My Friends 1992 Oldsmobile RegencyElite Has New Battery, And Alternator Has Been Tested The Car Will Start And Go If Battery Charger Has Been On For A Bit. Other Than That It Won't Start?
Test battery voltage and alternator output voltage. Also check all battery connections and the frame and motor ground connections. If all this checks out ok then check starter connections. Possibly starter going bad and the extra voltage extra voltage from battery charger is needed to turn starter over. Have starter tested.