FrSky ETHOS Charge while Flying \ Normal Operation and Spare Battery Caution 

Unplugging and replugging the battery from the ETHOS radio systems can be a bit of a risk of accidentally reversing or breaking off the connector.
You can use a cellphone battery bank to charge the radio while it can still operate normally.
The charging will be a bit slower than if you have it turned off while charging (of course), and it is recommended to use a minimum 2A or 3A charger, otherwise there may not be sufficient current to charge it while using it.