Capacity Loss on 2011-2012 LEAFs

[spike09]

I average 25 miles a day and live near the coast (not close enough to hear the surf or afford a Tesla!) which is at least 10 degrees cooler than inland where ocean cooling has no effect.

Nice! Sounds like you will be fine then.

Has any Hawaii Leafs passed the 20k mile or 20 month mark????

We don't know. But it looks like the Leaf owner in Hong Kong is averaging 1,700 miles per month. High ambient temps seem to exacerbate cycling losses, as we have learned in Phoenix.

[HUMOR]The Hong Kong LEAF probably had most of its components, including the battery, swapped out with grey market parts right after it arrived at the port! [HUMOR]

 

[RegGuheert]

Thanks for the excellent post, drees!

In contrast, the LEAF's battery is going never going to get much below 100F. Your typical garage does not cool off much at night. In the summer, Phoenix stays above 90F, so the garage will probably say around 100F through the night. In fact, TickTock plotted this for us: A day in the life of a Phoenician Leaf Battery You can see that the case of his battery is basically at 100F 24 hours a day despite having underground parking. You can see the spike to 110F during the commute home - you know for sure that a car parked in the sun will probably not take more than 3-4 hours to reach that temp since the LEAFs pack is not well insulated.

One thing that you touched on here that I think is worth emphasizing is that the battery "cooling" system in the LEAF is really nothing of the sort. The system is designed to drive the temperature of the LEAF battery to ambient, regardless of the ambient temperature. This system is not so effective when the car is not moving. That is one reason quick charging can cause so much heating. OTOH, the system is quite effective at moving the battery temperature to ambient when the car is driven. As a result, the LEAF battery is often rapidly heated as a result of being driven, not because of heat dissipated by the battery, but ambient heat that is being dumped INTO the battery. Driving the LEAF in the hot afternoon sun will quickly bring the battery up to a very high temperature. Subsequently parking the LEAF, even if it is in a cooler environment, will result in that heat being held for quite a bit of time. This effect is not fully seen in TickTock's plots, since he is measuring outside the battery pack. Inside a cell in the center of the rear stack, the thermal mass is high and the time constants with no airflow around the pack will be quite long. Parking over 150F or hotter pavement will result in the pack getting even more heat added, as I discussed a couple of months ago.

Compare that with the Volt, which ALWAYS forces the temperature toward 72F while the vehicle is driven. That system causes the pack temperature to get to a lower value during the morning commute, and not just on the surface of the pack, but all throughout. During the afternoon commute, the Volt pack will be cooled to 72F while the LEAF pack will be either heated to ambient or held there if it is already at ambient.

 

[JPWhite]

Compare that with the Volt, which ALWAYS forces the temperature toward 72F while the vehicle is driven. That system causes the pack temperature to get to a lower value during the morning commute, and not just on the surface of the pack, but all throughout. During the afternoon commute, the Volt pack will be cooled to 72F while the LEAF pack will be either heated to ambient or held there if it is already at ambient.

It's quite possible that the TMS naysayers would be right if a crude TMS were engineered. However I think there is plenty of room to make TMS systems more sophisticated. For example, say the LEAF gets a TMS and when parked outside in AZ for the day at work the car notices that even though the pack was say 72 degrees at the beginning of the day thanks to overnight TMS conditioning the pack still gets into the danger zone by the end of the day.

The TMS system sees this happen a few days in a row. An intelligent system would then predict, wow its gonna happen again tomorrow, so I'll chill the pack to 65 tonight. Then after a few more days monitoring it may chose to drop overnight chilling to 55. The efficiency of the vehicle will be impacted due to more electric being consumed but the battery would now last longer thanks to the TMS. I like to think of this approach as the "Baked Alaska" approach

I'm sure smarter minds than mine can come up with more and better approaches and algorithms. Heck Nissan can see what's up through the data via CarWings, with a TMS they could 'turn the dial up or down' on cars in different regions to optimize battery life.

 

[Weatherman]

That's very interesting! Thanks for the climatic data you provided. Any chance I could fit it in this spreadsheet?

What I can do is provide a little more data.

Hourly temperature distribution (percent of total time spent in each band) for Ft Lauderdale (FXE) in the first column and and Dallas (DFW) in the second column over the past five years. Temperature bands in degrees C.


