I own a 2012 Nissan Leaf which has had major battery degradation (first battery went under 70% in only 33k miles, second battery currently around 85% at 45k miles = 78k miles total on both). But on this site, the 2012 Nissan Leaf has less than 2 years of data and shows zero degradation during that time. So it seems like the data is questionable.
Yes, the Leaf uses passive battery cooling as opposed to Tesla and others with active cooling. Their first-gen battery chemistry was also worse in hot climates. The newer battery is a different chemistry that has held up better.
Alternatively, it could be used a state of charge tracking mechanism that conceals battery degradation. Say the battery has 100KWh, but the remaining energy gauge reads zero after 80KWh are expended. You could be degraded to 90KWh but you wouldn't perceive any reduced usable energy until it degrades below 80KWh.
Yes, and my point is that the mechanisms to prevent battery degradation can often end up masking the degradation. This isn't nefarious, it's the byproduct of good state if charge management.
I have a 2015 Leaf with 45k miles on it. Battery state of health is 90% according to Leafspy. I’m in the SF Bay Area. Maybe it’s because of the more temperate climate here, but we’ve just had zero battery degradation problems.
My gut feeling is temperature and constant deep discharging probably explain most of the issues with Leafs. Like a lot of things there is a curve with a knee and it's easy to drive a leaf so you're on the wrong side of it.
I don't really know how Leafs batteries are connected but one could also expect that a smaller battery pack has less redundancy. If due to bad luck a couple of cells go bad you lose a lot of capacity. More likely to happen the less redundancy you have.
I would call Leaf's cooling system as "body contact passive cooling". Calling it as "air cooling" is harmful. Proper air cooling with A/C should be significantly better for health.
I will mention that the leaf suffers from another problem that sets it apart from more recent ev's like the tesla.
I don't really think it's as much temperature management or some defect.
I think it's the size of the battery - it's small. You can figure out the lifetime with simple math. A tesla with 250 miles range with 1000 cyles would have gone 250,000 miles. A leaf with 75 miles range * 1000 cycles will have gone 75k miles.
And telsa recommends keeping the battery between 20 and 80% and I believe the slider says "daily" is 60% and "trip" is 90% (for occasional use)
A 2012 leaf will default to 100%. There is a way to change this to a lower value, but it's well hidden in the system settings and I believe you have to agree to telemetry to set it.
And if you DO set it on the leaf, you will limit your range to about 45 miles (of ideal driving)
Anyway, the idea is that newer cars have bigger batteries, a much higher lifetime mileage, and no need to cycle the battery charge so high, so low, or as frequently.
(a tesla driven 200 miles a week might cycle the battery once while a leaf would cycle every day)
>I own a 2012 Nissan Leaf which has had major battery degradation (first battery went under 70% in only 33k miles
A battery isn't like a tank of gas; it's never truly off. It's full of reactive chemicals and powerful solvents, and it degrades over time even if you don't cycle it. How long did it take your battery to drop?
The 2011/2012 Leafs had major problems with battery degradation in hot climates so much so that Nissan was forced to offer a free battery replacement. So I got it replaced for free. The newer battery is lasting better, but still not great. I think Nissan screwed up by sticking to passive battery cooling.
For reference I live in southern Florida so we have hotter than average climate.
I had a friend with a 2012 Leaf that experienced similar degradation. It was a problem with the early model year and Nissan's choice to use passively cooled batteries.
