Wednesday, July 23, 2014

Power-Board - 2nd Circuit

On the forward-side of the Power-Board, there is a 2nd circuit. Notice the extra (usually red) wire is connected to PWM signal (white) wire of Fore-Port ESC.

After getting a LiPo and now powering-up Nova quad for the first time ... it seems like this circuit is for the Power-Board's independent, speaker-based, Low-Battery Voltage Alarm with progressive scale audio count-down (and lower lights flashing). Seems to activate around 10.6v. With quad on bench and not running motors a lot, the battery lasts quite a while.

Edit: It's about a month later now. With help from the RCGroups Forums, it seems the mystery of the Red-Wire is mostly solved. Seem this wire is either controlling the lower LED lights (soldered to bottom of ESCs) ... or at least causes them to flash during a Low-Voltage-Alarm event. In MP/Terminal - run Motor Test to see why I say that. Speaking of Motor Test, note that the testing order starts at Motor#1 and then proceeds Clockwise around the quad.

From what I can tell, there is no 12v-to-5v DC-DC converter on the ESCs to power the LEDs. I think the +5v for the LEDs might come from the Power-Board through the heavy gauge white wire on the ESC PCB Input edge. Voltage is only supplied when it deems it appropriate (see above paragraph) and that's how they light and/or flash.

 
 
 
 
It's just a casual observance (I have not removed board for close examination) but it looks like most of the "traces" or large electrical metal-plate surfaces on top of the PowerBoard are 11.1v Negative (GND), while most on bottom of board are 11.1v Positive.
 
Apparently, my HK LiPos are on the slow-boat-from-China. Went the LHS (HobbyTown) and picked up a Predator 11.1v 2200mah LiPo battery pack for $21. It's not the max. size or mah, but it works fine. It also had the wrong connector, so I soldered my first ever XT60. Set Soldering Station to 390c. Strip back wire insulation 1/8 inch. Pre-tin wires and don't forget heat-shrink. Use flux when soldering connector. A vice or helping-hands will come in handy. 
 
Trouble-Shooting:
 
Temporarily remove all your ESCs from the FC and reinstall DuPont one at a time. Supposedly, you can Arm when only 1 is connected. If you are getting 5v to the FC and RX (from BEC circuit) then the PowerBoard is ok. There are no active components between the ESCs and the battery's 12v.
 
I've since made this post with more info about power-system and ESCs. I also have a post about BEC.


9 comments:

  1. So on a non-standard ESC to use LED's you would:
    Connect single red wire to + (RED)
    Connect old (now unused) white wire to LED's?

    ReplyDelete
    Replies
    1. I think so. You can always test existing with voltmeter (and props removed). When LEDs light, you should read +5.
      http://quadcopter-robotics.blogspot.com/2014/10/nova-esc-and-body-repairs.html

      Delete
  2. hi where to you plug the power in to get power to the controller

    ReplyDelete
    Replies
    1. Power from BEC-5v goes to RX first, and then to Flight Controller. FC really gets its 5volts from CH-1 connection.

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  3. What's your suggestions to power LEDs from this board. 5 in 1 Damping Plate Power Distribution Board 5V 12V BEC Current/Voltage Sensor for Pixhawk / APM 2.6 Flight Controller
    http://s.aliexpress.com/RFRj6zM7
    (from AliExpress Android)

    ReplyDelete
    Replies
    1. I think that might work. However, if you are rebuilding a damaged one (still in Nova or CX-20 white body shell) ... I think the real Cheerson Power-Distribution-Board is a better choice.

      Delete
  4. Those 5V outputs are stabilised, so there is no voltage drop until the board completely shut off and LEDs should be all the time solid, no low voltage drop warning by starting to flash. Right?

    ReplyDelete
    Replies
    1. I have no experience with that particular PDB, but yes ... I think it would work as you say.

      Delete

The stupid spammers have now forced me to approve each Comment before it appears (but I am usually pretty quick about it).