Micro Motor Community

When fun ends with magic smoke


So yesterday I was flying my hex shark fpv around the backyard. First battery went fine. Here is some footage:

Second battery not so much. I was about half way through and crashed. Upon the crash my fpv feed died. I took the goggles of and see a stream of smoke rising from my quad. I figure my battery went but as I approached the smoke stopped quickly. Upon inspection the wire powering the FPV system fried. The cheap plastic insulation completely separated itself from the wire. Two lessons to be had. Don’t use cheap wire with plastic insulation for power purposes and also use a higher gauge wire. Whoops.



Awww @Complacent1 that sucks! I like silicon insulation, it is flexy and insulationy lol. The hobby stuff is often rated at less than 200c, sounds like heaps, but in a short situation that is reached in milliseconds. I Often space my cables with hot glue, Ie hold the bunch, and glue it apart a few tenths of a mm. My dad was a mains electrician and army electronics engineer, the one thing I do remember him saying is isolate and insulate everything!

1 Like


I have good silicone wire. I used this crap because it came on the connector that fits into the multiflite serial port. I wanted to power the fpv from the port and didn’t have connectors and pins to crimp myself. Lesson learned hahaha

1 Like


Lol, Man, I pul cable from anything that breaks, so I use stuff from dead pc psu to broken cars lol. I am the salvage king. So I do not hold you accountable for the wire you use!



I haven’t checked the FC yet. Hoping its okay. I know multiflite has reverse polarity protection. Not sure if ts on the serial port though and not sure if it would protect against a short. We shall see.



I reverse polaritied a cc3d, and felt the heat in my fingers, and pulled it before it cooked, I am thinking and hoping you are OK!

Even if it isnt ok, the first part in line for the short will have fried, it will be a salvageable board, I feel confident saying that. You just need a better man than me to fix it lol.



I ordered a selection of silicone jacketed wire from Adafruit.

They have multi-stranded 30AWG, in 6 colors. 2m for $0.75

Shipping is $10 so find some other things to order to make it worthwhile.

1 Like


Damn! @Complacent1 hopefully FCs OK



Whoa. What MasterRC_sTudenT said. Hope the rest of the Shark is ok.



[quote=“Denovich, post:7, topic:1588, full:true”]
I ordered a selection of silicone jacketed wire from Adafruit. They have multi-stranded 30AWG, in 6 colors.[/quote]

I have the 30AWG silicone from Adafruit for signal wires and such…it is really good quality. For larger gauge power wires I’ve found Common Sense RC has a very good selection of all gauges of high quality silicone wire in pre-cut lengths or by the foot. For these small scale projects a foot or two of wire can go a long way. :wink:



I use common sense rc silicone wire as well. Love the stuff! Obviously I didn’t use it here hahaha



Same exact thing happened to me the other day. Everything else was fine. You really think the wiring gauge was the issue?



Yes, I believe wire gauge and insulation type combined was the culprit.



Wire gauge acted in your favor. It definitely limited damage when it shorted. I use 30awg for just about everything but battery cables. We’re working with a couple hundred mA. I also keep my wires super short and I solder everything. So YMMV.



Lucky there wasn’t more damage. So you think silicone wire would not have melted like this? I hate the PVC insulated wires because they melt so quickly when I’m soldering the wires onto the board etc.



PVC is thermoplastic, it melts when heated
Silicone is thermoset, it doesn’t melt when heated, it will eventually char, but at >300C.



Reviving this thread.
Similar thing happened to me with my tiny hawk scisky built today.
Had a crash, picked it up and suddenly the bird starts to smoke. Unplugged lipo as fast as possible.

Next thing: checking if FC is ok. It’s taking a bath in alcohol right now.



That’s not nice. Do you know why yet? FC doesn’t look to be burned, and we know what those things can survive now.