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Thread: No castle bec for a 7.4v servo?

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Old 06-24-2011, 11:02 PM   #1
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Default No castle bec for a 7.4v servo?

I looked for this for quite awhile, so I apologize if this has been addressed before.


Do the newer high-voltage servos that operate at 7.4 volts still need to be run though a Castle 10 amp BEC? If so, why is that?


Can't ya just wire the power leads right up to the ESC power leads and plug the signal wire into the receiver?


Thanks,


JTL
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Old 06-24-2011, 11:04 PM   #2
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Forgot to say that I run only two cell lipos for a 7.4 voltage. I can see why you would not want it to do this with a 3S.
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Old 06-25-2011, 06:20 AM   #3
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Originally Posted by jlanders001 View Post
Can't ya just wire the power leads right up to the ESC power leads and plug the signal wire into the receiver?
Sure, as long as you are certain that your battery is only putting out 7.4V......remember, a fully charged 2S lipo is at 8.4V.
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Old 06-25-2011, 12:59 PM   #4
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Sure, as long as you are certain that your battery is only putting out 7.4V......remember, a fully charged 2S lipo is at 8.4V.
7.4 is a nom. number, all 7.4v equipment says safe for 2s lipo right on it ( or in the instructions). The 7.4 volt stuff is designed to run nitro right off a 2s Rx pack with no BEC.

So hook it up and run it, it'll be fine as long as you stick with 2s. The voltage is only 8.4 for the first little bit anyways then drops. I run 3s and set my BEC to 8.4 so I can get the full 8.4 for my entire run. It's kinda a waste that so many people set thier stuff to 7.4 instead of 8.4, that's free power that just gets lost.
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Old 06-26-2011, 12:06 AM   #5
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Originally Posted by indiana mudcat View Post
I run 3s and set my BEC to 8.4 so I can get the full 8.4 for my entire run. It's kinda a waste that so many people set thier stuff to 7.4 instead of 8.4, that's free power that just gets lost.
Does your servo not over heat at that setting? Which one(s) do you have?
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Old 06-26-2011, 07:14 AM   #6
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Quote:
Originally Posted by indiana mudcat View Post
7.4 is a nom. number, all 7.4v equipment says safe for 2s lipo right on it ( or in the instructions). The 7.4 volt stuff is designed to run nitro right off a 2s Rx pack with no BEC.

So hook it up and run it, it'll be fine as long as you stick with 2s. The voltage is only 8.4 for the first little bit anyways then drops. I run 3s and set my BEC to 8.4 so I can get the full 8.4 for my entire run. It's kinda a waste that so many people set thier stuff to 7.4 instead of 8.4, that's free power that just gets lost.
It was the plane guys as well that got the whole 2s electronic thing going for the most part. The manufacturers all specifically built the 7.4 components off the bat for 2s lipo. The bec thing more or less came in for the electric guys running HV setups in their planes but not wanting to have an extra pack just for the electronics.
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Old 06-27-2011, 12:24 AM   #7
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Does your servo not over heat at that setting? Which one(s) do you have?
Why would it overheat running exactly how it's designed to be ran? But anyways no, 7980 and gets barely warm after a hard course. My old 8711 in the same truck and my previous build would almost burn you after every course (at 6.0 or 6.5V). Also running a cheap Hobbico servo (7.4V and 4?? oz-in rated) and 3racing winch at 8.4V threw the BEC on my SCX. Two LNC's that I maintain running 7950's at 8.4V also, no heat issue's on any of these four servo's.
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Old 06-28-2011, 10:10 PM   #8
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Hooked the power leads to my ESC leads. Works great.

Before this I was testing the servo (7950) a bit on some rocks with it just plugged in the receiver temporarily. Ran it for just a few minuets. Maybe 10 or 15. It seemed hotter than it should have been at that point.

I'm good with electronics in general, so I was concerned if it heats up this much at 6V would it go thermal at 7.4 or 8.4?
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