gunrunnerjohn posted:Yep, for passenger cars with an 18" segment, a 330uf or 470uf cap does the job.
There seem to be several conversations going on. I believe you are referring to the situation with a (a) 4-diode-bridge and (b) some type of regulator between the capacitor and the LED strip.
(a) if you only have a 1-diode AC-to-DC converter, you only charge the capacitor 1/2 as often and hence you'd need a larger capacitor for the same effect
(b) the regulator meters out the stored energy in the capacitor for times when there is no incoming power - the benefit being constant or "regulated" brightness. Without the regulator, you demote the effectiveness of the capacitor as an energy storage device.