power connection. Am I right?

Hi all! Am I correct doing this or should I not connect in parallel the batt for inputs and RX with the bat for outputs and fpv cam.

If I don't connect both batteries on parallel, I get only 5 mins of flight .When the battery supplying motor is at 20% the other supplying APM and recevier is at 96%. This is why I want to combine both to get more flight time.

power supply.jpg

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  • I have been looking at the diagram again. According to what you guys said, there is a big ground loop. Can someone point mme out where with an arroy or something??

    Anyway, maybe I did the diagram wrong but as you said BEC should be connected directly to the battery. Indeed they are. where it says "parallel Connector" is the type of XT60 that connects both batteries in parralel. Assuming I have 11.1V there, there is where I get the Vin for the Turnigy BEC. Then the Vout 5V is connected to the receiver. As the wires goes from the receiver to the Inputs of the APM this in turn gets 5V. Should i do it other way???

    In this case my cam and my transmitter works with 11.1V, whic I get from the Batt directly. And lastly, I get again 11.1V from the batt and I connect it the ESC/BEC. Motor gets the current he wants, and Then the BEC on the ESC gets my 5V to connect it to Output pins on the APM and get servos running with its power.

    I really appreciate your comments but I am still not knowing if its OK or not. Could you guys point me out how I should do it?

  • Guys,

    I found this http://copter.ardupilot.com/wiki/apm25board_overview/ . Although it is copter related, it seems to explain very well the different type of connection. As for my understanding and as you guys said, it seems that probably I should use one batt for outputs and one batt for receiver+APM+FPV. This is where I get lost, I mean, is it correct to use the same battery to power the BEC ( whic in turns power up the APM and RECEIVER ) and to power CAMERA and VTX whic runs on the 11.1V of this second batt?

  • I will test it today but I am almost 100% sure the grounds are connected, even with the jumper removed.

    I am flying a wing like the one on my avatar so, my question is then:

    if I want to run all the FPV gear, the APM, MINIMOSD, etc...and The motor and 2 servos of course, using a 4S battery for motor and a 3S for APM and FPV GEAR, which one should be the right way to connect everything up.

    Maybe the interference I amb having on my cam is due to all the things you guys are saying about ground loops. How can I avoid it?


  • Sorry when I said removed power supply pin. what I meant was jumper so, with it removed I have independent output and Input power connection. Under the fact that they must be powered independently, do you think there is still a ground loop? Anyway can somebody explain me what a ground loop is anyway because I google it and can see diagrams, formulas...but I need a much more simple way to understand it.

    Batteries are exactly the same so is like having a 4400maH 11.1v.

  • Im not sure what FPV gear you are running but I would make sure your have a nice clean filtered power source for your FPV gear...

    The fatsharks have their own filtered power supply that attaches to the balance plug... 

    running everything on one battery unfiltered (cheaper FPV gear) caused more interference than running 2 separate packs for me.

    With the filtered fatsharks I have seen no difference between  shared or separate batteries.

    Maybe you could run a MUCH smaller lipo for your FPV and apm (if you are only using 4% of the pack) and the decreased weight might give your MAIN pack more flight time from less load. 

    You should not have power lines running from the 7A bec to the receiver (did you mean power module?)

    My Octo used 2 identical batteries in parallel 

    @ Bill I believe he means, "JP1 jumper removed" by saying "removed power supply pin"

  • Developer

    You should only connect batteries in parallel if they are charged to the same voltage, same type (ie.3S) and are the same capacity (this last one is debatable, but lets keep it simple)

    Are you using Plane or Copter. I'm guessing Plane with only one motor shown.

    Are you using the Power Module?

    You either power your board from the Outputs rail with JP1 in place via the ESCs BEC or (by removing the 5V line from the servo cable) the 7A BEC.

    The receiver can be powered via the APM Inputs 5V line.

    The way your diagram looks you have a big ground loop, so not a good idea. I'm not sure what you mean by APM2.5 with removed power supply pin?

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