Capacity Loss on 2011-2012 LEAFs

[Herm]

One question regarding moisture and a car, you aren't concerned about adding a lot to a confined space?

You have to vent the garage so that the swamp cooler can pull more air in.. it does not work in a confined space like a regular AC.

 

[xtremeflyer]

I just lost my first bar as of this morning. 24,800 miles leased in March of 2011.

Looks like mwalsh loses out on the First in OC distinction that he wanted

 

[mwalsh]

ADRIAN!!!

 

[fattmerris]

I live in Plano TX and just lost my second bar yesterday after 13.5 months of ownership and 16,500 miles. I lost the first bar at about 12 months and 15,000 miles. Reported to Nissan with Case# 913-3854

Sorry to hear that, can you share how car was garaged day and night, please.

Car in the parking lot at work during the day, parked in the garage at night. Garage is not climate controlled. Last summer was the hottest on record in Dallas with nearly 100 days over 100 degrees.

 

[garygTx]

Well, I just lost a bar today. Yesterday the display looked very unusual as I had all twelve battery bars, but all the regen bubbles were double circles. Today there were only the 11 capacity bars. My car was made May 2011, but not leased until Nov and has 10,400 miles on it. I park outside the garage, and since it got hot have used just the end timer, so the car charges when it is cooler.

 

[Herm]

Car in the parking lot at work during the day, parked in the garage at night. Garage is not climate controlled. Last summer was the hottest on record in Dallas with nearly 100 days over 100 degrees.

Do you routinely charge to 100% or 80%?.. How many bars of charge do you have remaining when you get home from work?

 

[TonyWilliams]

I just lost my first bar as of this morning. 24,800 miles leased in March of 2011.

Mmmmm, Orange County. Not super duper hot there. The only explanation is that you turtle'd and VLB your red LEAF more than I did**** (in San DIego with 25,300 miles and still had all 12 capacity bars 10 days ago). Obviously, heat isn't the prime criteria for your capacity loss, or mine.

For the folks that think "all will be well" when the ambient temps come down this winter, I think it's time to start thinking about plan B.




****No, I don't really believe he did do that.

 

[leafkabob]

I lost my second bar today. Last night I was reading the forum and asked my wife (primary driver of the leaf) if we still had 11 bars. She said she had last checked on Tuesday and we did, but she didn't check yesterday. I told her I was surprised that we hadn't lost the second bar, given the first one went on May 26 and other folks who lost their first one after that date had already lost a second one. I then told her that with the higher temps of the last few days I expected we would lose it this week for sure. This morning she turned on the car and it showed 10 capacity bars. I think the odo is at 11,500.

 

[Adrian]

ADRIAN!!!

Great! I haven't heard that since high school! thanks for bringing back those memories.

 

[Adrian]

I just lost my first bar as of this morning. 24,800 miles leased in March of 2011.

Mmmmm, Orange County. Not super duper hot there. The only explanation is that you turtle'd and VLB your red LEAF more than I did**** (in San DIego with 25,300 miles and still had all 12 capacity bars 10 days ago). Obviously, heat isn't the prime criteria for your capacity loss, or mine.

For the folks that think "all will be well" when the ambient temps come down this winter, I think it's time to start thinking about plan B.




****No, I don't really believe he did do that.

I only turtled the car once. Never quick charged. Commute is 76 miles and I like to drive 80 MPH on the HOV lane. So that means I have to charge twice a day using L2 to 100%, once at home, once at work, in the Long Beach port area. My garage doesn't get that hot, and it it's typically 10 degrees cooler at work. Glad I leased. Will have to pay a few thousand for the extra miles above the allowed 15k per year, but if the car looses more than 2 bars by 50k miles I'm not keeping it.

 

[Valdemar]

I'm curious what will the (ab)used Leaf market look like in 2014 when leases start to expire. Who in the right mind would buy a Leaf with 2-3 missing capacity bars unless it is dirt cheap?

 

[Herm]

I only turtled the car once. Never quick charged. Commute is 76 miles and I like to drive 80 MPH on the HOV lane. So that means I have to charge twice a day using L2 to 100%, once at home, once at work, in the Long Beach port area. My garage doesn't get that hot, and it it's typically 10 degrees cooler at work. Glad I leased. Will have to pay a few thousand for the extra miles above the allowed 15k per year, but if the car looses more than 2 bars by 50k miles I'm not keeping it.

