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HV servos with stock RX??

Old 07-31-2013, 05:22 PM
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Default RE: HV servos with stock RX??

Looking at there reg's www.smart-fly.com/Products/Regulator/4.htm they're rated at 3A continuous.
Old 07-31-2013, 05:35 PM
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Default RE: HV servos with stock RX??

Look at the sport, the super, and the turbo being the highest at 17.5 continuos. And keep in mind these are for dual batteries, the system is split so there is more power for each side.
Old 07-31-2013, 05:39 PM
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Default RE: HV servos with stock RX??

And like I said earlier not everyone worries about it. I am just giving my opinion and offering options. The terminal block is the easiest, simplest, and cheapest way to go. Ten bucks, separate the power from the Rx, and have as much amps for the servos as the battery can put out.
Old 07-31-2013, 05:45 PM
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Default RE: HV servos with stock RX??

Thanks, are you talking about these? www.smart-fly.com/Products/PowerSystems/powersystems.html
Old 07-31-2013, 05:53 PM
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Default RE: HV servos with stock RX??

The power system sport plus sounds like a good option.
Old 07-31-2013, 06:11 PM
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Default RE: HV servos with stock RX??

Nope! Won't let me post it. Go to the regulators and click on the dual battery family of regulators.
Old 07-31-2013, 06:12 PM
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Default RE: HV servos with stock RX??

I see the Sport Plus has 6.0 volt, 5 amp continuous, 15 amp peak servo regulator . That may be the option to go for. More than I wanted to spend but I wanna be safe. I wouldn't be comfortable cutting wires to use those $10 terminals.
Old 07-31-2013, 06:14 PM
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Default RE: HV servos with stock RX??


ORIGINAL: acerc

Nope! Won't let me post it. Go to the regulators and click on the dual battery family of regulators.
? Link is to the home page.

Old 07-31-2013, 06:15 PM
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Default RE: HV servos with stock RX??

I have those terminals in three models costing 2-3 K.
Old 07-31-2013, 06:16 PM
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Default RE: HV servos with stock RX??

Won't let me post it. Go to the regulators and click on the dual battery family of regulators.         
Old 07-31-2013, 06:20 PM
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Default RE: HV servos with stock RX??

I'm sure you do, I just don't want to cut any wires. I see the reg's you are talking about now. Thanks
Old 07-31-2013, 06:22 PM
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Default RE: HV servos with stock RX??



Your welcome.

Old 08-01-2013, 05:47 AM
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Default RE: HV servos with stock RX??

I have been using digital servos into standard rx's for 13 years without any problems at all.

Had 8 digitals in a 1/3 scale Pitts. I use 5 in my 2 meter pattern ships. All through standard JR rx's.

I haven't used HV servos or rx's yet so can't comment on that, but i do run LiFes unregulated into a standard JR rx with no probs. As long as the servo is rated for 6 volts they are ok on unregulated LiFes as well.

I don't see that there would be a problem using HV servo's into standard rx's, but i wouldn't use Lipo's unregulated unless everything is HV. If you are not going to use unregulated Lipo's, then it's probably a waste of money buying HV servos??

I use JR exclusively so i know this works for me. Not sure how other brands would be, but shouldn't be that different.

Just my own experiences and opinion. Hope this helps.

PS. As a side note for those that maybe interested, in my 33% Edge 540 i use the JR1222 power safe rx. This is rated at 35 amps continuous and 50 amp burst.

Cheers
Scott
Old 08-01-2013, 11:28 AM
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Bob Pastorello
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Default RE: HV servos with stock RX??



Having JUST lost a pattern ship (e-power Osiris 65"), I can attest to two things that I thought would not bite me, ever.



1.  One parameter of a voltage regulator that is VERY important, and worth researching before installing is "voltage stability at rated output".  VERY few brands even disclose it, and if they do, they talk about "sag" of voltage under loads and not the "TRANSIENT" sag under heavy spike loads that exceed the amp rating of the regulator.  I found out the regulator I had on board (NOT using a SBEC Controller- rx/servo power was separate through it's own LIPO to the regulator) did indeed drop output voltage under a FAST and HEAVY digital servo load (consecutive snaps, opposite directions), causing the RX to go offline.  It came back, but not in time for me to save the bird.





