(FINAL Update )...Alternator voltage too high, question

Chassis battery sat for a month and you cranked over the engine and your voltage gauge showed 14.5 V? That is all entirely normal. I've measured some gas engines at the same voltage immediately after starting.

Run the engine and if your chassis battery is good, you should see the voltage gradually diminish to 13.5 V or so.

Mex may chime in to tell you exactly what that alternator is rated for.

You may want to confirm the accuracy of your gauge with a handheld meter. They can be off by a small amount.