Oh, well. It finally happened. Not that I was looking forward to it, but it was something we couldn’t avoid. Our LEAF has lost its first bar.
A brand new LEAF is delivered with approximately 100% of the rated battery capacity (24 kWh, of which about 22 kWh is usable). As it happens to all batteries, the ability to store energy slowly degrades with time and usage. The LEAF shows up to 12 bars of capacity on the dashboard, indicated by those short bars located to the right of the (longer) charge bars. While charge levels will always go from 0 to 100% (of the available capacity), the capacity itself will slowly decay from the original 100% down to a level where it is no longer useful.
The rate of decay depends of many factors — battery chemistry, mileage, age, average temperature, etc. Earlier versions of the battery, mine included, are mostly sensitive to high temperatures, which is not really a problem here in Ottawa. The second main factor appears to be age, as many of my 2011/2012 LEAF friends already lost their first bar regardless of their milage. Milage is also a factor but apparently not as much as age.
So, how much capacity have we lost? The first bar disappears after capacity drops below 85% (15% loss). I’ve been monitoring the battery capacity with an iPhone app connected to the OBDII port for the past two years. Capacity was about 88% when I first started monitoring it in 2013, and reached 84% in the beginning of June. It was just a matter of time until the computer noticed it and turned off the top capacity bar on the dashboard.
Capacity bars are not linear. The first one goes away after you lose 15%. Subsequent ones will disappear each time you lose 6.25% (2 bars lost at 21.25%, 3 bars lost at 27.5%, 4 bars at 33.75%, and so on). The Nissan warranty will swap any battery that loses more than 3 bars in less than 5 years, but that’s not likely to happen in our case.
Capacity loss is also not linear. We lost about 11-12% in the first two years, but only 4-5% in the last two.
Despite the disappointment, the loss of our first bar was by no means unexpected. The official estimate from Nissan, from the very the beginning, was for the LEAF to keep 80% of its original capacity after 5 years, which is pretty much dead on (ours has 84% after 4 years).
As for the future, I think it will be a few years before we deem necessary to replace our battery. Even at 84% capacity, the LEAF still offers enough range to cover most of our daily trips in the city, even during the winter. Being able to charge at work makes it even easier to get through the day. Actually, I still charge the LEAF to 80% most of the time. On top of that, we still have the Volt available for longer trips.
Nissan offers a battery trade-in replacement for about $6,000, which is not a bad deal, but not necessarily appealing if all you’re getting is an extra 25% of capacity back. HOWEVER, there are strong indications that a 30 kWh pack will be available this year (on 2016 models). If the form factory of the new battery is compatible with older models, then an upgrade will be much more appealing. Even today, such upgrade would give us 60% more capacity than what we have right now, which will be really attractive.
In conclusion, losing the first bar may have a big psychological effect on most owners but reality is capacity loss is a continuing factor. The LEAF will lose a little tiny bit of capacity on a monthly basis but it will take 3 to 4 years for that drop to be translated visually in terms of bars on the dashboard.
On there other hand, as my friend Kelly Carmichael says, the range of the LEAF actually increases with time as more and more fast charging stations are installed. In our case, DC Fast Chargers are expected to be installed along highway 50 between Ottawa and Montreal this year, allowing for trips that were not practical even when our LEAF was brand new.