first off if your amp meter needle is not moving you have a dead battery or an open in the amp meter...it does not require the generator for it to show discharge, but will working generator/regulator needed to show charging....with the battery connected and the lights on the meter should indicate a heavy discharge....disconnecting a battery lead for quick test can confirm some output of the generator but is just that a quick test, proper diagnostics need to put forth to pin point any generator issues and these should be done in proper sequence. The factory book will easily walk you through this. You will need to determine a number of factors as right before assuming anything is wrong...battery, wiring, generator, regulator, fan belt etc etc.