I got my 3.0 upgrade in early October, so it's been about 4 months. In that time, I've put roughly 6K miles on the battery. When I first got it, I did a couple of range charges both to see what it was showing and also because I had to do a long drive (and then back). The best that I saw was 344 ideal miles with a CAC of 215.04. Since then, I hadn't needed to do a long drive, so I didn't range charge it. I noticed that the ideal miles in a standard mode charge declined somewhat, from maybe 225 to 217 or so. I looked for the first time in a long while, and the CAC had declined to 201.45, a little more than a 6% loss. I thought that maybe the problem was that the battery couldn't balance properly with the roughly 75% SOC in ideal mode, so I range charged it, let it sit plugged in for a long time to balance, topped off, and repeated a few times. The result of this is that the CAC improved to 202.24 (total capacity at full charge 74.36 kWh as opposed to 77.26 kWh new) and the standard range charge is back to 221. However, the best range mode charge I saw was 326, a full 18 miles less than when the battery was new (again, 4 months and 6K miles ago, so not very long ago). I figure that one of several things may be going on, rated from best to worst in their implications: 1) The 3.0 battery has cells that have a quick initial dropoff in capacity, but then level out for a long while. I know that some of the Model S cells are like this (and I think in that case that Tesla just sells them as if they're at the plateau level). So, I should expect to stay near this capacity for a very long time, and the R80 is really more of an R74. 2) There's something wrong with my particular battery, and Tesla will just replace it for me since it's a dud. 3) The 3.0 batteries lose 30 ideal miles/10k of range (as opposed to ~3.7 in Tom Saxton's study for the 2.0 battery). So at 33K miles a 3.0 battery will have the same capacity as a new 2.0, and quickly descend after that. That is, the 3.0 batteries don't work and I spent $30K making my car be useless earlier than if I'd have kept the 2.0 battery. I really hope that Tesla didn't screw up in cell selection and it's not #3. Or that if it is that they'll suck it up and fix all of our quickly decaying batteries. Have any of the other 3.0 owners seen a decrease like this? How much mileage do you have on your new battery?