Capacity Loss on 2011-2012 LEAFs

TonyWilliams · May 21, 2012

Cheezmo said:
Was that mine Tony? I got to 9 bars after 4 QCs in one day, but that still wasn't a "red" bar" and I didn't think I was supposed to shut down. I though someone else had done 6 QCs in one day, did they not also get to 9 bars?

Yes, you were the second to report 9 temp bars on QCing. That temp is supposed to correspond to 126.5F

Yes, the car is supposed to shut down (or go to Turtle mode) at 122F (50C). That's right out of the service manual.

vegastar · May 21, 2012

TonyWilliams said:
vegastar said:

That was expected. 186 gids is just 80.5% of the 231 gids I get on a 80% charge, and not the 85% we thought when the first capacity bar should disappear.

Click to expand...

Yes, as expected for Tick Tock.

You seem to be confusing some numbers, however. 85% is the threshold of current capacity to maximum design capacity before you lose that first bar, and that means the threshold is 231 Gid on a 100% charge. It has nothing to do with 80% charges, which would meet the 85% capacity threshold at 185 Gid.

I just bring this up because the 231 gids I get at 80% charge are not 80% of 281 gids, but 82,2%. And I remember Engineer (I think) saying that the 80% charge is the true 80% capacity of the battery unlike the 100% charge that is below the true 100% charge. As the 80% charge gid value is much more stable (I ALWAYS get 231 gids) it could be a better value to evaluate battery capacity.

TonyWilliams · May 21, 2012

vegastar said:
I just bring this up because the 231 gids I get at 80% charge are not 80% of 281 gids, but 82,2%. And I remember Engineer (I think) saying that the 80% charge is the true 80% capacity of the battery unlike the 100% charge that is below the true 100% charge. As the 80% charge gid value is much more stable (I ALWAYS get 231 gids) it could be a better value to evaluate battery capacity.

Honestly, I'm having a bit of a problem following your thought. Yes, Gids are awesome to indicate battery capacity and degradation, as we've seen many times now.

We don't have (currently) access to an SOC measurement, and unfortunately, many refer to Gids as SOC. I specifically indicate Gids and % of Gids (not SOC) on the range chart for this reason.

Does this chart help any?

Code:

                                  SOC     SOC     Gid     Gid 
                                          w/50%          w/50%
                                      degradation     degradation
100% charge / 12 fuel bars        95%       95%    281     140
0% charge   / Auto shutoff        2%         2%     1       1

surfingslovak · May 21, 2012

vegastar said:
I just bring this up because the 231 gids I get at 80% charge are not 80% of 281 gids, but 82,2%. And I remember Engineer (I think) saying that the 80% charge is the true 80% capacity of the battery unlike the 100% charge that is below the true 100% charge. As the 80% charge gid value is much more stable (I ALWAYS get 231 gids) it could be a better value to evaluate battery capacity.

Yes, I see this behavior as well. I suspect that most of us do. The difference is likely due to the nature of Gids: a uniform measure of energy that has flown into the battery. Gids tell us how much energy came from the charger, not how much is stored in it or how much is usable. The SOC is supposed to reflect the estimated energy that's stored within the battery. It's close, but not exactly the same. It would make sense for the SOC % to be lower than the Gid %.

This would mean that some energy was lost in the battery, and won't be available during discharge. Since there is some non-linearity in the internal resistance on either end, and more heat is developed at high or low SOC, this discrepancy could be attributable to that.

http://www.mpoweruk.com/soc.htm said:
In most applications except perhaps in qualification testing, the user (or the system) needs to know how much charge is in the cell without discharging it.

It is not possible either to measure directly the effective charge in a battery by monitoring the actual charge put into it during charging. This is because of the Coulombic efficiency of the battery. Losses in the battery during the charge - discharge cycle mean that the battery will deliver less charge during discharge than was put into it during charging.

The Coulombic efficiency or charge acceptance is a measure of how much usable energy is available during discharging compared with the energy used to charge the cell. Charge efficiency is also affected by temperature and SOC.

JPWhite · May 21, 2012

TonyWilliams said:
Volusiano said:

they told me at 15K that I probably have enough tread for one more rotation and that'd be it (new tires around 20'ish K). Not sure if this has any bearing on battery longevity, though.

Click to expand...

My tires are trashed at 24,000 miles. I looked at the Michelin Energy Saver in 205/55R16, but Costco wants almost $200 each !!! I don't think I'll buy another Bridgestone.

