RT-880 / How to calibrate the battery.
Added 2025-10-09 09:39:02 +0000 UTCCharge battery fully. I.E. FULLY CHARGED
Open the Main Menu.
Select 'Calibration'
Adjust 'Batt V Cal' until the reading in the Extra Info area shows '8.4V'
Adjust 'Batt Full' to the same ADC value as shown in the Extra Info area.
Allow the battery to drain to what you consider to be almost flat.
Open the Main Menu.
Select 'Calibration'
Adjust 'Batt Flat' to the same ADC value as shown in the Extra Info area.
Note: Battery nominal voltage and fully charged voltage are different. The battery's nominal voltage is 7.4V and that is what is written on it. But fully charged, the voltage of the battery is 8.4V .
As a general rule
8.4V is fully charged
6.0V is typically considered discharged
However, you might want to up the lower limit, all of this is up to you, NOT ME!
Comments
As I suspected, the fully charged (8.4V) level is pretty consistent. But flat is wildly variable, likely down to cell differences in the battery packs. Some cells may perform down to 3.0V or lower but others may flake out higher than that. My original ADC 'flat' estimate of 553 that got put as a default was way too low. Further releases will be using a more sensible 1100 for flat. Thanks to all for posting real world data for me.
Marcus Dudley
2025-10-12 09:11:08 +0000 UTCFull: 1435 - Flat: 870
IK2XRO
2025-10-11 13:35:05 +0000 UTC
