Degradation not related to charge cycles?

It seems like everything I've read re: LEAF battery degradation talks about SoC or heat. Is it true that plenty of usage, if kept within LEAF-friendly temperatures, won't significantly degrade the battery?

I ask because I've had the car for like three months and I've already got 4,700 miles on it...

It's probably a case of moderately heavy use causing little extra degradation, but extremely heavy use causing some. There is usually a 'cycle life' listed for a given chemistry, but it's always WAY too optimistic about how many cycles are available before capacity drops to 80% or less. I'd say that keeping the pack cool becomes even more important with heavy use.

We don't know if cycling aging is additive to heat wear or we just see whichever is the worse of the two. My impression is the latter, but it is just an impression. In any case, cycling dependent aging is VERY dependent on depth of discharge and maximum SoC. If your daily cycling is staying within the middle 70% of the battery the cycling aging is drawn out to rates you do not care about.

My experience is time seems to be equally as detrimental as heat. My 2011 sat parked for about 5 years (occasional exercising/charging). I just started driving the car again in January. Dropped my 3rd bar at 16,000 miles in March. Fourth bar last week at 18,000 miles. The vehicle has never been exposed to heat extremes - always garaged.

LeafPowerIsIxE said:

My experience is time seems to be equally as detrimental as heat. My 2011 sat parked for about 5 years (occasional exercising/charging). I just started driving the car again in January. Dropped my 3rd bar at 16,000 miles in March. Fourth bar last week at 18,000 miles. The vehicle has never been exposed to heat extremes - always garaged.

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The first Leaf battery chemistry was very affected by time. Later versions much less so.

I bought a new 2016 with the 30 KW battery. I minimized 100% charges and fast charges. Lost my first bar at 9 months / 9500 miles. So, my use of the vehicle has now changed, not interested in babying the battery so Nissan can save on warranty outlays. In less than a year my 107 mile car is now an 85 mile car. Just a bit frustrating as I could have purchased a used Tesla for the price of the new Leaf. I am second guessing that decision. Of course, one bar down in 9500 miles is "normal".

victorjsmith said:

I bought a new 2016 with the 30 KW battery. I minimized 100% charges and fast charges. Lost my first bar at 9 months / 9500 miles. So, my use of the vehicle has now changed, not interested in babying the battery so Nissan can save on warranty outlays. In less than a year my 107 mile car is now an 85 mile car. Just a bit frustrating as I could have purchased a used Tesla for the price of the new Leaf. I am second guessing that decision. Of course, one bar down in 9500 miles is "normal".

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Wow, they should be replacing it for sure. That's crazy!

victorjsmith said:

I bought a new 2016 with the 30 KW battery. I minimized 100% charges and fast charges. Lost my first bar at 9 months / 9500 miles. So, my use of the vehicle has now changed, not interested in babying the battery so Nissan can save on warranty outlays. In less than a year my 107 mile car is now an 85 mile car. Just a bit frustrating as I could have purchased a used Tesla for the price of the new Leaf. I am second guessing that decision. Of course, one bar down in 9500 miles is "normal".

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In fact, anything above 4 bars down anytime during the warranty period of the first 8 years is "normal."

Do you know the Ahr capacity when the first bar was lost ?

victorjsmith said:

I bought a new 2016 with the 30 KW battery. I minimized 100% charges and fast charges. Lost my first bar at 9 months / 9500 miles. So, my use of the vehicle has now changed, not interested in babying the battery so Nissan can save on warranty outlays. In less than a year my 107 mile car is now an 85 mile car. Just a bit frustrating as I could have purchased a used Tesla for the price of the new Leaf. I am second guessing that decision. Of course, one bar down in 9500 miles is "normal".

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My mom's 2016 lost her first bar recently after having the car for about a year, It was pretty surprising, but I guessed it was because she leaves it at 100% overnight. Makes me thankful I have a used 2013 with the 80% charge option. Surprised you lost a bar too. If this rate of loss keeps up, Nissan is going to have to replace a lot of batteries.

I am surprised to hear that so many people have bars lost so early. I have a 15 that I bought new, and have almost 40k on it. I still have all bars left.

I have always charged it every day to 100% overnight. However, I drive 40-50 miles daily, so the battery has a chance to discharge to below 50%. On the weekends, when I do not use the car that much, and it stays at about 50%. I do not charge it until I need it, I have had many rechargeable products over the years, especially cordless drills and saws. What I have found is that batteries go bad when you don't use them. When you exercise them daily, they last a long time and have a good charge.

I really suspect that folks who buy a leaf and put very few miles on them are the ones with the biggest battery problems. That poster that did not use the car for 5 years is a real example. USE YOUR CAR DAILY to get your money's worth!!

I agree powersurge. My 2013 Leaf had a missing bar when I got it at about 36k miles. It works for me still and I'm happy I have the 80% charge option. I also usually trickle charge it as that fits my current needs. If I had a newer Leaf, I'd do the same as you.

victorjsmith said:

I bought a new 2016 with the 30 KW battery. I minimized 100% charges and fast charges. Lost my first bar at 9 months / 9500 miles.

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You left out that very important part of the story - where is your location? I also have a 2016 with a 30 kwh battery. It is still at 12 bars. You can see where I am located, which is surely a substantial factor.

I drove mine 55 miles a day in Phx AZ and still loss 4 bars @ 26000 miles ...I would charge it every 2 days ... 6.5 M/KW ...

I'm a bit surprised by what I read here.

My 2015 is my second Leaf. It now has 12,500 miles and all 12 bars.

My 2013 had about 20k miles and all 12 bars.

I rarely QC. But I don't think that's the problem with losing bars. I thought it was pretty well sorted that it was a combination of miles and age.

I'm not expecting loss of my first bar until about 30k+

I thought it was pretty well sorted that it was a combination of miles and age.

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Nope, it's age and heat exposure with the 2011-3/2013 packs, and primarily heat after that, with age a secondary factor. I've seen no evidence of mileage being a factor.

All batteries degrade due to cycling (using a wider % of the capacity, esp. a greater DoD), age, and heat, varying with the particular chemistry. Depending on an individual's climate and usage patterns one or the other may predominate, but with the LEAF's uncooled LMO pack it's usually heat that's primary. Li-ion batteries don't suffer from memory effect, so fully discharging and recharging them doesn't help (but may help balance cells, depending on whether the BMS uses top or bottom balancing).