I’ve had the leaf now for over a year. When I bought it I used the android app leafspy pro to check the battery wear and it was 86% at 3 years old.
The dashboard on the leaf shows the battery health (as opposed to charge) in 12 bars. The first bar is 15% capacity.
After 14 months and the car now being 4 years old I have reached 84% so I have 11 bars of battery health remaining.
So what does this mean? Well not a lot, since you don’t really notice the capacity or real world range difference between 86% and 84%. However it has happened at the same time that the weather has become decidedly colder which you do notice, in terms of reduced range. Lithium batteries can deliver less power when cold (but degrade less quickly). Currently from an 80% charge I get 60 miles range, so with the heaters and lights on I get to work with 30miles available. As I like to have a little headroom in case I have to make a detour on the way home I charge at work back to about 40 miles range before heading home.
The rate of battery degradation is an inverse log, the rate drops as the batteries age, so I am unconcerned. The pack dropped from 100% to 86% in years 0-3 then just 2% more in year 4.
That being said this occurrence and the fact that the 2016/2017 leaf will have a 30 kWh pack (mine is 24) has peaked my interest in potentially replacing the cells with higher capacity units in the future. This is likely to be both dangerous, if done without proper care and attention, and expensive. The replacement cells could cost £4000, so the economics of doing this are difficult. Nissan charge around £4000 for a replacement battery but you have to give them your old one. I know why this is as the old batteries I remove will still have great value as an energy storage system.
Assuming I do this myself one possible use for them would be to make a home energy storage system like Tesla’s powerwall. Ideally charged in the day from solar or wind, then delivering their charge back at night. However I do not have solar or wind but do have dual rate electricity and can potentially charge the system at night for half the price, then use it in the day.
It would also mean I would have a backup power source in the event of a power cut.
At this point I am very pleased by how well the car performs and the rate of battery wear seems very reasonable. The motor shows no sign of any trouble and whilst a 4 year old petrol/diesel car might easily have lost 16% of its engine power in an EV it’s easier to liken this to the fuel tank getting a bit furred up and therefore holding less fuel. As the costs of lithium cells drop and their capacity and performance improve the EV continues to become more realistic a prospect for more drivers.
It is worth adding that battery degradation has been for EV drivers in the temperate areas of the world (indeed the UK is considered the Goldilocks zone being neither too cold nor too hot) far less of a problem than many of the naysayers initially reported, further confirming my belief that we fear what we do not understand.