A Littmann model 3100 or model 3200 stethoscope battery will last for approximately 60 hours of continuous use. (Depending on Bluetooth® usage, you may experience a shorter battery life with model 3200.) Before the battery is depleted completely, you will hear a warning tone that the battery has only two more hours of continuous use. The life of the battery is being conserved if you are seeing the Littmann® logo; you are in standby mode. To enter active mode, tap on the diaphragm or push a button. To turn off the stethoscope, either do nothing (the stethoscope will power off after a period of time that is based on the POWER setting) or push the power button for two seconds (preferred).
There are several options to maximize battery life:
1. Minimizing backlight display time will conserve battery life. Select Menu > BACKLITE and then select either DISABLE or ON DMND (on demand). DISABLE will completely disable the backlight at all times. With ON DMND, the backlight will only activate after pressing the power button. If you feel the backlight is necessary in order to read the display screen, simply select Menu > BACKLITE > ALWAYS. This will activate the backlight at half power to provide visual assistance, yet minimize power consumption.
2. Ensuring that the Auto On / Auto Off feature is enabled (should be by default) will preserve battery life. This feature can be customized to allow for different periods of time before entering standby mode. To optimize the battery life, select Menu > POWER > LOW. This will program the stethoscope to enter standby after 10 seconds of inactivity.
Sound quality remains constant even on low battery. The electronic stethoscope will not work without a battery.