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SPEKTRUM AR 12120X any problems

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Old 05-02-2017, 12:09 PM
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CRye
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Default SPEKTRUM AR 12120X any problems

Getting close to my first flight for Aurora. Running Powerbox switch and set for 6v with Lipo 7.2. Came with an AR12120X running 8711 servos on all flight surfaces. Anyone having problems with the 12120? Manual claims it can handle the power load.
Thank you
Charles
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Old 05-02-2017, 01:21 PM
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Zeeb
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Ummm.....

That rx is quite capable of taking 9.9 volts input and is designed with an internal "Fail On" fail safe switch. In order for it to work correctly input power must be through the 16g. power wires and you need to use the On/Off switch which came with the rx as it jumpers the signal/ground leads of the switch port. It is NOT a conventional On/Off switch.

That said, how do you propose to hook it up using a PB switch?
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Old 05-02-2017, 05:12 PM
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Been flying nothing but the 12120s. I have it in my Carf 1.3 Hawk with life batteries running 12 8711s servos no issues. I have one in my BVM PNP F-16 1/5th Running Lipo 2s. It came with all HV servos. no name and no problems.

Like Zeeb said you have to use a good gauge power wire to the RX from the Batteries and the switch is a Dead man switch. I agree, No need for any regulators or PB. I like the KISS method.

JMHO
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Old 05-02-2017, 06:45 PM
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CRye
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Thank you for the replies.
Will the 12120 regulate servo voltage? My 8711s are original style and not HV.

I did not get the switch with the bird, but I did get the PB. I downloaded the RX manual today and saw that the switch is special. The smallest wire in my battery lead extensions are 14 ga and its 12 ga on the battery itself. I have them pushed forward for CG.
I just hooked up the PB per the manual with a 2 cell Lipo on each input line and the RX lines as line 1 and 2.
For the battery in position 2, the backup on the PB, I made a Y extension to power my smoke pump which is brushless with an external ESC. I pulled the power lead out of the control line as it has a BEC to keep the 7.4 back feed out.

I will try to review the RX manual as I also need to set the failsafes especially turbine shutdown.

What TX do "yall" use? I have a GEN1 DX18. Met a HH rep at MS Afterburner and he recommended doing all the software upgrades.

Thank you
Charles
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Old 05-02-2017, 06:52 PM
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bcovish
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The 12120 will not regulate servo voltage
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Old 05-02-2017, 06:54 PM
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CRye
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PS, no JR switch in the system PB only. On PB hold set button and press battery button, get led signal, then repeat for battery 2. Stays on regardless of v drop, I guess unless total mechanical un hook.
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Old 05-02-2017, 07:14 PM
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Hi Bob!
Looks like I will keep PB in system as v regulator.

I guess I saw you at MSA, I will have to start carrying a list of people I have communicate with and phone #s so I can meet them.
Lot of rain here may again delay test flight. Grass field in low wet area not good with 50Lb plane and narrow tires.
I was toying with the idea of going to Mt Pleasant.
Cheers
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Old 05-02-2017, 07:20 PM
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Zeeb
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Man, I really like the PowerSafe rx's and have a number of them in my gassers and one in my KingCat.

But I think that what you are proposing is a really "not good" idea. The PowerSafe rx's were designed to be simple, rugged and capable of putting a lot of power out to the servos all the while employing a battery isolation function and a fail on soft switch. You are adding a number of possible fail points and defeating a good chuck of the rx's features, or at least that's what it seems to me. I'm not even clear on what you've got going on.

The power system is the heart of the model and nothing else works without that and with a turbine, I urge you to consider a different "cleaner" install.

The way cleanest option would be to change out the servos. The next option would be to run a PowerBox PE which can regulate the voltage down and the last option which I consider to be the very best, is to switch your battery type to the A123/LiFe chemistry which has a nominal voltage of 6.6 volts and your servos will be perfectly happy with that power source.

Not only that, but you won't have to pull the batteries out of the model to charge them.....

Last edited by Zeeb; 05-02-2017 at 07:23 PM.
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Old 05-02-2017, 08:05 PM
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bcovish
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Agree with Zeeb on changing battery type. I'm running 6.6 batteries, no reg with non-digital servos.

