Here is the link to HobbyKing's dual voltage display OSD (US$ 12):
http://www.hobbyking.com/hobbyking/stor ... E_OSD.htmlBut it only supports 2s and 3s...
You COULD hook up a current sensor from Flytron (they have 50Afor US$15.00, and 100A for US$17.90)
http://www.flytron.com/sensors/64-ultra ... ensor.htmlto the secondary voltage input, as it scales the current draw into a voltage equivalent.
the 100A version: 1 volt output equals 20 Amper current
the 50A version: 1 volt output equals 10 Amper current (=better choice for most people).
For US$27 (plus shipping) you can have
- voltage main battery
- momentary current draw (displayed as voltage equivalent)
Not bad!?