battery leads and esc failure?

[Chris_Burgess]

A little while ago there was a comment in a thread that lengthened battery leads could cause an ESC to burn up, I'm curious if anyone on here has ever had this happen to them. Thanks for your help.

[John Cralley]

Chris,

Castle Creations warns about excessive battery lead length and advises that you add capacitors to help absorb ESC killing spikes.

I personally have not had any problems but I bet if you put your question on an RC forum like "Wattflyer" you will find some RC folks that have blown ESCs with long battery leads.

[eric david conley]

     I lengthend some battery leads on 2 of my carrier planes so the arming plug would be easy to get to. Added something around 8" so it would be located at the trailing edge of the wing near the fuselage. Lost 3 ESCs for no real apparent reasons and finally stumbled on the web side forum that said you shouldn't lengthen wire between the battery and ESC so changed mine all back to stock lengths and haven't lost anymore sense (a pretty good indicator not to lengthen leads). Course it was sure easy pulling the plug when it was at the trailing edge of the wing while the ESC was flaming and smoking. Then again it hasn't happened sense I changed things back to the original length.  Eric

[Andrew Borgogna]

Eric
What kind of ESCs were you using?  The reason I ask is I have lengthend the battery wires on a couple of setups, one to install a safety plug and another where I just need more length for a test setup.  In both cases the I only added about 3 to 4 inches, in one case I am using a ZTW ESC and the other a Turnigy ESC.  So far so good.
Andy

[Jason Greer]

Castle recommends adding additional caps if you add more than 4" to the battery leads.  They also recommend logging the battery ripple voltage.  If it exceeds 10% of the battery voltage then either the C rating on the battery is to low for the application or you need to add caps.  The ripple voltage can also indicate a battery that is getting old.

Jason

[eric david conley]

     Andrew, the first one was a JETI 77A, second was a COBRA 100A, and then a COBRA 150A. I kept thinking I wasn't using a big enough ESC so kept putting bigger ones in my planes thinking that would work. As I found out it was the leads that I had lengthened.  Eric

[Chris_Burgess]

I ask because I recently added between 4 and 5 inches to the battery leads on my primary stunter thinking it would be a simple way to move my esc into better airflow and keep my arming plug where I had it, but I didn't know anything about it possibly causing a problem.  Now I'm re-thinking where I'm going to put my esc and arming plug to keep it in good airflow but provide for shorter leads.  Thank you for all your responses it should hopefully save my esc, and possibly the airplane too!

[Andrew Borgogna]

Darn, maybe I have just been lucky! 
Andy

[Jason Greer]

This thread has some good information in it:
http://www.rcgroups.com/forums/showthread.php?t=952523#post10926525


Jason

[John Cralley]

Darn, maybe I have just been lucky! 
Andy

Maybe luck or maybe you are just under the critical limit for length. I believe that around 12 inches and beyond for battery length cables puts you in the danger zone.