Disappointment with battery capacity and "Nissan miles"

[palmermd]

What would you do with the kwh figure ? Figure out some range figure, right ?

That's what the compter is doing as well.

I think the SOC was wrong - in which case knowing the wrong kwh wouldn't have been useful as well.

yes, but the fuzzy logic does not work very well. If they just put in a pure amp-hour or kWh reading I can figure out my own range better than the logic is doing right now. It is the same complaint from almost every owner...the range estimate is not very good, and there is no pure SOC display on the car, and the only one we have does not appear to be purely kWh or amp-hour, but some calculation like the range estimate, and it is displayed in a 6miles/point resolution which is not very useful.

 

[LEAFer]

I think we all realize that the (nilly-willy) range estimate is based on the PAST, iow, on your recent energy efficiency, or how efficient you HAVE BEEN driving. But when things start to "get low" ... and you become worried whether you'll make it ... it's the future that counts.

If I knew more precisely how many kWh remain, and the fact that I have in the past been able to achieve (for example) 5 miles/kWh, and if I remember correctly HOW I achieved that same efficiency, and if I had an accurate kW current use meter (more comprehensive than three separate gauges) ... then I have a FUTURE reasonably accurate predictor. Which is EXACTLY what I need at that moment.

The Tesla Roadster implements such a "future predictor" of range. It calls it "Ideal Miles". And those "Ideal Miles" are based on its very accurate measurement of remaining SOC, and a standardized cycle (not sure, but let's say it's LA4). That's it. Simple. An Ideal Mile is based on approx 217 Wh/mile. And the driver is given a single instantaneous kW display, as well as an accurate Wh/mile display showing both instantaneous and average use (the average is over the past 5 or 15 or 30 miles at driver's option). Drive like 217 ... and you'll make the number of miles it predicts.

So ... once I get worried ... I can always look forward to ... "If I start driving like the Ideal Miles cycle RIGHT NOW ... then I still have xx miles." Currently, the way the LEAF is done ... it's nearly impossible (or too inaccurate with the "grainy" SOC bars) to do that.

P.S.: To be fair, the LEAF does have a nice, although grainy, instantaneous SINGLE miles/kWh Energy Efficiency gauge. It appears in the center on the main temp/SOC cluster, selectable with the buttons to the left of the steering wheel. You just have to cycle thru the various displays. I've used it, and it's helpful, more so than what's on the EE screen on the Navi display.

 

[JRP3]

If you have a SOC number it gives you some redundancy and something to compare to the bar gauge and the projected mileage. Let's say the SOC percentage was incorrectly reported, then if your digital SOC gauge said you had 2 kwh left but the vehicle stopped you know immediately that either the gauge is reporting incorrectly or there is something else wrong with the vehicle. As some have mentioned with the bar gauge you don't know if you have a "full" bar or one that is about to disappear, and after the bars are gone you don't really have any accurate indicator of how many kwh's you actually have. It would have been so easy to implement and those who didn't want it could just ignore it. I remember when regular cars were dummied down with dummy lights instead of informative gauges, you had no warning of a problem until it was too late.

 

[evnow]

If they just put in a pure amp-hour or kWh reading I can figure out my own range better than the logic is doing right now.

That depends on your experience. You give a kwh figure to an average green consumer (s)he wouldn't know what to do with it. People know about miles and they need to travel miles. Not burn kwh.

This is a mass produced EV - this needs to cater to a much wider target population. They need to get better at calculaing the range - not just throw in a SOC figure and be done with it.

Let me repeat - for the mass market, there is no substitute for an intelligently calculated range estimate.

 

[EVDRIVER]

If they just put in a pure amp-hour or kWh reading I can figure out my own range better than the logic is doing right now.

That depends on your experience. You give a kwh figure to an average green consumer (s)he wouldn't know what to do with it. People know about miles and they need to travel miles. Not burn kwh.

This is a mass produced EV - this needs to cater to a much wider target population. They need to get better at calculaing the range - not just throw in a SOC figure and be done with it.

Let me repeat - for the mass market, there is no substitute for an intelligently calculated range estimate.

