Does anyone know full charge kWh amount?

The 'nominal' voltage is open circuit voltage at 50% state of charge - 3.6V. The cells can be charged to over 4.4V per cell, but it costs cell life. These numbers are for regular LiPo not LiMn (a LiPo variant):

at 4.1 volts, you get over 2000 cycles.
at 4.2 volts, you get roughly 500 cycles.
at 4.3 volts, you get under 100 cycles.
at 4.4 volts, you get less than 5 cycles.

The LiMn cell has a 'sloped' discharge curve similar to lead - not like the more 'flat' or 'horizontal' curve of LiFePO4.

This is comparison between a 36V LiFePO4 battery (black trace) and a 36V sealed lead acid battery.



This shows the typical LiMn curve. This data is from EIG - not from Nissan's battery company.



Unlike lead or LiFePO4, LiMn carries most of the power at higher voltages - so we want to keep from overcharging, but we do want to use as much of the first half that we can.

I don't know enough about the voltage range for Nissan's cells so can't get too specific. IF they track fairly closely to other manufacturer's LiMn cells, then 90% state of charge will be around 4.1V per cell and 10% should be about 3.5V per cell. (The voltage and SOC guesses are just that - somewhat educated but probably not likely to be verified until someone gets some cells to play with.)

Back to AESC and their numbers. Some cell manufacturers report the full voltage and capacity range for their cells, others report only the voltage and subsequent capacity available to the 'consumer' without revealing the 100% and 0% voltage/capacity limits. While it's possible that the cells actually are 33Ah each, it's also possible that they're closer to 40Ah and the 33Ah number is the "80% available to the consumer" number.

I look forward to learning more but that's all I have at the moment.

Andy

Another interesting thing to consider is the fast charge - which would be close to 2C (grren line). That is supposed to give 80% of charge. The 3.3 KW charger gets us close to 8 hrs i.e. 0.13C (Orange line is the closest).

Another possible bit of useful info for range guestimates:

Leaf to be sold with battery pack at C-segment price, SAE, March 2010

Two excerpts (underlines mine):

"The "over 100 mi" (160 km) claim is derived from the U.S. EPA's LA-4 urban driving cycle, operation at well below the 90 mph (150 kph) top speed of the Leaf. The figure apparently does not include operation in an "ECO" mode, which could extend range about 15-20%, AEI was told. Also, there is the "running out of juice" mode, in which the car will operate at reduced power and accessory load.

What happens if the battery pack is "empty" and there is no place to plug in? The driver will get plenty of warning as capacity wanes—more than something akin to the "low fuel" icon, AEI was told by Mark Perry, Nissan Americas Director of Product Planning. Further, he said, Nissan is working with road service providers such as AAA to carry special charging packs that can recharge sufficiently in minutes "to get the car home or to a charging station.""

"How long will the Li-ion batteries last? California law requires a 10-year, 150,000-mi warranty, so even though the federal warranty may be only 8 years, 80,000 mi, the system is designed for the California regulations. Perry said the first-generation battery pack is expected to retain 70-80% of its initial life after 10 years. The Leaf reportedly will maintain a 100-mi range for 10 years, even with the 20-30% battery deterioration. That would indicate that the 100-mi range is a conservative specification."

So...if the car will still get 100 miles of LA4-like driving after 10 years, and if there's an ECO mode good for another 15-20% range...does that mean we might get 140 miles range when the pack's new even before opening the hypermiling bag-o-tricks?

Andy

AndyH, you might, but the entire point is, you really don't want to. As long as you stay within the daily range of 75-100 miles (lower end if you are on the highway more), it won't matter, since you plug it in at night to recharge it. It's not like a Prius, where you can run out of fuel, and then have someone bring you a gallon of gas, it won't be that easy to recharge it on the road. That emergency service they are talking about with triple A is going to be a 50KW 480V 3 phase generator connected to one of the level 3 fast chargers, it won't be an inexpensive setup, and there probably won't be very many of them per state (read: not fast or cheap to get one to a depleted Leaf)

Nope, there is no point in trying to squeeze out extra range from the Leaf, since running out will not be pleasant or an easy/quick fix. Even if you get it towed to a local populated area where you can use someones 120V outlet, you will only have your the trickle charger cable with you, and that could take 18 hours or more to fully recharge the Leaf, probaly less if you only have a short distance to go, but why go through this...

