TickTock
Well-known member
There has been a lot of speculation on the cause of the rapid battery degradation experienced in Arizona and other hot states beyond what Nissan appeared to expect. Some have suggested that the hot asphalt may be baking the battery beyond the 120F_24hr/140F_absolute_max that the battery is warrantied for.
To shed some light on the topic I purchased a couple of these and stuck one underneath my Leaf for a week. Specifically, on the driver-side, towards the back. I removed three 10mm bolts in the shield there, pulled the shield gently down, shoved the datalogger up against the battery housing, and replaced the screws. This, I believe, gives a good measure of the temperature the battery is being exposed to.
After a week, I've found that the battery was exposed to a maximum of 5 degrees more than the daily max reported by wunderground. This occurred on Thursday when I left work early to run an errand before businesses closed so I was out during the peak heat and saw the battery temp hit 115F versus the reported max of 110F. On my typical days, the battery temperature maxed out at a temp very near the daily max (since I usually leave work after temperature is starting to drop). I also took a log of the EVcan bus on 6/28 to show the amount of charge in the battery at the various temperatures seen throughout the day (plotted below). I did not see anything unexpected or alarming.
To shed some light on the topic I purchased a couple of these and stuck one underneath my Leaf for a week. Specifically, on the driver-side, towards the back. I removed three 10mm bolts in the shield there, pulled the shield gently down, shoved the datalogger up against the battery housing, and replaced the screws. This, I believe, gives a good measure of the temperature the battery is being exposed to.
After a week, I've found that the battery was exposed to a maximum of 5 degrees more than the daily max reported by wunderground. This occurred on Thursday when I left work early to run an errand before businesses closed so I was out during the peak heat and saw the battery temp hit 115F versus the reported max of 110F. On my typical days, the battery temperature maxed out at a temp very near the daily max (since I usually leave work after temperature is starting to drop). I also took a log of the EVcan bus on 6/28 to show the amount of charge in the battery at the various temperatures seen throughout the day (plotted below). I did not see anything unexpected or alarming.