There is easily enough surplus on a cb500 to run an extra stop tail bulb and a 5w sidelight as my sidecar had that much extra lighting, however after being told by a few drivers / colleuges that theyd nearly forced me off the road thinking I was a solo bike riding out in the middle as the sidelight was so pathetic I tried running a 35 / 40w bulb in the sidecar marker - that was catastrophic in preformance terms. On a 30 mile trip you'd wind up stalling if the indicators or brake light came on. So yes, not a lot of extra power in the system, but enough for a phone charger. I even had oxford heated grips for a year or so, it could cope with them on about 50% of the time if you were moving at a decent pace, on windy b roads or in town the revs tended to be lower and you'd get the telltale misfire, switch off the extra electrical load for a few miles to let the battery recover. I had similar on my first big bike, a 550k3, turned out there were only 2 of the 3 altertator coils working. 30 miles range with lights on then it was wing it with the lights off time. Lights only comming on if a headlight was close by. Fun times crossing the Clywedog dam road by moonlight not dating to let the revs under 3500.