0.000 or less - 0.00% 2.67%
>0.00 to 2.50 - 0.03% 2.39%
>2.50 to 5.00 - 0.18% 4.40%
>5.00 to 7.50 - 0.36% 4.65%
>7.50 to 10.0 - 0.76% 6.02%
>10.0 to 12.5 - 1.32% 5.29%
>12.5 to 15.0 - 2.73% 6.60%
>15.0 to 17.5 - 3.22% 6.37%
>17.5 to 20.0 - 6.86% 9.03%
>20.0 to 22.5 - 10.79% 8.10%
>22.5 to 25.0 - 24.35% 11.29%
>25.0 to 27.5 - 21.69% 9.06%
>27.5 to 30.0 - 18.42% 9.54%
>30.0 to 32.5 - 7.44% 5.61%
>32.5 to 35.0 - 1.84% 5.17%
>35.0 to 37.5 - 0.02% 2.38%
>37.5 to 40.0 - 0.00% 1.24%
>40.0 to 42.5 - 0.00% 0.18%
>42.5 to 45.0 - 0.00% 0.01%
More than 45 - 0.00% 0.00%



Ft Lauderdale tends to stay in a narrow band, around 17.5 to 32.5C, and never fell below 0C and rose above 37.5C in the past five years. Dallas has a much broader temperature range.

I'll see if I can grab the hourly data from a few other locations, over the next few days.

 

[leafwing]

No, I don't own one. I came from Autoblog Green.

Since you do not own a LEAF, you don't really know what you are talking about.

 

[spike09]

No, I don't own one. I came from Autoblog Green.

Since you do not own a LEAF, you don't really know what you are talking about.

That is pretty harsh. You can be quite informed about a car without ever owning it. That said there are a lot of half-truths and outright lies out there regarding the LEAF. There are even some that owners firmly believe are true! We should value anyone who has an intelligent opinion on a subject and ridicule the ignorant ones.

 

[DaveEV]

No, I don't own one. I came from Autoblog Green.

Since you do not own a LEAF, you don't really know what you are talking about.

Now, now, LEAF ownership doesn't automatically make you a guru and neither does the opposite. Let's be nice, eh?

 

[jamb999]

Shoot. I love this car.

But, I am down to an average range of about 50 miles from a 100% charge. I frequently drive on the freeway and average 4.3, but I am not getting less than 55 miles on a full charge. Allowing for 5-10 miles safety charge, I can no longer drive longer than 25 from my house on the freeway.

I have had this car for almost 2 years and have only 10,680 miles on it.

I would welcome any suggestions on action with Nissan.

 

[spooka]

Shoot. I love this car.

But, I am down to an average range of about 50 miles from a 100% charge. I frequently drive on the freeway and average 4.3, but I am not getting less than 55 miles on a full charge. Allowing for 5-10 miles safety charge, I can no longer drive longer than 25 from my house on the freeway.

I have had this car for almost 2 years and have only 10,680 miles on it.

I would welcome any suggestions on action with Nissan.

What state do you live in? Also if you drive a lot on the freeway, why are you only averaging about 15 miles a day over 2 years?

 

[opossum]

My wife and I don't have a Leaf either. I guess we should shut up. :lol:

999, clearly you are not driving the car enough to keep the batteries loose. Nissan believes you should be driving 12,500.000 miles per year and never use a freeway. Wait... or was it exactly 7,500.000 miles per year with the right rear window cracked 1.3 inches? Aaaah, I can't keep up with the changing, post-purchase message from the Mark-Katherine-Andy monster. It's the kind of ever-changing message that usually makes for a successful politician!

Attack it like a yeast infection, 999, and don't let up!

 

[palmermd]

Shoot. I love this car.

But, I am down to an average range of about 50 miles from a 100% charge. I frequently drive on the freeway and average 4.3, but I am not getting less than 55 miles on a full charge. Allowing for 5-10 miles safety charge, I can no longer drive longer than 25 from my house on the freeway.

I have had this car for almost 2 years and have only 10,680 miles on it.

I would welcome any suggestions on action with Nissan.

What state do you live in? Also if you drive a lot on the freeway, why are you only averaging about 15 miles a day over 2 years?

Perhaps this is part of the problem. Maybe Nissan did all their "real world" testing on the LA4 cycle. That is why they used it on all their advertising. Maybe the hot weather testing was also all done on this cycle. But that is not how Americans drive. We have lots of freeways and so we are much harder on the batteries than an LA4 cycle. I have only 9000 miles on my Leaf after 18 months or so. But I too do lots of freeway driving. My parents live 35 miles from me. I drive there at least once a month. So yes, I have low mileage and also lots of freeway miles. In fact I have mostly freeway miles, and I while I have not lost a bar yet, I have calculated about 20% loss of driving range in the car.

