100% vs 80% charge question from Charleston, South Carolina

[realestatetomtom]

Uploaded with ImageShack.us

Will charging my battery to the full 100% for 2 days a week and charging it to 80% for the remaining 5 days have much effect on the length of the life?

 

[smkettner]

I charge 100% every night to get full of low TOU rate. I doubt it makes much difference.
Some are charging twice a day 100% for a long commute and reporting no issues.
Time will tell.

 

[TimLee]

No real data yet to know.
Nissan indicates 80% charging will help reduce battery capacity degradation.
Multiple other topics on this, but no real answers yet.
We'll know in 2 to 4 years.
For the time being, I use 80% charging when it is feasible. Probably charge 100% less than 5% of the charges I've done so far.

 

[Stoaty]

Data from Tesla forums suggests that it is time and temperature at full charge that shortens battery life. Thus charging so that you finish the charge shortly before leaving (like an hour earlier) theoretically would be better for the battery. This is especially true if it is very hot.

 

[TimLee]

Data from Tesla forums suggests that it is time and temperature at full charge that shortens battery life.

Maybe. But Tesla is a different chemistry. So far from certain.

 

[BarryE]

realestatetomtom,

Nice to see another Leafer in SC. I live in Beaufort and have my contact information on PlugSare. Stop by sometime.


BarryE

 

[cwerdna]

Nissan indicates 80% charging will help reduce battery capacity degradation.

Mark Perry confirmed this when someone asked him while we were standing in front of the room after the SF BayLeaf meeting was over (where the chief vehicle engineer, a bunch of engineers from Japan and some pretty senior Nissan folks were present but elsewhere in the room). I heard this straight from his mouth.

 

[Herm]

what Stoaty said, it applies to the Leaf's chemistry as well.. but does not apply to the LiFePO4 chemistry of a Coda as an example.

 

[davewill]

It may, but what good is a car that you can't drive when you need it? I say if you know that you can get by on 80% then charge to 80%, and if you might need 100%, then charge to 100%. I do almost the same as you do, 4 day at 80% and 3 days (Fri-Sun) at 100%.

 

[adric22]

It may, but what good is a car that you can't drive when you need it? I say if you know that you can get by on 80% then charge to 80%, and if you might need 100%, then charge to 100%. I do almost the same as you do, 4 day at 80% and 3 days (Fri-Sun) at 100%.

Well, I just can't get comfortable charging at 80%. True, my daily commute is 10 miles, but sometimes I have unplanned trips in the evening. I would have some range anxiety if I started off the day with 20 less miles.

 

[ebill3]

Charging to less than 100% will increase the number of usable cycles.

Take a look at this reference: http://powerelectronics.com/portable_power_management/battery_charger_ics/804PET22li-ion-battery-life.pdf" onclick="window.open(this.href);return false;

Bill

 

[LTLFTcomposite]

Someone posted a link in another thread (sorry I don't have it handy now) that said lithium ion batteries are most stable when they are at or near 50% charge, implying that the more time they spend at the extremes of full charge or low charge the worse it is for them. The same article suggested that you should use the charge timer to have the battery finish charging a short time before you start using the car. So I gave that a try today, set the charge timer to have an ending time of 7am, and left the start time blank... it figures out the start time itself like a bread machine No idea if this really makes a difference, but it isn't hard to do.

If this really is the case, I suppose an ideal charge timer would bring the batteries up to 50% as soon as you connect the charger, then wait until however long it needs before your expected departure time to start bringing them the rest of the way up to 80 or 100%.

Seems the key pieces of information the car needs to make the best decisions when you come home are:
a) When do you plan to use the car again
b) When you do use it again, how far will you need to go (and under what conditions) before it will be connected to the charger again

 

[planet4ever]

Charging to less than 100% will increase the number of usable cycles.
Take a look at this reference: http://powerelectronics.com/portable_power_management/battery_charger_ics/804PET22li-ion-battery-life.pdf" onclick="window.open(this.href);return false;

You may be right, but that article is clearly about small batteries used in cell phones, etc., not about EV batteries. The chemistry is different and, perhaps most important, there is no way you can charge a LEAF battery to a true 100%. What carwings and the dash calls 100% is almost certainly no more than 95% of maximum capacity; probably less than that.

Ray

 

[ebill3]

Charging to less than 100% will increase the number of usable cycles.
Take a look at this reference: http://powerelectronics.com/portable_power_management/battery_charger_ics/804PET22li-ion-battery-life.pdf" onclick="window.open(this.href);return false;

You may be right, but that article is clearly about small batteries used in cell phones, etc., not about EV batteries. The chemistry is different and, perhaps most important, there is no way you can charge a LEAF battery to a true 100%. What carwings and the dash calls 100% is almost certainly no more than 95% of maximum capacity; probably less than that.

Oh, I agree that we never truly charge to 100% (4.2 volts/cell), as that would be 403.2 volts on the SOC meter. The most I have ever seen after a 100% charge is 392.5 which roughly equates to about 97%.

However, I take issue with your contention that the article does not apply to our LEAF batteries. Do you know for sure that they are a very different chemistry? Unless the LEAF cells are something like the A123 Lithium-phosphate cells, which they are not, then I believe the same rules apply. Size really doesn't matter except that larger cells have greater capacity.

Bill

 

[surfingslovak]

What carwings and the dash calls 100% is almost certainly no more than 95% of maximum capacity; probably less than that.

Good call, Ray. If this research report for LiMnO4 spinel cells applied to the Leaf, we can be nearly certain that a full charge at 4.10V cell voltage corresponds to about 90% of its rated capacity. Conversely, 80% charge at 4.05V cell voltage corresponds to about 75% of its rated capacity, or perhaps a bit less than that. Although the basic cell chemistry is an exact match, it's difficult to come up with precise estimates, since the AESC cells in the Leaf could have slightly different discharge characteristic.

 

[Lindabyb]

I'm a complete Newbie, bought a used leaf 2 days ago. How do you charge it to just 80%? I'm just using the car to run kids around and errands. can I top off the charge in between trips?

 

[thankyouOB]

No real data yet to know.
Nissan indicates 80% charging will help reduce battery capacity degradation.
Multiple other topics on this, but no real answers yet.
We'll know in 2 to 4 years.
For the time being, I use 80% charging when it is feasible. Probably charge 100% less than 5% of the charges I've done so far.

yes yes, but that was part of the owners manual written when old firmware gave us access to more of the pack, and when last red bar was really the end of the line.

 

[thankyouOB]

Charging to less than 100% will increase the number of usable cycles.
Take a look at this reference: http://powerelectronics.com/portable_power_management/battery_charger_ics/804PET22li-ion-battery-life.pdf" onclick="window.open(this.href);return false;

You may be right, but that article is clearly about small batteries used in cell phones, etc., not about EV batteries. The chemistry is different and, perhaps most important, there is no way you can charge a LEAF battery to a true 100%. What carwings and the dash calls 100% is almost certainly no more than 95% of maximum capacity; probably less than that.

Ray

read the section in the manual about how to set charging timers.
you have two options under %; 80 and 100.
you set it on the nav screen by pushing the bottom right button and then (touchscreen) go to charger icon.

 

[Lindabyb]

Thanks. I'm working my way through the manuals. There's so much to learn, but it sure is fun.