• Welcome to the new Flite Test Forum home! Please note that the migration is still undergoing and certain content, user privileges or features may be missing or limited until the transition is complete. Thank you!

Probably I damaged the BEC

So I connected my 25mW camera directly to the Rx servo pins to pull the needed 5V from the BEC on the 40 amp Emax ESC. I'm pretty sure that it has a 3 amp switchmode BEC on the ESC. I have the standard (4) 9 gram servos. I'm using a 3300 mAh battery that is at least 30C.

Here is the ESC:

I have flown the plane many times before with no issues. Now, after connecting the camera, I took off and was able to make it halfway around the pattern (30 seconds?) and the Rx browned out resulting in a spiraling crash.

I know that the camera was probably too much for the BEC to handle resulting in the crash. No problem, I'm a big boy and will own up to my own dumbness. Since I have removed the camera and everything tests OK on the ground. But now I take off (no camera, just 4 servos and the Rx on the BEC) and it is fine for climb out. As soon as I reduce the throttle the ESC goes into programming mode. I can hear it beeping the sequence for all of the programming parameters. I cannot get any power from the motor but have full control of the plane and am able to complete a forced landing.

I believe that the BEC is flaking out and the ESC is resetting and seeing the full throttle on startup causing it to go into program mode.

I suspect that I will either need a new ESC or install a dedicated BEC to power everything independently. I was just wondering if anyone else has come across this or can think of a fix.



Old and Bold RC PILOT
I would test the operation of the ESC etc before replacement.

A copy of the test methods I use to see if a brownout, (loss of BEC), is likely was posted on another thread just recently.

See - http://forum.flitetest.com/showthread.php?35710-Troubleshooting-RX-Brownout

Also check to ensure that you have adequate ventilation for the ESC. I have had a couple of designs that "leaked" air but over time as the paper swelled and with a few repairs it became almost airtight and the ESC started cooking up! Made a few ventilation holes checked the items posted above and she is back flying reliably again!

Just what works for me!

Have fun!


Obsession, not hobby
I'm sure you're over max current of the ESC's 3A BEC circuit with 4 servos, RX and AIO camera. Try running the AIO from a simple voltage regulator from the flight battery (ESC side) or a separate 1S battery if it can run on 3.7V. With the original ESC, I would try going through the programming to make sure it's setup correctly. Maybe even try it with another battery, RX and motor on the bench before calling it dead.

http://yinyanmodel.com/EMAX User Instruction for Simonk Series ESC.pdf
Thanks for the advice. The ESC is not vented that well. I'll punch some vent holes for it.

I will program it again. I suppose that it could have wonky parameters if it went into program mode and I was moving the throttle stock attempting to get power.

I moved the cam to one of the cells on the balance plug but I don't think it's a good idea (on a different plane). One cell will be under more load and I'm just asking to kill that cell and the whole battery. I noticed that as I gave full throttle on the last run, the cam feed died and then came back.