So about 600 cycles?.. how many bars do you have left when you get to work and home?.. Perhaps you just used a significant number of the cycles alloted to the battery. This might not be a high temperature issue but just regular tear&wear

 

[Herm]

I'm curious what will the (ab)used Leaf market look like in 2014 when leases start to expire. Who in the right mind would buy a Leaf with 2-3 missing capacity bars unless it is dirt cheap?

3 bars is 30% loss, that battery is spent.. similar to an engine burning a quart of oil every time you fill up the tank. Time for a rebuild.

 

[Adrian]

I only turtled the car once. Never quick charged. Commute is 76 miles and I like to drive 80 MPH on the HOV lane. So that means I have to charge twice a day using L2 to 100%, once at home, once at work, in the Long Beach port area. My garage doesn't get that hot, and it it's typically 10 degrees cooler at work. Glad I leased. Will have to pay a few thousand for the extra miles above the allowed 15k per year, but if the car looses more than 2 bars by 50k miles I'm not keeping it.

So about 600 cycles?.. how many bars do you have left when you get to work and home?.. Perhaps you just used a significant number of the cycles alloted to the battery. This might not be a high temperature issue but just regular tear&wear

I typically have about 25-30 miles left on GOM on both ends of the trip.

 

[surfingslovak]

Mmmmm, Orange County. Not super duper hot there. The only explanation is that you turtle'd and VLB your red LEAF more than I did**** (in San DIego with 25,300 miles and still had all 12 capacity bars 10 days ago). Obviously, heat isn't the prime criteria for your capacity loss, or mine.

Although I didn't have a chance to do proper evaluation, I don't think that multiple turtle events would have such a large impact. Turtle mode ends at about 308 Volt on the pack level, which is about 3.1 - 3.2 Volt on the cell level. Please recall that manufacturers cycle batteries from about 4.2 Volt all the way down to 2.5 Volt to measure cycle life.

Yes, it's not super hot in OC, but the average ambient is 5 degrees higher than in the Bay Area and 15 degrees higher than in Seattle. It's also about seven degrees cooler than Phoenix, on average. We know from Charles Whalen and some of the publications we went through that average battery temperature is one of the primary factors determining cell life. We would need to factor in temperature variance and the effect of solar loading to have a more complete picture.

For the folks that think "all will be well" when the ambient temps come down this winter, I think it's time to start thinking about plan B.

Although I don't agree with some of the posters, I do believe that Gid counts will go back up by 5 to 10% in winter. That said, we are seeing very rapid deterioration, which would be indicative of a serious problem. To say anything else would be disingenuous at this point.

I would like to respond to a couple of my esteemed EV colleague (and he truly *is* highly esteemed in the EV universe) Darell’s points:

> The bottom line is that we won't know about battery life
> until they've had a chance to live.

True, in a real-world sense. But we’ve got a pretty good idea about this and a lot of very detailed, in-depth, extensive empirical studies and hard-core science on this (specifically, lithium battery life as a function primarily of long-term ambient temperature exposure over time, and secondarily, of average SOC over time) conducted and published in dozens of technical papers on this exact subject over the last decade by leading battery engineers and scientists at Argonne National Labs (Ira Bloom et al), NREL (Kandler Smith, Ahmad Pesaran, et al), Idaho National Labs (Jon Christophersen et al), Lawrence Berkeley National Labs (Vince Battaglia et al), and Sandia National Labs (Dan Doughty et al), … some of which are available on some of those labs’ respective websites and many others of which are available for purchase online from the archives of the Journal of Power Sources (just do an author search on any of those authors and you will see dozens of technical papers on this particular subject).

For instance, just a couple of basic technical papers on this subject are:

“PHEV Battery Trade-Off Study and Standby Thermal Control”, presented at the 26th International Battery Seminar & Exhibit, Fort Lauderdale, FL, March 16-19, 2009, by Kandler Smith, Tony Markel, and Ahmad Pesaran of NREL,

and

“Battery Thermal Issues and Solutions for PHEVs”, presented at Plug-In 2009 in Long Beach, CA, August 10-13, 2009, by Ahmad Pesaran of NREL.

