FlightLineRC P-38L Lightning Allied Green

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Battery voltage telemetry help

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  • Battery voltage telemetry help

    Hi everyone,
    I am getting back into RC flying. Things seem to change frequently. My question has to do with battery voltage. Essentially I want to monitor my flight battery on my transmitter display screen.. I will be getting a Spektrum NX 10. I am trying to figure out the best way to be able to monitor my battery while in flight so I don't drain it to far and kill It mid flight.
    I know spektrum has a couple different things, but I don't really understand how all it works.
    Any help would be greatly appreciated. Thank You.

  • #2
    Seeing battery voltage telemetry is nice but you have to understand what you're seeing. Any battery, while being heavily drawn from in flight will show a sag in voltage, sometimes near or below the voltage cutoff. This is normal and you shouldn't worry about it too much. You may even see an alarming sag right after take off or after a loop where you're using lots of throttle. I won't go into this any further as this can be another paragraph worth of explanations.
    If you are using a TX with telemetry capabilities, you'll need a RX that can send that information. Spektrum's new "smart" stuff (smart ESCs, smart batteries, telemetry RXs) can do this. Staying with Spektrum, you can also get Spektrum compatible equipment like the Admiral and Lemon brands of RXs and other such devices to send the information to your TX screen. Admiral has RXs that you can add a voltage measurement unit between the battery and the RX. Lemon has such RXs also. Lemon also can sell you a stand alone telemetry unit where the voltage sensor and other parameters can be added.
    You can also add stand alone devices that don't use the electronics telemetry. There is cheap little beepers that you can attach to the battery and on a fly by, it can beep loudly if the voltage is below a certain set value, telling to land on the next pass. There are also stand alone electronic devices that you can add where you have a receiver unit in your pocket that will beep or vibrate when voltage gets low. However, these things are limited in range and like the battery telemetry, you have to understand what it is that it's trying to tell you.
    Your best defense against running low on battery is to set a flight timer. Start with a conservatively low time. After you land and are back at the bench, immediately do a voltage check. From this information and based on how you flew the plane, you can adjust the time for the next flight. Continue to do this till you are confident that by the time you land, the battery is still in good shape. You will also understand that if you fly harder than usual, you need to land before the time is up and if you fly very gently, you can add a little time after the beeper goes off.