to b.e.c. or not to b.e.c. ??

[Himalaya]

I always use BECs, include my 6S HPR115 and 12S 1.4m(55') mono setup. Others may prefer RX pack though I fail to figure why.

the Turnigy 120A ESC has SWITCHING BEC inside. I use HobbyWing 120A, the original version of the Turnigy one, on 6S, never disapointed me. Use a RX is just a waste of the money you've already spent and asking for the boring work to always be remembering to charge multiple packs.

[ozzie-crawl]

I take it you never took apart an good ESC to make a remark like this.
Every good ESC I took apart has a BEC on its own board or circuit, no I don't claim to have taken them all apart, so "spikes" in power have no affect on the BEC as they have no relation to one another. It is the same if adding a BEC on its own just placing it inside the neat package of the ESC. The extra heat produced is negligible compare to the ESC under load.
I've run several quality ESC under full 6cell load with build-in switching ESC at 80 to 100 amps with 4 - 5 servos and no failures, maybe I'm lucky?

at the end you should go with what you feel best for yourself.

not saying its a quality esc but have you taken a turnigy 180a apart looks like the bec is part of the esc using the same line to run the esc as the bec,wondering if people have disabled the bec on one of these and if it still works.

i run a rx pack in my cat 1800mah lasts for a long time,my tunnel hull doesnt have enough room so i run a ubec.

[GregS]

One thing to be aware of when using AA or AAA batteries in a battery holder for the receiver pack: A battery can shake loose in the holder and power to the receiver can be lost completely. This has happened to me on more than one occasion when the boat stopped dead. Once was in a race and I was hit by another boat as a result. I now wrap tape tightly around the batteries and holder to make sure this can't happen.

I don't like the idea of using rechargeables in a receiver pack as rechargeables can die very suddenly leaving you out of control. Non-rechargeables die very gradually so you're not likely to be totally surprised.

As for weight, it seems to me with the power we now have available, the problem is keeping the boats on the water so weight isn't necessarily a bad thing. I've had to add weights to my boats to keep them controllable.

Greg

[m4a1usr]

Hopefully we have shed some light on this subject. Seems like a Ford and Chevy debate tho.....

The answer is pretty simple. A speedo with a BEC function is limited to how many cells it can run with. Few are rated to full rated operating voltage while using the BEC function. Add to that speedo's with a BEC capability are not normaly opto-coupled. Whats that mean? You can get noise into the Rx thru the red power wire from things like your servo or long power wires from your motor leads.

Remember even in brushless systems there is emf being generated. Thats the noise or spike that can be induced in to your control system.

Now if you use a Rx battery pack you should be safe. And if you use a UBEC your about as safe as long as you dont run your Rx power wires parallel to those that can generate emf.

Its a matter of choice. Deal with the BEC capability of the speedo, remember to charge a seperate Rx pack, add batteries to a Rx power source or use a UBEC and ensure that it will provide Rx power over the range of your main power batteries.

The right UBEC powered by a 3 to 12S pack will never get below a min voltage level to provide power to your Rx if you run a LVC device. Its not going to happen unless the UBEC fails. The rest of the contenders have to deal their limitations. Everything comes with a price. Decide what side of the fence you want to sit on.


John

[blackcat26]

Well said John!