Re: receiver question 1: powering [TANKS]

[Frank Pittelli <frank-at-rctankcombat.com>]

Amir Tahvildaran wrote:
> While testing out my turret I noticed that my receiver was powered up 
> regardless of the state of the switch (controlling the 4.8v pack).
>  
> The set-up is that I have a 12v battery driving the rotate and elevate 
> motors.  The rotate is using a scorpion mini.  The elevate is using one 
> channel of the MRC controller.  The receiver has its own 4 cell battery 
> pack. 

All of the black and red connectors on the receiver are tied together, 
including the two power lines.  That is, the power comes into the 
receiver from the 4.8v battery and is distributed to all of the servos 
in parallel.

Therefore, if you hook a 12v battery up to any of the servos, then 
you'll be adding a 12v battery in parallel with the 4.8v battery, 
resulting in the receiver circuit seeing a voltage somewhere between 4.8 
and 12v.  Although we've been running receivers successfully at 7.2v for 
many years, I'm not sure about going higher than that.

If you want to provide more power to the servos, then the proper thing 
to do is cut the "red" lead between the servo and receiver, and hook the 
"red" servo wire directly to the servo battery.  You should also connect 
the "black" wire from the receiver battery to the "black" wire of the 
servo battery to create a "common ground".  If you want a single switch 
to cutoff both batteries, you can insert it on the common ground side of 
the circuit.  See the attached circuit.

        Frank P.