Also of interest is this article: Electric vehicle charging times will depend on both the charging station and the car.
Basically, it appears that the on-board charger limits the charging speed to protect the battery. The Leaf and the Volt are restricted to low-speed charging (3.3KW charger), which is about half of what a standard dryer outlet can provide. Future models, at least of the Leaf, are expected to have a 6.6KW charger. However, the Leaf does have the ability to accept DC voltage (like that available from the Blink stations), which skips the charger and goes straight to the battery.
So what we are saying is that a charging station at Cracker Barrel is eye candy for the envirowhacko’s, since you wouldn’t get a nickels worth of extra ride out of the electric car for the 60 minutes you are there.