BEC Melted Wires
 

Ok this has me puzzled.

Savage Flux with a Hobbywing 150A Esc Turnigy HV767 Servo and Spektrum RX, 4s Lipo set up. I hooked up the ESC to the receiver, with an extension lead with the red wire missing and then hooked up the BEC using one of these

http://www.hobbyking.com/hobbyking/s...r_adapter.html

between the Deans of the Lipo and ESC on one side. (ESC has dual Deans in a Series configuration like the Savage Flux Set Up does on the stock esc)

With the JST end plugged into the input wires of this BEC
http://www.hobbyking.com/hobbyking/s...ly_6_23v_.html

And the output connected to the Battery socket on my Spektrum Receiver.

Plugged everything in, RX has power, Servo moves fine, as soon as I turn on the ESC however, the wires between the BEC and Receiver melted as did the Servo Extension with the red wire missing between the ESC and RX

So I removed the adapter, extension and BEC, hooked up the ESC directly (using internal BEC obviously) and everything was fine.


....so what gives?

Any clues as I'm puzzled on this one!

You melted the red wire on the extension that isn't even connected?

No I remove the Red wire from the servo extension entirely, the Black and White wires melted.

As wire length increases so does resistance, as resistance increases so does the temp.

But I don't think that was the problem:intello:

It sounds like a faulty bec to me. Do you have a voltmeter to determine the actual output voltage of the bec?

This is a weird one alright. You obviously had more current than the wires could handle, but that shouldn't have melted the extension to the bec.

I don't fully understand why you chose an hv servo if you were only going to send it 6v anyway? Were you just using a bec to lighten the load on the esc?

Perhaps it was a combination of too long of an extension and a faulty bec and both failures occurred simultaneously?:neutral:

The servo was just one I had in the box which they state runs fine on 6V as well as 7.2V

http://www.hobbyking.com/hobbyking/s...idProduct=9983

The ESC internal bec seems fine with it, and thats without a Voltage Cap which I usually run on my Spektrum gear

It's gotta be the bec but I can't wrap my head around why it happened when you turned your esc on. Gremlins?

Which battery did you connect the BEC to, via the in-line adaptor?

http://i115.photobucket.com/albums/n...tteryinput.jpg

It should have been wired up like-so^, paying close attention to where the BEC input wires are going exactly ( which battery & wires ).

Yeah it was connected as a deans adapter between the harness and one of the Lipos at the battery end

Which Lipo? You MUST connect it to the ground side lipo otherwise you had a floating voltage issue.

Ground on BEC is actualy 7.4v to the ESC. Guessing this is were it got f'd up.

Ok I will double check that, if that's the case where I hooked it to the wrong battery (ie positive from batt not neg from batt) then it's easier to swallow

...but the BEC is rated 2-5s Lipo?

It's more that the esc ground is 0v but the bec ground is 7.4. Effectively creating a short.

...and we have a winner! It was plugged into the + side pack not the neg side pack

That will do it :)