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Thread: Receiver BEC (vs ESC BEC)

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Old 10-13-2005, 03:03 PM   #1
sim
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Default Receiver BEC (vs ESC BEC)

I noticed quite a number of 2 channel AM receivers have BEC's in them. For example, I was looking in my old RC stash and found a Futaba FP-R102GR receiver, and a quick look on the web found this link http://www.futaba-rc.com/manuals/2p-manual.pdf which says it can use a power source from 4.8V to 8.4V

I guess that means I can turn off the ESC switch and plug the 6-cell batt straight in? It's an old receiver I don't mind frying, but I'm more worried about it frying my Hitec 645MG servo. The main reason I'm trying it is to try and get 6V to the servo for more torque and I'm hoping the receivers put out more than the ESCs. Is there a way I can check the receiver output voltage?

Anybody else run receiver built-in BECs instead of ESC BECs?
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Old 10-13-2005, 03:06 PM   #2
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If you are running a receiver pack then you should not be turning on the ESC switch and only be using the auxilary receiver pack switch. If you turn on both switches then you run the risk of frying your servos depending on which ESC you run and the BEC output of it.
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Old 10-13-2005, 03:06 PM   #3
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you mean a battery pack? for 6V just get a 5cell receiver battery pack and you are ready to roll.
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Old 10-13-2005, 03:42 PM   #4
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Wow, thanks for the quick replies. I'm too lazy to charge 2 batteries for 1 rig, so no receiver packs for me.

What I'm saying is, since the receiver claims to have a BEC, I will run some wires from the 7.2V (6 cell 3300mAH Sanyos) to this receiver without going through another voltage regulator. I'll make sure to turn the esc switch off.

I guess I'll try it with a cheapo servo first and poke around with a voltmeter and report my findings.
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Old 10-13-2005, 05:08 PM   #5
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When a reciever says BEC on it, it does not mean that it can regulate voltage for the servos. It means that it is compatable with BEC esc's. Older recievers would only transmit power from the battery slot, wheras newer BEC enabled recievers will transmit power from any slot to all other slots.
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Old 10-13-2005, 08:36 PM   #6
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Ah ok. It all makes sense to me now.

Will keep my 645 far far away from all that then, and go back to the regular 5V (ESC BEC output) setup. If that doesn't turn the wheels, I'll run a 5-cell main pack and power everything (motor, receiver) with that. I don't think I'll need to though. It's only a 2.2 rig with 1 servo (locked diffs).

I'll still poke the old receiver with a voltmeter later tonight, but won't try wiring servos to it. Thanks all.
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Old 10-13-2005, 08:46 PM   #7
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Quote:
Originally Posted by sim
Ah ok. It all makes sense to me now.

Will keep my 645 far far away from all that then, and go back to the regular 5V (ESC BEC output) setup. If that doesn't turn the wheels, I'll run a 5-cell main pack and power everything (motor, receiver) with that. I don't think I'll need to though. It's only a 2.2 rig with 1 servo (locked diffs).

I'll still poke the old receiver with a voltmeter later tonight, but won't try wiring servos to it. Thanks all.
Running a 5 cell main back won't solve your problems, unless you splice the wiring to go th the ESC AND the receiver. You will have less power to the motors that way, (6v instead of 7.2). The ESC regulates its own BEC output. the receiver has nothing to do with this, it only routes that power to the servos. If the ESC has a weak BEC, then the receiver can't do anyhting about it. I can guarantee the receiver does not have a self-powering BEC, that just means it's compatible with a BEC equipped ESC as said above.

You can plug whatever you want into the receiver, as long as its not more than 6v. Your servos won't get fried unless the BEC output that the receiver is getting is greater than 6v.

You can NOT plug your main pack into the receiver and expect the ESC to somehow pick up this power through the receiver plug and give it to the motors. thats why the heavy gauge wiring goes straight into the ESC, and then to the motors directly..

is running a receiver pack that big of a hassle?
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Old 10-13-2005, 08:54 PM   #8
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Understood. Thanks again.
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