2.  Measuring AVERAGE total servo amp loads on the power bus is really only a "ball park", and it's a helluva big ballpark.....the REAL parameters you must know - for certain - about your onboard setup is what is the total PEAK LOADED amp draw from all those power hungry digital servos.





Before ya'll problem solve my crash, I duplicated these conditions, INCLUDING failure mode doing the post-crash investigation.  Very disturbing, yet truly a very valuable and awakening lesson about loads on board when using regulators.

Old 08-01-2013, 01:14 PM
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Default RE: HV servos with stock RX??

Bob that is the very reason I stated in one of my first post over this issue that before I can say I am done with a build all my controls are ran through a meter. In every configuration I can think of, I even add weights to the control surfaces. I despise losing a plane due to my own ignorance. And I can honestly say I have never lost a plane due to technical difficulties. Now operator error is another story, but not many of them either.
Old 08-01-2013, 01:38 PM
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Default RE: HV servos with stock RX??


ORIGINAL: acerc

Bob that is the very reason I stated in one of my first post over this issue that before I can say I am done with a build all my controls are ran through a meter. In every configuration I can think of, I even add weights to the control surfaces. I despise losing a plane due to my own ignorance. And I can honestly say I have never lost a plane due to technical difficulties. Now operator error is another story, but not many of them either.
How do you test for maximum transient momentary load on all servos and monitor the Rx power bus voltage? I'd like to know how to do that in a typical shop setup....measuring "loaded" as you describe gets you informed about "normal" loads... the abnormal unexpected peak was what got me...
Old 08-01-2013, 02:04 PM
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Default RE: HV servos with stock RX??

Well I don't know if I get every absolute facet but I do feel very comfortable in my equipment after I'm done. I put a meter right off of the battery, with everything plugged in, I tell my radio to cycle the servos. The Futaba T8FG has a program that will cycle all the servos simultaneously. I physically stand there and watch the loading. After that has ran for a couple minutes I go through a routine of slamming the sticks quickly in every direction. And once complete with that I will add weights to the control surfaces equivalent to half the servo capacity and do all the above again. I do know on my little Pitts, the only one currently with digital servos, at a couple points in that routine (with the weights) it pulled near 20amps, a couple minimal spikes over 20, and the mah's ran like an open faucet during those peaks. Needless to say the Pitts received a second battery.And for the Rx port my power does not run through the Rx. I use terminal blocks from Radio Shack to separate the servo power from the Rx.
Old 08-01-2013, 02:25 PM
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Default RE: HV servos with stock RX??


ORIGINAL: Bob Pastorello



Having JUST lost a pattern ship (e-power Osiris 65''), I can attest to two things that I thought would not bite me, ever.



1. One parameter of a voltage regulator that is VERY important, and worth researching before installing is ''voltage stability at rated output''. VERY few brands even disclose it, and if they do, they talk about ''sag'' of voltage under loads and not the ''TRANSIENT'' sag under heavy spike loads that exceed the amp rating of the regulator. I found out the regulator I had on board (NOT using a SBEC Controller- rx/servo power was separate through it's own LIPO to the regulator) did indeed drop output voltage under a FAST and HEAVY digital servo load (consecutive snaps, opposite directions), causing the RX to go offline. It came back, but not in time for me to save the bird.





2. Measuring AVERAGE total servo amp loads on the power bus is really only a ''ball park'', and it's a helluva big ballpark.....the REAL parameters you must know - for certain - about your onboard setup is what is the total PEAK LOADED amp draw from all those power hungry digital servos.





Before ya'll problem solve my crash, I duplicated these conditions, INCLUDING failure mode doing the post-crash investigation. Very disturbing, yet truly a very valuable and awakening lesson about loads on board when using regulators.

Good info Bob.

Using LiFes directly into the rx for 6 volt servos without a regulator and HV servos with HV rx's will at least take this one possible failure point out of the equation.

I also don't use switches where i can help it, depending on accessibility to the batteries and rx. My current pattern ships plug straight into the rx when ready to fly. Another possible failure point eliminated.
Old 08-01-2013, 10:19 PM
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Default RE: HV servos with stock RX??


