TEG
Posts: 1388
Joined: Thu Jun 10, 2010 8:43 pm

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 1:03 pm

Stoaty wrote:...Perhaps the initial loss of capacity (first year) is so rapid in places like Arizona from the effects of heat that the effects of high SOC tend to be lost in the noise...
Yes, that sounds like it might be it. Perhaps if the ambient temp is already causing the breakdown process, then the high SoC affects aren't as statistically significant. I think another reason why Nissan (and others) may be hesitant to say too much about all of this is that it is complicated. A lot of factors play into what exactly happens. If they start having chemists lecture us about internal battery chemical processes it could make more people think the whole thing isn't ready for "prime time".

(I suppose as an analogy, you could study just how much gas/oil/car companies really say to consumers about the chemical properties of gasoline as it relates to MPG and emissions.)

User avatar
DaveEV
Posts: 6246
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 1:09 pm

TEG wrote:Ni-Cad and NiMH with reduced SoC range due to "memory effect" could be "reconditioned" and regain some of their former range, but Li-Ion that has been overheated repeatedly is probably irrecoverably "toasted".
Old myths die hard - NiMH has no memory effect, either.
Stoaty wrote:All true, but oddly enough while my battery aging model doesn't (yet) account for this it seems to be pretty accurate in many cases. I haven't yet run into a case where charging to 100% was the factor that made the prediction model too optimistic. For example, I was surprised that when I checked Azdre/opossum my current model nailed their capacity loss almost exactly. As I recall, they charged to 100% most of the time. Everything I have read indicates it isn't good for the battery to leave it at high SOC for any length of time. Perhaps the initial loss of capacity (first year) is so rapid in places like Arizona from the effects of heat that the effects of high SOC tend to be lost in the noise. It may be more of a factor in subsequent years.
I think there's simply too much noise and not enough data to really say that for the following reasons:

1. 100% charging people tend to drive more miles (look at the miles azdre/opossum put on) so they need to charge to 100% to avoid range anxiety - at the time time, the length of their commute brings their average SOC down to a reasonable level by mid-day.
2. 80% charging people tend to have very short commutes. They could very well end up with a higher average SOC than the 100% charge people.

Unless you take 2 cars driven similar distances, I think you're going to have a hard time seeing the difference.

User avatar
surfingslovak
Vendor
Posts: 3809
Joined: Mon Jun 13, 2011 1:35 pm

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 1:11 pm

TEG wrote:Perhaps anecdotal, and more hearsay, but here are some related suggestions:

plugin-cars: Eight Tips to Extend Battery Life of Your Electric Car
Patrick did an awesome job with that article, and I believe that it's as good as it gets. These are all conservative recommendations, and we have discussed many of them on this board before Patrick published his write-up. Even with the most robust batteries, it should be up to the drivers to decide if they wanted to follow a conservative protocol or simply use the car, and not have a care in the world. Owners might be more interested in learning more about battery care than lessees. The only problem I can see is that we cannot quantify the benefits of a conservative approach easily on our own.
Stoaty wrote:All true, but oddly enough while my battery aging model doesn't (yet) account for this it seems to be pretty accurate in many cases. I haven't yet run into a case where charging to 100% was the factor that made the prediction model too optimistic. For example, I was surprised that when I checked Azdre/opossum my current model nailed their capacity loss almost exactly. As I recall, they charged to 100% most of the time. Everything I have read indicates it isn't good for the battery to leave it at high SOC for any length of time. Perhaps the initial loss of capacity (first year) is so rapid in places like Arizona from the effects of heat that the effects of high SOC tend to be lost in the noise. It may be more of a factor in subsequent years.
Please correct me if I'm wrong, but the model is just an educated guess. Although it's a reasonable assumption created to fill a void, it's still speculation. Hopefully it will help set expectations, and prevent misinterpretation on the part of new owners and prospects.

