KDE 5215 435kv Coax MK Octo

Discussion in 'Cinestar 8' started by Ryan McMaster, Feb 15, 2015.

  1. Thijm le Grand

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    Right. Sounds fine.
    6s is ok for these motors. But not on 18" and this weight!
    What was the amp draw on 6s?
     
  2. Sam Fleishman

    Sam Fleishman Member

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    The amp draw on 6s was 120 I think. on 8s it was about the same because I was over propped I assume. Ill have to find the numbers I reordered everything in 1 file. The first 2 flights I did were just kinda to see if it would work.
     
  3. Sam Fleishman

    Sam Fleishman Member

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    thats funny you say that because everyone is flying these with 18s. I havent heard of anything less. KDE also says these egg cooking temps on the escs at 6s normal and within temp tolerances. on 8s its ice cold.
     
  4. Thijm le Grand

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    And there tow is?
     
  5. Sam Fleishman

    Sam Fleishman Member

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    tow? what is that?
     
  6. Thijm le Grand

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    Sorry. Take off weigth
     
  7. Sam Fleishman

    Sam Fleishman Member

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  8. Sam Fleishman

    Sam Fleishman Member

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    more like 17.3 actually about 38 pounds
     
  9. Sam Fleishman

    Sam Fleishman Member

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    using the power hungry pdb and wookong. This is a weight and power issue so the only wiring of concern would be the pdb the esc wires or the motor wires. I'm using whatever bullets came with the power hungry board. not sure the size.
    also the power hungry copper plates never get warm on 6s even though the escs and motors and wiring to the lipos do. On 8s Not even the lipo leads to and from the pdb were hot
     
  10. Thijm le Grand

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    I have seen that. But at cost of high amp usage!
     
  11. Sam Fleishman

    Sam Fleishman Member

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    what do you mean
     
  12. Thijm le Grand

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    There's a optimum for every motor. But after calculating the difference it will only safe 10Amps. not worth the hassle
     
  13. Sam Fleishman

    Sam Fleishman Member

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    so what do you think would be the best solution? throw another 10 amps worth of batteries on top?
     
  14. Sam Fleishman

    Sam Fleishman Member

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    are you using ecalc to determine that?
     
  15. Thijm le Grand

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    Difficult to say if flight times are the same with 6s@20A and 8s@17A.
    As Steve suggested > check temps on various components to start with. Esc, wires, connectors etc


    Specs from kde and ecalc. Not real world but doable.
     
  16. Sam Fleishman

    Sam Fleishman Member

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    Theres also going to a smaller prop. Did you calculate for 16" on 8s?
     
  17. Thijm le Grand

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    No. calc for 17,3kg with 6s and 18" versus a more efficient setup

    Whats weird is that the amp draw is 120A 2a/min but you get 4 min. I don't think this is a prop/motor problem. 14A in 4 minutes would be around 200A
     
  18. Howard Dapp

    Howard Dapp Active Member

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    I don't get it. Why are 75a controllers getting so hot when only 15-20 amps are being drawn? I have the same kde motors and 75a controllers that will soon be installed on a new copter that will prob weight in at 35lbs, I hope I don't experience the same heat issues.

    @Sam, check your ESC-to-power distro connectors, do they all mate snug? Are all the solders good? There must be a hidden issue somewhere
     
  19. Justin John

    Justin John Member

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    I am also experiencing poor flight times and looking for suggestions.

    I'm running a 2 x 10,000 MAH = 20,000 setup with 16 x 5 blades for our indoor tests and the corresponding numbers below.

    35.6 AUW 435's KDE's with 75 Amp ESC - 1.3 volts Draw during hover with a hover point of 35 %

    I'm getting about 5 minutes just during hover tests. Motor and ESC temps are around 40 Degrees Celsius

    Two Tips I can share

    - Only use Xoar or T-Motor blades - We tried foxtech and the voltage draw during hover is almost double. This made our ESC's and Motors Extremely hot.

    - KDE escs have pre tinned (soldered) ends - while bench testing each esc and motor we noticed the solder connections were not the best even if they felt strong. It had to do with the melting point of our solder vs the solder that came with the KDE's. It was hard to tell if they actually fused properly although the felt like it. We cut the ESC wires and re-soldered each ESC to Power Distro connection, this helped considerably for our bench testing.
     
  20. Howard Dapp

    Howard Dapp Active Member

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    Justin, have you tested larger props with your setup? I'm starting to think a lower kv and larger prop setup are the way to go to for flight time and efficiency for any setup weighing over 15kg.
     
    Dave King and Steve Maller like this.

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