This is for calibrating ADC(voltage) accuracy in factory or re-calibration after using for a long time.
Press & hold button for 2 seconds, it shows "CAL" & then flashing "Hi", apply stable "25.50V", then shot press button, wait for a flashing "Lo", apply stable"10.50V" , short press button and wait for it to finish.
if apply voltage is far away from ideal ref voltage, it shows "Err"
Heater target temperature: 50C / 120F
USB Charger Input: 3S-6S
USB Charger output: up to 2A
Low Voltage Cutoff voltages: 3S @ 10.5, 4S @ 14V, 5S @ 17.5, 6S @ 21V
Maximum voltage: 25.5V
Minimum voltage: 10.5V