X8 (Quad x2) PDB Design Question for an X8 build.

Hello folks,

Just wondering if this method of wiring 2 quad pdb's together will be effective to work as a pdb for an X8. 

I should note that I will be wiring them without (+/-) connectors, so Esc's direct to pdb and also that I may mount the pdb's in a stack formation in order to save space but thats not for certain yet. Also the power will enter the one pdb on top and exit to the second pdb out the bottom so as to limit the amount of build in wires entering a single ring hole on one side of the primary pdb. Finally I will run one single (+/-) apm wire to pixhawk from primary pdb I simply have the wires from the secondary to the same holes in order to link everything up sorta speak ground wise ect... I may be wrong though however and this jumper link is not needed, with the 4 wire signal cables form each pdb to the pixhawk. Thanks in Advance!3691186151?profile=original

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  • Hi Craig P. My name is Chad L. I am very curious as to whether or not you ever actually built your X8+ using 2 PDB's or if you ended up buying a different (8 motor compatible) power distribution board? I ordered a DIY quad kit plus the extra motors and ESC's to build an X8 but I'm a bit stumped about how to do it correctly since (to my knowledge) 3DR doesn't sell the one used in their RTF X8's. I do have an extra 3DR quad PDB so I was considering doing exactly what your diagram shows. Thanks for any info. Sincerely, Chad

    • Hi Chad I did finish building my X8, and actually just finishing my camera mount for a canon s100,

      I couldn't find a PDB for an 8 motor setup that had all the esc pins ect... so I did end up using the diagram above with a few minor changes.

      1) I did not bridge the 5v power/negative from the secondary board to the primary board, but rather simply just connecting the primary boards 5v+/- cable to the pixhawk, I made this change as the pixhawk only requires the one cable for power so I concluded that it wasn't necessary to bridge (I could be wrong as I have no actually flown the X8 yet).

      2) I did end up stacking the pdb's using small nylon spacers that came with the pdb's, to simply separate them enough to solder the bottom motors to the bottom (secondary board). This also made it possible to know which motors are which (in my case all bottom motors on bottom board). I don't have any connectors in any of my setup in order to save weight and room so my esc's are soldered +/- cable direct to pdb's. 

      3) I then soldered the XT-60 modules to the Bottom board but extending the wires through the holes reaching to the top board, soldering each wire to their respective holes (bottom board) creating a sort of wire extensions to power the top board (I also soldered the extensions to make them completely solid), then placing hot glue over all connections to avoid loosening.

      4) Finally, I placed the Top (primary) board on the separators lining up the power +/- extensions from the bottom, then using nylon bolt to bolt top board down. Then solder extensions +/- in their respective holes finishing the main power supply to each board, then last but not least top motors are soldered to top board, arrange signal wires in proper oder in 2 quad servo cables, glue top board to secure connections, and finally plug into pixhawk...

      I did power up my X8 and the pixhawk powered up no problem so all seems well in that respect, I'm just currently trying to figure out if I can swap out xjt modules in order to switch from my X8 or my Y6 as they both have X8R modules and I would like to control each from my Turnigy 9XR, but am simply not sure as to wether the XJT module syncs with the X8R or if its the Turnigy 9XR itself that syncs also thus requiring me to resync each time I switch XJT modules....or better yet is there a way to sync one XJT to 2 X8R modules and simply switch between modules in the software?......Seems to be a question no one would like to answer unfortunately.... 

      Hope this helps.

      Craig P.

