Author Topic: Does an ESC care how many chs. the TX/RX has?  (Read 4300 times)

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tug-arlyn-nelson

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Does an ESC care how many chs. the TX/RX has?
« on: August 15, 2015, 20:36:08 »
Reason I ask is on another place on the net in a discussion of ESC's, one gent opined that a particular ESC was good for 2-3 chs. only. I don't see any ESC's being listed as good for any particular amount of chs. Any truth to that?

des

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #1 on: August 16, 2015, 15:07:30 »
The only thing I can think of is that some ESCs have a BEC Battery Eliminator Circuit auxiliary output to provide a power supply to the radio receiver.  I can imagine that these BECs would be limited in the number of channels they can support.

Des.

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #2 on: August 16, 2015, 17:09:59 »
Well that's a thought.  I suppose one should inquire from the maker of the ESC for their thinking.  Thanks!

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #3 on: August 17, 2015, 17:35:26 »
I asked the folks at Mtroniks and they confirmed what des said about the BEC being a limiting factor, it can be depending on the amps being used etc. Its more electrics than I fully understand though.  Do all modern brushed ESC's have BEC or just some?

Calimero

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #4 on: August 18, 2015, 08:59:10 »
Most ESCs have built-in BECs except for high voltage/high power stuff.

But keep in mind that those built-in BEC can typically only supply low currents (1-1.5A). If you have multiple servos, they'll be too weak which can cause you to lose control of your model.

That's what was happening with my Odin. Both with the original Graupner (old school) ESC I had and the MTronik Viper I recently got.

My rudder servo is too fast and too power hungry. At best I would sometimes have the lights shut down because the multi switch (uses 1 channel, lets me loop through 7 circuits) would reset as the voltage supplied by the BEC would dip. Worst case: the RX would go berserk and leave the tug stranded.

I now have a standalone BEC which taps in the main 12V SLA battery and delivers 5V@4-5A. They can be had for a few bucks from HobbyKing. You would have to disable the builting BEC of your ESC (ie: pull the red wire from the 3-wire plug that goes in the RX).

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #5 on: August 18, 2015, 09:40:03 »
Thanks for that info Calimero.  I was thinking of a future build being twin screw, with two ESC's and one steering servo.  Seems like that should not put too much strain on the BEC.

Calimero

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #6 on: August 18, 2015, 10:49:32 »
Should be good. You'll just have to unplug the red wire from one of the ESC.

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #7 on: August 18, 2015, 11:20:57 »
I know of this but don't understand what that does exactly, can someone explain in layman terms? Thanks!

Calimero

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #8 on: August 18, 2015, 11:25:46 »
Most ESC use switching DC/DC converters to step the voltage down from 12V (or whatever input your have) to 5 or 6V. And these switching circuits usually don't like working in tandem.

By removing the +/red wire from the plug that goes to the RX, you only end up with -/ground and the signal wire so that one of the ESC doesn't feed power while still getting the signal from the RX.

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #9 on: August 18, 2015, 11:40:55 »
OK, I think I get that. Its interesting though that in the schematic of Tank steering on the Action Elec site, it shows 2 ESC's being used but does not mention or show either ESC having had the red removed. I wonder why.

Thanks again!

Tiny69

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #10 on: August 18, 2015, 12:07:25 »
The ESC's Type P80 on the tank steering diagram on action electronic web site don't utilise BEC.  The receiver and ESC's gets the 5v from the separate power distribution board type P92.

In the VIC 32 I am using a Mtroniks ESC were the BEC can be disabled via the on/off switch when left in the off position.  This means I can use a separate 5v supply from a P92 distribution board to power the receiver and three servos.

Regards

Tiny
« Last Edit: August 18, 2015, 12:10:44 by Tiny69 »

tug-arlyn-nelson

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #11 on: August 18, 2015, 12:53:09 »
Thanks Tiny for clearing that up for me!  I have a LOT to learn about RC electronics.

FLJ

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Re: Does an ESC care how many chs. the TX/RX has?
« Reply #12 on: November 09, 2015, 06:58:18 »
T-A-N
You need to know very little about electronics, actually. This will give you pretty much all you need to start with http://www.modelboats.co.uk/news/article/but-i-don-t-understand-electronics/18054
BTW There seems to be some people who think it's 'cool' to be dumb about things electric. I even heard someone bragging about it just this last weekend at a model show. My contention is that if you operate radio-controlled model boats which have electric motors for propulsion then you MUST have a grasp of the basics. Being dumb isn't cool - it's just being dumb, and possibly dangerous.
And no - an ESC doesn't care how many channels the radio has, subject to the caveats above about BEC.
DM