There is a pro rated warranty on the tires. That may save you a few bucks, but of course they'd replace with original tires.

RegGuheert · May 21, 2012

Here is a summary of the capacity bars lost to date:

azdre - Phoenix, AZ - Purchased Mar 2011 - Frequent 100% charges - Lost bar April 2012

azdre said:
In the last few weeks, we've lost one of the 'available' bars (see picture). We've put 17,000 miles on it in 14 months.

bturner - Phoenix, AZ - Purchased May 2011 - Frequent 100% charges - Lost bar May 2012

bturner said:
I just lost a bar this weekend. I have had my Leaf almost exactly one year. Mileage is 13,633.

turbo2ltr - Phoenix, AZ - Purchased Feb 2011 - Frequent 100% charges - Lost bar May 2012

turbo2ltr said:
It's official.. Lost the bar today.

TickTock - Queens Creek, AZ - Purchased May 2011 - Infrequent 100% charges - Lost bar May 2012

TickTock said:
I lost my first capacity bar this morning.

Volusiano - AZ - Purchased June 2011 - Seldom 100% charges - Lost bar May 2012

Volusiano said:
I guess I'm the 5th(?) guy in AZ now who officially lost a capacity bar (happened today).

Honorable Mention:
LEAFfan - Phoenix Area, AZ - Purchased June 2011 - Frequent 100% charges (?)- Has not lost bar yet

LEAFfan said:
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.

LEAFfan said:
I may lose a capacity bar soon because today, a 100% QC only registered 78% SoC/12 bars. I only had 72%/nine bars after the first charge. I drove 10 miles on the 12th bar @ 45-50mph.

So, what do they all have in common? Their LEAFs went through the record heat of Phoenix in August, 2011. Here are some more temperature details from NOAA. There were 7 record high days and 7 record high lows. The month holds the high record for average high, average low and average temperature.

While Nissan expressly refuses to warrant the battery when exposed to above 120F ambient temperatures for over 24 hours, I will state that what these cars went through last August was probably worse than what Nissan has excluded. And note that July, 2009 recorded the same average temperature as August, 2011.

At the end of the day, I guess I agree with the sentiment of kmp647:

kmp647 said:
If I lived in Phoenix. I would buy a focus or a volt

OTOH, I'm not convinced that an active cooling system is a solution, either. Suppose the OP had parked an FFE for a month in August, 2011 instead of May? I guess if it were plugged in it may have survived, but not on it's own. In the end, I feel that only high-temperature Li-ion chemistries like the one I mentioned in other threads will resolve the EV battery life issue for places like Phoenix.

Finally, please note that while the first capacity bar represents a loss of 15% of the original capacity of the battery, every other bar represents only 6.25%. I wonder if anyone in Phoenix will lose a second bar this summer...

Herm · May 21, 2012

Volusiano said:
It used to be around 4.6 for the longest time, but for the last couple of months, it's slipped down to 4.5

Thanks..You are a very gentle driver. It should have a benefit in battery life.

Stoaty · May 21, 2012

RegGuheert said:
So, what do they all have in common? Their LEAFs went through the record heat of Phoenix in August, 2011. Here are some more temperature details from NOAA. There were 7 record high days and 7 record high lows. The month holds the high record for average high, average low and average temperature.

While Nissan expressly refuses to warrant the battery when exposed to above 120F ambient temperatures for over 24 hours, I will state that what these cars went through last August was probably worse than what Nissan has excluded. And note that July, 2009 recorded the same average temperature as August, 2011.

I have to wonder whether it was wise for Nissan to sell the Leaf in Arizona, all the while claiming the battery would stand up to the heat just fine. That is an awful lot of Leafs losing capacity quickly.

TickTock · May 21, 2012

According to the engineers who rejected my original complaint, the degradation is supposed to slow after the first six months. A bit counter-intuitive to me. My experience (with other battery chemistry's, granted) is the opposite (once you start seeing it, the days are numbered). However, I'm willing to stick it out for another year to see if this "leveling off" really happens. Maybe they have some secret-sauce that self-limits degradation. Could be optimism; could be denial - probably a bit of both.

edatoakrun · May 21, 2012

Have any of the AZ 11 bar-ers confirmed the 15% capacity loss figure with a range test?

It's not like all of the other battery display info from the LEAF is precisely accurate...

