dale691

Hi all i have been using only JR recievers since i have started modelling all are PCM 770s. I have just got some high torque servos 7.7 kg and they are quoted as drawing 300mA. If im running five servos for the flight control surfaces is this going to be too much current draw for this reciever? will i need a bus bar setup with seperate battery for the servos and reciever.

Cheers Dale

Ed_Moorman

My Feedback: (1)

Nearly all of the receivers I fly are the 770 PCM.

About the only time you would need separate battery packs are if you are running a lot of digital servos, which do require a lot of juice. I am referring to the 4 servos rudder set-ups on the big planes. Many of them run 4 digitals on rudder 2 on each aileron and 2 on elevator. You'd want a separate battery for these. I run 4 digitals on several planes with just a 1650 mil NiMH pack with no problem. On my 3D planes, I run a light, 720 mil pack.

I would check your voltage after 2 flights and each flight there after just to be safe. If you are running analog servos, I wouldn't think you'd have any worry.

dale691

That sounds like what I was thinking, the only thing that put a doubt in my mind is that the servo spec sheet quotes 300mA as the current draw for the analog servos that i have and the same for the digital version of my servos. The servos i'm using are hitec 645mg the digital version is the 5645mg.

Dale

Ed_Moorman

My Feedback: (1)

It has been my experience that digitals draw a lot more currect in practice than do analogs. Generally, you must displace an analog servo about 20 degrees for it to give you the full torque, which would be full currect draw. A digital servo gives full torque at a 1 degree displacement, as I understand it. This means you would be using a lot more current from the digital.

dale691

That makes sense as the quoted figures are their maximum current draw