I can't say for sure what your problem is, but my situation was similar to yours. 2011 RTL, battery four years old, seemingly starting and running perfectly, no dimming of lights, etc. but I started to have problems with VSA warning light popping on, and occasionally the ABS light with it. Judging by posts I had read on this forum, the age of the battery, and the fact that I live in a very hot part of the country, I began to suspect the battery, even though it seemingly was working perfectly. So I bit the bullet and installed a new one. The VSA and ABS problem disappeared. I don't have a clue how this would work, but it sure seemed to.