ahicks

My Feedback: (2)

Might not be? I'm just concerned over the amount of current going through that circuit board and the connections to/from it. I'm no electronics expert, but if I can reduce the load on the receiver buss and provide the rudder with a nearly straight shot to the battery, why wouldn't that be a good plan?

That, and I know it works. I've been flying it for quite a while now (3 seasons?).

Just tossing the idea out there. If it doesn't make sense, or makes you nervous, keep going the way you are!

BarracudaHockey

My Feedback: (11)

I have no doubt that it works and I dont want to come across as busting your chops.

It certainly can't hurt anything.

That said, plenty of folks are running big rudder servos on 3D planes with big surfaces and a lot of load, off a receiver bus w/o any problem.

I'll give you an example of how I have my Corvus (avatar pic) setup.

1 2500mah A123 with two outputs. A heavy duty 18 ga output with a deans. This plugs into a Smartfly super switch. The superswitch has two JR outputs that go to a Spektrum AR9020 receiver.
The other lead is a standard JR connector that goes to a JR heavy duty switch, an RXEXL ignition kill, and on to the ignition.

I have or have had the same setup in 3 or 4 50 and 60cc planes with hundreds of flights. Several of those flights are by a couple of guys that fly a lot harder and better than I do, and the electronic installation has been flawless.

Savox 1231 or Hitec 7955TG servos for the most part as well.

speedracerntrixie

My Feedback: (29)

I can't see where it would make a performance difference but I can't see a reason not to go directly to the rudder servo either. Just a different voltage path.

ahicks

My Feedback: (2)

BarracudaHockey,

OK, just talkin...

It's nice to see somebody pushing an A123 with a 50-60cc engine. That confirms the thought that the single battery has no trouble supplying adequate amperage. I'm not flying, nor do I plan to fly, anything bigger than a 30cc. My flying style (abusive!) won't let me fly the bigger stuff. I run out of talent, ideas, and altitude too often to have that much money in the air.....

Regarding your setup, you're running your receiver and all servos through a single switch? That doesn't make you nervous? Providing for extra amperage using my plan with 2 switches is just half the reason I do that. The other is for redundancy!

The other thing is, that Smart-fly super switch looks JUST LIKE the ones I use from EMS

http://www3.towerhobbies.com/cgi-bin...?&I=LXPNU2&P=7

and Hobbyking - which also features a power LED

https://www.hobbyking.com/hobbyking/...dProduct=65765

Another advantage for running dual switches I don't talk about much...
I actually use those charge receps to charge my A123's, without having to remove them from the plane or dig around inside it for connectors. The power leads coming from the bat. pack I build will both be HD 3 wire Futaba connectors (22ga I believe?). Red and black are used as you normally would, while the white is used as the 3.3v lead needed for balancing purposes.

This lets me plug those leads into HD switches like the ones we're talking about with the built in charge port.

The only caution is that the white wires on the receiver side of these switches needs to be cut/disconnected. The signal circuit on the receiver buss has no use for the 3.3v. found on the battery side of the switch.....

This setup lets you build charging leads/adapters using 24"+ servo extensions that plug into the switch's charge jack. Done correctly, you can't plug them in wrong on the plane side. On the charger side of the extensions, you just set the charger side up properly so one lead is a balance lead, the other just power. Nice and neat....
-Al

speedracerntrixie

My Feedback: (29)

A single switch on a 30cc-60cc airplane would concern me too. Anything larger then that and I will automatically go to a soft switch setup. Anything 100cc and up I automatically go to a Power Expander setup. I have seen way too many mechanical switches fail to the point I would want redundant switch before redundant batteries.

BarracudaHockey

My Feedback: (11)

The super switch has one big lead in and two smaller ones out to the receiver thus it carries more amps. Its not the same as the one you linked to Tower.

If i'm worried about power delivery (my 60cc Mustang for example) then I go to a power safe receiver setup with a soft switch and dual heavy duty inputs, my 120cc Pawnee is setup that way as well.

But this plane has the setup described above and doesn't suffer any issues with current delivery, thats a 50cc with all 7955's

http://youtu.be/J8DZ-gyauXg

ahicks

My Feedback: (2)

I was thinking of the switch itself, and the fact there's just one of them? I understand the wiring to/from it is different (way heavier!).

You're obviously getting all the amps you need, but you might want to address the redundancy thing some time?

-Al

Lproee

About using one battery with dual switches feeding RX, I simply need to split the wire coming out of the battery and solder to it another wire with a male end that will feed the second switch? Like making some sort of Y harness directly from the battery, this is how yo split the power from single battery to two switched and then to the RX?

Thanks alot!!

speedracerntrixie

My Feedback: (29)

The way I would go is have a battery with two outputs that connect to two switches. one switch goes into battery slot of RX, the other into an unused channel slot. The battery leads and switches should be a minimum of 22 gauge.

