bgold

Somewhere I have been reading about the amp draw of the big servos (5945 & 5955) and that the biggest limitation in most systems is the standard servo connector that plugs into the receiver from the regulator having a 3 amp compacity. Fromco and Smartfly have been putting two to three outputs per regulator to help overcome this limitation. I have regulators with two outputs each but only three ports available in the receiver. Would it be advisable to plug in two outputs from one regulator and one from the other reg or will that upset the aplle cart in some way.
Ten port receiver, 9 channels plus battery
Aileron - 2
Elevator - 2
Rudder - 1
Throttle - 1
Electronic Kill Switch - 1

Tired Old Man

My Feedback: (1)

That connector capacity is 4 amps, not 3. They begin melting down a little over 4. As for most receivers, they can easily handle and distribute over 60 amps, but as noted the individual servo connectors cannot. I know of no installations having a servo plugging into a regulator and then to a receiver. Typically, multiple leads on a regulator would be used for direct powering a receiver, and then a Matchbox or other function if a direct power source isolated from the receiver is desired. Using more than one power lead from a single regulator to a receiver IS NOT a redundant power source. There's no point in using more than one power lead into a receiver from any single regulator. Matter of fact, don't run more than one power lead from any given regulator to a receiver. That was said various ways three times to get your attention.

If you have a good power supply with more than adaquate capacity you will have few electrical fears unless you install servo linkages improperly. Meaning either binding linkage, unequal servo travels and linkage lengths between ganged servos, and/or "over driving" a servo. Using a servo amp and volt meter during those portions of the surface control installations will eliminate any issues if you pay attention.

Hammbone

My Feedback: (309)

Huh?
If you run one lead from a regulator to your RX, you are limited by the current flow capabilities of that lead. If it is a standard connector, the limit is 3 amps (or maybe 4 amps as you said). If you run 2 leads from the regulator to the RX you have just doubled your current flow capabilities, if you run 3 leads, you have tripled it. You are correct in saying that it does not make it redundant, but saying that there is no point in doing this is just wrong. Why then would Fromeco even make regulators with multiple outputs?

To answer the original question, I think it would be O.K. to do what you suggest. One battery may drain quicker than the other though. You will have current flow capabilities of 9 amps (or maybe 12 amps, I'm not sure so I will not argue that point). Depending on the number of servos in your system, this may be enough current flow.

I will say that this is the reason that I use 2 RX's on 35% planes. Not for redundancy, but for proper current flow. 2 RX's gives me more ports to plug in more leads from my regulators. It also allows me to plug in 4 aileron servos directly, without the use of Y's or matchboxes or power boxes.
Now on 40%ers, I use a power box. This gives me good current flow, and allows me to plug in 6 aileron servos without the use of Y's or matchboxes.

Jim

krayzc-RCU

My Feedback: (31)

so what is safe limit on 5955 on one receiver? no power box and all those fancy gadgets?

Hammbone

My Feedback: (309)

I know of no "set in stone" answer to this. It's personal opinion.
On 33% to 35% planes, I always use 4 aileron servos, 2 elevator servos, 2 rudder servos. a throttle servo, and sometimes a smoke servo. That's 10 servos. I use 2 RX's on all my 33% to 35% planes, along with 2 RX batteries, and 2 regulators with multiple output leads to the RX's.
Some guys only use one servo per wing and one servo on the rudder. I don't think that's enough, but if that's all you are using, then maybe you only need one RX. It's a personal choice.