> Yes, active liquid cooling is better for the batteries.
> And it comes at a high cost. Is 10% longer life worth 50%
> more money? (just to grab numbers out of my hat).
> That's the decision that needs to be made by the makers.

I think Darell’s numbers that he “just grabbed out of his hat” -- of 50% greater cost for 10% longer life -- might not be too far off the mark (though I myself would guess that it’s probably more like 50% greater cost for a 20-25% longer life), ... BUT … with a very important caveat ... that being that such numbers (whether Darell’s 10% longer life or my 20-25% longer life) are applicable to 90% of the country, with the exception, the other 10% of the country, being the hottest climates like Phoenix and South Florida, where a very different set of numbers and relationship applies. In the hottest climates, places like Phoenix and South Florida, the numbers look something more like … a 50% greater cost for somewhere between a 2X and 3X longer life. You really have to get into all the science and empirical studies and data on lithium battery life as a function of long-term ambient temperature exposure (plus, additionally, very importantly, the effects of solar loading), that I referred to above, in order to fully understand and have an appreciation for this. It also helps if you have had your own personal experience and exposure, as I have had, with battery life, performance, degradation, and ageing characteristics over a long term in a hot climate.

The salient point and operative principle here is that lithium battery life follows an exponential Arrhenius relationship with respect to temperature, where just to try to greatly simplify the explanation … battery life basically doubles for roughly about every 25 degrees F reduction in temperature (to simplify again, let’s call it long-term average ambient exposure, though that ignores the important roles and factors that both temperature variation and solar loading play). So, here pulling my own numbers out of my hat, let’s say that at 100F lithium battery life is 3 years; then at 75F it’s 6 years, and at 50F it’s 12 years. Those probably aren’t too far off the mark, though there is some differentiation for the various different cathodic subchemistries (e.g. LiCoO2, LiFePO4, LiNi.33Co.33Mn.33O2, and the LiMn2O4 chemistry, that both GM and Nissan are using in the Volt and Leaf, being the most heat sensitive and having the shortest life at higher ambients).

If you understand what I’ve just explained, then you can see and understand that it is the combination of: a) the high ambients in hot climates like Phoenix and South Florida, b) the exponential nature of this Arrhenius function relating lithium battery life to temperature (where battery life roughly doubles for about every 25 degrees F reduction in temperature), and c) the high current cost of lithium batteries [$625/kWh for the Volt ($10,000/16kWh) and $750/kWh for the Leaf ($18,000/24kWh)], … that makes a liquid-cooled, water-chilled, active thermal management system economically advantageous and viable ***FOR AN EV THAT WILL SPEND ITS LIFE IN A HOT CLIMATE***.

However, this is not necessarily going to be the case for the other 90% of the country with more temperate climates, to varying degrees, where -- as Darell suggests with his “out-of-his-hat” guesstimate numbers -- a liquid-cooled, water-chilled, active thermal management system might not present such a compelling value proposition and be entirely economically viable.

The problem is that automakers don’t have the luxury of being able to micro-design and custom-tailor their EVs for each climate, offering a different version, with a different type, level, and scale of thermal management system, depending on the particular climate. Nor do car owners always stay in the same location. People move from one place to another, like from a temperate climate to a hot climate, and take their cars with them. Automakers have to design their EVs to work in ALL climates. What this means is that if an automaker is really going to do it properly, they have to design the EV to operate in and withstand the harshest, hottest climates, like Phoenix and South Florida. We can call that the 10% climate outlier tail. So the automaker that does it properly has got to design to specs for that 10% tail, unfortunately, which then of course drives up the cost, … which is one reason why the Volt costs $8k more than the Leaf. (And yes, it is somewhat of a case of “the tail wagging the dog”.)

… Whereas, on the other hand, other automakers will take a very different path, where in the aggressive pursuit of their ambitious goals to establish an early market-share lead, they succumb to the temptations and imperatives of cost and time-to-market pressures, making those their top priorities, at the expense of engineering, by making engineering compromises, shortcuts, and trade-offs in the process, … by, for instance, making a deliberate, calculated sacrifice of that aforementioned 10% climate outlier tail, in the interests of expediency and cost savings. To paraphrase Carlos Ghosn, there are a few notable, and quite telling, quotes in the last year where he has basically said, in so many words … “shoot the engineers and put the marketing guys in charge”.

