For those with smaller, weight critical aircraft FrSky have released the Mini Lipo Voltage Sensor w/ Smartport, a mini version of the FLVSS and designed to collect battery data which can be transmitted via the smart port of telemetry-enabled receivers such as X8R, X6R, X4R, etc to a Taranis transmitter 

By removing the OLED screen from the original FLVSS and reconfiguring the remaining circuit FrSky has managed to reduce the size and weight of the original by almost 50% which is ideal for smaller aircraft models. The functionality of the MLVSS is identical to that of the FLVSS except that you cannot connect two of these in series to measure voltages in excess of 25V (6s). 

Specifications

• Dimensions: 43 x 19 x 8mm
• Weight: 2.8g
• Voltage Range: 2s - 6s (6 - 25V)
• Power Consumption: 10mA 
• Operating Temperature: -10 - 70°C 
• Compatibility: Smart Port enabled receivers

Note - No reverse voltage protection.