BEC or not???

[2-shot]

I'm in the process of building a SCX10 JK. I'm running a Hitec 7954 servo, which is capable of 7.4v.
My thoughts were to use a rx bypass plug and supply the voltage to my servo directly from my 2s lipo that will be running my Jeep - without the use of an external BEC. I would crank the voltage up on the BEC to 7.4v anyway.

Is there a benefit to running an external BEC, other than being able to adjust the voltage going to my servo?

Any input would be greatly appreciated!!!


Sent from my modded TI-83 plus.

[Dostradamas]

Yes you need an external bec

[Dostradamas]

Originally Posted by 2-shot

I'm in the process of building a SCX10 JK. I'm running a Hitec 7954 servo, which is capable of 7.4v.
My thoughts were to use a rx bypass plug and supply the voltage to my servo directly from my 2s lipo that will be running my Jeep - without the use of an external BEC. I would crank the voltage up on the BEC to 7.4v anyway.

Is there a benefit to running an external BEC, other than being able to adjust the voltage going to my servo?

Any input would be greatly appreciated!!!


Sent from my modded TI-83 plus.

What receiver are you using?
My spektrum rx will handle that high (up to 9.6V) of voltage but most others do not.
SR300 3-Channel DSM Sport Surface Receiver (SPMSR300): Spektrum - The Leader in Spread Spectrum Technology

[2-shot]

I'm running an Airtronics receiver. With the receiver bypass plug, the receiver gets it's voltage from the internal BEC in the ESC. The servo gets direct voltage from the external BEC.
Here's a link to the receiver bypass adapter plug that I'm talking about.

http://holmeshobbies.com/RXBypass.html





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[btoungette]

Why is buying & installing a $20 BEC so confusing to people? I understand it takes some soldering to get it to work. If you can't solder, I'm sure you know someone who can.

Some things in life are what they are--no need understand why. Why is the sky blue? Because it is. Why is grass green? Because it is. Why do I need a BEC? Because you just do.

Joking aside, the RX bypass plug is a great idea. I use one with all my BECs so I don't have to remove wires on ESCs. Helps when you need to reprogram the ESC. All you do is unplug it from bypass plug and connect to programmer.

[2-shot]

I understand how to install a BEC! LOL!!! I have a new CC BEC that was purchased for this build.
I was thinking about it today at work. If I'm using a RX bypass adapter, the rx is getting its voltage from the internal BEC in the ESC, then my servo can get the 7.4v directly from the 2s lipo.
Is there anything else that the external BEC does, besides regulating voltage.

I mainly asked, wondering if anyone has tried it.

Oh! LOL!!! And the sky is blue due to the Earth's atmosphere.
Grass is green because of the chlorophyll in it... LOL!!!


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[Calderwood]

Don't pay any attention to these guys. They are just regurgitating what others have told them. If you are only ever going to run 2s like you said there wouldn't be any benefit to running a bec vs. running 2s voltage directly to your servo and powering the rx with your esc's bec.

[The Violator]

Originally Posted by 2-shot

I understand how to install a BEC! LOL!!! I have a new CC BEC that was purchased for this build.
I was thinking about it today at work. If I'm using a RX bypass adapter, the rx is getting its voltage from the internal BEC in the ESC, then my servo can get the 7.4v directly from the 2s lipo.
Is there anything else that the external BEC does, besides regulating voltage.

I mainly asked, wondering if anyone has tried it.

Oh! LOL!!! And the sky is blue due to the Earth's atmosphere.
Grass is green because of the chlorophyll in it... LOL!!!


Sent from my modded TI-83 plus.

You can run that servo directly off of a 2s lipo. Of course if you ever decide you want 3s you will have to rewire it. Also do not forget the servo is rated at 7.4 volts, but a full 2s is 8.4 so it will be on the high side. I run all my comp servos at 9 so I know they will take it for 6 minutes at a time. But if your running for hours on end you might ( no way to say for sure until you do it) have heat issues.


If you have the BEC, and think there ever ever ever might be a possibility you want 3s installing it would be a grand idea.


Personally I would. But I would never run 2s on anything but my short course truck.

Originally Posted by Calderwood

Don't pay any attention to these guys. They are just regurgitating what others have told them. If you are only ever going to run 2s like you said there wouldn't be any benefit to running a bec vs. running 2s voltage directly to your servo and powering the rx with your esc's bec.

There are lots of advantages. First and foremost would be the ability to change to 3s on the fly. Second would be to keep the voltage limited to 7.4 volts if there is heat issues. And third, powering the servo and the rx by the same source eliminates many funky ground loop issues.

[holycaveman]

Last two posts were spot on. I run 2s only on one of my rigs. The servo hooked up directly to the battery. To me this is the best way because it eliminates one more potential electrical failure.

However like the violater said. You are limited to 2s use only.

[2-shot]

I am trying to keep my ESC, BEC, and receiver together in one area. I am running a Tekin RS Gen2 esc.
Would I be safe to connect the + & - wires from the external BEC, to the + & - posts on my ESC? The same posts on my ESC as the wires for the lipo connect to, and where the capacitor connects to. I'm just trying to keep my electronics contained as much as possible.

Thanks for all of the input guys, I really appreciate it!

[Calderwood]

Originally Posted by 2-shot

I am trying to keep my ESC, BEC, and receiver together in one area. I am running a Tekin RS Gen2 esc.
Would I be safe to connect the + & - wires from the external BEC, to the + & - posts on my ESC? The same posts on my ESC as the wires for the lipo connect to, and where the capacitor connects to. I'm just trying to keep my electronics contained as much as possible.

