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Moebius Skipjack

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  • Bob Gato
    replied
    Man I am sorry-when you said you " burnt up two ESCs" my head jumped to twin motors-the diodes wouldn't come into play on a single-it really sounds like it might be a "big Prop" mismatch with the motor or very long leads from the battery to the ESC.(Ron van Sommeren from over in RCG has done a lot of writing on the water hammer type effect of long supply leads and the slow death of model ESCs)
    https://www.rcgroups.com/forums/show...ns-workarounds
    Please feel free to PM me if you want as not to hijack Ken's thread.
    Last edited by Bob Gato; Today, 08:10 AM.

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  • Das Boot
    replied
    Thanks, Bob. What I don't get is I was using a 15 amp ESC then a 40. Both would work, get hot, stop and work again. I imagine it's the thermal SCRAM, but I don't know why. I never ran it full bore. Read your post. I've used diodes countless times to incur voltage drops in ham radio gear, especially the old Heathkit stuff. That's all we used until the surface mount stuff came out.
    Last edited by Das Boot; Yesterday, 09:45 PM.

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  • Bob Gato
    replied
    Casey-this might help- I use it on my Mark V and I can access 10 amps combined from both ESCs at the same time. I came up with this a few years back-it also keeps my radio running if one side fuse blows. https://www.rcgroups.com/forums/show...-Diodes-anyone

    Leave a comment:


  • Das Boot
    replied
    Originally posted by SubHuman View Post
    https://m.youtube.com/watch?v=qrXxNlTTYKI

    this video outlines what a BEC is and why a lot of people like them versus using the built-in BEC in many speed controllers.

    Bob
    Well hell, that may be why I've burned up 2 ESC's in that fishing boat. That's probably the only one of your video's I haven't watched.
    Last edited by Das Boot; Yesterday, 08:09 PM.

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  • Bob Gato
    replied
    LOL Sorry man!!

    Great video-tells all! If you are still on the hunt for a UBEC, I wonder if you could use a buck converter-I use them for accessories-they'll take up to 40 volts and hold it at your setting at least 1.3 volts below the input voltage regardless of changes in input voltage-they are quite cheap...and small. I've bought them for as low as 10 units for $7...dial in the voltage and it just stays and it doesn't waste power as heat. These are 3amps at $4 each-but if you shop around you can do better . https://www.amazon.com/LM2596-Conver...a-754523673785


    Click image for larger version  Name:	614cOQRcjqL._AC_SL1000_.jpg Views:	0 Size:	72.6 KB ID:	149962
    Last edited by Bob Gato; Today, 07:08 AM.

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  • Ken_NJ
    replied
    Good thought Bob. Tried your suggestion, it was actually worse.

    Made a video to show everyone the problem. The stuttering may not be a big deal, I don't like it. I may just not use a BEC and stick to the ESC BEC. As you can see at the end of the video, the current draw is 230ma which the ESC BEC can handle.

    https://youtu.be/94mP_PZ43fQ

    Why is my video not embedding here?

    Leave a comment:


  • Bob Gato
    replied
    Ken just for s's and g's... Try disconnecting the black wire to your ESC from the radio also.. and just leave the signal wire connected you could be getting something trying to find a ground/back feed through the m-tronics ESC... The ESC and radio already have power and ground without that black wire... So they should not need it anyway-just a thought-BG
    Last edited by Bob Gato; Yesterday, 04:30 PM.

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  • Ken_NJ
    replied
    Casey, Bob covers everything as to why using one in the video. The ESC I am using has an output of 1.2 amps. In my testing, with as many things working, running that I could, I measured 0.5 - 0.7 amps drawn from the BEC. So adding a BEC with an output of 3 amps ensures I wouldn't be overtaxing the ESC BEC.

    But, in my setup, the ESC-motor is getting noise from the two BEC's that I tried so far. According to Mtroniks I need to use a opto-isolater that they sell. Can't find it in the US and it's costly to ship it across the pond. This week I'll be trying to add additional caps to the motor to see if the problem clears up. If that doesn't work then may go back to the ESC BEC and not use a dedicated BEC. Or will have to go for another ESC.

    Leave a comment:


  • SubHuman
    replied
    https://m.youtube.com/watch?v=qrXxNlTTYKI

    this video outlines what a BEC is and why a lot of people like them versus using the built-in BEC in many speed controllers.

    Bob

    Leave a comment:


  • Das Boot
    replied

    New diagram/layout....
    Click image for larger version Name:	Skipjack diagram.jpg Views:	0 Size:	83.6 KB ID:	146954[/QUOTE]

    Ken, I'm missing something. I see you have a BEC from the battery going into the receiver for power. Don't all modern ESC's have a built in BEC? I just plug my ESC into channel 3 on my targets receiver. Is this just extra protection or a power issue? Forgive my ignorance.
    Casey
    Last edited by Das Boot; Yesterday, 12:08 AM.

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  • Ken_NJ
    replied
    Plenty of waterproof ESC's with 3amp output. Brushed and brushless.

    https://www.amazon.com/ESC-Boat/s?k=ESC+for+Boat

    Leave a comment:


  • Bob Gato
    replied
    Oh pleeze! I have heard this from Mtroniks many times-Every body drinks the Kool-aid I don't know why anyone talks so highly of Mtroniks! All the other (cheap) ESCs can tolerate a noisey BEC!

    It would be cheaper to buy a new ESC!!

    Leave a comment:


  • Ken_NJ
    replied
    Email from Paul at Mtroniks...

    It sounds like the BEC you are trying to use is a switching BEC? These are very noisy electrically and could be causing a lot of interference with the control signals to the motors. Evidence for this is that the system works ok when running on batteries.

    We would recommend you use the following, one on each speed controller. These opto-isolators cut all noise and leave a crisp signal for the speed controllers.

    https://www.mtroniks.net/prod/RC-Accessories/ZGM.htm
    In a quick search did not find that ZGM anywhere in the US. Cost with shipping from overseas is about $55. Not worth it. I'll keep looking for one here. In the meantime will look at what I have on hand for an ESC to try out and look for something other than the Mtroniks brand. Any other ideas?
    Last edited by Ken_NJ; 05-13-2021, 10:48 AM.

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  • Ken_NJ
    replied
    I'll have to check the the spare parts box. I probably do.

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  • Bob Gato
    replied
    In the mean time.. do you have a spare brushed ESC-like a $15 hobby king 45amp crawler unit..to try and see if its an Mtroniks problem or something else?

    Leave a comment:

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