MAVLink BATTERY_STATUS is decoded incorrectly #424
Description
On the attached log file from a recent development build of ArduPilot, the BATTERY_STATUS message is decoded and displayed incorrectly in the log viewer. The file was captured with QGroundControl.
It shows the id field as a constant NaN and the current_battery field as a constant 65535. Other fields within that message and other messages seem to decode properly but I didn't search thoroughly for problems. All the messages look fine and the fields change how I expect when decoding with pymavlink. The SYS_STATUS messages also have the correct battery values.