yoster

I found these ESC's cheap.. but want an opinion on them. On the 60a and 80a esc versions under "BEC Current" it says "no." (scroll down on the first link). What does that mean? Thanks for any input!

http://www.uce-tech.com/rcetechomopo...E%3Emore%3E%3E
http://www.made-in-china.com/china-p...or-FM80A-.html

gigelus2k3

BEC means Battery Eliminator Circuit. It's a voltage regulator that takes the battery input and lowers and regulates it for powering the receiver and servos. The connection to the RX is done through the throttle plug (the outer wires are ground and regulated 5V). The name comes from the fact that you don't need a separate battery to power the RX and servos.

Now, the problem with the BEC is that most of the time it's a linear regulator (i.e. it's behaving like a variable resistor on which the difference between the battery voltage and the 5V output drops). This means reduced efficiency and power dissipated in the ESC. The larger the input voltage, the larger the power dissipation. It's typical for an ESC supporting high input voltages (5s LiPo) to not have a BEC; the power dissipated while providing one Amp only would be (5*4.2V-5V)*1A=16W, which the puny ESC PCB can't handle.

I can't comment on the performance of these ESC's; they look well built, but unless someone has first hand experience with them, just order some and try for yourself; I bet they're pretty cheap.

Serban

yoster

So.. do these esc's allow it to power the servo's through the receiver like I do with my great planes esc's? I think that's what I am confused about when it said no current BEC or something like that.

..oh and what's that RPM setting all about that is in the description of it?

Magrat

No, these big guys don't provide a BEC function. I suppose the reasoning is that they will be used in a big plane with many big servos with voltages higher than 11V which would exceed most BEC regulator ratings. With these you should get a separate switching UBEC which will allow up to 5A current draw ( $16 from (Taiwa: http://www.wattsuprc.com.au/index.asp)

Don't know what RPM option refers to.

maiden-crash

Where does it say how much they cost?