Charging issues
Please do NOT depend on disconnecting a cable to "test."
First, what do you have for an alternator / and regulator?
Is this the "single field" connection 69/ earlier style?
Or the 70 / later isolated field "dual field" connections with the flat regulator?
Or some aftermarket etc? Denso, etc?
YOU MAY have put an isolated field unit on a 69 style system and may need to ground the extra field.
We need to know this before we can "guess" on anything