flyinsolo11

I know what a ESC is, but what is a BEC?

Thanks!

Rafael23cc

My Feedback: (6)

Battery Eliminator Circuit
Most ESC have a BEC integrated into their circuitry. If you have a separate BEC is most likely because the ESC you have is not capable of handling the batteries you want to plug into the ESC to power the radio components.

For example, some people are hooking up 4S batteries into a stock Trex 450 ESC. The BEC in the ESC is not capable of handling the 4S voltage and feed it to the receiver. So some people bypass the BEC, still use the ESC to power the motor but power their radio components from the separate BEC.

I hope I was of help. Sometimes this gets confusing.

Rafael

Druss

Just as a note, Rafael made a good explanation above but I'd like to point out that the Align RCE-BL35X is rated for 2-4 lipo so you could use the on board BEC but I wouldn't recommend it. I actually plan on putting ubecs on all my helis regardless of what the on board bec is rated for.

OldScaleGuy

My Feedback: (2)

I have a BEC that i sell through my company at Leisure RC Models. Don't really want to do a sales pitch but if you need them please PM me.

flyinsolo11

Thanks for clearing that up guys.

Just to make sure I have got it straight n my head, the ESC regulates how much power goes from the battery to the motor, right? The BEC basically protects the Rx and gear since there is such a high voltage?

Sorry Oldscaleguy- just curious about them- I don't need one yet. When I make the step up to a bigger bird, I will keep ya in mind

Rafael23cc

My Feedback: (6)

Electronic Speed Control
The ESC controls the speed of the motor.

In some sense, yes...

From what I know, all ESCs have built in BECs. (correct me if i'm wrong) The BEC is there to reduce the voltage of the battery to a level that the radio gear can handle. Yes, the ESC is there to just pass on the power of the battery to the motor by interpreting the throttle commands of the receiver. The BEC (built in or not) is there to provide power to the radio gear from the motor battery.

You could get rid of the BEC if you have an onboard battery for your receiver and servos, but if we are talking about small aircraft, it makes sense to have a BEC (built in or not) and reduce weight.

Rafael

flyinsolo11

Gotcha- makes sense now. Thanks!

OldScaleGuy

My Feedback: (2)

Most ESC's (not all) have a built in BEC. However, in a lot of cases the BEC does not function as well as it should. As an "insurance policy" you can add an external BEC a lot of times labeled as a UBEC with the U simply meaning Ultimate.

flyinsolo11

Gotcha. Are there different sizes?

For example, the ESCs come in different Amperage ratings.

OldScaleGuy

My Feedback: (2)

Not that i am aware of. The UBEC's i have are all the same.

Druss

there are definitely different ubecs, some will handle up to 10S lipo, others less. they will also handle different levels of amps, most are rated for around 3amps but you can get them up to 10amps.

you don't necessarily have to use a separate battery with them either, just solder it in parallel with the esc deans connector then remove the red wire from the esc to receiver.

OldScaleGuy

My Feedback: (2)

Sorry, i stand corrected. Here are the specs for the ones i carry.
Up to 3 amps continuous.
Input voltage 7.2 – 23v.
Output 5v or 6v using a jumper.
Weight: 14grams .5oz.

flyinsolo11

Thanks again for the clarification, guys!