My understanding of the recommendation was that it's fine to charge from 80% to 100% but that you should take it down to 80% or lower before charging up all the way, at least routinely. Then the winter came along and the car is getting prewarmed daily, definitely charging over 80% after previously charged to 80%. It's not unusual for me to prewarm all the way to 100%. For me, the question is how bad is it to prewarm after 100% charging. everyone routinely charging to 100% then prewarming appears to be allowed to "overcharge" the battery. seeing that most folks in the EV project are charging to 100% daily and prewarming, it seems if this were a problem, it could become a big problem. My conclusion is that Nissan has provided us with some general rules of thumb but for the most part have engineered out any ways to truly abuse the battery. I'm not worrying much about it. I charge to 80% and prewarm/top off as much as I need and figure the battery spends little time hanging out at 100% or however much over "100%" we are allowed to charge using prewarming if already at 100%.
from what I've read, the real issue with true 100% charging li-ion batteries is that leaving the battery at a high state of charge for long periods can lead to cladding of the anode/cathode and reduce capacity over time and it's within the upper 20% of the true 100% of the batteries capacity where more of the energy is lost to heat, and the heat is also degrading to the battery. there has been a lot of discussion about whether we are truly able to get at the true 100% of the battery or not, I tend to think we don't or at least we tend not to leave the car at a high enough charge long enough for it to really be a big issue. If the studies of li-ion batteries and cycle life apply to the Leaf's particular battery chemistry, it does seem to be worthwhile to reduce the time the battery spends at very high or very low charge states. Fortunately, the battery management system of the car makes it easy minimize impact based on the users preferences and needs. I have adopted the assumption expressed in other threads that time is ultimately going to rob the battery of capacity regardless of how it's charged. Ultimately though, I figure I'm way more likely to replace the battery before significant degradation occurs because a cheaper, higher capacity version will likely come out soon enough. How I charge this one will probably be moot.
Gasless: Silver 2012 SL, traded in for Lease on 1/13
Tesla S P85, Gray, pano, carbon fiber, took delivery: 2-9-13... LOVE this car!
9.8 kW PV Solar installed 9/12, http://www.westseattlenaturalenergy.com
" onclick="window.open(this.href);return false;