You need to recharge it manually with the battery charger. Turn off the power switch and plug in the battery charger into an AC outlet and insert wire terminal into the power jack which is located next to the on/off switch. It is similar to the way you recharge your cell phone. The POWER green light will flash during charging, and will become a steady green once the battery is fully charged. The LOWER BATT CHARGE red light will come on with a buzzing noise to indicate that the battery should be recharged. It will take about 2 to 2 1/2 hours to fully recharge the battery. The battery will not be over-charged if AC charger remains connected after battery recharging is complete.