BEC and separate rcvr battery at the same time?
 

My ESC has a built in BEC, but I want to be able to power the radio without connecting the motor battery. Is it OK to power the receiver with a separate battery while the throttle cable from the ESC is also plugged in? When I tried that the ESC issued its startup beeps and the motor tried to run if I moved the throttle stick. That doesn't seem right, but I don't know.The receiver and servos did work, though.

Jack

Hi Jack. Try disconcerting the red wire from the ESC plug that goes into the receiver. I had to do that when I hooked up a setup like you are trying.That way the BEC in the ESC is not trying to power the receiver while you are useing a separate power supply for the receiver.

Thanks for the fast reply .

tango53

I know someone who uses the BEC and he also installed another battery with a switch. That way he can operate the electronics w/o powering the motor battery. He said he leaves both turned on when he flys. That way, if the motor battery dies, he still has power to the electronics.

Dunno. I asked Castle and they said to not do that.

Yes, what you are doing is okay, sure, if you move the throttle the motor will try to run. Just leave the throttle control at low if you just want to test the servos. You could also just unplug the connector from the ESC to the throttle channel while you are testing with a separate battery. However, no problem if you do not, you just get the ESC trying to run the motor with insufficient voltage when you advance the throttle...so do not advance the throttle during your servo testing.