I think I need to replace the alternator (maybe voltage regulator). Lights steady before starting the engine, as soon as it's running, lights go noticably brighter and pulsate, seemingly faster with higher RPM. My voltmeter across the battery reads steady at 14.5V at idle and steady 14.4 with some RPM, but the pulsating is probably too fast for my meter to notice (several times a second).
It may have been doing this for months and I'm only noticing now with the winter darkness. With all the electronics I probably shouldn't let it go very long?