If your running a three brush and cutout relay, The current regulating brush must be set at 2 amps to 4 amps depending on lighting load, your probably set at 2 amps.
On the voltage cut out relay check the contact tip surfaces, remove only high spots with a burnisher, then gap it to .020" 6.6V closing.6.3 to 6.8V
Ensure all electrical connections are tight
with DC bad or corroded connections can ruin your day.
this includes a worn contact bar on your ignition switch.