12v with key on

Good approach. Sounds as though you don't have the ammeter in place either which is an issue with pulling power at factory starter relay location.

Nice panel and good for powering accessories, etc. Troubleshooting is so much easier when everything is in one spot!
Yeah I got tired of the wiring rats nest under my and engine compartment. Yes I have made the ammeter modification. By the way, running your regulator power from the relay eliminates the flickering headlight syndrome.