RegGuheert said:
Here is a summary of the capacity bars lost to date:

azdre - Phoenix, AZ - Purchased Mar 2011 - Frequent 100% charges - Lost bar April 2012

azdre said:

In the last few weeks, we've lost one of the 'available' bars (see picture). We've put 17,000 miles on it in 14 months.

Click to expand...

bturner - Phoenix, AZ - Purchased May 2011 - Frequent 100% charges - Lost bar May 2012

bturner said:

I just lost a bar this weekend. I have had my Leaf almost exactly one year. Mileage is 13,633.

Click to expand...

turbo2ltr - Phoenix, AZ - Purchased Feb 2011 - Frequent 100% charges - Lost bar May 2012

turbo2ltr said:

It's official.. Lost the bar today.

Click to expand...

TickTock - Queens Creek, AZ - Purchased May 2011 - Infrequent 100% charges - Lost bar May 2012

TickTock said:

I lost my first capacity bar this morning.

Click to expand...

Volusiano - AZ - Purchased June 2011 - Seldom 100% charges - Lost bar May 2012

Volusiano said:

I guess I'm the 5th(?) guy in AZ now who officially lost a capacity bar (happened today).

Click to expand...

Honorable Mention:
LEAFfan - Phoenix Area, AZ - Purchased June 2011 - Frequent 100% charges (?)- Has not lost bar yet

LEAFfan said:

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.

Click to expand...

LEAFfan said:

I may lose a capacity bar soon because today, a 100% QC only registered 78% SoC/12 bars. I only had 72%/nine bars after the first charge. I drove 10 miles on the 12th bar @ 45-50mph.

Click to expand...

So, what do they all have in common? Their LEAFs went through the record heat of Phoenix in August, 2011. Here are some more temperature details from NOAA. There were 7 record high days and 7 record high lows. The month holds the high record for average high, average low and average temperature.

While Nissan expressly refuses to warrant the battery when exposed to above 120F ambient temperatures for over 24 hours, I will state that what these cars went through last August was probably worse than what Nissan has excluded. And note that July, 2009 recorded the same average temperature as August, 2011.

At the end of the day, I guess I agree with the sentiment of kmp647:

kmp647 said:

If I lived in Phoenix. I would buy a focus or a volt

Click to expand...

OTOH, I'm not convinced that an active cooling system is a solution, either. Suppose the OP had parked an FFE for a month in August, 2011 instead of May? I guess if it were plugged in it may have survived, but not on it's own. In the end, I feel that only high-temperature Li-ion chemistries like the one I mentioned in other threads will resolve the EV battery life issue for places like Phoenix.

Finally, please note that while the first capacity bar represents a loss of 15% of the original capacity of the battery, every other bar represents only 6.25%. I wonder if anyone in Phoenix will lose a second bar this summer...

Herm · May 21, 2012

RegGuheert said:
So, what do they all have in common? Their LEAFs went through the record heat of Phoenix in August, 2011.

It cools off a bit overnight, so the average is much lower. The high thermal mass of the battery means it does not react quickly. Perhaps its a good idea to keep the Leaf in an air conditioned garage.

edatoakrun · May 21, 2012

Herm said:
RegGuheert said:

So, what do they all have in common? Their LEAFs went through the record heat of Phoenix in August, 2011.

Click to expand...

It cools off a bit overnight, so the average is much lower. The high thermal mass of the battery means it does not react quickly. Perhaps its a good idea to keep the Leaf in an air conditioned garage.

AFAIK, no one has accurately reported how quickly the LEAF battery heats or cools to ambient temperature.

I used to operate under the assumption that the LEAF battery would react fairly slowly, but given the very imprecise dash bar measurement, I now believe it probably warms and cools fairly quickly, reaching ambient in only a few hours.

The configuration of the battery pack, a long flat sheet of varying thickness, and virtually uninsulated, guarantees that some of the cells are heating and cooling more quickly than others.

I would not be surprised, if when the first LEAF packs are sent to the "re-builders", the batteries that are most exposed, and experience the most extreme temperature changes, tend to have the greatest capacity loss.

RegGuheert · May 21, 2012

TickTock said:
According to the engineers who rejected my original complaint, the degradation is supposed to slow after the first six months. A bit counter-intuitive to me. My experience (with other battery chemistry's, granted) is the opposite (once you start seeing it, the days are numbered). However, I'm willing to stick it out for another year to see if this "leveling off" really happens. Maybe they have some secret-sauce that self-limits degradation. Could be optimism; could be denial - probably a bit of both.

