Battery endurance for every day commuting

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Tokyotony

Member
Joined
Sep 24, 2009
Messages
21
Hello Nissan representative, me and my wife are wondering if the range capacity of maximum 160km per charge will remain after years of everyday commute of about 70km? And if the battery's capacity will decline with frequent usage what kind of decline are we talking about, say after4-5 years?
Thanks,
Tony
 
Hi Tony,

The LEAF range per charge is for average, everyday driving conditions - which it seems like you are describing. However, we're not yet addressing battery degradation.

When I am able to share more, I will respond again.

Thanks,
Jessica
 
Also interested in hearing about this. The car will be used exclusively for a 60 mile round-trip commute each day, so I can take some degradation over the first few years with no impact. I could even trickle charge @110v for the eight hours I'm at the office once degradation does become significant.
 
Just to add a bit more since last update, the range is 100 miles based on the LA4 drive cycle – an EPA testing and rating system. Battery capacity decreases with time and use. Actual range will vary depending upon driving/charging habits, speed, conditions, weather, temperature, and battery age.

(Based upon US EPA LA4 city cycle conducted in laboratory tests. See http://www.fueleconomy.gov/feg/fe_test_schedules.shtml.)
 
In CA, the hybrid batteries must be under warranty for 10 years (or 150,00 miles?).

Does that CA law apply to the Leaf (EV) batteries also?

Does the CA law say the batteries need to maintain at least 80% of their original rating during the warranty period (or get replaced)?

What are the drive train, electronics, and battery warranties on the Leaf?
 
garygid said:
In CA, the hybrid batteries must be under warranty for 10 years (or 150,00 miles?).
Don't push them too hard, Gary. I don't want them to withhold them from the California introduction just because they cannot afford to meet unrealistic requirements.

Batteries are too much of an unknown at this point. I think California should not have that rule until they know it can actually be met.
 
I agree. It would be COMPLETELY AWESOME if the battery packs DID last for 10 years AND still retained 80% of their capacity, but it's not a deal killer for me if that were to not be the case.

I think you have to accept being a bit of a guinea pig, but that's not unfamiliar territory for most early adopters.
 
Jess> I'm afraid even your recent short update haven't shed more light on the battery pack degradation issue and warranties as you addressed in this thread in Nov 2009. Don't you think it's a bit high time to annouce answers to these legitimate questions and concerns openly? Lets put on the table the facts we know or we think we know as of now ;) :?

- batt. pack passive aircooled only (inside pack air recirculation only)
- perhaps some positive side-effect from precooling/heating the pack indirectly via above cabin A/C
- dashboard features batt. temp gauge (so it's significant parameter)
- Nissan's presentations talk about ~5yrs lifespan -> after that swap needed for new pack, the old one being used for utility storage application and after that it goes to recycling, some form of credit issued against the purchase of new pack
- given the above the pack degradation will likely vary significantly among different climate regions and usage
- after ~5yrs the real range of Leaf might be derated to ~50-70% of stated range
- therefore the potential customer wants to know what will be the credit given for new pack replacement after say those ~5yrs and how costly is it going to be
- are you going to proactively instruct/warn customers in hot climates how to charge safely?,
i.e. letting the pack to cool off few dozen minutes before charging again, say at high noon in suburban concrete/asphalt jungle conditions, not parking/charging during the day at non shaded areas/sun spots etc.
- pls. don't use the "Nissan's 17yrs expertise in lithium batt. powered vehicles" PR slogan, it's a bit silly, like for me saying I'm a pro-marathon runner in aggregate, after 20yrs of short range jogging..

Do you plan to address these concerns openly before the actual sales commence?
Why don't you, meaning the entire Nissan-Leaf project dept., opt for more transparent approach, say like Tesla or Volt/GM, when they are openly talking about these "detrimental" issues inherited with todays batt. technology from the start and how they deal with it from their respective egineeringing perspectives, e.g. focus on temp managed - watercooled packs. I think it's in your best long term interest to take it seriously, unless this is deliberate strategy to put people into position of "mandatory" upgrading your packs on regular basis, as revenue generating system. Which is obviously your right as business oriented profit seekers, but pls. firstly inform the customers about it.

In Race to Market, Nissan’s Electric Car Takes Shortcuts:
http://www.wired.com/autopia/2010/01/nissan-leaf-2/

Range derating explained
Ex-Tesla Spokesman: EPA's Electric-Vehicle Range Figures Are Grossly Inaccurate:
http://blogs.edmunds.com/greencaradvisor/2009/05/ex-tesla-spokesman-epas-electric-vehicle-range-figures-are-grossly-inaccurate.html
 
While I would certainly like the information requested by Mesuge, I think that Nissan is adopting a more phased approach to answering these questions. First, they seem to be setting up the entire launch to carefully monitor who gets their cars and to gather a great deal of information about the first vehicles released. Second, I expect that every car sold in the first year is going to be sold via a Leaf dealer specialist, who is going to be careful about ascertaining who can effectively use this car. I know many think the dealer would just sell any car to anyone. However, in this case, the large bet placed by Nissan on this car is likely to negate that natural inclination.