      • I am not sure about that Craig. I've done some digging and I think they should work together. I use a Spektrum DX8 with an AR8000 but I ditched the base receiver so my setup is quite different. I will do some digging and try to get back to you as I have a current build that I'm doing for a client that requires me to brush up on Transmitter Receiver combos as he's leaning towards Turnigy or FrSky's Taranus. I noticed while price searching for both online that the "Pro" version's of both are available. I will know more soon. As for my X8 conversion (from 3DR Quad kit), I'm going to solder two boards together tonight to connect it all and I will be doing it the same way you have, just linking up the mail power and ground wires, then connecting everything else as usual. Only 1 auxiliary power supply should be needed on the Pixhawk. I will just leave the other there in case I need to run lower voltage to a camera or video TX instead of the PX4. As for the original, XT-60 from the (top) or primary PBD, I will simply cut it off and soldier directly to the other "nubs" sticking through the secondary PBD. Each is already wired to power and control (through ESC's) a quad setup and the Pixhawk has ports 1-8 for up to 8 motors to operate given that the correct firmware is uploaded from Mission Planner (or in my case APM Planner 2.0 for Mac). I think basically we have done the same thing, just described it differently. I'm probably not going to directly stack them (using plastic spaces) like you have since that would make the whole thing too thick to fit in the factory 3DR Quad/X8 body kit. I will likely leave 3 or 4 inches of main power +/- wire (red and black) between the two boards to allow for more of an X X layout since all of the wires connecting to ESC's are all plenty long. Anyway, I will get back when I know more about the other Transmitter/Receiver combo compatibility. Please let me know if your "2X3DR Quad PDB combination to convert to "X8" config worked before I go all in and commit ;) Thanks! -Chad L. 

        • Hi Chad,

          From what I have learned from another site, that it is believed that the sync protocol stores within the module itself (XJT) so essentially I should be able to swap out modules syncing one module to one X8R, although I have not had an opportunity to test this out yet, since it's the end of the university semester things are a little crazy around here so time has been very limited (haven't even had time to test out my new Iris+ since I picked it up a few months back). I'm hoping to try it out in the next week and go from there, so I will let you know how it works out.

          For the PDB's It actually wasn't to snug at all using the spacers...at first I thought this may be the case but the orientation of the +/- pads were side by side for each esc so using a hot glue gun I covered all connections to for piece of mind.  I also cut all wires to fit (with some play for movement of arms ect...) just to clean things up inside, so there's definitely no worries about it sitting with the standard quad frame with some minimal room (if i get around to it i'll take some photos of the finished setup).

          So far everything powers up and all so it would seem to work, but now that the snows almost gone finally it will be a lot easier to get out flying, and test the functioning out.

          As for the video power, I know jDrones sells a voltage step down chip, I myself use a 3s lipo on my Y6b and the Iris+ does also, so I simply run a cable direct from the pdb mains that has a servo cable end so I can easily connect my video transmitter from drone to drone without resolidering a connection each time. For the X8 I'm using the same size motors as the Y6B (850kv I believe) in order to save energy and I also don't require the added payload ability, so I have not decided on a Lipo yet but if I do end up with a 4s I will definitely go the voltage step down route.

          I'm also a mac user (I don't get along well with windows), so APM planner 2.0 is also what I use, although I wish it was updated adding new features like offline map cache ect..., but I'm ok with it for now. I would prefer to use iOS devices but as of yet that ain't possible (until the SOLO comes out but that will be limited to the SOLO itself so for all intensive purpose not much use for my other drones), so for field work I use an android tablet, but it still doesn't compare to iOS. 

          Craig P.

          • Check out this link :)  http://fightingwalrus.com/ I just made your day ;)

            • Hi Chad,

              Thanks for the link! I've actually came across this before. I'm just not sold on their software and very hesitant on the hardware (I think its only good for half a mile? I could be wrong on this)

              I'm hoping they come out with either A. a lightning cable and port Tower to iOS or B. come out with a new 3DR telemetry that allows for me to connect via bluetooth or something to the telemetry for control from my iOS device (Bluetooth to Telemetry to Telemetry) (or worst case a small bluetooth chip that connects to the current telemetry allow for control) unlike the current bluetooth system they sell that allows for a connection between to bluetooth chips to relay data.

              But I think I may be hoping for a lot, since the solo was just released which virtually offers this solution and much more....

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