Will this be ok to fly???

  • Hello Powerbox


    I recently purchased a Mercury SRS (no gps) from a good friend which he never used.


    Before he gave it to me, he told me that when setting up the Mercury in a model, with the unit on its own ( no switch, no OLED, no RX, nothing connected) he accidentally connected one 3S lipo to one of the ports to measure the length of the battery cable when setting up the model. The unit was never turned ON as nothing was connected. As he said, he heard a noise and tiny spark on the Mercury MPX connector thinking that it was probably the battery as sometimes they do funny noises when connecting to a model.


    He realised afterwards that he mistakenly connected a 3S... shortly after he put together the unit with a 2S lipo, the Mercury worked fine, RX connection is ok on both ports, servos move and as per the OLED voltage is being regulated.


    I am a bit worry as although it works on the standl, will this be ok to fly?, will the regulators be ok inside?, I am putting a new model and don't want to burn any servos or even worse a crash while in mid air cos of the Mercury failing in the future.


    :/


    Not sure what to do.


    Any feedback will be appreciated.

  • Hello,

    hard to estimate... if there was a Spark and a noise it was the overvoltage supressor diode. This has no function in the regular operation.

    Where are you from - maybe we should check the unit here

  • Hi Richard


    Is the diode first thing inline in the input voltage circuit before it goes to the rest of the components inside to protect the unit from overloads?

    I just want t one 100% sure this unit will work ok in the future, going onto an expensive model, sending it via post wouldn’t be a problem although with the covid19 circumstances, not sure how reliable are couriers nowadays. I am from Spain.


    thanks!

  • Hello,

    no the Diode clamps overvoltage down to ground.


    From Spain it should arrive. We are here!

    Hi Richard


    So I pressume the reason for the PB Mercury to have x2 voltage suppression diodes is to suppress all spike overvoltages above its breakdown voltage, but why are these installed in the first place, in case of spike voltages coming from 2S lipos when in operation? - can any spikes occur from a fully charge 8.4v 2S?


    As the Mercury SRS seems to work fine I guess the diode (on whatever battery port) clamped down the overvoltage of the 3S LiPo successfully? - I asked my friend when he did that, and the 3S lipo he used was on voltage storage so assuming this, it is very likely that the diode didn’t fail and that protected the entire circuit from burning down? - and so will the suppression diode still work?


    Sorry for so many technical questions!, I am trying to understand and analyse the situation.


    Thanks!

  • Hello,

    yes it is also necessary at the input as there can occur overvoltage spike from a 2S battery it the moment of connection (inductive feedback from circuit). It for circuit protection.

    With a 3S the Diode will get quickly hot and may die. But as said: not necessary for regular function

  • Hello,

    yes it is also necessary at the input as there can occur overvoltage spike from a 2S battery it the moment of connection (inductive feedback from circuit). It for circuit protection.

    With a 3S the Diode will get quickly hot and may die. But as said: not necessary for regular function

    Thanks Richard


    I am just trying to figure out if it’s worth sending the unit to Power box or not as I am setting up a model these days and it would be a pain to send it to Germany, long wait and shipping costs are not cheap.


    Although not necessary for regular function, having this protection is obviously a good thing as I wouldnt want to fry the board in the future if a voltage spike occurs connecting the batts? Hence why I asked if the diode on that input would still be operational, I guess there are no tests that I could do to find out?

  • Hello,

    no tests - I would say as long as the regulators give out 5.9V you are good to go.

    Yeah, I am running 7.4v on all electronics. And seems to be fine although I wanted to ask, is it normal that when using 2S batteries fully charged, the voltage is regulated to 7.40v but as the battery drains, the regulated output voltage decreases over time?