external BEC vs. cap
 

i am curious after looking around in here where is the cutoff for needing something like this
https://www.tanicpacks.com/images/cc-bec.gif

vs. this

http://www.rctech.net/forum/attachme...pm1600-250.jpg

proposed setup ESC is mamba max pro on 3s in an scte
servo is spektrum s6040

thanks.

the cc bec is so you can run higher voltage and have more available amperage for your electronics . all a cap really does is flatten out voltage peaks and it does store some energy so if there is a drop from the esc it can help to keep the amperage up . i use the cc bec for crawlers running 3s and even 2s so you can run the radio gear off the main pack and the voltage is constant whereas a esc can fluctuate and overheat the internal bec,especially with good high torque servos

Look as a capacitor as a short term battery. It takes and holds a charge and gives it up on demand. It doesn't retain a charge for long. These are useful if you are using a motor or servo with a high power consumption that leaves the receiver starving for juice.

A BEC is a Battery Eliminator Circuit, it is meant to replace a receiver battery pack by taking power from the main motor battery and reducing the voltage for the receiver and servo. This is built into almost all modern Electronic Speed Controls. Generally the internal BEC reduces the voltage to 4.8 to 6V at 2 to 3 amps.

Some ESC's have BECs that can not handle a 3S (11.1V) lipo battery and in this case you use an external BEC as you pictured. An advantage of the CC BEC is that you can set the output voltage but its default is 5V.

thanks.

i guess the real question is when a given combination of parts in a given vehicle will require one or the other, or none.

Cap is a bandaid

External bec is a much better option

It takes load off the ESC
Protects against the internal bec failing (which will brick the ESC)
Allows the ESC to run cooler

$25 is cheap insurance

Cheers

A bit more to it than that.
The cap also acts as a noise supressor on voltage line into the RX
Ive actually seen this, Bluebird servo putting noise into the RX causing my Spektrum RX to restart. Cured with either a cap or descent servo

A Spectrum RX is good down to about APPROX 3v (ish), if the voltage will drops that far, a cap wont be enough to sort it.

If your esc's BEC output is only 1A, you need a external BEC if running hi-torqe servos, or cheapy servos that draw too much current.

i have the same truck and setup except i have the spektrum 6030. the cap made a big improvement but still gets taxed with heavy steering use. go with the external bec and be done with it!:nod:

thanks all.