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Old Jul 06, 2012, 06:10 PM
Euphoric flights
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What do you guys use to power 6 or more servos?

Hello,

I wanted to know how 6 or more servos are "fed" via an alternative source besides the ESC itself.

How do you safely determine enough current / voltage is available per servo to draw on? Should one opt for 6V going into the servos, or is 4.8V good enough?

What if an ESC also has a voltage "thing" to feed the servos and you also want to run a BEC on the side... ?

What is the best way to do this? Also consider that there are different sized servos being operated.

Thanks for your time.
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Old Jul 06, 2012, 06:23 PM
Duane
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Use a separate 4-cell NiCd or NiMH battery to power the receiver and servos. Follow the ESC's instructions for disconnecting the BEC (usually pull the red/orange wire from the connector that plugs into the receiver).
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Old Jul 06, 2012, 07:11 PM
Jesper Frickmann
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You can use a CC BEC from CastleCreations.
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Old Jul 06, 2012, 09:54 PM
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Seperate battery for any 6 servo sailplane with e-power. I am using 2S LiFe's myself on both straight sailplanes and e-sailplanes, no voltage reulator, with HV servos (which is most anything at 6.6V other than MKS).

Do not use regulators under any circumstance in my book if you can. 2S LiFe's do not require them and they are just one more failure point in a stream already crowded with them anyway. The LiFe's store well, charge at about any charge rate and just seem to like the job of running a RX. In our modern sailplanes, regulators are under heat stress and those small fuses we fly just take away more of their ability to dissapate heat, which is what most do. The CCBEC of Castle Creation does just that (in some cases nearly 200 deg. F), and ask me how I know what happens when they fail...

Marc
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Old Jul 07, 2012, 01:07 AM
Euphoric flights
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United States, NY, Fredonia
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I apologize that I wasn't more clear. I can't afford another battery. I wanted to power the servos from the same battery as what I am running the motor with, I was going along the lines of the esc may not be able to power 6 servos.

So how can I attach something from the battery to the rx which will feed all 6 servos.

Interesting note regarding the red/orange wire.

OVSS Boss, what happened to ya when "they" failed?
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Old Jul 07, 2012, 07:53 AM
Jesper Frickmann
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Here is how to do it with CC BEC. Taken from the User Guide, which can be found here: http://castlecreations.com/products/ccbec.html
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Old Jul 07, 2012, 08:38 AM
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Quote:
Originally Posted by jfrickmann View Post
Here is how to do it with CC BEC. Taken from the User Guide, which can be found here: http://castlecreations.com/products/ccbec.html
10amp is what I have been using for the past 6-7 years now, no failures yet.
Negatives; A little more complex setup, Positives; it's lighter than adding another battery. Buy mine on flebay, http://www.ebay.com/itm/Castle-Creat...item2c63ea4659

Rich
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Old Jul 07, 2012, 02:36 PM
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Originally Posted by GreenAce92_v2 View Post
OVSS Boss, what happened to ya when "they" failed?
Well, I was about 1 minute out of a landing in a contest and had just pushed to start bleeding some altitude and was about 150' up. Just a minor trim change but that was the last input that she had she just kept right on going down till contact. Total failure and and no coming back like a brown out. I thought it was the radio, but we benched it and it got to excess of 200 degrees F in about 2 minutes, she failed again. It was hot day, and in a very small fuse, and as a friend said that does a lot of elctronics professionally, "It worked till it did not work,..."

No more regulators, except in something like a big warbird or something with lots of room in it.

Marc

Also, if you have spent the money you have already, what is a $20 some dollar battery in addition?
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Old Jul 07, 2012, 08:36 PM
Euphoric flights
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It's not about two batteries it is space. True I could incorporate twin packs, but the servo problem isn't a battery addition problem but a problem regarding how much power the esc can supply to the servos which I suspect most only support 4 servos.

The servos I am looking to "feed" are small; 2 HS-55's, 4 HS-65's.
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Old Jul 07, 2012, 09:53 PM
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Your call...
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Old Jul 08, 2012, 11:08 AM
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A lot of higher end sail planes use an s buss system.I don't know much about it but have seen it .
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Old Jul 08, 2012, 08:55 PM
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Quote:
Originally Posted by GreenAce92_v2 View Post
It's not about two batteries it is space. True I could incorporate twin packs, but the servo problem isn't a battery addition problem but a problem regarding how much power the esc can supply to the servos which I suspect most only support 4 servos.

The servos I am looking to "feed" are small; 2 HS-55's, 4 HS-65's.
I think you are right to be concerned that the built in BEC (probably linear) of your ESC may not be able to provide enough power for six servos... and/or cause heat issues in the ESC/BEC... which could lead to receiver brown out.

What is the BEC on your ESC rated at... in amps? You could just hook everything up; bash the sticks a bit and see if everything works OK. It might work... it might not.

Most folks opt for either:

Use a separate LiFe or NiMh pack directly running the receiver and servos. LiFe packs can take amazing amp stress and still keep the volts up.

or...

Use a separate high amperage "switching" BEC (as per above) that runs off the big Lipo "motor" pack. You cannot use one of these AND the BEC of your ESC. You have to disable the red/orange wire as the graphic above shows.

Dawson
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Old Jul 08, 2012, 10:46 PM
AMA7224 LSF1832
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Quote:
Originally Posted by GreenAce92_v2 View Post
....

The servos I am looking to "feed" are small; 2 HS-55's, 4 HS-65's.
Been running the same servos and numbers for two years in a Avia off a Castle Phoenix ICE ESC with switching BEC. BEC is rated for 5 amps. Whole setup has hundreds of flights on them and have had zero trouble. For what it's worth.
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Old Jul 12, 2012, 05:11 AM
Euphoric flights
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Hey thanks a lot guys. I'll have to look into these "LiFe" batteries they sound great! Made in the US by chance? Not that that is really important.

I'm interested for "feeding" 5V-12V cameras with the description of "Take ... amp draw...keep voltage up..."

Even a video transmitter which seems to pull some power.

Perhaps 6 servos is a bit much for a 47" airplane. Especially a "smash and bash" type of an airplane.

I'll have to look into the Castle Phoenix ICE ESC, that sounds like it could be perfect for a 6 servo airplane ( heavier loading).
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Old Jul 12, 2012, 06:26 AM
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Quote:
Originally Posted by GreenAce92_v2 View Post
Hello,

I wanted to know how 6 or more servos are "fed" via an alternative source besides the ESC itself.

How do you safely determine enough current / voltage is available per servo to draw on? Should one opt for 6V going into the servos, or is 4.8V good enough?

What if an ESC also has a voltage "thing" to feed the servos and you also want to run a BEC on the side... ?

What is the best way to do this? Also consider that there are different sized servos being operated.

Thanks for your time.
Maybe I missed it but I don't see where you tell us what ESC you are using. Some have quite robust BEC.

I Don't know what you are flying but Radian Pros are flying 6 micro servos on 750 mah BEC, but I think that it is right at its limit.
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