Some Hitec transmitters have poorly calibrated voltage display and/or low voltage warning. Both of my radios were reading high on their voltage display, giving an overly optimistic view of battery state. There is a separate adjustment trimpot on the circuit board for Display Voltage (upper trimpot) and Low Voltage alarm (lower trimpot). You need a thin flat-bladed screwdriver to adjust these trimpots.

• Display Voltage . Connect an accurate voltmeter onto the battery contacts, and slowly turn the DV trimpot until the radio's LCD display matches your meter's readout.

• Alarm Voltage . Turn on the radio (aerial extended) and wait until the front-panel display drops to 9.2V. This may take a while if the battery was fully charged! Then adjust the AV trimpot until the buzzer just sounds.