MaxSouthoz

You can tell I'm new at this.

I'm going to run eight HiTek 5645MG high torque digital servos in my 1/4 scale Pawnee.

Which battery should I use?

Does it connect to the three pin port marked battery?

Cheers
Max

Edit . . . I will be running a gas engine.

kdunlap

My Feedback: (12)

Max you may want to rethink that power setup. I would suggest adding a Powerbox or Smart-Fly system. With 8 servos you have a pretty good chance of encountering a brown out situation if you just plug a battery into the receiver. You might be able to get away with just a regulator with a dual battery but you should measure your power draw.

Ken

kdunlap

My Feedback: (12)

And to answer your question you can plug the battery into any port, just NOT the telemetry. This receiver needs a minimum of 3.5 v. If one or two of your servos binds or stalls you can draw down pretty quickly if the power is not regulated. .

DGrant

My Feedback: (4)

Power input will connect to the battery port. Usually the battery connects to a switch, the switch connects to the Rx input AKA battery port. I'm thinking you have 2 aileron servos, 2 elevator servos, 2 flap servos, 1 rudder servo, and 1 throttle servo. Is that pretty close?

You didn't mention anything about ignition, so the plane is powered by a glow-engine(?) I'll say... I would also imagine you're using a Spektrum AR 9350 receiver (how am I doing so far....) wtih a DX 9 transmitter...

The HiTec 5646 is rated for 6.0v.... of which you'd be good with a 6.6v LiFe battery if you wanted. I have many Hitec servos running from that same source. With all you have there I would say try and go wtih at least a 2500mah LiFe battery if you're running a glow engine. If you're running a gas engine with a BEC (battery eliminator circuit) device, thereby running the whole plane from one battery.... I would say go to a 4000mah LiFe battery.

Your servos are what limit your voltage at this point... which is fine.. they'll work just fine at 6.6v... but I know you're running the 9350 Rx, which that's good up to 9v... but the servos are only good to 6.6v... If it weren't for those, I'd say go to dual LiPo batteries(parallel circuit) that would 7.4v... but with what you've got, I would say a 4000mah LiFe would do fine.... even if you have to run ignition.with it. I've got a very similar configuration on 6.6v with a 4000mah LiFe battery.... So what engine are you running in it?

MaxSouthoz

The motor is a 60cc twin DLE. I plan to have a separate battery for the ignition system.

I have an Arduino board for my flashing beacons; and the board and the nav lights and landing light will also have their own battery.

A friend has suggested the Turnigy Receiver pack 5000mAh 6.0 Volt NiMh. I've ordered one to try it.

I plan to build a test board with everything mounted and possibly loaded, before I bolt anything into the aircraft.

That way, if I get brown outs, I can look at Ken's suggestion. Power Box is a lot of money, but not compared to the cost of replacing a crashed Pawnee.

In the meanwhile, I'm up to 12 hours on the Sim and looking forward to flying the Apprentice soon.
Cheers
Max

Mark Powell

Yes, always use a separate battery (and switch of course) for the ignition. The same is true if you ever use retracts except air operated ones - don't believe the claims of the manufacturers of electrically operated retracts that they always 'switch off' if jammed.

Be careful with these assorted 'Powerboxes'. The genuine Powerbox ones are well made but some of the others aren't.

And many of them are more complicated than any other part of the aircraft electronics so introduce another point of failure.

But if you 'go simple' use a 5 cell NiMh of a decent capacity, never a 4 cell one as they can be at 'near brownout' voltage when you put a load on them. A 5 cell NiMh one won't damage anything whereas a 2-cell Lipo can be over the maximum operating voltage of some equipment, and if you introduce a voltage regulator to overcome this it's another point of failure. The same is true of a 'backup battery' system that uses two batteries and diodes to prevent one charging the other. Diodes fail more often than batteries do.

Remember that many NiMh batteries (except genuine Eneloops) don't hold their charge well so charge the night before, or even better, on the day you fly.

MaxSouthoz

Thanks, Mark.
All Good Advice. It seems like my friend has advised me well - as well.

https://hobbyking.com/en_us/turnigy-...er-series.html

Now. I'd better get back to the simulator.

