How should Nissan respond to dropping capacity?

[surfingslovak]

Would 10KW L2 charging be "easier" on your battery than QC L3? would it be slower or faster?

At the same rate? 10kW? The same.

10 kW is approximately C/2, and would be considered ideal in the long run. Nissan has recently admitted that the car won't suffer disproportionately if QCd often. It's smart enough to limit the power draw and protect itself.

If the on-board Leaf charger is accepting--say--16 Amps of draw, does it make any difference if you're using QC or L2? Wouldn't the charging time be the same?

It depends what the voltage is. Voltage times amperage is watts. E=IR

The onboard charger is only relevant for L2. QC goes straight into the battery, and bypasses the charger.

[youtube]http://www.youtube.com/watch?v=UXrrQ6vM2OM[/youtube]

 

[derkraut]

I'm rather technically challenged (ie: dumb) concerning electricity. So, I have to ask some dumb questions:

1. Does 6.6KW L2 charge your battery twice as fast as 3.3KW L2?

Yes

2. Would 10KW L2 charging be "easier" on your battery than QC L3? would it be slower or faster?

At the same rate? 10kW? The same.

3. If the on-board Leaf charger is accepting--say--16 Amps of draw, does it make any difference if you're using QC or L2? Wouldn't the charging time be the same?

It depends what the voltage is. Voltage times amperage is watts. E=IR

Thanks Tony; So..If I am charging 16 amps @ 208 volts, I am putting about 3200 watts (3.2KW) of electricity into the battery per hour, right? Gee....I feel smarter already!

 

[LEAFfan]

To put 3.3kW h into your pack takes 3.8kW hs of juice.

 

[KeiJidosha]

6.6 would have made our 4 hours sitting in our car till midnight, as our family of 4 waited for a charge, 2 hours shorter, but still a fiasco. Even L3 is going to be a stretch for many folks. I suspect L2/6.6 kW charging may actually delay the advancement of L3 as officials will get fooled into thinking it's adequate and the overall adoption of EV's may then be slowed.

I'm not suggesting that a family of four should wait for 4 hours for a complete charge. Moreover, it's likely going to be 3.5 for a full charge, and about 1 3/4 hour for half a charge. Certainly, quite long and not for everyone, but it will get you over the hump if needed.

The problem with L3, as I see it anyway, is multifaceted. We have utility demand charges in California, plus sizable installation and equipment costs. There are less than six QC stations here after a year of trying. This might be different in other states. Although it's obvious that the Leaf was conceived and designed with QC in mind, the infrastructure buildout has been slower than anticipated.

Don't get me wrong, I would rather have L3 deployed sooner than later. What I was trying to say is that Nissan could have improved the utility of the car substantially by including a 6.6 kW L2 charger. This would take maximum advantage of infrastructure that is cheaper and easier to deploy. From a design perspective, I can see why the included a slower L2 charger, but from a end-user perspective, they did not give us much of alternative.

Carlos Ghosn could fix all of this by putting the Renault Chameleon 43kW on-board charger in the 2013 LEAF. 17kW L2 now. No California demand charge. SAE "frankenplug" becomes irrelevant. No obsolete CHAdeMO QC standard. No $10-$100k DC chargers to site and maintain, offering charge services that are unaffordable.

 

[skippycoyote]

I did a bit of research and found something that might make a few of the Arizona drivers feel a little better. The Nissan LEAF was tested at Nissan's Arizona Testing Center right here in the Sonoran desert of Arizona. It is located between Casa Grande and Maricopa. My uncle is a retired proving grounds driver, and I have seen first hand just what they put those cars through (alas, no more behind the scenes rides and tours for me) He worked for Chrysler, but I'm sure Nissan is just as thorough.

 

[LEAFfan]

I did a bit of research and found something that might make a few of the Arizona drivers feel a little better. The Nissan LEAF was tested at Nissan's Arizona Testing Center right here in the Sonoran desert of Arizona. It is located between Casa Grande and Maricopa. My uncle is a retired proving grounds driver, and I have seen first hand just what they put those cars through (alas, no more behind the scenes rides and tours for me) He worked for Chrysler, but I'm sure Nissan is just as thorough.

A long time ago, I posted about these battery packs being tested here. I actually talked to a few of the techs that were present during the testing because they used a DCQC from ECOtality for some of the testing. They said they were tested for a simulation of 8 years/100,000 miles and the degradation was what is being said now...70-80% capacity after 8 years. They didn't tell me though that it lost 15% in the first year or so.

 

[GerryAZ]

6.6 would have made our 4 hours sitting in our car till midnight, as our family of 4 waited for a charge, 2 hours shorter, but still a fiasco. Even L3 is going to be a stretch for many folks. I suspect L2/6.6 kW charging may actually delay the advancement of L3 as officials will get fooled into thinking it's adequate and the overall adoption of EV's may then be slowed.

I'm not suggesting that a family of four should wait for 4 hours for a complete charge. Moreover, it's likely going to be 3.5 for a full charge, and about 1 3/4 hour for half a charge. Certainly, quite long and not for everyone, but it will get you over the hump if needed.

