The accessory hook up behind the right side side cover will work but the reading won’t be pure. A wire from the battery to the meter is the best way. What I did to avoid degrading that pure line was to wire a switch in line on the ground wire. This is helpful because you can turn it off once you kill the engine but you can switch it on to check the battery when the bike is not running. Turning on the ignition does not give a good battery reading because of lights and other stuff that gets power as well
Yep. My Escort/Passport which functions as a voltmeter is wired direct to battery via the unswitched buss in the PC-8 panel, which has 10ga supply line from the dogbone. Power not reduced by the other small loads on that buss - all of which have their own switching via other relays/triggers. The radar is bright red and right in front of me - never forget to switch it off. Quite accurate voltage readouts. Very useful to keep me apprised of my power situation. Not to mention cops.