DGrant

My Feedback: (4)

As you learn more, you will learn different things... and you will use what works for you and your budget. Your transmitter and receiver alone can handle everything you're contemplating... along with an ignition battery eliminator circuit (IBEC). There's a device that is being widely used by Tech Aero that's called an Ultra IBEC, Ultra IBEC - Tech-Aero Designs LLC . Just something to ponder for you as an option. There's certainly many people using these(including myself) with great success.

In any case you should have a switch of some sort to be able to shut down the engine from the transmitter.... of which the Ultra IBEC operates from the transmitter... We used to put micro-switches(which still take a channel from the tranny)... and a main switch on the plane(in the form of a Rx switch usually), as well as the seperate ignition battery....... but the IBEC eliminates all of that, as it plugs into the Rx, takes power from the Rx battery, and operates through the tranny. What is recommended though is redundant batteries to the whole system... and there's main switches (Wolverine comes to mind)... that accomodate 2 batteries (wired in parallel through the switch).... and you can run higher voltage packs... such as LiFe's,(at 6.6v+) or LiPo's(7.4v)...and take advantage of the modern system to a much greater degree.

Of course you can use NiMh batteries, and micro-switches, and all that stuff... and if your comfortable with that then you should... Heck, we used to use 1400mah NiCads, they worked fine as well... but the demands of these newer digital devices are such that the advantages are really in the higher voltage batteries. Newer battery chemistry's go well with higher end equipment...
.... Just sayin'. Really for sake of conversation. I'm sure our cell-phones wouldn't do as well on NiMh batteries, so they use lithium based power... same for notebooks, lap-tops, and yes... I do believe current RC equipment as well.

I'm only suggesting options is all... If you do the math, figuring the cost of the IBEC device($40), vs. the cost of another battery and switch(es)... and the fact the IBEC gives you the transmitter control... well.. it's something I just throw out there for you to ponder and look into.
Welcome to radio-control in 2017!!! Isn't it great! I'm sure you'll do fine with whatever you choose.

DGrant

My Feedback: (4)

Here's a poll I just ran across that someone put up over on FlyingGiants.com. That's another leading website for large/giant RC planes. The poll is on ignition kill devices... so there's some products named in it that are being used as ignition kill, or IBEC's.(again Ignition Battery Eliminator Circuit). Just Google each product and you'll get an idea of what's interesting, and what, if any, that might work for you.

https://www.flyinggiants.com/forums/...d.php?t=221694

MaxSouthoz

Thanks, DG.
I've been in model railways for decades and watched the technology grow there.
I've definitely heard of the IBEC.

I've got HiTec servos, so 6 Volts is the limit. That's why I went for the 5000mAh 6.0 Volt Turnigy.

I'll follow the link and give it a good looking at.

Cheers
Max

MaxSouthoz

Ken

Is a Powerbox what some people call a power expander?

Cheers
Max

DGrant

My Feedback: (4)

What model Hitec?.... Anything that's rated for 6v is fine with a 6.6v LiFe battery. I run everything on LiFe's. Older servos(very old) were prone to chatter even at 6v(which is why we used regulators when using a 6v battery(this was 30yrs ago)), but all newer generation servos work very well on 6.6v.... especially the digital variety.

Oh wait... I reread, and you're using 5645 digitals. They'd be very happy with a LiFe battery. I have well a few dozen 645's(non-digital on different planes of course) running on 6.6v. Very good performance. It's up to you though,

The fact is, a 6v Nimh pack will peak at near 7v... and a LiFe peaks right near that also. I've got a 50cc plane I run on a 4000mah LiFe(6.6v) that runs everything..digital servos, etc..including ignition(Ultra IBEC). LiFe packs weigh about half of what Nimh do, with more capacity, and power, which those factors are the biggest advantage. I dare not ask what a 5000mah 6v NiMh pack weighs... haha.. but the 4000 is lighter then a 1500mah nicad and a ton more power.... again it's up to you.

Check out that whole FlyingGiants site, and double check what I'm sharing of course.... just make sure you know where it connects... ha... ... I'm only sharing this other info, as you've got some good equipment, and you'd probably want to know how to get the most out of it.... and all of it would work well with a LiFe battery.