The problem with L3, as I see it anyway, is multifaceted. We have utility demand charges in California, plus sizable installation and equipment costs. There are less than six QC stations here after a year of trying. This might be different in other states. Although it's obvious that the Leaf was conceived and designed with QC in mind, the infrastructure buildout has been slower than anticipated.

Don't get me wrong, I would rather have L3 deployed sooner than later. What I was trying to say is that Nissan could have improved the utility of the car substantially by including a 6.6 kW L2 charger. This would take maximum advantage of infrastructure that is cheaper and easier to deploy. From a design perspective, I can see why the included a slower L2 charger, but from a end-user perspective, they did not give us much of alternative.

Carlos Ghosn could fix all of this by putting the Renault Chameleon 43kW on-board charger in the 2013 LEAF. 17kW L2 now. No California demand charge. SAE "frankenplug" becomes irrelevant. No obsolete CHAdeMO QC standard. No $10-$100k DC chargers to site and maintain, offering charge services that are unaffordable.

Utility demand charges would be incurred by high capacity L2 charging just like with DC chargers. By the way, California is not alone with demand charges. At least some Arizona utilities charge demand charges for commercial service starting at 20 kW. We also have time of use rates with demand charges for 1 hour peak demand for residential use. Demand charges and peak rates apply weekdays during the day (9:00 AM to 9:00 PM or noon to 7:00 PM depending on rate plan).

Gerry

 

[Ingineer]

The battery in the Leaf sees a maximum of about 3.4kW input when charging on full power Level II. It's usually pulling about 3.8kW from the AC line. The on-board charger actually outputs more than 3.4kW. The extra amount that doesn't make it to the battery is used to run the DC-DC converter which in turn keeps many of the Leaf's required systems powered up while charging.

-Phil

 

[planet4ever]

I wouldn't dream of disagreeing with you in this area, Phil, but isn't it obvious that current is also being used to run the high voltage cooling system (which is cooling the charger and the DC-DC converter)? Whether that is also subtracted from the 3.4kW or is treated as a concurrent drain from the battery may be not much more than a matter of semantics, but I understood it amounted to about 0.3kW.

Ray

 

[RegGuheert]

A long time ago, I posted about these battery packs being tested here. I actually talked to a few of the techs that were present during the testing because they used a DCQC from ECOtality for some of the testing. They said they were tested for a simulation of 8 years/100,000 miles and the degradation was what is being said now...70-80% capacity after 8 years. They didn't tell me though that it lost 15% in the first year or so.

I believe this testing is the core of where Nissan got into trouble.

Let's take a look at what the accelerated testing likely looked like. The LEAF takes about an hour to discharge at highway speeds. An L2 charge takes about 6 hours and an L3 charge takes about 30 minutes. So let's assume that Nissan chose to test a set of LEAFs over a two-year period with each car getting four cycles per day in the Arizona heat. Each car would receive two L2 charges and two L3 charges each day. That would require 17 hours, which would allow ample time for maintenance and rest at night. That would simulate eight years of driving in the Arizona heat.

From the statements they have made and the data we are starting to see, I am going to guess that they saw the range and capacity of their test LEAFs drop to about 70% of the original value. IMO, that is what gave them the confidence to claim that "70-80% after 8-10 years" would be reasonable, even in the heat of Phoenix.

But the data we are seeing tells a little different story. A gently-driven LEAF in Phoenix which was rarely charged above 80% lost 15% of its capacity in 1 year while a LEAF in Washington was charged to 100% twice nearly every day and driven 38,000 miles and only lost about 1% of its capacity, if that.

So, if Nissan saw a nearly-linear capacity drop to 70% during their testing, they are left with the task of estimating which portion was due to two years in the Arizona heat and which was due to the cycling that was done. My guess is that they had estimates for both types of degradation and they applied their model to apportion to the test results. Since the calendar testing was only 1/4 of the toal time, perhaps that was allocated 10% of the drop to calendar life at high temerature while cycling was allocated 20%. But in reality, perhaps cycling life on the LEAF battery is better than Nissan has projected and it only accounted for 5% while being in the heat accounted for a full 25% drop.

Of course I do not have the numbers from Nissan's Arizona LEAF testing, but I think it should be clear that unless Nissan ALSO took some LEAFs out there as controls and let them soak in the heat without the cycling they could easily come out with wrong conclusions from accelerated life testing in the desert. Of course, we do not have any customer LEAFs beyond the 20% point yet, but I will predict we will get reports from Phoenix of that second bar disappearing before the end of 2012. (I hope I am wrong!)

The bottom line is that I believe the LEAF battery system appears to have outstanding cycle life. It also appears to have extremely good calendar life, to date, in mild climates. But in very hot climates, the calendar life may be poor. Only time will tell the full story. In the meantime, since Nissan never communicated to anyone before purchase that 15% battery capacity degradation in the first year is "normal" for very hot climates, they need to start doing something now that we are seeing that in customer vehicles.

