leafkabob wrote:Mon-Fri my car is parked in a large parking structure that is very open to breezes and airflow. I'm not sure what the temperature difference would be from being in the full sun on hot pavement, but I would think it would be significant. In the evenings and weekends my car is parked in my detached garage (uninsulated, but gets partial shade from large trees).
I also cleverly (I thought) timed my 80% charges to begin at 3 am. In hindsight I'm not sure that made any difference.
I really feel for you:
charging to 80%, late at night did not protect you
parking in perfect condition did not protect you
low mileage did not protect you
More suggestions, which may or may not be practical for your situation:
The data at the Battery University site link posted by JPWhite, while not specific for our Li-Mn chemistry, suggests that storing at charge levels below 80% yields additional benefit. Any change you can do to minimize time spent at high charge and high temperature will help. Perhaps you could add a fan to your garage to reduce how much time the car spends at elevated temperatures on the weekend. Perhaps you can sometimes top-off your charge just before you head-out.
Charging at 3 am probably does not help too much, but the charging process adds some heat of its own.
BTW, over a year ago, when I posted some other battery data from the Battery University, some comments in this forum suggested their data was obsolete and our wonderful Nissan batteries would perform much better. With real experience, we are learning.