Hi guys !! Tech help needed

Discussion in 'Fast Electric Forum' started by Robert Dewater, Jul 25, 2019.

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  1. Jul 25, 2019 #1

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    I have a blackjack 24, has a traxxas vel. Bl in it. Seem fairly hot. Single 3s doing 45 - 50 mph, issue is after a decent run motor and esc stay fairly cool however wires and batt were very warm. ( hot )
    Why ?? Over proped ?? If so, how can i unload motor and retain current speeds without over loading system ...?
     
  2. Jul 25, 2019 #2

    MarkF

    MarkF

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    Your either running to long, meaning you can't run the batteries past 70% discharged or your packs are not up to the job. Are your packs old or a low C ?
     
  3. Jul 25, 2019 #3

    Robert Dewater

    Robert Dewater

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    No they are quite new.
    Wires and battery pk get very warm.
    Was running about 5 min or so.
    When on the throt hard it torques right a bit.
    Diff prop selection ??
     
  4. Jul 26, 2019 #4

    longballlumber

    longballlumber

    longballlumber

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    I think we need more information to help diagnose a suitable answer for you.

    What prop are you running now? is it balanced and sharpened?
    What is the capacity of the battery/s your running?
    What brand and C rating of battery are you using
    What size of connectors are you using on your motor and/or battery?
    You say 3S battery, but in what configuration 3S1P or 3S2p?
    How many mAh's are left in the battery after your stated 5min runtime?
    Have you shorten your battery and motor wires to a usable length?
     
  5. Jul 26, 2019 #5

    GraysonTaylor

    GraysonTaylor

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    If it's only the wires, smaller guage (bigger wire), or double up on them.
     
  6. Jul 26, 2019 #6

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    The pack used is 3S. 50C. The wires are of factory size.
    No clue of the amp draw is, but i can imagine its pretty high.
     
  7. Jul 27, 2019 #7

    GraysonTaylor

    GraysonTaylor

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    I was just thinking, if you double up on your wires, you may find the next weak link in your system. That could be expensive.
     
  8. Jul 27, 2019 #8

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    As far as running to long, i thought the esc had a cut off when a certain voltage was reached ???
     
  9. Jul 27, 2019 #9

    DickJones

    DickJones

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    Robert,
     
  10. Jul 27, 2019 #10

    DickJones

    DickJones

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    Since most of the go fast electric boats, come with, to big of a prop, blade, area wise, from, the manufacturer, the best way to get rid of the hydroscopic affect, if U turn your boat, bottom up, at about a 25 degree angle, nose up, pour some water on the bottom center of the hull, U will see the hydroscopic affect, as the water runs down the in a group affect, on the hull, the water does not want to let go of the hull, which equals, excessive drag. I use 3x3, flat block of wood, using 1500, water proof sand paper, I start sanding on the bottom surfaces, keeping the sanding paper tight, on the sanding block, changing the sanding paper often, with new sheets of sanding paper. When glaze, on the bottom is alllllllll gone, switch to 2000 grit sand paper, and go over all of the bottom of the hull again, after U have done the bottom, with2000, I go to 3000 grit, for the final sanding over all of the bottom of the hull. This procedure, when done correctly, (lots of time) should add, 5 to 10 miles per hour. TRY, the factory prop and see how is accelerates, and drives thru the corners.
    On all my boats, I put smaller blades on, with less area, but more pitch, on the blade tips.
    I wrote a lot about this, hope I haven't con fused U, if U have any questions, send me a message
     
  11. Jul 27, 2019 #11

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    Heres the thing. The motor is NOT stock for this boat.
    When i get on it a bit, it will torque n twits a bit to the right. So im not sure
     
  12. Jul 27, 2019 #12

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    Ok. Was just looking and the speed control wires are factory length.
    It is a turnigy marine 120 amp
    Motor is a traxxas. Velineon if makes any diff
     
  13. Jul 28, 2019 #13

    MarkF

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    I will say 5 minutes is a long time. My electric boats run for 2 to 3 minutes max. For 5 minutes you would have to have a mild set up. Also your packs should be 3.8 volts per cell when your done. 3.75 or lower is too low for an electric boat. The heat in the batteries happens during that last minute of run time when you run for too long.
     
  14. Jul 29, 2019 #14

    Robert Dewater

    Robert Dewater

    Robert Dewater

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    Gotcha !! Now. How would i program
    A turnagy 120 amp marine for cut off ??
     
  15. Jul 30, 2019 #15

    MarkF

    MarkF

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    I don't know. I never trusted cut offs to work correctly. I race so I'm use to making 7 or 8 laps for a race. So when I practice I just do 7 imaginary laps and bring it in. You can use a timer to but you need to experiment with how long you can run. Maybe shoot for 3 minutes and then see where your batteries are at and adjust accordingly.
     
  16. Aug 2, 2019 #16

    darryl whitman

    darryl whitman

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    what are you using to connect battery to ESC .I use 6mm bullets, that will help
     
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  17. Aug 3, 2019 #17

    Robert Dewater

    Robert Dewater

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    MOST likely i ran too long.
     
  18. Aug 4, 2019 #18

    Michael Ehrhart

    Michael Ehrhart

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    xt90’s work very good and are easy to soder
     
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  19. Sep 10, 2019 #19

    David Ashcroft

    David Ashcroft

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    Dick I sand all my hulls nitro/ gas with 300grit and although It certainly helps to take away drag,,however a 10mph increase is a lot.
     
    Last edited: Sep 10, 2019

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