How Many/What kind BEC (searched)

[meffie]

Yes I searched, but found nothing directly related to these questions

3s Battery

2 Hitec 7954SH servo's 403oz 7.4v (Front/Rear Steer)

1 MG946R 208oz 7.2v Servo (winch)

Tekin FXR esc.

What is my best/safest option to run all this

3 BEC's - 1 to each

2 BEC's - 1 Front Servo & 1 Rear Servo/Winch w/ Y connector

1 BEC Pro - Run all 3 with a Y connector for Rear Servo/Winch

Thanks folks. I've gotten so many different answers, but then again I've changed the setup too. This is my final setup so hopefully I can get a solid answer.

[Duuuuuuuude]

One regular bec should do the trick.

[Charlie-III]

I would do 2 10A BEC's (a single may work...).
1 each for the front & rear servo's (wired direct to the servo), run the winch powered by the RX (thus the ESC BEC is powering the RX & winch).

The winch is intermittant duty, thus not as much of an issue.

[meffie]

Originally Posted by Charlie-III

I would do 2 10A BEC's (a single may work...).
1 each for the front & rear servo's (wired direct to the servo), run the winch powered by the RX (thus the ESC BEC is powering the RX & winch).

The winch is intermittant duty, thus not as much of an issue.

That's what I had planned originally until I read how horrible the fx-r's internal bec is. If I was running a brxl sure thing. Even though it's intermitant duty, you think the fx-r's bec would handle it ok?

[Duuuuuuuude]

Originally Posted by meffie

That's what I had planned originally until I read how horrible the fx-r's internal bec is. If I was running a brxl sure thing. Even though it's intermitant duty, you think the fx-r's bec would handle it ok?

Try running it all on one bec. If it browns out, add a second.

I still say you'll do fine with one. Chances are very unlikely that you'll load up all three servos at the same time to the point of drawing more power than the bec can provide.

[SMR 510RR]

Originally Posted by Duuuuuuuude

Try running it all on one bec. If it browns out, add a second.

I still say you'll do fine with one. Chances are very unlikely that you'll load up all three servos at the same time to the point of drawing more power than the bec can provide.

I agree.

If it does become a problem add a second BEC powering your rear steering and your winch. Chances are you wont load both of those at the same time.

[meffie]

Sweet I will give it a go like that. It won't hurt anything without a brownout, just be a loss of power correct?

You think setting the BEC for 7.4 would hurt the 7.2v max on the MG946R? Or should I just do 7.2 period? I would assume 7.2v is still more than enough power for steering servo's on a scaler.

[Duuuuuuuude]

I doubt you'll notice too much difference by dropping down .2 volts.

[ik632]

I doubt you'll even notice the difference in speed/power dropping those steering servos by 0.2v.

[meffie]

Yah didn't figure so, but figured I'd ask anyway ya know :P

I spent the last year with my comp rig @ 5.1v instead of 7.4v and didn't know it, so now I'm trying to squeeze every bit I can, and making sure I do so, lol.

Thanks again for all your answers folks.

[JeremyH]

I've always wondered this myself. Really, you should only need to add up all of the stall currents for the servos and then find a BEC that will put out that amperage.

The little blue CCBEC is rated at 10A, the CCBEC Pro is 20A.

I called Hitec about the stall current on the 7980 when powered at 7.4V and they told me the value was 10A.

Out of curiosity, I asked about your servo (7954), they told me that the stall current at 7.4V is about 9A.

So, since you are running two, then it is possible for both of your steering servos to draw 18A when they are both stalled (not too common of a situation, but it does happen).

This info should tell you that one little blue BEC might work in some situations, but that the 20A CC BEC Pro would be best in your setup.

Another thing to keep in mind, the BEC Pro is a bit larger than the blue one, but the Pro also has two outputs which might make your wiring easier....

[92LILREDYJ]

Im with Jeremy go with 1 CCpro bec.

[meffie]

Originally Posted by JeremyH

I've always wondered this myself. Really, you should only need to add up all of the stall currents for the servos and then find a BEC that will put out that amperage.

The little blue CCBEC is rated at 10A, the CCBEC Pro is 20A.

I called Hitec about the stall current on the 7980 when powered at 7.4V and they told me the value was 10A.

Out of curiosity, I asked about your servo (7954), they told me that the stall current at 7.4V is about 9A.

So, since you are running two, then it is possible for both of your steering servos to draw 18A when they are both stalled (not too common of a situation, but it does happen).

This info should tell you that one little blue BEC might work in some situations, but that the 20A CC BEC Pro would be best in your setup.

Another thing to keep in mind, the BEC Pro is a bit larger than the blue one, but the Pro also has two outputs which might make your wiring easier....

Wow way to go Jeremy. This is exactly the reason I was considering multiple BEC's or the Pro, but I figured since worst case scenario I'd just loose some power I could get away with the 1 as the others have said.

I really can't see a situation where I'll be dual steering in binds AND winching, but I guess you never know.

I already have a BEC sitting here so I'll probably just stick it in and make an adapter to power off the 1. If I get any brownouts at all I'll just jump up to the pro and be done. And yah 2 inputs would make it easier since I'd only have to make a Y adapter not a 3 way.

Thanks again for all the input folks.

[SMR 510RR]

Yes the CC BEC is rated at 10a but at 12v (roughly 3s) they drop to 7a, unfortunately they dont list the drop on the pro version.

I still say try it and see if you need more, I doubt you will be in a situation where you are bound up bad on 2 servos or one servo and your winch.

Castle Creations | CC BEC and CC BEC Pro

[JeremyH]

Originally Posted by meffie

Wow way to go Jeremy.

Not a problem...

Originally Posted by SMR 510RR

I still say try it and see if you need more, I doubt you will be in a situation where you are bound up bad on 2 servos or one servo and your winch.

I might have missed what type of truck this is, so if it is a scaler, then it might not be as important, but on my super comp rig, I regularly bind both servos and can stall them.

[meffie]

Originally Posted by SMR 510RR

I still say try it and see if you need more, I doubt you will be in a situation where you are bound up bad on 2 servos or one servo and your winch.

Plan on it

Originally Posted by JeremyH

Not a problem...


I might have missed what type of truck this is, so if it is a scaler, then it might not be as important, but on my super comp rig, I regularly bind both servos and can stall them.

Well it's a Scaler of course, guess I should've said that, but I figured by posting I'm using a winch that would be a given. My bad

[JeremyH]

Yeah, I kind of figured that it was, but there have been comp rigs in the past that used a suck down winch....

[CRAWLER-DAD]

I have the best solution...send the rig to ME and let me figure it out for you..
When its figured out...I will send it back to you......in a box!
Dude call me....you have been already !!!!!!!!!

[meffie]

Originally Posted by JeremyH

Yeah, I kind of figured that it was, but there have been comp rigs in the past that used a suck down winch....

Yah gotcha. I was just giving you crap. Much appreciated

Originally Posted by CRAWLER-DAD

I have the best solution...send the rig to ME and let me figure it out for you..
When its figured out...I will send it back to you......in a box!
Dude call me....you have been already !!!!!!!!!

LOL Marc, I was wondering how long it would take you to respond. I was just curious :P

I'll call ya in a sec

[CRAWLER-DAD]

cool, thx for calling..sent you all my shipping info..looking forward to thrashing..oops building a wraith for a buddy!!! LOL will be checking the mail everyday for the package!!!!