flat grey rock roof.)

My car was routinely getting 281 Gid readings after 100% charge, with occasional drops to as low as 278 Gid, but my records show outliers for 100% charges in January of 275, 267 and 271, February's lowest was 278 Gid, March had one reading of 269 Gid after a 100% charge from only 28 Gid, April only one low reading of 275 Gid. May started out with 280 and 281, but started dropping on May 6 with 272 Gid after a 100% charge from 103 Gid. I haven't seen anything above 279 Gid since May 4, with low readings of 272, 274, 274, 275, 272, 272, 276, 273, 269, 275, 270, and today 274.

One other point: I started seeing readings not higher than 278 after May 12, a day when I put 95 miles on the car, having driven to Cerritos and then charged mid-day to be able to do some evening driving. Again, 280 and 281 Gids were reliably routine with my car, the last such reading being May 4.
 
I was back to the "new normal" - 91.4 / 257 Gids / 393v this morning. And last night I got home with 28.8 / 81 Gids /367.5 v, despite leaving the office with only 50.8 / 148 Gids (and there is no way I can drive 30.5 miles on 22(%) worth of charge), so something was DEFINITELY anomalous with my AM readings yesterday. But it was from the car, not the Gidometer (I reference my very low GOM as evidence). Phew!
 
If you gain GID with that speed you should be 292 tomorrow. Form your miles/SOC usage yesterday looks like car reported GID inaccurately. But open question is why?
 
Got my 1 year checkup today... capacity has dropped 100%.

No I'm kidding... everything is fine. 12,500 miles all capacity bars. Battery check all 5 stars. I didn't get a percentage though.
 
cdub said:
Got my 1 year checkup today... capacity has dropped 100%.

No I'm kidding... everything is fine. 12,500 miles all capacity bars. Battery check all 5 stars. I didn't get a percentage though.

None of that will identify capacity loss less than 15%

You could be 14% down on capacity and still get five stars and have all 12 capacity bars.
 
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