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Can you run multiple red wires from your bec/escs to the rx?


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miles&Jules
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Can you run multiple red wires from your bec/escs to the rx?

Hi All
I have always run only one esc red wire to the receiver to power it....but was chatting with Sean and he reckons that all the red wires would not hurt....if so that would be great cause ...a few times judge has lost power cause the single bec/esc gets unplugged...what do others do?
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Post Fri Oct 05, 2012 10:39 am 
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dyrodium
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I ran both in FUGU because the single bec couldn't handle the lifter servo. Probably wrong... but I think with the linear regulators in cheap esc's it doesn't matter, but switchmodes might be a problem ?
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Post Fri Oct 05, 2012 10:43 am 
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Glen
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Yes don't use more than one if it's a switchmode BEC. Have to ask Steve what type the tz85s use. You might get lucky and it'll be a standard old linear one and you can connect them all em up in that case.

Here's a good analogy of why you can't double up switchmode BECs:

"Two (three) captains on one ship, trying to keep voltage the same. They may get into a fist fight on the bridge, who's the boss?"

Does it really matter if it gets unplugged though lol, You'll still loose one side of the drive which would make the robot pretty much dead Razz

Hot glue the servo wires into the RX on one side and just peel it off when you need to unplug it all Smile
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Post Fri Oct 05, 2012 10:57 am 
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Valen
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You could if you add a diode to it on the switchmode and perhaps an inductor but they won't current share particularly well.
A linear reg you must have a diode as they will die fast if driven backwards.
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Post Fri Oct 05, 2012 7:38 pm 
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Jaemus
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FYI, i DGAF and plugged 3 TZ85 BECS into my RX at the Nats.

All was fine.

Also that was a lot of acronyms
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Post Fri Oct 05, 2012 7:42 pm 
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Valen
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If the switchmode is done well it should work ok, it may just be making drastic assumptions about Chinese electronic design lol.
But yeah without talking to each other or some precision design they probably won't current share well, so doing it for "reliability" could work, but perhaps not so well in Anguses over current case.
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Post Fri Oct 05, 2012 7:47 pm 
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dyrodium
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I think when it comes to 7805's it's care factor 0. Laughing
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Post Fri Oct 05, 2012 7:57 pm 
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Knightrous
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Well the Plush10 ESC's come with dual 7805 soldered together front factory (i remove one of them for my ants for size/weight reason...) so it can't be too bad Razz
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Post Fri Oct 05, 2012 8:13 pm 
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Valen
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Soldering them together will help to stop thermal runaway causing one reg to take all the current load while the other does nothing.
It also stops the problem where if one of them looses power it will get reverse driven by the other and blow up.
I'd put that in a special category called heroic measures but kinda dumb lol.

If your using more than a 7805 will put out unless its a surge (~.5 seconds) load, soldering 2 together won't help like paralleling fets will because they are *designed* to burn the excess energy as heat, you can't make a more "efficient" linear reg by definition.

Having a diode in the chain between regs that aren't thermally connected works because it stops the reverse drive and voltage drop across a diode is proportional to current flow, so it'll act as a balancer (well until you start heating the diodes to any significant amount)
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Post Fri Oct 05, 2012 8:24 pm 
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marto
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I plug all mine in together regardless. I just tell others not to.

Hypocrite but I tend to error on the safe side when giving advice. I also ran 4S rated beetle controller in my feather on 6S and someone is running EV warriors off Tz85as which is crazy. So ignore my advice and go nuts. *If it dies I take no responsibility*

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Post Fri Oct 05, 2012 11:29 pm 
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miles&Jules
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yeah im going to try it next time...cause sometimes Judge mysteriously stops mid fight ...then I turn it off then back on and everything is fine...just like a pc!
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Post Mon Oct 08, 2012 5:24 pm 
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Knightrous
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Imma just gonna throw this out there and say it's the HK radios Razz
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Post Mon Oct 08, 2012 5:47 pm 
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Valen
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do your drives or anything have flashing lights on them?
can you see if the drive has locked up or the RX?

could be a case of too little capacitance in the electronics and power surge/dips are killing stuff.
Another BESC could well help with that, even if it is "wrong" ;->
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Post Mon Oct 08, 2012 5:49 pm 
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miles&Jules
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no flashing lights.....might try a spectrum...as the hk software seems alien to me. Can ya do mixing on the dx5?
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Post Mon Oct 08, 2012 7:39 pm 
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