I think your intuition is dead-on, TickTock. If this level of degradation were normal and known to Nissan's engineers, then they should have disclosed that to their customers. They did not.

Your car is way older than six months and the hot weather is just now picking up again. It seems the capacity loss in your car continues unabated.

I believe Nissan was COMPLETELY unaware of what would happen to these batteries in Phoenix and instead of taking deliberate steps to protect their customer's investments, they are stonewalling. If they do not resolve this issue quickly by buying out the LEAFs in the affected areas and converting them to leases, they may never be able to recover from the bad press that will result.

Herm said:
It cools off a bit overnight, so the average is much lower.

Sure. Those averages are given in the NOAA link that I provided. But weather data is recorded in the shade by instruments high above the ground level.

What happens to a dark-colored car parked on a gigantic black parking lot in the full sun in Phoenix when the temperature is 117F? Plus the battery in the LEAF will be heated during charging as well as while you are driving. As a result, the temperature of the LEAF batteries last August 26 was probably above about 100F in the middle of the night and perhaps 130F to 140F during the middle of the day (if parked in the sun). I wonder if anyone did a QC at lunch that day?

Herm said:
The high thermal mass of the battery means it does not react quickly. Perhaps its a good idea to keep the Leaf in an air conditioned garage.

Agreed. Especially during the day. I wonder how many LEAF owners in Phoenix work for employers who provide air-conditioned garages?

(Sorry for the snark! It is not directed at you, but rather it is intended to shed some light on the plight of LEAF owners in Phoenix.)

EdmondLeaf · May 21, 2012

Herm said:
It cools off a bit overnight, so the average is much lower. The high thermal mass of the battery means it does not react quickly. Perhaps its a good idea to keep the Leaf in an air conditioned garage.

My dilemma is a bit different, where to park while at work, can't find any shaded area, so as do not drive or direct OK summer sun

kolmstead · May 21, 2012

One other detail would be of interest in the list of "lost-bar cars"... what color the car is. I live in Ridgecrest, CA, which runs about 10 degrees cooler than Phoenix, but we still get plenty of 115 degree days. I bought a white LEAF, specifically to reduce battery temperature. My car sits out all day at work. I've seen battery temps from three bars to seven or eight in the past 17 months.

TickTock · May 21, 2012

Mine is white, too, but that only really matters while driving. It is parked in an enclosed garage at home and in the bottom level of a parking deck at work so it sees very little direct sun.

It charged to 80% last night as that is what my timer is set for (got 186 gids again) but then I hit the button to take it to 100. At 100% I got 225 gids (almost exactly 80% of a new battery). Last week when I had all 12 bars I was getting 228 gids.

edatoakrun · May 21, 2012

TickTock said:
Mine is white, too, but that only really matters while driving. It is parked in an enclosed garage at home and in the bottom level of a parking deck at work so it sees very little direct sun.

It charged to 80% last night as that is what my timer is set for (got 186 gids again) but then I hit the button to take it to 100. At 100% I got 225 gids (almost exactly 80% of a new battery). Last week when I had all 12 bars I was getting 228 gids.

It might be useful for you to summarise your car's capacity history, TickTock.

AFAIK, you are the one of the few (only?) LEAF owners who believes their car was significantly below spec on battery capacity, on delivery.

So, what level of battery capacity do you think you have lost since new?

vegastar · May 21, 2012

The degradation seems to continue... You (TickTock) get less gids in a 100% charge than what I get in a 80% charge (231 gids).

turbo2ltr · May 21, 2012

RegGuheert, what do you care, you don't even live near here.

I believe Nissan was COMPLETELY unaware of what would happen to these batteries in Phoenix...

Nissan has tested the LEAF extensively here. They have a proving grounds a few miles south of the Phoenix area.

For me, the loss has not been noticable. I will reserve judgement to see what happens in year 2.
But I still think there is something more than just battery chemistry at work here. There is no way that we get this many people losing a bar in such a short period of time with such varied mileage, age and charge practices.

September · May 21, 2012

edatoakrun said:
AFAIK, no one has accurately reported how quickly the LEAF battery heats or cools to ambient temperature.

From my experience 8 bars to 4 bars takes not more than 7 hours. I will try to record it more carefully next time I have battery heated much over ambient temp.

Capacity Loss on 2011-2012 LEAFs

Help Support My Nissan Leaf Forum:

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Similar threads

Join the conversation!

Join today and get all the highlights of this community direct to your inbox. It's FREE!