Running High voltage servo of BEC???
 

Heres my setup

SCRT10, mamba max pro, novak 4.5 550 motor. Red and black power wires from Hitec 7940 servo plug directly into a lipo hump pack (yellow signal wire plugs into rx). Internal BEC on the esc plugs into the rx and powers the rx and transponder

I couldnt get my 7940 servo to run off my lipo rx pack - do i have to put the power from my lipo hump pack through a bec before it goes to the red and black servo wires?

That servo maxes out at 7.4v. Your fully charged lipo 2s rx pack will be 8.4v when fully charged. That is why I ran mine through a CC reg first.

You need a ground wire between the receiver and servo, along with the signal wire, to complete the signal circuit.


Running a regulator on a 2s (I assume) lipo receiver pack with a high voltage servo kinda defeats the whole purpose doesn’t it?

Yes it does defeat the purpose thats why im hoping I dont have to run any regulator at all. I just could not figure out why my servo wasnt working at all.

So you are saying I need the black ground wire to also go to the rx

question 1: If I do that do i also stilll have a black wire going to the ground on the lipo rx pack. i.e. the black wire from the servo splices and goes to both the rx(along with the signal) and to the lipo rx pack?

question 2: If I do connect the black ground to the rx do I run the risk of sending 7.4 volts to the rx? My original intent here is to have the rx be at 6.0v and have the servo be at lipo voltage (7.4-8.4)

This is my intent because my rx (futaba r603fs) cannot go above 6.0v

what RX are you using??

futaba r603fs

1: Yes. Everything needs to be grounded together. Use a splice-Y as mentioned, can be spliced from any of the 3 components. (you want a spliced Y ground connection, not a full loop around the 3, known as a ground loop, not good)

2. As long as you don’t connect the red positive wire from the receiver pack to the receiver you won’t complete the power circuit, thus won’t get that Voltage to your receiver. (for the same reason your servo doesn’t work now, haven’t completed the circuit)

I tried splicing the ground from the servo (one went to teh rx with the yellow signal wire and one went to the ground of the rx pack - still nothing from the servo - totally dead

Weird. Do you have a multi-meter, to carefully check all of the wiring and connections, voltage to servo, etc? Make sure you have wire orders and polarity right.

Thankyou Dave

yeah I was running the power through a switch before it got to the servo and I think that was messing it up - I hooked the battery straight to the circuit and now it works awesome.

Good to hear you got it going.

Cheers

PS:

I'd like another shot at this. Probably best to split from the receiver, most direct ground for each control signal.