Do I need a BEC?
 

I just need a motor, paint, and a battery to complete my new mrc pro. I have a new B1R esc for it. I thought I might just use a 33t hh motor and a 2s lipo, as that's what I have on my old mrc. With that setup would I need to use a bec? With the stock losi esc on my old car I have never needed one, and I even run a hs 5955tg servo on it:shock:. If I didn't need one it would be less stuff & spaghetti to run on that little car.

http://www.rccrawler.com/forum/chit-...ernal-bec.html

:ror::flipoff:

The B1R only has a 2amp BEC with a 2S. That's pretty marginal for the servo you plan to use and then add on the current hungry motor and you run out of juice.

At least the CC BEC is small and you can wrap or cut the wires to the length you want.

gee thanks that's exactly what I didn't want to hear:flipoff:. It would be nice to not have to run the little blue thing with 6 feet of wire on a itty bitty car:ror:

Get the CC BEC, shorten your wires, live a stress free life ;-)

OK fine thanks guys I'll get a dang bec. My mrc is intended to help releive stress, not cause it:flipoff:"thumbsup"

yes, my B1R gets warm from just pushing a Hi-tec 645, im sure if i added a BEC it'd cool off. Im running a similar set up, B1R, HH mini- tourq master, on 2s, with a 645mg servo.

Several of the top cars at Nats ran with no bec. Jake Wright when he was Losi team driver said it wasn't necessary. Tuner didn't mention it in his build list (2011 winner). Rubbaneck never mentioned it in his build thread (past winner). So if you run w/o bec, you're in good company.

Edit: I did see that tuner wired his servo straight to battery. 'Nother option.

The stall current on that servo is 3.4A @ 4.8V or 4.2A @ 6V. A BEC will let's you maximize the torque of that servo, although at 333oz/in, you might break some parts even without a BEC. "thumbsup"

I forgot to mention that I'm going to just leave my old mini alone, it works pretty good. Stock esc with a 5955 servo, and it's always worked fine with no problems?!:)So I have an old 985 mg mounted on the new mrc pro. I read the b1r instructions and its bec is only rated for 1.5 amps. Wiring the servo right to the battery is a cool idea, but would it handle 8 volts from a fully charged lipo? A friend is using a $6 bec from hobbyking with good results, I may try one of those

With a 2S, you can simply wire your servo directly to the battery.

ok then, I'll try wiring directly to the battery. Just the white wire goes to the receiver and black & red wires go straight to the battery-right? Too cool & simple, maybe I'll wire my old mrc like that too8)

Yep. Just like that.

I ran a Futaba s9551 servo like that in my mini for quite some time. I put a new servo in there recently, but havent had time to make up the wiring harness. I use a deans micro between servo and battery for easy disconnection.

Could you take a pic of the servo wired to the battery please or a wiring diagram as many speak of doing this but I've yet to see how it is done?

I'm surprised nobody answered this. It seems pretty straight forward. What I've done is pull the red and black pins from the servo connector. The white stays in the connector and plugs into the RX / Ch 1.

Tear the red and black wires away from the white wire, route them to the battery connector plug and solder them to the cold (esc) side.

There are other ways involving extra in-line connectors and Y-pigtails and such, but mine is the simplest. You'll want to unplug the battery when not in use, not just turn off the esc. Good idea anyway.

I just had an idea to use the plug off an old junk servo and a servo extension cord plug to hook it up, easy on-off"thumbsup"

i run the mongoose system with a 5955tg and i dont run a bec and i can move the rear end around and my esc and motor get warm

In case anyone's concerned, I called Hitec tech support today and he said no problem running the 79XX series straight to 2S batteries. And their warranty policy is 2yrs, prettymuch no questions asked.

Yep, it is simple to install. I pulled the red and black leads from the servo plug and hooked them up to a micro deans and plugged that into the esc leads that go to the battery. The white/orange wire from the servo goes into the Rx like normal.

Yep, I've had the same results with Futaba servos.