I use the TourMaster Synergy heated vest with collar, no other heated gear. Per their website, it takes 51.6 watts and 4.3 Amps.
My grips are Warm-n-Safe with an in-dash variable controller.
It all works out to be sufficient heat for down to freezing temps, with First Gear jacket and pants, liners
KTM 1190R, 950S, 500XC-W