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[Reddy]

So for the past 17 months, you've run 800+ charge/discharge cycles at 80 mph, and you've lost 15% battery capacity. Wow, try that with a cell phone and see what happens to the battery. Except for the heat-related losses in AZ, TX, and OK, it sounds like the Leaf's battery is operating pretty well to me. Of course, I don't need even 1/2 the capacity, don't drive 80 mph, don't have high acceleration/deceleration cycles, keep the mileage down, etc. I think bars will continue to drop like flies as all of the high mileage/hot climate 2011 Leafs pass their 1 yr mark. We can disagree with what constitutes high mileage and temperature, but I think all will agree that lower is better for the battery degradation. Also, numerous battery studies have shown that lower charge/discharge depth (DOD) and rate (C) are better for battery degradation. Double charges each day and 80 mph might get you 1500 cycles (3 yrs) if the temperature is moderate. I'm hoping for 5000 cycles (12+ yr) at about 40-60 % SOC, but then again I'm babying the battery and don't need to drive more than 20-30 mi in a day.

Reddy.

 

[DesertDenizen]

So for the past 17 months, you've run 800+ charge/discharge cycles at 80 mph, and you've lost 15% battery capacity. Wow, try that with a cell phone and see what happens to the battery. Except for the heat-related losses in AZ, TX, and OK, it sounds like the Leaf's battery is operating pretty well to me. Of course, I don't need even 1/2 the capacity, don't drive 80 mph, don't have high acceleration/deceleration cycles, keep the mileage down, etc. I think bars will continue to drop like flies as all of the high mileage/hot climate 2011 Leafs pass their 1 yr mark. We can disagree with what constitutes high mileage and temperature, but I think all will agree that lower is better for the battery degradation. Also, numerous battery studies have shown that lower charge/discharge depth (DOD) and rate (C) are better for battery degradation. Double charges each day and 80 mph might get you 1500 cycles (3 yrs) if the temperature is moderate. I'm hoping for 5000 cycles (12+ yr) at about 40-60 % SOC, but then again I'm babying the battery and don't need to drive more than 20-30 mi in a day.

Reddy.

+1, almost. I really baby my battery, charge to 80% at 6 in the morning, I typically leave around 9 so it doesn't even spend much time at 80%. Never been below 2 SOC bars. Charged to 100% exactly twice in over a year of ownership. Long term 5.6 m/kwh tells you how I drive. I use the frontage roads instead of the highway so I never drive over 45. Drive around 20-30 miles a day also so I charge every second or third day. I have seen some capacity loss, it often only charges to 9 bars. I am in Tucson. When I do finally lose a bar I will conclude that it is completely from the heat.

 

[smkettner]

OC may not be that hot but the highs can easily be 15-20 degrees differential between coastal and inland.
HB, Newport, San Clemente is very different from La Habra and Yorba Linda.

 

[mksE55]

I'm curious what will the (ab)used Leaf market look like in 2014 when leases start to expire. Who in the right mind would buy a Leaf with 2-3 missing capacity bars unless it is dirt cheap?

3 bars is 30% loss, that battery is spent.. similar to an engine burning a quart of oil every time you fill up the tank. Time for a rebuild.

I Think 3 bars would be more like 40% +, if one bar is 15%. I know the 2nd bar is not 15% but still more like 10% at least. Is this listed some where from Nissan.

 

[GRA]

I'm curious what will the (ab)used Leaf market look like in 2014 when leases start to expire. Who in the right mind would buy a Leaf with 2-3 missing capacity bars unless it is dirt cheap?

3 bars is 30% loss, that battery is spent.. similar to an engine burning a quart of oil every time you fill up the tank. Time for a rebuild.

I Think 3 bars would be more like 40% +, if one bar is 15%. I know the 2nd bar is not 15% but still more like 10% at least. Is this listed some where from Nissan.

As has been previously listed here direct from the Leaf service manual, the first bar is 15%, subsequent bars are each 6.25%, so 3 bars is 15 + 6.25 + 6.25 = 27.5% loss.