I think the article contains some incorrect information:
I believe (but might be wrong) that CA only requires the long warranty on the batteries of a Hybrid (has emissions), and that the law does not apply to a no-emission vehicle like an EV or NEV.
But, the law might have changed.

Mitch - I agree with you to an extent. I have a bit over a year of EV drive time and can certainly agree that at some point the pack will run out and that's when one pulls their sneakers out of the 'emergency kit' and hits the road. (I won't go into the experience of 'Flintstoning' a motorcycle down the shoulder of the road at 3 mph on the last couple of electrons in the pack 'cause, well, that would be self-incriminating. :lol: ) A properly designed battery management system will not allow me to damage the pack so I'm not worried about that. And I'll certainly run 'max range' tests with the car (as I've done with every other vehicle I've owned) so I know for certain what I can and cannot reasonably expect. But I'm certainly not suggesting that every trip should be a 'max duration' mission.

But...if one reads the article they can get some 'indicators' that, when combined with some of the info we have on this forum, helps us judge how conservative Nissan's range numbers might be.

For example - Lithium cells are judged to be at 'end of life' when capacity drops to 80% of new. That means that a vehicle that will travel 100 miles when new will only be able to travel 80 miles at pack 'end of life'. If an automaker is responsible for the pack for the 8 year drive train warranty, then they may have to increase the pack size so that the vehicle can still meet the 100 mile range number when the pack hits end of life. That means the owner should be able to get 120 miles range when new. The Eco mode is reported to add another 15-20% range so now we're out to possibly 135 or so miles. The article also reports some type of 'reserve' or 'limp' mode that kicks-in before the battery is shut down.

I've found SAE's reporting to be accurate in the past so give it a higher 'plausibility' rating than general press. The source of info in the article appears to be Nissan USA's Mr. Perry so that's another 'accuracy plus'.

Gary - I agree that the California 10 year warranty may not apply to EV packs the way it does with hybrid batteries. I also have to agree that Nissan might not have to warranty the pack for the '49 state' 8 year period. But I don't know for sure that they're not bound by those, either. But setting that aside for a moment, here's the paragraph from the article:

"How long will the Li-ion batteries last? California law requires a 10-year, 150,000-mi warranty, so even though the federal warranty may be only 8 years, 80,000 mi, the system is designed for the California regulations. Perry said the first-generation battery pack is expected to retain 70-80% of its initial life after 10 years. The Leaf reportedly will maintain a 100-mi range for 10 years, even with the 20-30% battery deterioration. That would indicate that the 100-mi range is a conservative specification."

What we appear to have is a very strong indication that Nissan built the pack a bit oversized to allow for pack degradation - regardless of warranty requirements. And that's a VERY good thing!

Compare this with earlier EVs with lead-acid packs - they might have gotten 55-65 miles when new, but range was generally down to 20 miles after much fewer than 10 years. Many of the lead-acid vehicle owners have to drop the 2000 lb pack every 1-2 years to swap weak batteries.

If the Volt can go 40 miles on 8 kWh, then 120 for the Leaf sounds reasonable with 24 kWh, assuming similar Cd and weight. I'm not sure what an "eco" mode could do to extend that, but we'll see.

I'd guess the Volt weighs a good bit more than the Leaf. The Volt has a better Cd.

Isn't it fun to speculate endlessly while we wait for the details? :lol:

A battery warranty is usually worded as a limit to the reduced capacity (like retain 70% of original) after N years, right?

garygid said:

A battery warranty is usually worded as a limit to the reduced capacity (like retain 70% of original) after N years, right?

Click to expand...

Dunno. Post an EV battery warranty and we'll analyze it.

Please - let go of warranty wording for a minute and take another look at the REST of the paragraph - because that's the important part.

It appears that Nissan is engineering to a PERFORMANCE spec. Nissan USA has said that they don't yet have warranty details yet, but DO have a 10 year battery performance metric that says we can expect full range even after the pack has reached end of life.