Jim

Tired Old Man

My Feedback: (1)

On planes of the same size I typically run a dual battery/regulator installation, providing a power lead from each regulator to the receiver. I also still use Matchboxes for mating things up where I plug an extra regulator power lead directly into a Matchbox for direct pwer to the matched servos. They don't draw from the reciever at all. That minimizes the number of ports used in a receiver dedicated to power supply and still provides more than adaquate supplies to the servos. All in all, if a system is dragging more than 6-8 amps combined through all the ports with everything working something is probably set up wrong. Adding all the neutral currents together for my installations, which sound the same as yours, and I typically come up with just over an amp at worst case, and under an amp in most. Full deflections only create extremely brief load increases with holding deflections having significantly less than full pull draws.

bodywerks

My Feedback: (4)

Typical amp draw is only like 2-3 amps average on a 35% plane, assuming no servos are fighting each other and the engine doesn't vibrate more than normal. Max amps it will typically ever see is 10 amps or so, and that is usually only in short spikes, like in a snap or blender, and such.
With your setup, three leads are fine, but you probaby should plug all four leads in to balance the current distribution. You can "Y" that extra lead into any open channel without consequence, except maybe the slight voltage loss through the additional connector.

sillyness

My Feedback: (25)

You could Y your extra lead with another servo as stated.

I just maidened my 41% Extra today... 2RXs... 2 Fromeco regs with 3 outputs each, 3 into each RX. The system can handle 18 Amps total, limited by the regs themselves. I am using 11 servos in total... each with their own power supply... no Ys or matchboxes or power boxes. Plane is set up for IMAC. Works like a champ.

In answer to your question... the chance of all servos stalling and drawing max current simultaneously is virtually nil. Look around on the Fromeco site... they used to have a graph of a 35% plane's current draw in flight. By far the biggest draw was a blender... I can't remeber the current though. Good thing there're no blenders in IMAC. It's a no-talent maneuver anyway... just a stress test. I'll just keep ooohing and ahhhing when other people do them.

krayzc-RCU

My Feedback: (31)

sillyness
was the test on one receiver and battery ?

yarom

My Feedback: (82)

I have just been measuring power consumption on the HS 5955TGs and comparing them to JR 8411s and 8611a's.

The answer is, there is no difference at all. I measure roughly the same power draw in both types of setups, using 5 servos each and directly connected to the Rx (Spektrum) which is rated at 20A.

Recharging the battery shows exactly the same consumption per flight, or roughly 150mah to 200mah per 14min flight, depending on how much 3D was done.

All were flown on similar size aerobatic airplanes in similar situations - QQ YAk 86, BMW Extra 330L. I use SmartFly SuperReg on all my airplanes with two LiPos and going with two 20G leads to the Rx.

If you want to reduce some of the current going through the Rx, you can use a Matchbox, which can be powered directly on it's own.

I am beginning to think some people have setups with surfaces that are not traveling freely, installed too tight at the hinge line, sealed too tight at the hinge line, or simply linkage binding and it's draining their batteries through the servos. If the surface does not drop from its own weight when not connected to the servo, it's not installed right...

krayzc-RCU

My Feedback: (31)

tks for that scoop that is def good info to know as i thought the newer stuff drained more even though i have the old stuff 8411

bodywerks

My Feedback: (4)

Truer words were never spoken! The only time it is remotely impressive is if it is done low enough to where it almost hits terra firma, lol!

ajay1

Have just started using JR 8711 servos on my Comp-Arf Super Extra with a 200 cc engine and Powerbox---2/Ail---2/Ele---Cant use my standard 4200 Mah Li-Po's any more as they are insufficient.Now using 2 ThunderPower Li-Po's of 8000 Mah each.Does anybody have power draw nos: on this.

Tired Old Man

My Feedback: (1)

Too easy to obtain your own numbers, which are the only ones pertinent to the installation anyway. Buy a Hanger 9 servo amp and volt meter and measure what things are taking, then note the battery capacity used for a flight. Then you will have numbers that actually pertain to your own installation and not someone elses. The problem with using numers developed by someone else is that you are taking as gospel numbers that may be developed with an extremely poor installation. You don't have a clue if the other person knows what they are doing or not, with not being fairly common.

BaldEagel

Had issues with my power regulator cutting out, so I put an Wattmeter between the battery and the Rx, with just the fus servo's on board no wings fitted and stirring the sticks violenty admitted I was drawing momentaraly up to 15amps with three 5955 and one 3003 on the throttle, linkages all checked and nothing binding or on its limits, this installtion has now flown and takes 250Mah out of the battery for each 10min flight, the battery is a five Sub C cell 3700Mah and all seems well. Posted for information.

