I bought my 2012 used with 12 battery health bars in December 2014. Just lost my 4th battery bar, at this rate it’s about one bar per year so far.
What should I expect for range for the next 8 years until the car is 15 years old? Will it continue to lose one battery health bar per year until is has zero?
Not sure why you bought a '12.... it seems like the chemistry in 4/2013 and later built Leafs thru model year '14 are better. But, that might not have been known back in Dec 2014.
My 5/2013 built '13 Leaf in a hotter part of the SF Bay Area is still at 11 bars (Leaf Spy SOH around 82.xx%) and I'm past 64K miles. We've seen cases of '13 Leafs in mild climates have 11 or still 12 bars after 90K miles.
It's hard to extrapolate given Leaf has only been out since Dec 2010. Some have done better than others based upon climate and charging habits. The worst I've sen so far was a 9 bar loser (https://www.facebook.com/groups/nissan. ... 885581945/
, in a closed FB group, you'll need to join). Heck, even someone in the mild PNW with an '11 that wasn't lost his 7th bar in Dec 2017 (https://www.facebook.com/groups/seattle ... 620968334/
I just spoke to a guy with a '12 earlier tonight in the parking garage at work and IIRC, he said he's down 3 bars (which is better than I expected).
I think your best bet short of buying Nisan's crazy prices of a new battery (low $7Ks to $8500+) is to have someone like a Cor (http://www.mynissanleaf.com/viewtopic.php?f=51&t=21997
, see his posts there) swapping all the modules from a newer pack in good shape from a wrecked Leaf into your casing.
Can you update your location info via your user name in the upper right > User Control Panel > Profile tab? That way, we don't need to ask in future posts/threads or do sleuthing to deduce it.