The new 2015 R1 has shed a truck load of weight compared with the previous model. Looks like the battery is one area they found some weight reductions. Here is the photo of the new R1 battery followed by a comparison of the 2000 R1 battery. The new battery is tiny.
2015 R1 Battery
2000 R1 Battery left and 2015 R1 battery right
I've read a few stories on the R1 forums about the new R1 battery going dead after a few weeks of not riding. So far nothing has happened here yet but I'll have to wait and see.