Mike

bodywerks

My Feedback: (4)

you sure it wasn't 1.5 amps?? It's been a while since I did that test, but I know I didnt get into the double digits - same setup as yours, 3 5955's and a mini throttle servo, no wing servos...

BaldEagel

It was 15amps, I was being very brutall with the sticks moving everything at the same time corner too corner, I only wish I could get three 5955's and a 3003 to pull only 1.5amps, I would not have to charge my batteries for a month.

Mike

yarom

My Feedback: (82)

Anybody knows what is the difference between the HS 5955TG and the HS 5995TG?

Got my servos from the Servo City sale and it seems I ended up with some old stock 5995s. Looking for info online, I can find specs but it seems they are discontinued.

Are these suitable for flight?

BaldEagel

yarom

There has been some disscusion on this very point on the Radio forum, unfortunatly I can't remember where, but is started with the premise of "Can the 5955 be used with 7.4volts" the 5995 are a robot servo that can, but the 5955 is an aeroplane servo and its not recommended to use 7.4volts because of the reduction in life and possible unreliability, that was from the Manufacturer.

Mike

Tired Old Man

My Feedback: (1)

The 5995 is a robotic servo, has 180 degrees of rotation, mogambo torque, and is driven at 7.2 volts.

In reply to the person that drew 15 amps with only four servos, here's another situation. Dual 8611's on aileron, dual 8611's on rudder, single 8611 for each elevator half, 4721 on throttle. That's a total of 9 high torque servos, 8 of them digital. Max throws and swinging the crap out of the surfaces and hit momentary peaks of 7 amps, I had to attempt to hold surfaces in place to draw more. As I said before, the difference will be in the installation. Look again to see where you're binding things up.

Richard D Bahmann aka/Wrongway

My Feedback: (42)

Yarom,

I have one of those 5995's in a 29% Extra on the rudder. I have not had a lick of trouble running it for over 40 flight hours. I run two 1200-6v NIMH on that plane and along with the 4 other 5945's was never the hint of a glitch.

People will tell you that the resolution is diminished in the 5995 but I was unable to see any difference as compared to the 5955 in my other plane on a similar power system.

Richard

BaldEagel

Silversurfer

It was I, the reason for checking all this was that my Medusa regulator was cutting out with the amp draw, I have no binding surfaces the flappy bits drop by thier own weight, the only binding there could be would be friction in the ball joints, I will check this and report what I find.

Mike

bodywerks

My Feedback: (4)

Just for grins, check the current with just your elevators both halves at the same time) by not plugging in the ailerons and unplugging the rudder. Then check your rudder servos seperately and each wing half seperately. In theory they should all pull about the same amps.

Tired Old Man

My Feedback: (1)

That's pretty much the way I start an installation out after the matching process. Going through each surface group of servos I'm looking for anything that jumps out from the rest. Typically, my paired servos will only draw from .01 to .03 at idle current, with max draw for any given pair for a max deflection pull rarely going over 1 amp and instantly backing down to .5 amp or less.

The times I've found higher draws has generally been when angles in the linkage caused a bind. Sometimes the linkage would be making contact with a flight surface at max deflection and at others the ball link would need to be moved to the other side of a servo arm to relieve binds. Ball links by themselves are a super linkage toll but it's absolutely possible to bind one up unknowingly.

sillyness

My Feedback: (25)

Correct me if I'm wong here, but if you program the servos correctly and there is no sound when you lift the weight of the surface off the servo at any given point throughout the travel and you can feel the tiny bit of gear slop in both servos simultaneously while you lift the surface, does this not negate the need for current meters etc?

FWIW... the most useful tool I found for matching servos is a paper protractor I printed out and glued to thin cardboard. I cut out a notch for a servo to fit in so it places the output of the servo at the center of the protractor. If both of your servos have exactly the same center and travel exactly the same amount it is very easy to match up your surfaces with pushrod and control horn length.

The a video on DoD that shows the process. Worked better than anything I ever tried.