Battery Charging Practices Data

From what I have read, it would seem that if you discharge your battery to 30% and only charge to 70%, the battery would last longer than if you routinely discharge to 10% and charge to 100%, all other factors being equal. Is there any data from Leaf owners that would shed some light on this?

As of 3/20, the underwhelming response would indicate this data does not exist.

Everything I have read tells me you are correct. 70 to 30 is better than 100 to 10. But more importantly (since it represents different ways to do the same trip...) 70 to 30 is better than 100 to 60.

And the best practice is to charge just-in-time. Keep the average SOC as low as practical.

I would love to verify this with hard data. However, here's my battery longevity plan:

1. Monitor battery temps like a hawk - never charge a hot battery.
2. Try to keep SOC between 70% - 30%.
3. Don't charge at more than 0.7C, even though I have a QC port and access to L3 chargers.

Luckily I am in CT so ambient summer temps are nowhere near AZ. I also use my Leaf primarily within a 15 mile radius as a second, local car so I don't need maximum range. Driving locally, my experience has been I get about 1 mile for every %SOC - this translates to about 100 mile range if I were to fully charge and drive locally. So far my average speed after 670 miles is 20.1 mph, which does include highway driving as well as local.

Maybe I'm Nissan's target market.

Sounds like you're on the right track. The only other thing I would add is don't accelerate/decelerate too vigorously. Some of the early adopters who drove hard seemed to report faster degradation (although temps are the vast majority factor). I hope to get a LeafSpy application soon and confirm my degradation is less than 10% in almost three years. I know it's less than 15% (12/12 bars), but don't have any concrete evidence beyond that. I wouldn't obsess about it, just drive it as much as you can and as gently as you can and you will be fine. That said, I do park outside the garage in the summer which helps the desert cooling effect on the battery.

The bottom line is that, outside of outright abuse, nothing you do will have that much affect on battery degradation... It is all about location, location, location. E.G.: long term temperature.

Hi, new Leaf owner (2014 model Sv), went looking for the way to stop the charge at 80%. it is no longer there. If I charge to 100% overnight and begin driving the next morning, should it really hurt my battery that much? I can try and play with timers but I figure if they say they will warranty to the battery to 70% capacity in 8 years, does it really matter?

Someone with knowledge of this please feel free to pm me.

Using just 40% of the battery is not practical for most.
Heat seems to have a much larger effect than level of charge every day.

The highest mileage LEAF was charged to 100% twice a day and depleted 80%+ each time.

TrevorD said:

I can try and play with timers but I figure if they say they will warranty to the battery to 70% capacity in 8 years, does it really matter?

Click to expand...

The battery warranty is 5 years or 60,000 miles whichever comes first. Nissan will put in a new (or used) battery if you lose 4 capacity bars (which is about 66.5% capacity remaining). Not much of a warranty unless you live in a pretty hot place.

Stoaty said:

Nissan will put in a new (or used) battery if you lose 4 capacity bars (which is about 66.5% capacity remaining). Not much of a warranty unless you live in a pretty hot place.

Click to expand...

"Refurbished", rather than used (in Nissan parlance), and only guaranteed to be 10 or more bars when installed. Though it appears they're using brand new battery packs for the time being, but who knows how long that will last.

TrevorD said:

Hi, new Leaf owner (2014 model Sv), went looking for the way to stop the charge at 80%. it is no longer there. If I charge to 100% overnight and begin driving the next morning, should it really hurt my battery that much? I can try and play with timers but I figure if they say they will warranty to the battery to 70% capacity in 8 years, does it really matter?

Someone with knowledge of this please feel free to pm me.

Click to expand...

If you have to deal with hot weather, it's worth trying to leave before the charge finishes, even if it's at 98% (except for letting it equalize at 100% a few times a month). It's even more important to, as noted already, not charge a hot battery, especially not to 100%. I just retired, and I've repurposed the "Work" timer setting to enable recharging overnight, when it's cooler. Now if I can just find a way around the "only one timer set per day" obstacle, I'll be happy.

TrevorD said:

Hi, new Leaf owner (2014 ... I can try and play with timers but I figure if they say they will warranty to the battery to 70% capacity in 8 years, does it really matter?

Click to expand...

Who did you hear say such an erroneous statement :?: :shock: :shock: :shock:

I used to think that shallow cycling of the battery would help extend its lifeAnd I actually tried this on a cell phone battery.

Obvious differences aside,The experiment failedTo show shallow cyclingWas beneficial.
Another thing to consider is that Nissan incorporated self-balancing into the charging process.Apparently this process is much more important than we previously thought. Add to that a lot of anecdotal evidence that a full charging cycle helps increase battery stats. Several weeks ago I reported seeing degradation on my 2013 after four thousand miles. This happen after a period of inactivity and minimal driving. Later I noticed as have others thatDriving greater distances and doing full chargingIncreased my battery numbers includingState of health and totalCharge capacity.So if using this charging profile I strongly recommendThat you do a full charge at least once or twice a week. The reason is a fully charged PAC is more balanced reducing stress on any individual cell.

joerivct said:

From what I have read, it would seem that if you discharge your battery to 30% and only charge to 70%, the battery would last longer than if you routinely discharge to 10% and charge to 100%, all other factors being equal. Is there any data from Leaf owners that would shed some light on this?

Click to expand...

Everything we know is in the wiki. See this section and surrounding sections:

http://electricvehiclewiki.com/Battery_Capacity_Loss#Battery_Aging_Model" onclick="window.open(this.href);return false;

I think the Battery Aging Model does reasonably well, heat is definitely the main factor. However, there is enough evidence that other factors are at play that I think it is a good idea to do shallow cycling of the battery if it doesn't affect your use of the Leaf. My Leaf is currently running slightly ahead of the Battery Aging Model (predicted loss - 18.2%, actual loss - 17.5% by LeafDD), while some others in the same general geographic region have lost significantly more capacity while having roughly the same mileage. I shallow cycle the battery about 85% of the time, only charge to 100% about once a week. I accelerate gently about 90% of the time. Your mileage may vary.