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Old Dec 27, 2012, 08:45 PM
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United States, CA, Hollister
Joined May 2011
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Servo voltage draw?

Hello fellow RCer's, I just got an E-flite Pitts M12 that I have put a Turnigy G25 (710Kv) http://www.hobbyking.com/hobbyking/s...dProduct=23325,

Turnigy Thrust 45A http://www.hobbyking.com/hobbyking/s...dProduct=24235

with 4 Turnigy 210DMH (Digital, metal gear, coreless motor) http://www.hobbyking.com/hobbyking/s...dProduct=30688

Turnigy 3000mAh 4S 35C Lipo http://www.hobbyking.com/hobbyking/s...dProduct=16632

My concern is, since this is a great model and a very nice plane, I would like to know or figure out some how, how much current these servos pull to make an educated decision on whether I should put a separate BEC in this beauty or not. I don't really mind the extra 3 or so ounces from a separate rx battery, however I don't want to add the weight if I don't have to. Now, I know these electronics are certainly not top of the line but for the money, I just couldn't beat it.

Thanks for the input,

Scale_sloper
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Old Dec 27, 2012, 09:23 PM
Wake up, feel pulse, be happy!
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United States, AK, Fairbanks
Joined Aug 2009
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Yeah, you'll probably want to run a separate BEC to power those servos. This one should be plenty, but if you want to spend a little more for some extra peace of mind, this 10A Castle Creations BEC might be the better choice.
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Old Dec 28, 2012, 08:19 AM
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United States, NJ, Frenchtown
Joined Mar 2003
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4 digitals COULD be ampere hounds if operating at the same time on normal surface deflections.
You would need to get some servo amperage data first to decide . Most important is the stalled servo amps. Then you know what the total draw will be in a panic pull out.

I will see if I can also find the stalled amps.

Oversizing anything can sometimes be not the best thing.

Edit Those servos are rated as 8.6 pounds of thrust in .13 seconds !!...............That is some SERIOUS current if you deflect 2 servos instantly. Possibly causing a severe voltage drop of the BEC wires & receiver brown out. Since the plane would then not respond at all....You would panic & hold the controls tighter in the deflected positions.
Warning !! The BEC has a maximum rating of 3 amps..............You will need a seperate battery pack in all probabilty for a 17.2 pound servo draw when both race to a new position.
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Old Dec 28, 2012, 09:05 AM
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United States, NJ, Frenchtown
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I cold not find current draws for the hitecRCD digital servos on the HitecRCD site for standard series of digital servos.

HK did list .3 to.4 Amps as the idle current ? My assumption.
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Old Dec 29, 2012, 08:25 PM
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United States, CA, Hollister
Joined May 2011
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I really appreciate the help and the info was excellent. I couldn't find an Amp draw chart or link on the HOBBY KING page or even the Turnigy page...but I figure I don't really need to worry bout it much now since I put a 600 mA battery on board seeing how it only added 3 oz for a combined AUW of 3 3/4 pound plane but that Turnigy G25 works very well with that setup.

Thanks again for all the help.
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Old Dec 30, 2012, 05:44 PM
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Way to go scale.

I think nothing can beat a seperate battery for the powering of servos & receiver. After the main battery or ESC dies in flight.
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