Alternator Pulse

Sooo, I replaced my old round back alternator that died with a squareback dual field I had (not sure of amps). I grounded one of the fields with a metal washer and ran a heavy wire to the large post on the battery relay, but now when I start the car the interior lights are pulsing. What’s causing it to pulse like this? Did I miss something?

Thanks in advance to the electrical wizards