I don't think he suggested that and Nissan could have given the info in the display as a toggle option, how many consumers use the advanced features on their digital cameras, like exposure compensation and auto exposure bracketing? Few, but it is there for those that want to use that information or functionality. No big deal to provide this.

 

[evnow]

Few, but it is there for those that want to use that information or functionality. No big deal to provide this.

True.

I'm just saying it is more important for Nissan to improve the range estimation. People asking for SOC are just thinking about themselfs - but for wider acceptance of EVs (my motivation in getting into EVs), it is important that the estimation be improved. This is why I differ from "old timers".

 

[bowthom]

Hello,
For me I just need to get used to the metric. Like when I'm on the boat estimating RPM, run time, wind, current, fuel use (when not sailing) I get a "feel" for the metrics of the gauges and having refueled over and over. The Leaf is the same, the gauges give me feedback, and the conditions dictate usage. Once I am comfortable with repeated charge discharge cycles it will be as normal as anything else. That being said I just ignore the range calculations at the beginning because they jump all over the place. Kinda of the opposite of driving over a hundred miles before the fuel gauge begins to move in my ICE. Until it moves I have no way to predict how full it is or how far I can go.

On another topic, there seems to be so much misunderstanding about charging the Li battery it's size and it's affect on life span. I suggest those confused go to any Li battery manufacturers website and read the specs.
I know it can be technical reading but it boils down to this:
1. 100% depth of discharge (DOD) nets you less than 800 cycles (until capacity falls to 80%). If you used the Leaf battery this way every day it would last 2 years (up to 96k miles).
2. 80% DOD (90% to 10%) nets ~2500 cycles. Cycle it every day and you get 6.8 years of life (up to 240k miles). This is the 24 kW "std capacity" of the leaf battery. It's regulated at 80% to give 8 years of battery life (yes Nissan is counting on you not fully cycling the battery every day).
3. 65% DOD (80% of 80% Nissan's long life setting) nets up to 4000 cycles. That's 11 years (up to 312k miles) of battery life.

There is no option in the Leaf to use 100% DOD, the system will not overcharge / overdischarge, it shuts down first.
You can decide which you want to use 80% or 65%. If you don't commute very far (22 miles for me) then the 65% DOD makes sense and I can expect a long and healthy battery life. I'd better, I plan on keeping this car until I'm planted. If I need extra range 80% DOD (Nissan's 100%) will not harm the battery and I'm still going to get my eight years + battery life.

I hope this will help some people interpret the battery recommendations in the Leaf owners manual.
I'm also hoping it's fairly accurate, Nissan has never released battery test data (I wish they would).

 

[jkyu99]

Bowthorn, I have no EE experience. Are you saying it is primarily the depth of discharge that decreases the life? I was under the (blush) impression that it was the charging past 80% of full that was limiting the life of the battery by overcharging the battery.

 

[DaveinOlyWA]

Both will do it.
Have a charge meter would be cool. The more info the better.
after all I doubt the charge level will increase if I drive more efficiently

 

[bowthom]

Hello,
Overcharging and over discharging shortens the battery's life.

Li batteries have pretty flat charge/discharge curves. The trick to long life is avoiding the ends of the curves, staying in the middle 80% of the battery's capacity.
I suspect Nissan charges until the voltage starts rising sharply then shunt's those cells until the other cells hit that curve.
On discharge when the battery reaches a certain voltage the leaf reduces power then goes into turtle mode and then shuts down when the voltage begins to drop more quickly avoiding the bottom 10%. All it takes is one cell in the battery pack to hit the curve for the Leaf to shut down.

The warning / tip the Leaf gives you on powerup is talking about REPEATED full charges in a day. Heat is the big killer of Li batteries. Heat goes up on the ends of the curves too so they are saying don't heat the batteries repeatedly in a day. Remember, their concern is about their warrantee and they are counting on you not fully cycling your batteries everyday or multiple times in a day. The inference is, if you must charge multiple times a day, set it to long life mode to mitigate battery heating thereby preserving battery life.

Does this help?

 

[edatoakrun]

"65% DOD (80% of 80% Nissan's long life setting) nets up to 4000 cycles. That's 11 years (up to 312k miles) of battery life."

