How long does the battery last?

The battery life is very dependent on what model BlueFly you have, how you use it, and how you have the audio settings configured. For models with a battery, you either have a 600mAh (v11 and earlier) or 750mAh (v12) battery. This is what consumes power:

  • The baseline power consumption is about 10mA for the processor and pressure sensor.
  • The bluetooth radio consumes about 25mA when it is connected, or if it goes to shutdown mode because you are not using it, then about 3mA
  • The onboard speaker is the the largest consumer of power.
    • When it is making continuous sound, at full volume, it is consuming about 95mA. This is what happens if the sink alarm is sounding.
    • The volume setting is roughly linearly proportional to the power consumption of the speaker. So if you change the setting from 1.000 to 0.500 then the speaker consumes about half as much power when making continuous sound. However, see the hardware settings manual for a description of the volume setting and how it relates to the actual sound. A volume setting of 0.100 is actually about half as loud as 1.000. So, you can save a lot of power by just reducing the volume a little. It is hard to tell the difference between a volume setting of 1.000 and 0.500 at your ear, but it only uses about half as much power on the BlueFly.
    • The audio buzzer consumes about 9 mA at full volume, or 5 mA at a volume setting of 0.500
  • The PA6H GPS consumes about 20mA GPS (25 mA before fix).

So, based on the default settings for the BlueFlyVario_Bluetooth_USB_v12, when connected to a phone and in normal flight conditions, the power consumption is about an average of 60mA. This means the 750 mAh battery will last for about 12 hours from a full charge. The calculation is:

  • 10 mA baseline + 25 mA bluetooth + 25 mA audio = 60mA. The 25 mA audio is based on:
    • When in lift your speaker is beeping and only making sound for 50% of the time. If your flight is in lift only about one third the time, and you have the sink alarm turn off, and no audio buzzer, at volume set at 1.000 then the power consumption from lift beeps is about 16 mA.
    • The sink alarm is set at -2.0m/s by default. If we assume that occurs about 10% of the time, then the average consumption from sink is about 9mA.

If you want to get super careful about saving power for the BlueFlyVario_Bluetooth_USB_v12, but you still want to connect via bluetooth and hear lift beeps and the audio buzzer. I suggest the following settings to change from the defaults:

  • Set liftThreshold to 0.1, and keep liftOffThreshold at 0.05.
  • Set sinkThreshold to 5.0 and sinkOffThreshold to 4.9. This will only sound the sink alarm in pretty serious sink.
  • Set useAudioBuzzer to true and buzzerThreshold to 0.5. This will make the audio buzzer come on at -0.4.
  • Set volume to 0.5 to see if it is still loud enough for you.

Based on similar assumptions for other BlueFly models you can calculate your own power consumption.