The only battery you can't use is a LiPo(7.4v or more)... that would put your servos over the top... but your receiver, and ignition would work. Has your friend used LiFe's?... If not, maybe you might try them, and share the info with him. We're all going to LiFe's these days.... and HobbyKing really does have some great deals on those, and the chargers too, as they take a newer style charger(around $30 for a decent one)... and those chargers charge any battery on the planet... and chemistry, cell-phones, notepads, laptop, even old Nimh's.. So... just food for thought.

MaxSouthoz

Thanks, again, DG.
This thread is becoming quite a reference resource.

kdunlap

My Feedback: (12)

Max,
PowerBox and Power Expander are trade names for roughly the same device. Here are some links below and suggestions that you can use depending on your setup.

Castle BEC Pro:
CC BEC PRO 20A MAX OUTPUT, 12S (50.4 VOLTS) MAX INPUT SWITCHING REGULATOR
Pro: Lowest cost alternative. Good, regulated power, redundancy.
Con: It uses 2 channels on your receiver. So, if you need all nine channels or if all 8 servos need 8 channels, this will not work for you unless you use some creative wiring and lots of Y cords.

Smarty-Fly Power Expander **this is my system of choice***
​​​​​​
PowerExpanders
Pro: Higher end units allow you to have a failsafe for your ignition attached. Dual power supplies, dual power inputs. Bat sharing.
Con: A bit tricky to set up as the instructions could be better

PowerBox Regulator -only-
Parallel Regulator Sensor, from PowerBox Systems, pbs-6310 - Chief Aircraft Inc.
Pro: A bit more refined solution than just the BEC Pro. It has dual power inputs, failover. Nice switch interface.


Full PowerBox system
Evolution, with Sensor Switch and Patch Cables, from PowerBox Systems, pbs-4230 - Chief Aircraft Inc.
Pro: The Cadillac of airplane power systems. Does everything you can think of.
Con: $$, but what did you spend on the airframe and engine??

kdunlap

My Feedback: (12)

PowerSystems
I use the EQ6 on my 1/4 scale Lysander

DGrant

My Feedback: (4)

Yes... there's a few terms for very similar devices. I know there's a few or more on the market right now, I've not used one yet, as most everything I have can run fine without the biggie need for such a device. I don't have first-hand experience with them, so I won't comment too much on them, I've got 50cc planes, and a 100cc plane that I don't use one on. No problems here though... and I run 9 servos on one of these planes... and at least 7 servos on the others.

These devices are probably mentioned more on FlyingGiants, as they're used in ... well... flying giants... larger planes, with large power needs, and sometimes very sophisticated high-voltage systems... and I'm sure sometimes not so sophisticated systems also... Definitely Google and study them though if you might think they'd help... .as well someone with first hand experience might comment right here.... If not someone on FlyingGiants would know first hand.... either there or the Giant Scale forum on this site... This being the radio forum encompasses more radio oriented traffic and feedback... and although power systems are very much a part of radio systems... It might be easier to get a bigger audience that's proned to use these devices, and good experienced feedback if you're question on that were in another forum or 2...of course it's just a suggestion to get some good first hand feedback for you. As right now, your question is hidden down in this thread... it is a very good and important question though, so you might throw it out in other forums more specific to power-board use.

MaxSouthoz

. . . and here's another one, KD . . .

RCCSKJ POWER BOX X4105 [X4105-GL] - USD $89.00 : Austars-Model.com

This appears to have 16 possible outputs.

It "feels" like I'm on the line between needing nothing more than a good battery and an IBEC; and/or going for the Power Expander.
DG's first sentence seems to confirm the former option.

My plan is to set all of the system up on a bench board. The eight servos will be loaded with springs and then I'll give the sticks a good working over to see if I can cause a brown out.

This system has served me well over the decades - although model locomotives don't fall out of the sky.
(Having said that, I must admit some have committed suicide by leaping off the layout).

I really appreciate your input/s.
When I get it built, I'll post up my results if anyone is interested.

Cheers
Max

DGrant

My Feedback: (4)

Max... study it all. kdunlap has some great info there. I'm learning myself... thinking about future gadgets now.. haha.