Electrically heated gear (grips or clothing), should be wired back to the battery with its own separate fuse. Heated equipment can draw more amps than your existing fused circuits have to spare.
Clothing isn't a big problem since you have to "unplug" from the bike when you get off, so there is no chance then of draining the battery if you forget to turn it off.
Power for heated grips should also go back to the battery, but the line (also fused) should be switched via a relay controlled by your ignition switch so if you forget to switch off the grip heat, it doesn't drain your battery.
Last edited by cHarley; 02-13-2011 at 06:21 PM.