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  1. #1
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    Mamba monster bec dead?

    Today I finished some upgrades and ran about 10 feet before my esc quietly died. I read about the bec failing and tried hooking up the external battery and removing the red receiver wire. It did not work. If I leave the red receiver wire in and hook it all up with an external bec battery, then the esc and motor run off the 6v receiver battery (tries to, goes super slow). Then if I attach the lipo battery things run like normal. I should add that it now makes no beeps. When the esc switch is off the esc still runs the motor but stops and flashes yellow and free after a few feet. If the power switch is on then it runs like normal except no beeps. Anyone have any insight as to what's going on? Should I leave the red wire in and hook up a on/off switch the the external receiver batt?


    Chris

  2. #2
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    So, you're attaching another battery to power up the external BEC? If I understand you correctly, the presumably smaller battery to run your external BEC will not be powerful enough to run the ESC. Have you tried to wire your BEC to the ESC power wires?

    When using an external BEC to power you radio / servos, you'll have to disconnect the ESC's Red 5V line. This way, the ESC's internal BEC will not conflict with the voltage that the external BEC is providing to your receiver.

    The first time I plugged everything together I was a bit surprised that the fans and servos started to come to life even though the ESC was off, which is normal in this case.

  3. #3
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    Sorry, there is no external bec, just connecting the 6v battery to the receiver.

  4. #4
    RC Turnbuckle Jr.
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    Have you tried unplugging the servos?

  5. #5
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    Or do I need an external bec instead of doing it this way? It seems to be fine if I hook up a switch to the 6v battery going to the receiver. And just make sure the lipo is plugged in before switching it on.

    Quote Originally Posted by 50togo View Post
    Have you tried unplugging the servos?
    Trying it right now and doesn't seem to help anything. Do you think that might be causing the esc to not power up regularly ?

    The 6v receiver battery I am using is out of my revo 2.5. It seems to run down super fast though. It might have been because I tried running the entire esc/motor off it for a min while testing.
    Last edited by cooleocool; 02-09-2013 at 06:02 PM. Reason: post merge

  6. #6
    RC Turnbuckle Jr.
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    It has been known to cause similar problems but your bec might be toast

  7. #7
    RC Turnbuckle Jr. 87 GN's Avatar
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    What batts are you running?? not the 6v

    The red wire has to be plugged in, you only disable the red wire if you have an External BEC...
    Would you go flip my truck back over??

  8. #8
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    The lipo are 2 3s 5000mah 25c traxxas. The fan seems to reach very high rpm with this 6v receiver battery attached. Do you think this will cause problems? With an external bec I'd still need a battery in addition to the lipos, correct?

  9. #9
    RC Turnbuckle Jr.
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    No the bec gets its power from the lipos

  10. #10
    RC Turnbuckle Jr. 87 GN's Avatar
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    Do you have Castle Link or a field card, hook up the ESC & tell us if it will link up....

    Do you have an EXT BEC??

    links are of my Revo but same non the less

    BEC
    http://traxxas.com/forums/showthread...=1#post5394611

    MM2 but solder on Ext BEC pic #5 & #6
    http://traxxas.com/forums/showthread...=1#post5400879


    Just because, do you still have the on/off switch, might need to by pass the switch.


    can you get some pic, how are you hooking up the 6v to the Receiver??
    Last edited by 87 GN; 02-09-2013 at 12:53 AM.
    Would you go flip my truck back over??

  11. #11
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    The esc won't link to castle link. The link gets hot like they say it will with a dead bec. I don't have an ext bec right now but will consider getting one if I can go back to just lipos. I had been plugging the 6v (5cell) receiver battery just into the batt/ch5 port on the receiver.

    I just went and got the castle 6a bec and hooked it up. It is still acting the same way. The esc won't power on at all u less the red wire is hooked up to the receiver. If I disconnect the red wire like it says to do, the receiver powers up fine but no power at all to the esc. It seems like the esc needs to have a charge coming in through the receiver wire in order to work? I guess I may just have to leave the red wire in. Also the power switch on the esc doesn't turn it on of off, just when the switch is off, the esc quickly goes to flashing yellow and green after driving a few feet.

    Red wire is supposed to be the middle one right? Got this thing used and you never know when previous owner could have messed with.
    Last edited by cooleocool; 02-09-2013 at 06:04 PM. Reason: post merge

  12. #12
    RC Turnbuckle Jr.
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    I think its time to shop for a new esc

  13. #13
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    Quote Originally Posted by Crailtap25 View Post
    Red wire is supposed to be the middle one right? Got this thing used and you never know when previous owner could have messed with.
    With just the ESC and normal batteries, yes, the red 5V line goes into the receiver. With using an external BEC, the ESC's red 5V line is disconnected to allow the external BEC to power the receiver. This may clear things up: http://www.castlecreations.com/produ...ec_wiring.html

  14. #14
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    I know what's supposed to happen. Using the external bec. It will not work unless I leave the red receiver wire in. It works when both and red wire and bec are in use.

  15. #15
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    Went out and tried to run it today. 3s seemed ok but on 6s after about 1/2 throttle it would cog like crazy and jump around as the wheels locked and spun over and over. Bought a new esc on eBay today. Same one v3. Good move I hope?

  16. #16
    RC Turnbuckle Jr.
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    Motor wasnt getting hot?
    If not sounds like the right move

  17. #17
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    Motor was only very slightly warm after running for about 5 mins. Hopefully that's ok.

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