In other areas of this forum folks suggest that they'll have to derate the pack's 24kWh to 80%, others are trying to figure out how pack degradation will affect range, others want to know what the LA4/UDDS rang number means to them. The info we have here talks to all of those fears/unknowns. 24kWh is likely a 'consumer level' capacity - the cell would have to have 20-30% more capacity to meet the 10 year range number. The 'more than' 100 mile range comment appears to be significant - we'll likely get better range right from the start in order for the pack to still deliver 100 miles at end of pack life.

These range and pack size indicators strongly match other areas of Nissan's apparent desire to make the Leaf an overall positive experience. And for me, that totally kills the 'fear' that they're aiming for a 'minimum standard' experience because they're 'forced to' by some 'regulation' or other 'stick'.

Andy

I am not trying to argue.
I see no quote from Nissan that they intend to warranty the 100-mile range performance.

I supect that ... that part of the paragraph was the reporter's conjecture, not a Nissan-provided "warranty" fact, or even a design "fact".

Bicster said:

Isn't it fun to speculate endlessly while we wait for the details? :lol:

Click to expand...

No! It's making me nuts. I need to see....hear....touch...taste. OK, maybe not taste.

AndyH said:

In other areas of this forum folks suggest that they'll have to derate the pack's 24kWh to 80%, others are trying to figure out how pack degradation will affect range, others want to know what the LA4/UDDS rang number means to them. The info we have here talks to all of those fears/unknowns. 24kWh is likely a 'consumer level' capacity - the cell would have to have 20-30% more capacity to meet the 10 year range number. The 'more than' 100 mile range comment appears to be significant - we'll likely get better range right from the start in order for the pack to still deliver 100 miles at end of pack life.

Click to expand...

Another possibility is that Leaf will use a certain low & high voltage figures through out the life of the battery. That means a lower DOD in the beginning and higher ones as the battery ages - but all the time maintaining what is needed for 100 mile nominal range.

garygid said:

I am not trying to argue.

Click to expand...

Nor am I.

garygid said:

I see no quote from Nissan that they intend to warranty the 100-mile range performance.

Click to expand...

And you won't yet - because Nissan has made clear that they haven't yet released warranty details to the public. They have plenty of time - it's still seven months till Christmas.

garygid said:

I supect that ... that part of the paragraph was the reporter's conjecture, not a Nissan-provided "warranty" fact, or even a design "fact".

Click to expand...

Again - no warranty details released means that nothing in the article can be taken as 'warranty fact'. And it has to mean that NOTHING in any article can be so taken. And that means that if one keeps looking for something that isn't there, they'll likely go blind before they can drive the car...

That's why I asked to let go of warranty questions for the moment and read the words. These, for instance: "Perry said the first-generation battery pack is expected to retain 70-80% of its initial life after 10 years."

Another: "AESC has had considerable developmental and testing experience with the battery design and is confident both in the durability and opportunities for cost reduction. So, Nissan will price the Leaf based on an optimistic view of battery useful life expectancy, Perry said."

Here's what I see here. Perry is a Nissan USA employee and in charge of the Leaf roll-out in the US. In others words - if he messes this up he'd better have a resume in order. Nissan has more road time with Lithium than any other automaker. Nissan isn't using someone else's battery - they're using their own - made by their folks in their factory, inspected by their QA folks. They can control the entire system and can thus determine exactly what their cash flow and risks are. And they say that they expect the pack to retain (at least) 70% capacity after 10 years. If they had any doubts about the pack, it would be in their best interest as a corporation to have a pessimistic view of battery life and performance - that way they can properly position their marketing and warranty support. But the optimistic view is potentially riskier for Nissan - if they over-promise and under-perform they'll be looking a lot like Toyota...or worse - and that's a LOT more expensive a mis-step.

No - it's not legally binding and it's not a warranty. But it IS a significant indicator of the company's confidence in the pack.

I hope that makes sense. I'm trying to give you the benefit of the tax dollars you spent putting me thru school and giving me 21 years of analysis and indications/warning experience.

Andy

I totaly agree.

I note for myself that 70% of 100 miles is ... only 70 miles.

Hopefully, your conjecture is true that the real "new battery" LA4 range will be more like 140.