BarracudaHockey

My Feedback: (11)

How many batteries does your transmitter have?

AllTheGoodNamesAreTaken

My Feedback: (180)

Nice! I'll have to remember that quote.

speedracerntrixie

My Feedback: (29)

One, but it's not exposed to high levels of vibration or high temps from a canister exhaust system.

cloudancer03

My Feedback: (22)

thanks/.just wondering about servo extension heavy duty from the second battery to the rx.the throttle servo would use one lead and the extra batteryn the second lead and go to available port on rx.not sure why i would need it. as for the weight on second life battery.if i were going to do extreme 3d as I do on electric 3dh planes i would dump the 3 ounces but this being my first gasser i really dont care i am sure it will have plenty of power.

ahicks

My Feedback: (2)

Regarding a fair comparison, one could look at amperage requirements, or the number of flight pack switch failures you've experienced/witnessed?

Time to move on. I didn't mean to be critical of your set up either.....

BarracudaHockey

My Feedback: (11)

No its cool, I'd love to have this chat over a cold diet Coke at the field. I always enjoy talking to folks, learning what works for them, and applying it to what I practice.

I have a lot more issues with my thumbs than my radios though.

Muttdog

Try making the extensions yourself. Hitec sells 50 foot lengths of it's 22ga servo wire ($17) and HK supplies the JR/Futaba terminals and crimpers. For less then a $50 initial investment you will be able to make extensions for the next 5 planes. Not only will you recoup the initial investment but your planes will have that custom tailored look. I started making my own extensions a year ago and have not looked back. Now I laugh when I see the high prices of extensions hanging on the wall at the LHS or online vendors selling those $15-20 multi servo "quick click" style extensions. Those cost me about $3. 20Ga is all well and good but unless your running 20 foot lengths there really is no reason. A standard JR type plug is only rated at 3 amps so unless your upgrading the connector or running obscenely long lengths, it's simply extra weight and $$.

cloudancer03

My Feedback: (22)

I purchased the futaba heavy duty extension .it's 20 and will connect second battery and throttle servo .better to be safe than sorry.

Lproee

So at the buttom line, what do you think can cause the RX battery voltage to go under 4V using 5 222oz./in. savox 0251mg servos ?

The time it happened the battery was connected to regulator that regulated the voltage to 5.9V.
This kind of worries me... maybe somthing is wrong with the battery itself.
6.6V LiFe 2300mah 30c.

Thanks!

All Day Dan

My Feedback: (5)

Batteries are mortal just like us. Never assume that one is good until you cycle it to determine its capacity and that includes a new battery. So, cycle it to determine its condition. Dan.

speedracerntrixie

My Feedback: (29)

I would not bother using a regulator with LiFe batteries. That may have been the issue.

ahicks

My Feedback: (2)

So the potential for a bad cell has been mentioned, and an unnecessary regulator. I'll add an amperage bottleneck caused by inadequate wire size, a switch acting up or possible one with inadequate capacity, or even a frayed connection/cold solder joint.

There's also the potential the receiver buss may not be up to supplying the kind of amperage required to run 5 servos of that size? I took a quick look around and could not find that spec. Might be worth a phone call?

speedracerntrixie

My Feedback: (29)

Al, at one time Peter Goldsmith ( Team JR., TOC pilot ) told me an RX is good for 60 amps. The power bus on the PCB is actually quite large. Now if a regulator that is intended for 2 cell LiPo was used with the jumpers set to 5.5V was used on 2 cell LiFe who knows what the actual voltage with load would be.

Lproee

Ok, I just ordered some HD wires for all the servos.
I'll connect all the system using those extensions and connect the battery to the RX using HD switch(without regulator).
Hope that would fix the problem, anyways I'll let you know about the results.

Thanks guys! Have a nice day.

ahicks

My Feedback: (2)

60 amps? Really?

Let's consider this for a second. I don't see how that's possible. Each of the servo connectors is rated at what? 3-5amps maybe is what I keep seeing. If that load were perfectly split between them, a 7 channel receiver would handle 35 amps max, or a 9 channel 45.

Further, if the entire load were being fed with one input (say the one coming from the switch), that connection is limited to 5 amps due to the connector. How is it able to supply 60 amps? Or, backing up to the thought previously posted, the receiver itself, possibly the ign. switch and module, and enough power left over to run 5 really big servos?

Seems like a stretch to me. That's how I justified what I'm doing.... -Al

speedracerntrixie

My Feedback: (29)

Al that was his point. The bus will handle more current then we have means to provide. For most cases having two standard connectors feeding the RX will provide enough current for airplanes up to 100cc. Anything that big or bigger then the options are Power safe RX ( Spektrum only ) dual receivers to split the load or a power box.