Anyone able to answer a few more Q's:

1) What number of cycles could be expected if this level of charging occurs over a longer period of time, such as only 200 or 300, charge cycles a year-I assume there is at least some additional deterioration due to aging alone?

2) If some (of L1/L2) charge cycles are to 80%, rather than 65%, should battery capacity decrease proportionally to the percentage of these higher levels of charge?

3) Any idea of the amount of decreased battery life occasional DC fast changing causes, say if 5% to 10% of charges are DC, to 65% ?

I hope to confirm your answers over the next 15-20 years.

 

[bowthom]

OK so I'm speaking generally about Li batteries so too my answer will be general. As I said before, Nissan has not released technical specs on their batteries.

1. Yes there is a time coefficient to electrolyte breakdown, 10~20 years expected which varies by manufacturer and doping.

2. My best estimate is yes, since the whole scale is a proportional one.

3. Fast charging will proportionally shorten battery life. Fast charging heats the battery more than L2. The Leaf instructs the fast charger to ramp down current as the battery heats up.

I'm going to be testing the onboard charger again tomorrow. What we really need is more data which is why Nissan and Etech are collecting it from us.

 

[palmermd]

Few, but it is there for those that want to use that information or functionality. No big deal to provide this.

True.

I'm just saying it is more important for Nissan to improve the range estimation. People asking for SOC are just thinking about themselfs - but for wider acceptance of EVs (my motivation in getting into EVs), it is important that the estimation be improved. This is why I differ from "old timers".

I concur 100%. They need to have the calculated range estimate, but they need to also have somewhere a pure state of charge for those that want to see it. If they had provided it right now, I bet there are a whole lot of "mass market consumers" who would quickly learn how easy it is to use for estimating their own range until the calculation is refined.

 

[jkyu99]

The inference is, if you must charge multiple times a day, set it to long life mode to mitigate battery heating thereby preserving battery life. Does this help?

Thank you. Yes, up until the comment about long life mode. would that be the trickle charger, 110v charger? I don't recall a setting about charging with the regular 240v evse having a long life mode.

 

[planet4ever]

Long Life Mode = 80% timer setting. From the Owner's Manual:

NISSAN recommends charging the Li-ion battery using the long life mode to help maximize the Li-ion battery useful life. Long life mode can only be set using the charging timer function. The long life mode is set by changing the [% Charge] to [80% Charge (Improves Battery Longevity)] using the following procedure.

See pages CH-20 to CH-22.

Ray

 

[leafme]

The fact is, we follow those driving habits... we can't help it if we live on a hill and drive 90 percent on the highway for a daily commute, that's just how it is. And my original point was that plenty of people do only highway driving, and that means that Nissan will have a hard time selling these cars on a wide scale if buyers first must submit to a a lecture about proper driving habits and never getting on the highway before they can buy it. (snip). Thanks to some of those users who did not react with condescension to my OP and understood that I am happy with the car, but not happy with Nissan's marketing of the car and range/battery capacity estimates.

Josh

I'm with you Josh. You were just making a valid point about the marketing. Freeway driving is a range killer and more people drive on the freeway than not (it seems to me in San Diego anyway). Nissan is selling it as they can (need to) after a huge investment.

I am getting the 65 freeway miles I expected but I am disappointed that I was not aware of the 80% charge reco until after I bought it. It practically forces me to charge to 100% daily if I want to drive at 68-70 mph (as is practically the minimum required speed on I-805 south in the morning) with climate control on auto and not be constantly thinking about not being able to do a mid day run to lunch and/or a store somewhere that you somehow can't see coming.

