[Blue Bowtie]

That's normal. Current flow will light the lamp, and it's due to more than just the alternator or ignition coil. The accessories are powered when the ignition is on. The alternator field is also energized, so if you didn't disconnect the two-wire field connector, that would be more current flow. Gauges and warning lamps are powered with the ignition on. As long as you don't park it overnight with the ignition on, the battery should maintain charge. You may want to have the battery load tested to be sure it is good, even though it is new.