It just makes me wonder if this constant steady draw from the batteries is something that Nissan overlooked in their battery testing. It is quite common for us to drive this way and not common in other parts of the world. They have hinted at this in their recent comments about the freeways in Arizona.

 

[Nubo]

No, I don't own one. I came from Autoblog Green.

Since you do not own a LEAF, you don't really know what you are talking about.

Now, now, LEAF ownership doesn't automatically make you a guru and neither does the opposite. Let's be nice, eh?

Agreed, I'm just as clueless as I was before I got a LEAF.

 

[JPWhite]

My wife and I don't have a Leaf either. I guess we should shut up. :lol:

Not only that but you are misleading the whole forum because your profile shows that you have LEAF number 500 which is clearly a fabrication by your own admission.

Tut, Tut, Tut.....





:mrgreen:

Seriously, sorry things turned out the way way they did for you and you no longer have the EV Grin.

 

[JPWhite]

They have hinted at this in their recent comments about the freeways in Arizona.

Ah, you make a great point. We may have misinterpreted recent Nissan messages as a slight on our driving habits. Nothing of the sort, its the roads that are at fault. Essentially Nissan and its customers are vindicated, it's the State of Arizona who are at fault a) for building too many freeways and interstates. b) not actively cooling the asphalt of the aforementioned road infrastructure. I mean really, make the road surface black where it will absorb more heat energy?!!?

 

[palmermd]

They have hinted at this in their recent comments about the freeways in Arizona.

Ah, you make a great point. We may have misinterpreted recent Nissan messages as a slight on our driving habits. Nothing of the sort, its the roads that are at fault. Essentially Nissan and its customers are vindicated, it's the State of Arizona who are at fault a) for building too many freeways and interstates. b) not actively cooling the asphalt of the aforementioned road infrastructure. I mean really, make the road surface black where it will absorb more heat energy?!!?

I'll assume your being sarcastic, but in case it needs clarification, my comment is not an attack on the owners, but Nissan is trying to come to grips with what went wrong in their testing of the battery. One thing they may have overlooked was they way we drive in the US. We have lots of freeways and they are used quite regularly, and not just for intercity travel but for intracity travel.

 

[RegGuheert]

Maybe Nissan did all their "real world" testing on the LA4 cycle. That is why they used it on all their advertising.

I suggested this previously and I believe TickTock confirmed with Nissan during his last meeting that they are NOT using LA4 for their testing.

 

[ewodraska]

My car has been on the highway twice, for a total of 20 miles in it's entire life.
I drive it to and from work, with occasional side trips.
My average speed is 22mph over the life of the car.
I average 9980 miles per year.
5 star reports on my battery checks.
Charge only to 80%, 95% of the time. Set the end timer to 30 min before I leave for work.
Never been QC'd.
Move it from shady spot to shady spot during the day at work.

So their claim of highway driving is BS, IMHO.

Curious how many cars in the Pacific NW have higher miles with no battery capacity issue. You can't tell me they aren't driving on the highway or that they charge less than I do.

I think the Leaf is an awesome car, I love driving it. I hate that I've done everything I could to extend the battery life, and have still lost a bar after 16 months of ownership. The Leaf is not a car that should be bought in Arizona. Leased yes. Too bad I bought.

I fully expected to lose capacity, but not this quickly, especially following their advise on extending the longevity of the battery.

Too bad my resale value is dropping faster than battery capacity, I was offered $16k on trade-in value, that's a 53% drop from what I paid, or 40% after tax rebate. New car's are never a good investment, but I think this one takes the cake.

 

[JPWhite]

I'll assume your being sarcastic,

Absolutely. It was humor aimed at the situation, no one in particular, don't take it personally

 

[leafwing]

No, I don't own one. I came from Autoblog Green.

Since you do not own a LEAF, you don't really know what you are talking about.

That is pretty harsh. You can be quite informed about a car without ever owning it. That said there are a lot of half-truths and outright lies out there regarding the LEAF. There are even some that owners firmly believe are true! We should value anyone who has an intelligent opinion on a subject and ridicule the ignorant ones.

It is not that harsh.
Every five pages or so, someone comes from who knows where and throw his two cents in our faces.
I'm not saying that I'm an expert (Nissan engineers are and some of the forum's members have more knowledge than others), but I have been driving this car more than a year and half and I know how it has been performing in two springs, two summers, one winter and during this second autumn.

 

[leafwing]

My wife and I don't have a Leaf either. I guess we should shut up. :lol:!

You have been very vocal my friend.