Thanks for all of the input guys, I really appreciate it!

That's how I do it. Its safer for the bec wires since they wont get snagged on anything while you are plugging in or unplugging the battery.

[2-shot]

Originally Posted by The Violator

You can run that servo directly off of a 2s lipo. Of course if you ever decide you want 3s you will have to rewire it. Also do not forget the servo is rated at 7.4 volts, but a full 2s is 8.4 so it will be on the high side. I run all my comp servos at 9 so I know they will take it for 6 minutes at a time. But if your running for hours on end you might ( no way to say for sure until you do it) have heat issues.





If you have the BEC, and think there ever ever ever might be a possibility you want 3s installing it would be a grand idea.





Personally I would. But I would never run 2s on anything but my short course truck.























There are lots of advantages. First and foremost would be the ability to change to 3s on the fly. Second would be to keep the voltage limited to 7.4 volts if there is heat issues. And third, powering the servo and the rx by the same source eliminates many funky ground loop issues.

You wouldn't be powering the servo and the rx from the same source. Well, technically you are, even if you run an external BEC = 2s lipo. LOL!!!

The rx would be powered from the internal BEC in my RS Gen2, and the servo would get it's power straight from the 2s lipo.


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[The Violator]

Originally Posted by 2-shot

You wouldn't be powering the servo and the rx from the same source. Well, technically you are, even if you run an external BEC = 2s lipo. LOL!!!

The rx would be powered from the internal BEC in my RS Gen2, and the servo would get it's power straight from the 2s lipo.


Sent from my modded TI-83 plus.

When you have it all together and you put up a post saying how your car went nuts, or the servo twitches, or some other gremlin, just remember I told you so.

At the minimum keep the black wire from the servo split and back into the rx.

[redsawacs]

This dance has been going on way too long. I, for one, have answered this question (what seems like) a dozen times. There is too much data on this forum to have any BEC related questions....then again, that would require acquisition skills.

You will see glitching and response issues...whatever happens when you over power a servo. Mine glittered and caused turbo lag

[2-shot]

Originally Posted by redsawacs

This dance has been going on way too long. I, for one, have answered this question (what seems like) a dozen times. There is too much data on this forum to have any BEC related questions....then again, that would require acquisition skills.

You will see glitching and response issues...whatever happens when you over power a servo. Mine glittered and caused turbo lag

LOL!!!

I don't think it has to do with "acquisition skills". I apologize that I didn't take the time to search, and spend 2 - 3 hours sifting through a million build threads trying to find the answer to my question. "Use the search function" seems to be the popular, easy response to questions asked.

I question some responses because I'm being told that it's fine to run my servo directly off the 2s lipo without an external BEC, and I'm being told that it's not good, and I should definitely use an external BEC.
I agree, there's a wealth of info on this forum, with a lot of knowledgeable people. I'm sure if I spent a couple hours going through all of the search results, I would have found the same info. I only question responses to become more knowledgeable, and to find all angles of the pros and cons. That's why I welcome all input. I'm not asking for people to tell me what I want to hear. From all of the responses, the majority say that I should run an external BEC. I have a brand new CC BEC sitting on my bench, ready to be installed. I happen to be thinking about it yesterday, so that's why I posted asking the question.




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[cartronicshn]

I understand not wanting to spend hours looking through hundreds of bec related threads, but as pointed out earlier by Dostradamas, did you read through this? Yes you need an external bec , almost all pertinent info is there, you can run the servo wired directly to your 2s lipo, but i would recommend a bec just because i have tried that setup and then when i wanted to go to to 3s and up i had to redo my installation and ad that bec
Congrats on that bec btw.

[johnnyh66]

BEC's are overrated!
My Nikko runs fine without one.

[2-shot]

Originally Posted by cartronicshn

I understand not wanting to spend hours looking through hundreds of bec related threads, but as pointed out earlier by Dostradamas, did you read through this? Yes you need an external bec , almost all pertinent info is there, you can run the servo wired directly to your 2s lipo, but i would recommend a bec just because i have tried that setup and then when i wanted to go to to 3s and up i had to redo my installation and ad that bec Congrats on that bec btw.

I agree. After reading all of the posts in this thread, the majority of the post are saying that I need the BEC. I had already planned on running one - even purchased one. It was a thought/idea that popped into my head yesterday while I was at work. I thought I would post it and get everyone's input on it. I was also unsure if a BEC did anything besides being a voltage regulator.

I just get a little frustrated when people assume that I didn't, or don't know how to use the search function on the forum. If I didn't use it, I would probably be posting 2 or 3 questions everyday!!! LOL!!! I use the search a lot on here!!!

So, it's a yes on the BEC!! End of discussion!! LOL!!!

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[Whiplashdjs]

I don't have one with my waterproof brxl, but I'm using an airtronics servo, the 400+ oz. I think it's an m74980? Haven't had any issues besides some numbskull noob busted the ears on the servo learning stuff the hard way
I added a cap and don't have any issues whatsoever!
If I had an extra bec around during the build I would have installed it though!

[Master Basher]

Originally Posted by Calderwood

Don't pay any attention to these guys. They are just regurgitating what others have told them. If you are only ever going to run 2s like you said there wouldn't be any benefit to running a bec vs. running 2s voltage directly to your servo and powering the rx with your esc's bec.

yeah, some of these guys are just being *&$%s, directly from the battery no BEC needed. Even if you do go higher than 2s you can still draw from only 2 cells with the right connector and wiring.