That said, I believe you are correct, and we might be seeing the worst of the calendar loss in the first year or two. Vehicle mileage and other factors, such as charging protocols, could become more pronounced later. It's tough to say based on the data we have.Image

Stoaty
Posts: 4490
Joined: Fri Jun 18, 2010 9:50 pm
Delivery Date: 12 Jun 2011
Leaf Number: 3871
Location: West Los Angeles

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 1:20 pm

surfingslovak wrote:Please correct me if I'm wrong, but the model is just an educated guess. Although it's a reasonable assumption created to fill a void, it's still speculation. Hopefully it will help set expectations, and prevent misinterpretation on the part of new owners and prospects.
It is an educated guess, but one based mostly on interpolation of Nissan's own data. I think it is the best we have to go on currently, but obviously could be too optimistic (possibly) or too pessimistic (probably not).
2011 Leaf with 62,000 miles given to Nephew
2013 Tesla Model S85 with 251 miles rated range at full charge
Leaf Spy Manual
Battery Aging Model Spreadsheet

TEG
Posts: 1388
Joined: Thu Jun 10, 2010 8:43 pm

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 2:02 pm

drees wrote:...Old myths die hard - NiMH has no memory effect, either...
Well, I do also have an old NiMH Ranger EV...
It has a tendency to offer shorter ranges if you top it off frequently.
Factory recommended procedure is to full cycle the pack a few times to wake it back up again.

Official Ford document:
http://www.evchargernews.com/miscfiles/ ... -22-04.pdf" onclick="window.open(this.href);return false;
FORD: 1999-2001 RANGER
Some Ranger Electric Vehicles (EVs) may experience steadily declining driving range. This may be caused by Nickel-Metal Hydride batteries that suffer from a condition where, if not fully discharged on a regular basis, the battery may lose much of its ability to deliver energy, thus reducing the vehicle’s range.
ACTION:
To maintain vehicle range, it is recommended the battery be deep discharged once every two weeks.
This procedure may require several cycles to recover energy/range...
Perhaps there is some semantical argument that the problem is not true "memory effect", but reduced range over time is still a symptom of something... Out of balance pack? Voltage depression effect?

BattteryMD could also put the battery units on reconditioning machines to restore capacity of irregularly charged batteries.


( I think RAV4EV, using similar batteries, doesn't suffer from this situation... So maybe Ford is attributing a BMS software problem to the batteries? ... Or maybe RAV4EV is able to "self-condition" the batteries when left on charge for a while? )

Anyways, technical debates of battery behavior, and seemingly superstitious charging habits predate the LEAF and even Li-Ion based EVs.
Last edited by TEG on Tue Oct 23, 2012 7:09 am, edited 1 time in total.

DaveinOlyWA
Posts: 15049
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 2:22 pm

charge memory is only "supposed to affect Ni-cads but i have seen it recommended for EVERY battery type except Li. now, whether that is a valid thing or not is the question.

we also have a phenomena where machines thrive on constant use and lightly used machines seen to age faster.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 13,705 mi, 93.41% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

ALLWATZ
Posts: 92
Joined: Sun Aug 05, 2012 8:15 am
Delivery Date: 14 Aug 2011
Leaf Number: 6877
Location: Palm Springs area

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 3:04 pm

evchels wrote:
thankyouOB wrote:yes, and the LEAF service manager at Power Nissan in LA did not know that leaving a battery at 100% was not recommended for the car....imagine what they are doing to all those LEAFs sitting on the lot.
Based on what I've seen and heard, the whole dealer process and training needs to be overhauled and refreshed.

However, it's really sort of silly that if it's that important to only charge to 80% (and while I'm not doubting, I'd love to see some data on the real-world effects, esp if only on Level 2), that the car doesn't automatically default to that mode and require an override to go to 100% when desired, a la Tesla's "range mode" for charging. Anything that crucial shouldn't be left up to the knowledge of the newest lot porter, or body shop employee, or valet, etc...

