In my experience, a partially charged Oudie should never be connected to the S80 (S7,S8,S10,S100)and allowed to charge through the vario. It does draw too much power to charge it. You are better off to charge it at home and install it fully charged.

The other option is to install the Oudie power and data cable to take power from the 12V system directly to the (through the 5V converter)Oudie and the NMEA signal from the vario.