Yes I was at MAB. Also will be at Mt.Pleasant. If you go, ask for Bob-O
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Old 05-02-2017, 08:30 PM
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CRye
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Zeeb and all
Thank you for the inputs.
The bower box part is only a switch that will regulate voltage and swap batteries if main drops below v threshold. I should have realized the 12120 has an internal power input swap function since it has 2 input leads like my old multiplex RXs. I will at least give it some serious ground testing.
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Old 05-03-2017, 03:12 AM
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You mention that the plane came with a PB but, not the PB switch, is this correct? If so, which PB do you have. If it's the PB Baselog, it's an excellent way of providing regulated power to the Spek power safe receivers. I use it to provide power to the Jeti CB200 now as well.
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Old 05-03-2017, 09:34 AM
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flyrc,
I should have stated its a switch. I previously downloaded the manual but cannot find it on PB net site now. Thankfully I did print a hard copy I still have.

It may be an older version with a set button and two more, one for each battery.

Manual for PB switch seems to indicate it will drop out at 3.0v. That makes me really concerned, what if the 12120 decides to switch input lines but the BPS has not???
Also my quick read of the 12120 manual gives me the impression that under higher loads the 12120 will pull amps from both leads????

Spektrum fix for 7.4 to 6.x volt operation per 12120 manual is a regulator on each battery line SPMVR6007. And then I looked at the 35-50 amp capacity of the 12120 vs the 7.5 11 peak amps for the regulator!

Simpler solution does look like go to 6.6v batteries and plug in direct. But I spent a lot of time making battery trays that slide through the cockpit almost to the nose and got 25 oz of dead nose weight out of the airplane.

Another can for worms.
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Old 05-03-2017, 10:16 AM
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I feel your pain but a lot of us have faced the same kind of issues at one point or another. What I finally decided to do is standardize my battery setups and I have always liked the A123 cells since we had to harvest them from DeWalt cordless drill battery packs.

As I started getting into turbines, they all had LiPo batteries for the ECU so I had mixed batteries in the models and had to pull the ECU battery out to charge. A number of the battery suppliers will build you an A123 pack in whatever configuration you like and I did that with a couple of Warbird gassers where the packs had to be basically buried and not very big. So WrongWay built me some four cell A123 packs using the 1100 mah size batteries in a 2S2P configuration. So I put those in my first turbine but still had a LiPo ECU battery. Same deal for the next models until I finally said okay, I'm going to go all HV and get the same type batteries everywhere in the model. Then I decided on KingTech turbine without knowing they were restricted to three cell LiFe batteries.... UGH!

Long story shorter; since most of the turbines can now use the LiFe chemistry three cell batteries, all but one of the turbines have A123/LiFe batteries everywhere except for the one Behotec engine which still has a LiPo. Makes life easier for us old guys to have the same type batteries in the models.... lol
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Old 05-03-2017, 10:26 AM
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Originally Posted by bcovish View Post
Agree with Zeeb on changing battery type. I'm running 6.6 batteries, no reg with non-digital servos.

Yes I was at MAB. Also will be at Mt.Pleasant. If you go, ask for Bob-O
My bad
I said non-digital servos. I meant non-HV servos
I got a couple of PM's questioning me on the digital servos, thanks guys
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Old 05-03-2017, 11:22 AM
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Originally Posted by CRye View Post
flyrc,
I should have stated its a switch. I previously downloaded the manual but cannot find it on PB net site now. Thankfully I did print a hard copy I still have.

.
Ahh ok, if it's just the regulated PB switch, I agree with the others, it defeats the purpose of the powersafe Rx.

Mike
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Old 05-04-2017, 06:42 AM
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AR12120 is a good performer. I use a couple of them with direct connection to 2cell LiPo when using HV Hitec servos. Works great.
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Old 05-04-2017, 10:54 AM
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I really appreciate the inputs. Especially Zeeb, "not a good idea" got me to consider what if 12120 wants batt 2 but PBswitch had not switched. Now the Power Box switch only makes sense to me if it outputted to only one line.
I am still on 6v servos, 8711 NOT HV.

I not going to play chicken with a switch and a receiver than can each select batteries. And it looks like the 12120 can at times draw off both. I may set up an intentional test.

I have ordered 2 Life packs and will run 6.6 directly into the 12120. With those I can still mount them where I had the Lipo s and similar weight. And since I have open access to the power lines I dont even need the fail on spektrum switch, just pull the power leads. And I will see if it actually switches 2nd batt after every flight.

(May be a big lesson in just because a thing, PB switch, came with the airplane it may not be a good idea.)
Thanks again, may have saved a smoking hole in the ground
Charles
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