My normal 90% Battery is 226-227. My last range charge (38,000 miles approx.) was 253. I have a theory on the battery that I have used since day one. I charge at the lowest possible charge rate to get to 90% before I leave for the day. I always charge to 90% unless I need a range charge. I have ranged charged about 8-9 times. I always set to 90% otherwise. So, if I am leaving at 7 a.m., I will set my charge rate to be charged by that time (a little earlier). So, the key for me is to slowly charge the car as much as possible. I think that it puts less strain on the battery. That being said, I have no training as a scientist or engineer. It's just what I have done.