I would use the MAN (manual) setting for NiMh instead of the AUT )automatic). In manual mode you press the right button and the amperage flashes and pressing the middle two buttons increases or decreases the value. Set the amp value to 1/2C. For your 1500 and 3000 it would be 0.8amps and 1.5amps respectively. Connect the pack and press and hold the right button and it will start charging. When the pack is peaked /full the charger will beep and END the charge.