2001 Gas TXT Battery Charging Issue

[GFDevlin]

All,

Our 2001 Gas TXT seems to be draining the battery when running. Battery is recent (18mo) and fully charged is at 13v. Voltage across the red/black at the regulator is (now) looking good at medium idle at 14.5v UNTIL the lights are turned on, when it drops below 12v.

Lights and horn are direct wired to the battery as this cart never had them from factory. Confident with this circuit as I just replaced the wiring and fuse holder, but I can hear the engine rpm slow when the lights go on.

Just replaced the voltage regulator today after seeing bouncing voltage numbers (4-14v) at running RPM (read a similar posting). Got a steady 14.5v across the V/R after new until I hit the light switch and it dropped below 12v again.

The lights and horn are factory units installed after. They must be amp hogs. Anything I'm missing here?