Malcolm

 

[Deleted member 1622]

Malcolm --

Thanks for being one of the voices of reason. I find it sad that there are certain paranoid people on this forum like TRONZ who think that there are somehow anti-Nissan spies lurking around trying to bring down the car. You should be careful, though, Malcolm, about expressing any disappointment at all about the Leaf here... I'm sure TRONZ is going to accuse you of also being a spy and demand that you enter your VIN# into the spreadsheet so he can, what, confirm it himself? Call the dealership to make sure you're not a spy? I mean, what's really behind TRONZ seeing threats where there are none? His paranoia would be funny, but it's too scary and weird to be funny.
I reserved my car on April 21, and got it delivered from Hanlees Hilltop Nissan in Richmond, CA on Feb. 17... I've already told you that my name is Josh. I guess, TRONZ, that knowing that a red Nissan Leaf SL was delivered to me on that date at that dealership should be enough for you to go do your investigation and put all your fears to rest. But you really should listen to some of the others on this forum and put your paranoia back into the box it came from.
Yes, I love the car. It's great for any commute under 50 miles round trip. But yes, I have a point of view, and I'm not going to censor my point of view because some Leaf owners can't stand to hear a little criticism about the car. I thought this discussion was supposed to be a free and open discussion about the car. Free and open means hearing all points of view, even when you disagree with it, friends.

Josh

The fact is, we follow those driving habits... we can't help it if we live on a hill and drive 90 percent on the highway for a daily commute, that's just how it is. And my original point was that plenty of people do only highway driving, and that means that Nissan will have a hard time selling these cars on a wide scale if buyers first must submit to a a lecture about proper driving habits and never getting on the highway before they can buy it. (snip). Thanks to some of those users who did not react with condescension to my OP and understood that I am happy with the car, but not happy with Nissan's marketing of the car and range/battery capacity estimates.

Josh

I'm with you Josh. You were just making a valid point about the marketing. Freeway driving is a range killer and more people drive on the freeway than not (it seems to me in San Diego anyway). Nissan is selling it as they can (need to) after a huge investment.

I am getting the 65 freeway miles I expected but I am disappointed that I was not aware of the 80% charge reco until after I bought it. It practically forces me to charge to 100% daily if I want to drive at 68-70 mph (as is practically the minimum required speed on I-805 south in the morning) with climate control on auto and not be constantly thinking about not being able to do a mid day run to lunch and/or a store somewhere that you somehow can't see coming.

Malcolm

 

[EVDRIVER]

Josh,

You are right you should be entitled to your opinion and there are some members that struggle with anything that is not positive about the car, some people also struggle with facts they won't accept.

 

[charlie1300]

The great thing about this forum is that a variety of opinions are expressed, and by in large there are very few trolls or wack-jobs. My wife has been on marathon runner forums and there are more personal insults there!

Relax, have a beer, and don't take conflicting views personally.

 

[ENIAC]

Malcolm --

Thanks for being one of the voices of reason. I find it sad that there are certain paranoid people on this forum like TRONZ who think that there are somehow anti-Nissan spies lurking around trying to bring down the car. You should be careful, though, Malcolm, about expressing any disappointment at all about the Leaf here... I'm sure TRONZ is going to accuse you of also being a spy and demand that you enter your VIN# into the spreadsheet so he can, what, confirm it himself? Call the dealership to make sure you're not a spy? I mean, what's really behind TRONZ seeing threats where there are none? His paranoia would be funny, but it's too scary and weird to be funny.
I reserved my car on April 21, and got it delivered from Hanlees Hilltop Nissan in Richmond, CA on Feb. 17... I've already told you that my name is Josh. I guess, TRONZ, that knowing that a red Nissan Leaf SL was delivered to me on that date at that dealership should be enough for you to go do your investigation and put all your fears to rest. But you really should listen to some of the others on this forum and put your paranoia back into the box it came from.
Yes, I love the car. It's great for any commute under 50 miles round trip. But yes, I have a point of view, and I'm not going to censor my point of view because some Leaf owners can't stand to hear a little criticism about the car. I thought this discussion was supposed to be a free and open discussion about the car. Free and open means hearing all points of view, even when you disagree with it, friends.

Josh

Josh, no offense, but there's no need to lash out at TRONZ and the other members on the board. No one on the board called you a spy. Back on topic, I simply don't understand how a new LEAF owner would be satisfied with 50 mile range. That's not right. One day in Jan I put 112 miles on my LEAF. So when I read you are getting only 50, I'm shocked. Have you talked to your dealer about this issue? I asked this earlier in the thread and I'll asked it again, are you sure your battery pack is functioning properly?