My suggested experiment relates to charging strategy and the battery capacity bars (not the SOC bars) for different temperatures. It may apply more to Leaf owners living where overnight temperatures are lower than mwalsh gets, so I hope other owners are reading this.
The "Joining 80% Club" thread pg 5
http://www.mynissanleaf.com/viewtopic.php?f=9&t=2265&hilit=joining+club&start=40
includes discussion how the battery capacity falls with lower temperatures. The number of SOC bars can actually go up just with a drop in temperature without any more charge, because the same energy is sitting in a battery that can hold less. This would seem to imply that charging to 100% when the battery is warm, right after getting home in the afternoon from a drive, would not be wise if during the night the battery gets much colder. Under this scenario the battery charge could exceed 100% during the night, which might be stressful for it.
Conversely, if the car shuts down its charging at 100% SOC late at night when it is cold, you will have less kwh in the tank than you expect. Temperature variation from night-to-night could explain some of mwalsh's early variation of measured kwh charged vs range the next day.
So how cold must it be to lose one bar of capacity, or see one bar rise in SOC ? Has anyone seen this ?
Here is my suggestion for an optimal charging strategy during cold night-time periods. It requires extra effort, so I am not suggesting one do this on a daily basis, but only when you are planning an extra long drive the next day. Program the overnight charge to 80%, or 90% using timing. In the morning, well before you leave, warm the car with some pre-heating and then top-off the charge. You should be rewarded with more total kwh delivered to the battery and longer actual range.