ORIGINAL: acerc

Yes it is as simple as that. Use a Y off of the battery if the battery does not have dual leads. One to the Rx battery port and the other to the servos red and black. Absolutely no load through the Rx with this method. Leaving the black wire as in GibbsGuides as posted does leave a path for loading the Rx.
Yes,I understand this will work when using the same battery for RX and Servos.

What about this scenario..

1 Battery for RX - EG 4.8 V

2. a seperate battery for the HV Servos - eg a 2s Lipo.

Are you saying that you can connect red and black servo leads directly to the 2S Lipo and only the "white" servo lead to the RX which is powered completely independently by the 4.8V battery? IE with no common ground and it will work?




Old 08-01-2013, 10:27 PM
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Default RE: HV servos with stock RX??

Yes, please extrapolate on exactly what you do with the white wire. Thanks!
Old 08-02-2013, 12:53 AM
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Default RE: HV servos with stock RX??

There can be another often unmentioned "little" problem!
Basically, the amplitude of the servo control signal.
Classically, it was more or less a convention that around 1/2 of the voltage supplied to the servos and receiver was
considered to be the approximate amplitude of the control signal to the servo.
Obviously, if a receiver is operating on ~5v, this would seem to be around 2.5v or so.
What happens when the servo is operating at 6v or more, and the receiver at five volts?
Does the HV servo have compensating circuitry?
Old 08-02-2013, 02:25 AM
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Default RE: HV servos with stock RX??


ORIGINAL: Rob2160


ORIGINAL: acerc

Yes it is as simple as that. Use a Y off of the battery if the battery does not have dual leads. One to the Rx battery port and the other to the servos red and black. Absolutely no load through the Rx with this method. Leaving the black wire as in GibbsGuides as posted does leave a path for loading the Rx.
Yes, I understand this will work when using the same battery for RX and Servos.

What about this scenario..

1 Battery for RX - EG 4.8 V

2. a seperate battery for the HV Servos - eg a 2s Lipo.

Are you saying that you can connect red and black servo leads directly to the 2S Lipo and only the ''white'' servo lead to the RX which is powered completely independently by the 4.8V battery? IE with no common ground and it will work?




Correct me if I'm wrong, but the rx doesn't require power in this case. The white wire is signal only to tell the servo what to do.
Old 08-02-2013, 04:57 AM
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Default RE: HV servos with stock RX??


ORIGINAL: drac1


Correct me if I'm wrong, but the rx doesn't require power in this case. The white wire is signal only to tell the servo what to do.
The receiver will still need power.. to receive the signal from the TX and generate the signal to the servo..

Without power the RX is just like a mobile phone without a battery.. IE totally dead..

Old 08-02-2013, 05:42 AM
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Default RE: HV servos with stock RX??


ORIGINAL: Rob2160


ORIGINAL: drac1


Correct me if I'm wrong, but the rx doesn't require power in this case. The white wire is signal only to tell the servo what to do.
The receiver will still need power.. to receive the signal from the TX and generate the signal to the servo..

Without power the RX is just like a mobile phone without a battery.. IE totally dead..

OK, then you could run a 5 volt regulated power supply from the LiPo to the rx. No need to use a separate battery.
Old 08-02-2013, 05:45 AM
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Default RE: HV servos with stock RX??


ORIGINAL: drac1


ORIGINAL: Rob2160


ORIGINAL: drac1


Correct me if I'm wrong, but the rx doesn't require power in this case. The white wire is signal only to tell the servo what to do.
The receiver will still need power.. to receive the signal from the TX and generate the signal to the servo..

Without power the RX is just like a mobile phone without a battery.. IE totally dead..

OK, then you could run a 5 volt regulated power supply from the LiPo to the rx. No need to use a separate battery.
Yes that would be possible also.. My question to acerc or anyone who knows the answer.. relates to having two seperate batteries.. one just for the RX.. one for the Servos and no common ground (ie black wire) in this case just plugging in the white wire to the RX - would it control the servos

Genuinely just curious.. I will test it myself when home in a few days..
.

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