I had a combo USM cigarette lighter outlet on my bike mounted on the glove box panel. I had it hooked to the power wire under the glove box on the left side. There were two problems with it. 1 You would loose the USB outlet if you take off the glove box and 2 since the wires there were always hot it would eventually drain the battery.
Got a Dual USB outlet and mounted it in the dash so I will always have power even when I take the cowling off. I need the power to keep my laptop charged while I am driving and tuning.
I got power from the positive wire on the spark coil. That wire is only live when the switch is on so I don't have to worry about draining the batter when I park it overnight.
got it from Amazon for $10
https://www.amazon.com/gp/product/B01N6S2SNM/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1https://youtu.be/dapU1naIExo