In the end, given the great variety of factors, this is data that we will only know in detail over time. In the interim, both buyers and Nissan will be better off by using a conservative estimate of both range and battery life. The original poster had a daily commute of 70 miles (I think). I would not risk a daily commute of that length for a new technology in the first generation. I am applying a discount of 50% to any figures given, simply because of the unknown factors and the cost of the purchase.
 
sjfotos> agreed, however the Nissan's approach seems so far more like flood the market, be first at all costs. How come that the GM-Volt people can say on camera, they guarantee 8yrs @40mi range with +/- 20% factor? While Nissan refuses to answer it in straightforward fashion. I think people will accept different strategy of Nissan, if explained in rational honest terms, to bring these full BEV kind of vehicles on the market fast and in large numbers at the cost of more "disposable" kind of battery strategy, at least for this first generation.
 
Hello Mesuge,
Yes, I agree with you on your recommended strategy to Nissan. I think they would be better served to be more forthcoming and more conservative in their claims. I am not at all sure about the GM strategy. I just do not know enough about the variables they are dealing with and the choices they are making in the Volt.

I do think that the Volt rollout is far less sophisticated than the Leaf. The detail in the placement of the vehicles, the number of journalists who have actually driven the car, and the appearance of a vehicle with production values in fit and finish show a much better prepared organization. I am thinking that this will be reflected in the 'choice' of initial buyers by Nissan and additional data before December on battery and range values. I hope I am not proved wrong!
 
100 is the magic number. Go below 100, you won't get that many interested.

If you want 100 miles of hard-driving highway range, it will cost more.

There is no free lunch.
 
Can battery life can be stretched by charging less often? I'm retired and seldom put in more than 10 miles a day. For longer trips I can swap cars with my wife anyway and she drives less than I do. I could go ten days (in theory) between charging, although of course I wouldn't cut it that close unless I was well under 100 miles in that period. But my question is, is that the best way to charge a battery to preserve life? Does it degrade a battery more to charge up from 90% to 100% 10 times or to go from 0% to 100% one time? Something in between? Jess, can you answer that?
 
Rat said:
Can battery life can be stretched by charging less often? I'm retired and seldom put in more than 10 miles a day. For longer trips I can swap cars with my wife anyway and she drives less than I do. I could go ten days (in theory) between charging, although of course I wouldn't cut it that close unless I was well under 100 miles in that period. But my question is, is that the best way to charge a battery to preserve life? Does it degrade a battery more to charge up from 90% to 100% 10 times or to go from 0% to 100% one time? Something in between? Jess, can you answer that?

Avoid running it down to 0% as much as you can; li-ion has no "memory", like ni-cd. Optimally, most li-ion EVs prefer to have as shallow of cycles as possible usually hovering somewhere around 60% charge. Most of the damage, however, is done at the very upper and lower ends of the charge range (near 100% charge and 0% charge, respectively). The far upper and lower ends are usually capped off, and what remains is known as the "depth of discharge". Sometimes the lower end isn't totally blocked from usage, but is left as an "emergency reserve". Given the numbers Nissan has provided, it will have a very high depth of discharge.

Basically, to sum up: Charge whenever you get the chance. It won't make a big difference, but if you're super-concerned, stop charging when you have enough charge that going half the distance you usually go in a day would bring you down to 60%. But really, it won't be worth bothering.
 
I thought I heard 90% to 10%, but I think 96% to 8% might be relatively easy to do and still have good battery life.
Remember, a series (of cells) battery pack is only as good as its weakest cell.

The Leaf's LiMnO battery chemistry could easily have different limitations, but Nissan has had considerable experience with using it, I believe.
 
garygid said:
Remember, a series (of cells) battery pack is only as good as its weakest cell.

Hmmm .... why ?

Except if the cell becomes open ... (or resistence becomes very high)
 
When the "weakest" series cell starts to get fully discharged, it can get totally ruined by continued "discharging" - which looks like reverse charging to it.
Also, the cell, unless switched out of the series, will likely look like a resistor, dropping the pack voltage quite significantly, and generating a lot of heat.

So, by continuing to operate, the "weak" cell gets weaker, ... and dies.
 
When the full charge voltage of a cell drops, is that also because of increased internal resistence ?
 
garygid said:
When the "weakest" series cell starts to get fully discharged, it can get totally ruined by continued "discharging" - which looks like reverse charging to it.
Also, the cell, unless switched out of the series, will likely look like a resistor, dropping the pack voltage quite significantly, and generating a lot of heat.

So, by continuing to operate, the "weak" cell gets weaker, ... and dies.

Yeah, Tesla had a pretty good approach to deal with that -- the hybrid series/parallel "brick" approach. Each brick is made of a ton of cells in parallel. The bricks are then linked up in series to form sheets, and the sheets in series for the total voltage. You could outright rip out several cells from a brick and it'll still function mostly normally. Of course, they pay for that approach in terms of assembly complexity due to the large number of cells.
 
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