tazzzz

does having a 6 or 8" extension on a receiver battery have any effect on the battery insofar as power loss or extra drain etc?

TAZZZZ(again)

speedracerntrixie

My Feedback: (29)

There are a few things that need to be considered. How many servos are in the airplane? How much power do the servos consume? What type of airplane/flying style? What is the voltage of the battery? I currently have an airplane that has a 10" battery extension with no issues. It has 5 standard BB servos and a retract servo so no huge load on the battery. The extension is 22 gauge wire and I run a 6.6V LiFe battery though. A bad example would be a 3D airplane running 6 digital servos with a standard switch, 8" extension and 1000 mah 4.8V battery.

mscic-RCU

My Feedback: (6)

check out this voltage drop calculator. Pretty insignificant drop.
http://www.calculator.net/voltage-drop-calculator.html

Bozarth

My Feedback: (15)

I regularly use two 10" (20" total) servo extensions between my battery and the receiver in all of my racers. I have done this for 10 years without a problem.

Kurt

BarracudaHockey

My Feedback: (11)

Its no problem but I know if it were me I'd use some heavy duty extensions, I get mine from Tail Dragger RC
www.taildraggerrc.com

Bozarth

My Feedback: (15)

Why heavy duty?

Kurt

speedracerntrixie

My Feedback: (29)

We have no idea what type of airplane the OP has, what type of servos or battery voltage. Looks like all suggestions to this point have been on the safe side. I agree that if it were a Q500 or Q40 then a long extension is not going to be an issue. With a 40% 3D airplane running 400 oz digital servos using a 24 gauge extension of 10" could be an issue. Voltage drop goes up as the current goes up. Anyone who does not buy into this, go try running your air compressor with a 30 ft cord.

Bozarth

My Feedback: (15)

But when is enough enough?

Kurt

speedracerntrixie

My Feedback: (29)

Hard to say, that's why the safest thing to do is wire up your power system with a good safety margin. For most it's not going to be an issue but as the airplane gets bigger it's something that needs to be thought out. My warbird racers uses a 850 mah 6.6V RX battery through a 22 gauge switch. Very simple and functional. My 40% Extra uses dual 7.4V 5000 mah batteries with 16 gauge extensions and Deans connectors. The batteries hook up to a power box that regulates down to 6V and will deliver 30 amps. No mechanical switch on this one either.

Bozarth

My Feedback: (15)

Speedracer,

I know we are on the same page, but most of us don't really know what the safety margin is and follow the "heavy duty must be better" mantra...but is it needed? Should I build my new house with 2x6 or 2x8 or...? What about the "extra heavy duty"?

I like your "no mechanical switches"

Kurt

jetmech05

The smaller gauge wire, the higher the voltage the bigger the drop will be. You can't be wrong using heavy duty extensions. Which are larger gauge wire and hopefully larger gauge pins

Bozarth

My Feedback: (15)

Here are the results of tests I did this morning using my very basic Hobbico Digital Voltmeter MkIII on a Zippy LiFe 6.6v 700mAh Rx battery.
The voltmeter has 12in leads and the optional load is 250ma

Battery only: 6.62 volts
Battery with 6" standard extension: 6.62 volts
Battery with 6" HD extension: 6.62 volts


Battery only with load: 6.46 volts
Battery with 6" standard extension with load: 6.40 volts
Battery with 6" HD extension with load: 6.06 volts (THIS IS NOT A GREAT EXTENSION - I need to test another one)

Battery only: 6.58 volts
Battery with 18" standard extension: 6.58 volts
Battery with 24" standard extension: 6.58 volts

Battery only with load: 6.48 volts
Battery with 18" standard extension with load: 6.44 volts
Battery with 24" standard extension with load: 6.44 volts

Kurt

speedracerntrixie

My Feedback: (29)

Kurt, that's pretty much what I would have expected and a good representation of a run of the mill .40 or .60 powered sport airplane. If you have the equipment you may want to try another test using 40" extensions and a load of 2 amps. This is what one could expect to see on a large scale airplane with a digital servo in the tail. My guess is that you would see close to a full volt drop. Yes I changed the game over to a servo lead and not a battery lead but think about this, if you lost a volt at the servo without any considerations on battery leads what would the servo see if the battery lead was not sufficient? I know there are charts out in the world somewhere that do illustrate voltage loss across certain gauge wires under determined load.