I would change the voltage regulator . Also in the console you have bulbs that light up the dials ,, the row of bulbs on the bottom have to tell you all is working right . Can you see the charging light bulb as you switch on the key ?. without starting the engine .No charging light,, then its just a bulb replacment you need to do . If the bulb for the charging sequence is not iluminated it breakes the charge up citcuit . . And without the bulb in place battery will go flat .