Then the "new-battery" range for moderate, restrained freeway driving might be 95 (or something close to 100).

But, without other compensation as suggested above (variable DOD), it would still seem like a 20% to 30% reduction in "useful" range is to be expected as the vehicle's battery "ages".

"Hiding" the ageing would indeed be a clever (and likely easy-to-implement) trick, but I suspect that Nissan would rather opt for the good press of an initial "better-than-advertised" range.

garygid said:

I note for myself that 70% of 100 miles is ... only 70 miles.

<snip>

But, without other compensation as suggested above (variable DOD), it would still seem like a 20% to 30% reduction in "useful" range is to be expected as the vehicle's battery "ages".

Click to expand...

This is precisely the significance of the statement made by Perry in the SAE article - that they designed for full range after capacity has degraded.

Scenario 1: If one builds a pack to a price or physical space point, they'll use the cell they can and accept that the range they get once the pack is broken in will be the best they ever see - and that they'll be down to ~70-80% range once the pack reaches 'official' end of life. This is where our motorcycles are, and this is the the primary DIY EV conversion scenario, and my experience with cell phones and laptops.

Scenario 2: But if one builds a pack to ensure full range at end of life, then they must start with a larger pack. If they need 20Ah cells to meet their range goal, they'll need to use 25-26Ah cells from the start to ensure they still have 20Ah available at end of life.

It seems to me that we can eliminate our 'fear' or 'concern' about reduced range because of a 'scenario 1' pack because we've learned that Nissan is using a 'scenario 2' design.

As the article is written, it only says that Perry said ... 70-80% ..., not that he said anything about 100 mile range.

Do I read it incorrectly?

garygid said:

As the article is written, it only says that Perry said ... 70-80% ..., not that he said anything about 100 mile range.

Do I read it incorrectly?

Click to expand...

Again - I said 'indicator' not 'guilty beyond any doubt in a court of law'. I have a much higher regard for SAE reporting as it's proven to stick with the facts in prior reporting. While this could be the first time they've become like the WSJ or a 12-year-old blogger, it's not likely. There's only one person quoted in the article. The type of information reported throughout the article is more characteristic of interviews with Nissan employees and/or official Nissan docs. The little words are important, but the root of the importance isn't what we think they mean, but what the source thinks they mean.

I believe the SAE author had a conversation with Mr. Perry and wrote the article from that interview. Because of that, and my regard for SAE as a source (8 years of subscribing to their newsletters and reports, actively cross-checking the info for the areas I'm interested in, and not finding factual errors), I have no trouble attributing the info to Mr. Perry. My assessment could be wrong, the author could be wrong, and Mr. Perry could be wrong.

We'll know in December. I can't wait!

Andy

I would hope to know before December. They really need to be forthcoming when taking firm orders in August.

Bicster said:

I would hope to know before December. They really need to be forthcoming when taking firm orders in August.

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I agree, and will be hard-pressed to begin modifying my garage for the charger without a definite feel for the range. Real-world for me range, not LA4...If I had an indication that the Leaf battery was unable to cover a 40mi commute @ 60mph with some hairy hills thrown in I would give up my reservation.

scottsim said:

I agree, and will be hard-pressed to begin modifying my garage for the charger without a definite feel for the range. Real-world for me range, not LA4...If I had an indication that the Leaf battery was unable to cover a 40mi commute @ 60mph with some hairy hills thrown in I would give up my reservation.

Click to expand...

I'm beginning to have a bit of pre-purchase range anxiety myself, after reading posts about how range will drop at freeway speeds. Not knowing exactly how the LA4 figures vs. real world will play out for me is making me a tiny bit nutty. I really want my Leaf to deliver 65 miles per day at freeway speeds, assuming carpool lane legislation continues beyond next January. Or in stop-and-go traffic, if solo carpool use goes away.

Truth of the matter is, it doesn't really matter....I can plug in at work for the entire time I'm there. I mean, the car sits doing nothing for eight hours. But I think it would be a bit hard to explain to my wife, and the folks I work with (so basically the uninformed), why I'm not getting the "advertised" range. If I can slope (all the way) home before having to charge, it would be better for my machismo!