+1 on the Battery Tender. I had been meaning to do it for years, having a fleet of vehicles to keep running, but always managed to NOT spend the money somehow, instead cheaping out using my other trickle charger. For whatever reason though, my wife's damn Aprilia EATS batteries. I think its the alarm system, I wish it were easy to remove from the loop, but it's really too integrated for that. Anyway...after buying multiple batteries over the years for it, cause the old one wouldn't stay revived, I finally bought a battery tender and do an easy plug in at the end of the work week. Nice not to worry about overcharge, which is easy to forget and do on a m/c battery.

As for battery choice, Interstates are hard to beat.