Go Back  RCU Forums > RC Airplanes > RC Jets
Reload this Page >

Servo extension wires

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Servo extension wires

Old 05-16-2020, 07:47 PM
  #1  
DHC6
Thread Starter
My Feedback: (6)
 
DHC6's Avatar
 
Join Date: Dec 2011
Location: Limoges, On, Canada
Posts: 253
Likes: 0
Received 2 Likes on 2 Posts
Default Servo extension wires

Hey guys, I got a question regarding extension wire. From what I understand generally (depending the purpose of course) you want larger wires. I have pretty much always used the 20gauge wire from Tbolt, either pre-made or I make my own. I decided to try Powerbox Maxi wire on my last build. When I got it I was surprised that itís pretty thin gauge wire. The signal wire is pretty thin, but thatís fine, thereís no real amperage going through it. So itís good that itís thin, helps save weight. However the power wires are pretty thin as well, not sure of the gauge, but doesnít look more then 22, possibly smaller?

So what your take on that? Would you/do you trust it in higher load systems. Iím thinking to re-wire my A10 with a Booma system and will need to instal new extensions. Whatchu guys think?
Old 05-16-2020, 08:16 PM
  #2  
bodywerks
My Feedback: (4)
 
bodywerks's Avatar
 
Join Date: Dec 2004
Location: Elgin, AZ
Posts: 3,887
Received 58 Likes on 53 Posts
Default

What kind of toque rating are your servos? Anything under 330oz torque and 40" of wire and 22awg is fine, for one servo.
Old 05-16-2020, 08:27 PM
  #3  
paulhat
 
Join Date: Dec 2006
Location: , AUSTRALIA
Posts: 397
Received 10 Likes on 9 Posts
Default

The powerbox wire is according the website 0.35mm2.
Using http://scottontechnology.com/wire/mm2-to-awg/ that equates to 22 AWG.
Using http://www.powerstream.com/Wire_Size.htm you can push 7 amps through it.
Lets say your servo pulls 5 amps max at whatever voltate you are using and your cable is 2 meters long.
Ohms per Km is 52 for 22awg so ohms for 2 meters = 0.104 ohms.
V=AR so voltage drop = 5 * 0.104 = 0.52.
If you are using a 7.4V system that equates to 7% voltage drop.

Voltage drop is all you are really worried about. 7% is starting to get up there but I would be happy with that. Wouldn't want to go any higher.
I mean I kind of made this up on the fly so I would take all this with a pinch of salt
The thing is you have to do the maths and then some real world testing to be 100% happy. That's my take on it anyway.

Paul.

The following users liked this post:
jason (05-18-2020)
Old 05-17-2020, 12:47 AM
  #4  
makis
My Feedback: (2)
 
makis's Avatar
 
Join Date: Nov 2004
Location: Nicosia, CYPRUS
Posts: 59
Received 4 Likes on 4 Posts
Default

Hi guys,
Just to clarify that the premium MAXI servo lead is 0.50mm2 cross section for red and blue wire, the white one for the signal is 0.35mm2.
The premium servo lead, all three cables are 0.35mm2 cross section.

https://www.powerbox-systems.com/pro...rvo-kabel.html

https://www.powerbox-systems.com/pro...rvo-kabel.html

Regards, Makis.

The following users liked this post:
paulhat (05-17-2020)
Old 05-17-2020, 02:58 AM
  #5  
aehaas
 
Join Date: Jan 2015
Location: Venice, FL
Posts: 256
Likes: 0
Received 4 Likes on 3 Posts
Default

Generally I have seen servo connectors as being rated to 3 amps continuous. I have seen some saying they were good for 5 or 6 amps. So a cable good for 5 to 7 amps is, if anything, rated higher than the connection. There is a voltage drop across any connection under high current loads as well.

I have used the .35mm2 cable for years in my planes. I make my own as the weight of the insulation on other cables adds up to a lot of weight. I also eliminate the connection at the servo end when possible. I cut the servo leads coming out of the servo as short as possible. I have yet to see a high torque servo lead that was thicker than the servo extensions I make.

AEHaas
Old 05-17-2020, 01:21 PM
  #6  
Dave Wilshere
 
Join Date: Jun 2002
Location: Watford, UNITED KINGDOM
Posts: 12,754
Received 601 Likes on 434 Posts
Default

PB extension wire has a thinner insulation skin, feels thin, but it’s not. It just saves 25-30% weight which in a Jet with 10+ metres of wire is good.
Old 05-17-2020, 06:54 PM
  #7  
causeitflies
 
causeitflies's Avatar
 
Join Date: Jan 2003
Location: EASTERN OHIO
Posts: 2,392
Received 33 Likes on 27 Posts
Default

TBOLT now sells a similar wire they call "Extreme" with 20 - 30% weight savings compared to Silicone or PVC based wire.
Old 05-17-2020, 07:51 PM
  #8  
JackD
My Feedback: (4)
 
JackD's Avatar
 
Join Date: Feb 2002
Location: Berkeley, CA
Posts: 759
Received 3 Likes on 2 Posts
Default

Originally Posted by Dave Wilshere View Post
PB extension wire has a thinner insulation skin, feels thin, but itís not. It just saves 25-30% weight which in a Jet with 10+ metres of wire is good.
+1 what Dave said! So much metal on those thin wires
Old 05-18-2020, 03:17 AM
  #9  
gunradd
My Feedback: (9)
 
gunradd's Avatar
 
Join Date: Aug 2008
Location: Springhill, FL
Posts: 3,425
Likes: 0
Received 50 Likes on 43 Posts
Default

I have used the power box wire and connectors on huge planes with no issues. The wire is the best and love the stuff. Its also very heat resistant.
Old 05-18-2020, 06:15 AM
  #10  
aehaas
 
Join Date: Jan 2015
Location: Venice, FL
Posts: 256
Likes: 0
Received 4 Likes on 3 Posts
Default

Originally Posted by gunradd View Post
I have used the power box wire and connectors on huge planes with no issues. The wire is the best and love the stuff. Its also very heat resistant.
Yes, by far the most heat resistant cable. The insulation is thin, tough, light weight and I even use it on smaller planes. Most recently I got a hold of a new Habu kit (? around 42" wingspan) and used this cable exclusively, again, mainly to save weight. I had a handful of the cable extensions I would have used and an equivalent length of the PB wire to compare. I was asking myself if it mattered in such a "small" plane. Guess what - big difference.... I did not measure the savings but I would guess it was around a half pound !!

AEHaas

PS: The comparison was with an equivalent thick gauge, twisted cable wire that I could have used in otherwise larger jets. In fact I wanted to get rid of it as I no longer really wished to keep the stash of "store bought" extensions.

Last edited by aehaas; 05-18-2020 at 06:25 AM.
Old 05-18-2020, 11:05 AM
  #11  
makis
My Feedback: (2)
 
makis's Avatar
 
Join Date: Nov 2004
Location: Nicosia, CYPRUS
Posts: 59
Received 4 Likes on 4 Posts
Default

Originally Posted by gunradd View Post
I have used the power box wire and connectors on huge planes with no issues. The wire is the best and love the stuff. Its also very heat resistant.
Same for me, I used maxi servo lead and connectors to my T3 jet equipped with MKS HV 777+ servos, just excellent, no issues at all.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.