(I'm sure there's a thread about this or discussion that's already been had- happy to read up if someone wants to point me in the right direction! :) )
As an ordinary person, I am not a geek, wonk, scientist and as my wife would say "not brilliant in any way", I have one observation. When we purchased the Leaf, we were told (and the manual backs this up) that 73 miles would be the avg. distance in D, the default driving setting. But, we could get more by using a "longer-range" mode called ECO. This is true. Now we come to the battery and the manual again states there is a "longer-life mode" by charging the battery to 80% even though the default setting is 100%. Any normal person would think that would be an extender to the advertised life of the battery (80% for 5 and 70% for 10 years). As I see it, I get more than advertised range by using the "longer-range" mode but I only get advertised (or in my case, less than advertised with a 2 bar loss) by using the "longer-life" mode of charging. To a normal person's ears, this sounds like "bait and switch"

User avatar
mwalsh
Posts: 9753
Joined: Thu Apr 22, 2010 10:10 am
Delivery Date: 05 Jan 2011
Leaf Number: 0213
Location: Garden Grove, CA

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 3:17 pm

DaveinOlyWA wrote:we also have a phenomena where machines thrive on constant use and lightly used machines seen to age faster.
Li-Ion batteries too maybe. I bought two Toshiba laptops for my office in April. One is never turned off, and charged as needed (the one I use personally), and the other is a loaner that I seldom allow use of and is charged maybe once a month. The battery on the laptop I use is showing 1% degradation. The seldom used battery is showing 7% degradation.
2011 Blue Ocean SL with 86,000 miles
2015 pack on 12/30/15
Tinted windows
Bosch AGM 12v
Ecopia 422+ tires
L1 EVSE upgrade
FIAMM horns
Superbright LED lighting
2013 sun visors
LED shifter
Heated seats
GT-R map lamp lenses
Altima illuminated door switches

DaveinOlyWA
Posts: 15049
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 4:55 pm

mwalsh wrote:
DaveinOlyWA wrote:we also have a phenomena where machines thrive on constant use and lightly used machines seen to age faster.
Li-Ion batteries too maybe. I bought two Toshiba laptops for my office in April. One is never turned off, and charged as needed (the one I use personally), and the other is a loaner that I seldom allow use of and is charged maybe once a month. The battery on the laptop I use is showing 1% degradation. The seldom used battery is showing 7% degradation.
ya when i got my 4 G droid, it did not take long to realize that that blazing 4G speed came with a huge power penalty. the standard battery would be near dead by lunch time. so i went and got extended battery for 2 reasons.

1) to not have to worry about going dead in the middle of the day

2) to test the 80% long life charge. now; there is no setting to charge a cellphone to any SOC so i made a habit of just boosting it a few hours at a time. have i charged to full? oh ya, several times. sometimes it was not convenient to partially charge because i knew i would be somewhere where charging would not be an option for several hours so thought it best to charge up completely but all of that seems to have worked.

normally, i am very hard on batteries. i use speech to text EXTENSIVELY, average over 2 GB of data transfer over the cellular network and 1500 text/pix monthly, but this current battery has been going for 14 months now and is just now showing signs of weakening (however, i strongly suspect its the droid FB app that is the culprit)

now contrast that to the original battery which was only used full time for less than 2 weeks 14 months ago. it normally sits at 30-40% SOC with a dozen or so times when I charged it up to use as a spare. each time i charged it, the smaller battery was used first until it was back down to the 30% SOC level before the extended battery was used so its time at high SOC is pretty minimal. it has already shown a loss of capacity and all this is really anecdotal evidence i have that is probably tainted somewhat by my subconsciously comparing the characteristics of the extended battery.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 13,705 mi, 93.41% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

TEG
Posts: 1388
Joined: Thu Jun 10, 2010 8:43 pm

Re: Andy Palmer and Chelsea Sexton Discuss the Nissan LEAF

Mon Oct 22, 2012 5:59 pm

mwalsh wrote:
DaveinOlyWA wrote:we also have a phenomena where machines thrive on constant use and lightly used machines seen to age faster.
Li-Ion batteries too maybe. I bought two Toshiba laptops for my office in April. One is never turned off, and charged as needed (the one I use personally), and the other is a loaner that I seldom allow use of and is charged maybe once a month. The battery on the laptop I use is showing 1% degradation. The seldom used battery is showing 7% degradation.
I used to work in a lab which had many laptops. They came brand new with factory Li-Ion batteries, and were basically plugged in and left running 24x7, never getting taken out and run down. Within a couple of years most were popping up alarms saying that the battery was no longer healthy and needed to be replaced. That experience alone has convinced me that leaving Li-Ion at 100% for extended periods of time is not a good practice.

This is in stark contrast to old Lead/Acid batteries, which seem to last longest if kept full and never used.

Return to “General / Main Owners Forum”