Deve, just sitting around watching a ball game and a thought hit me. If you were to put the big fuse on the down stream side of your amp meter (between the meter and battery), then if It popped you would only lose the charging circuit to the battery. It should be easy to spot as your amp meter needle would never move. Just a thought you understand
On the other questions...once the engine is started the alternator takes over the job of supplying electrical power to all running circuits plus bringing the battery back to a fully charged state, if possible. There are many ways to wire a amp meter incorrectly but only one way to wire it correctly.
