c550

My Feedback: (16)

Thought I would ask the gallery for your opinions. I want to mount the battery and switch in the nose of my model and have the receiver in the mid section. This will require running a 30 inch lead from the switch to the receiver. Are there any issues with this or is this going to work?

Thanks in advance for your input.

TedMo

You do not mention if this is an electric or glow. Since you have a switch I will assume it is glow. The only problem I see is loss of voltage but that could be easily overcome by using larger battery leads or better yet go to 5 cells, 6v.'s for Rx servo battery. Good idea anyway 6v. more and faster servo action plus extra voltage available. I use 6v. all the time. Just check Rx and servos to be sure they can take 6v. most can.

Red Scholefield

My Feedback: (9)

ā€œWhat size wire do I need?ā€

Iā€™m frequently asked this question. A chart of that answers this can be seen at http://www.powerstream.com/Wire_Size.htm

For #22 wire, common for battery leads it has a resistance of 16.24 ohms/1000 feet. So for 30 inches that would be 60" coming and going which would relate to 0.08 ohms. Say your max servo draw is 5 amps, then this would be a 0.4 volt drop. Enough to cause some problems when the battery is partially discharged. Use larger wire!

c550

My Feedback: (16)

Thanks for the replys. It is glow and there will be 15 servos. I will be running a 4200mah 6v bat.

gboulton

My Feedback: (15)

Just as a thought...

Perhaps consider a 2S LiPo to a regulator as well. That way, you can put the regulator near the receiver, and any voltage drop will occur from the 7.4V nominal at the batt to the desired 6V out from the reg. Since it's being regulated down anyway, this is less of a potential issue, there's more margin for error, servo draw is less likely to be a dynamic factor, and you'd likely have no extra weight, since the difference between a 2 cell lipo and 5 cell NiMh or NiCd would roughly equalize the addition weight of the regulator.

Certainly nothing wrong with your plan afaik, just thought I'd toss out the alternative.

cahusker

My Feedback: (50)

Another choice is to run dual packs. Two 2,300 mah A123 packs through two switches and plugged into your Rx in two places would service the 15 servos better IMO. With dual packs you will use half the current per pack dropping less voltage over that long 30" extension. With the A123 batteries you won't need a regulator either.

BobMaine

15 servos? At least two batteries. How big is this aircraft?

c550

My Feedback: (16)

Its the Top Flight B-25. Alot of the servos will not be used at the same time(retract, bomb bay, bomb drop ect), and all but the elevator are standard servos.but I just don't want to cause a problem. I was thinking of 20 gauge wire, because I have it on hand. If I read the chart that Red li ked to I think I might need to buy some 17 or 18 gauge wire. I might need to go to Fry's!

Regards,

Dave

Raymond.Mao66

helloļ¼Œlatest Ni-MH 4800mAh ļ¼Œdo you have some interest? maybe a try is necessary. Good luck! Any question, contact [email protected]

Red Scholefield

My Feedback: (9)

Get silicone wire - here is a good source http://www.atlantahobby.com/shopexd.asp?id=5910 This is for 18" lengths but the last time I was there they had it in bulk off a large spool. Just ask them. e-mail [email protected]

RCguru09

Shorter is always best. less wire mess.

c550

My Feedback: (16)

Red,

Thanks for the tip. I have ordered the wire, and am standing by with my soldering iron.

Dave