PowerBox Sensor Switch - Output Independence

  • Hi,


    I'm considering using a PowerBox Sensor switch to run two receivers, but want to understand what is truly meant by the outputs being fed from independent regulators.


    If I set up each input on a separate lipo and send output 1 to receiver 1 and output 2 to receiver 2 (ie completely separate systems) then, the condition I would like to protect myself from is if receiver 1 (or servos attached to it was to suddenly short circuit and produce a high current drain situation. Would the voltage on the other output (output 2) be protected, or would it be dragged down by the fault on receiver 1?


    Another way to describe the situation would be if the switch was set up with two separate lipos, but the outputs were connected to two separate resistors of 10 Ohms. This should result in both outputs having a voltage of 5.9v and a current of about 0.59A. As the resistance on one of the resistors is reduced lower than 1 Ohm, then the current on that output would exceed 5 Amps and the voltage would start to drop. But I need to understand if the voltage on the second output would be protected at 5.9v.?


    ...ie is it possible under high load conditions for the voltages on each output to be different, or are they common within the switch?


    Many Thanks


    David Bevan

  • Hello,

    the two outputs are of course connected inside. So a battery loss has no effect to both outputs.

    The outputs are not protected. If you short circuit them the output wires will get hot, same as the regulators. If you want to be safe against short circuit servos you have to use a Evolution or any other Powerbox with servos connected directly to the Powerbox

  • Thank you for clarifying this.


    I have an RB-20 that will disconnect (i.e. isolate from power) a servo if the current to that servo exceeds 10A. If I use a Dual Powerbox Sensor switch ( https://www.powerbox-systems.c…tems/powerbox-sensor.html ) to power the RB-20 then if a servo shorted (and so drew more than 10A) would the Powerbox Sensor switch be able to provide the 10A required to trigger the isolation of the servo?


    ...the spec sheet is a little confusing, as it says 2x4A in one place and then 12A in another, but also suggests this Amps can be exceeded?


    What is the maximum instantaneous (ie for less than 1 second) current that the Powerbox Switch can supply? (assuming it's connected to a power source capable of higher Amps)


    Many Thanks


    David Bevan

  • Hello,


    for 1 second it can more than 12A. They are using Polyfuses - they are very unreliable and are very inaccurate. Also with modern servos they may lockout at high current peaks from the servo.


    What model do you want to power with that?

  • It's for a 50cc warbird, I used to use a single futaba rx powering 10 analog hitec servos plugged straight into the rx for many years without problem, but for the past year have been using Frsky with my smaller models and am now considering converting my larger models.


    I think that analog servos are unlikely to draw anything close to 10A unless they have completely failed? So the accuracy of the fuse shouldn't be as much of a problem.


    ... My main concern was that the Powerbox Sensor would limit the current to 8A so wouldn't trip the fuse, but you have confirmed that it could briefly exceed this.


    Regards


    David Bevan

  • Thanks, do you mean it would be warm due to 10 servos? Most of the time only 5 servos are moving (aileron left and right and elevator left and right and throttle)


    I'll monitor total current via telemetry and keep a close eye on temp of the switch.


    Thanks for your help


    Regards


    David Bevan