There is nothing more aggravating than hitting the starter button and hearing nothing. I've heard that sound more than I care to so my Shadow had a battery tender. I got one for my Nomad, and now I'm putting one on the Goldwing. They're around $22 and worth it. They keep the battery conditioned and fully charged.
I connected the battery tender directly to the battery. The plug is accessible via the vent hole in the side trim.