 

[Herm]

The bottom line is that I believe the LEAF battery system appears to have outstanding cycle life. It also appears to have extremely good calendar life, to date, in mild climates. But in very hot climates, the calendar life may be poor.

The bottom line is that accelerated testing of lithium-ion cells is well understood and has been practiced for many years... also, from all reports Nissan has been working with this chemistry for a long time.. perhaps Nissan engineers messed up but I doubt it.

Look at the troubles Honda had with their hybrid batteries so its possible even for mighty Honda.

Perhaps the Leaf's design to control battery temperature is not conservative enough, time and location will tell.. and soon.

 

[surfingslovak]

The bottom line is that I believe the LEAF battery system appears to have outstanding cycle life. It also appears to have extremely good calendar life, to date, in mild climates. But in very hot climates, the calendar life may be poor.

The bottom line is that accelerated testing of lithium-ion cells is well understood and has been practiced for many years... also, from all reports Nissan has been working with this chemistry for a long time.. perhaps Nissan engineers messed up but I doubt it.

Indeed, and that's why what we are seeing in AZ appears to be unexpected and a bit of mystery. While I agree that road data is noisy, inaccurate and generally a pain, it might be worth looking at what Tom Saxton has collected from 20 Roadster owners in the Pacific Northwest. It's a small sample size, and more anecdotal than anything, but it might be of interest. There aren't that many production lithium-ion EVs out there long enough to have a solid baseline.

 

[HXGuy]

I'll be honest, as a potential buyer of a Nissan Leaf in Phoenix, this is concerning. We are actually seriously considering leasing a Leaf but if these claims are true, we may not do it at this time or in the near future.

I've read through the whole post and it didn't seem anyone living in Phoenix had actually confirmed these claims. I saw that "4-5" people were mentioned with another one to soon join the list...where are those figures coming from? Have they made separate posts with the problems they have had?

 

[BudRaymond]

If you're that worried about it, you probably should have just leased to begin with. The lease rates were very competitive, as has been discussed ad nauseam on these pages.

 

[RegGuheert]

I've read through the whole post and it didn't seem anyone living in Phoenix had actually confirmed these claims. I saw that "4-5" people were mentioned with another one to soon join the list...where are those figures coming from? Have they made separate posts with the problems they have had?

There are now 6 whose cars are reporting a 15% drop. Here is the thread that contains those details: Lost a "high-voltage battery status" bar, down to 11

Edit: I changed the link to point to the page which contains my summary of the first five reports of a lost bar in Phoenix.

 

[thankyouOB]

i gave a quick look at that link and I dont see the data.

seems to me that leasing is the answer, if you rugrat has created doubts in your mind.

 

[HXGuy]

Lease is what the option always has been. I feel the technology is too new and will advance very quickly which would make it a bad decision to own a Leaf for longer than the standard lease term. In 3 years, Im willing to bet the range of these cars will be much improved.

Not really sure what to do now, I was on the fence about it already and this doesn't help. We just sold our car yesterday that the Leaf was to replace...maybe a more fuel efficient ICE car is still best for now.

 

[RegGuheert]

Lease is what the option always has been. I feel the technology is too new and will advance very quickly which would make it a bad decision to own a Leaf for longer than the standard lease term. In 3 years, Im willing to bet the range of these cars will be much improved.

Not really sure what to do now, I was on the fence about it already and this doesn't help. We just sold our car yesterday that the Leaf was to replace...maybe a more fuel efficient ICE car is still best for now.

My personal recommendation is to lease a LEAF if your daily round trip is below about 50 miles in Phoenix. As you have read, the other LEAF owners in Phoenix LOVE their cars, as do I. If you lease for three years, then it is Nissan's issue if they have misjudged the rate of capacity degradation. If you are looking at commuting 60 miles or more round trip each day, then the LEAFs capacity in Phoenix over the course of the lease becomes a question mark. We simply don't know enough, yet.

 

[TonyWilliams]

Not really sure what to do now, I was on the fence about it already and this doesn't help. We just sold our car yesterday that the Leaf was to replace...maybe a more fuel efficient ICE car is still best for now.

I don't really understand your hesitation. You seem to know that the lease is available, and that's what you wanted to do anyway, so why hesitate? Are you pushing the range, and a 15% or 20% drop in range would be bad?

If not, just get the car. Who cares if it loses 13%, or 22%, etc, if it still works within your parameters for the 39 months. Then, hand in the keys, and start looking around for the next great thing.

Obviously, NOT EVERY CAR THAT WAS EXPOSED TO 120 DEGREE PHOENIX STYLE HEAT HAS LOST 15% !!!!

 

[HXGuy]

I actually do not have a set daily commute as I work from home. I did log a typical week with my car, using it as if it was the Leaf, and ranged between 20-75 miles per day depending on what customers I had to go see and what errands I had to run. I never considered not charging to 100% everyday though as my days can be pretty unpredictable. I'll know how far I need to drive the day of, but I may not know the day before (like if a customer's job is ready and I have to deliver it).