This was on our Pearson, Sabre, and J/Boat.
On our J/Boat we have two alternators both integrated voltage regulators (on the 55 Amp "standard" alternator) and external smart regulators for the Balmar. The smaller runs the engine "start" battery; and the larger is for the house bank. We've switch regulators, first for the Heart interface, and now a different external regulator on the house banks; so,
I would guess that your fingers on the key is not the key to your problem.