Discussion Castle Introduces CC BEC PRO

[lestingoy]

CC BEC PROs are in the oven now. First batch should ship early next week. Look for them at the usual dealers in about 2 weeks.

Technical details are listed in the attached docs.

Lee

[Raydee]

Hmmm, no indication that these will work in boats?

[OnTheSnap]

Can you explain why the output current drops so dramatically with the input voltage?

Is it a thermal issue, or just IR limitations of the switching FETs?

[Patrick del Castillo]

Originally Posted by OnTheSnap

Can you explain why the output current drops so dramatically with the input voltage?

Is it a thermal issue, or just IR limitations of the switching FETs?

As voltage goes up, duty cycle goes down, and current through the inductor and main FETs goes up. So it's both a thermal issue, and a maximum inductor current issue.

At 16V in, 5.0V out, the circuit runs at a 30% duty cycle. At 48V in, 5.0V out, the circuit runs at a 10% duty cycle. Therefore, peak currents at 48V are about 3 times as high -- this limits maximum output current at higher voltages.

[Andy W]

..a

[Vinger]

Looked at the press release and thought WAHOOO 20A for helis on 12S, untill I read the specs only 8A and the max continuous ever can only be 15A on 6S.

Come on guys/girls give us the truth instead of some sales hype. Pretty Pleeeeeezzzeee

[RC Man]

I have run a data recorder on my 620-size helicopter and only got peaks of 2.6 to 2.7 amps during 3D with high-powered servos. So 8 amps is way more than any helicopter flyer will need. Besides the radio wiring is the limiting factor. Not sure what the limit is but I’m sure it’s way below 10 amps.

I think that you might be right about advertising. Saying 20 amps and 12s in the same statement is very misleading. The table does not even list how low the input voltage has to be to get 20 amps output. It’s probably lass than 12v which means that you have to use a 3s LiPo to get max output current. That would be good for nitro applications.

I wonder why you are limited to 6s for cars and 10s for airplanes?

[Raydee]

I have been using a 3.5amp Western robotics BEC on my 6s Logo Vbar for two seasons now without a single glitch in the system. 8 amps is plenty unless you have some serious servo binding.

[Mike66]

Originally Posted by Vinger

Looked at the press release and thought WAHOOO 20A for helis on 12S, untill I read the specs only 8A and the max continuous ever can only be 15A on 6S.

Come on guys/girls give us the truth instead of some sales hype. Pretty Pleeeeeezzzeee

The specifications provided for the $40 CC BEC PRO are marginally better than the Western Robotics Ltd. specifications for the $55 WRL-HBECHV, the $60 WRL-HBECHC, or the $100 WRL-HBECS. It would be more helpful to know the output voltage of the CC BEC PRO for the test data provided. Even better would be test data for a range of output voltages.

The WRL website provides some test information, but it is lacking because it gives two of the three test parameters: input voltage, output voltage, and output current.

• HBECS was laboratory tested at 7A continuous output current with 9V out, but does not state the input voltage (9V to 58V range)

• HBECHC was laboratory tested with cooled ventilation at 5A continuous output current with 40V input voltage, but does not state the output voltage (4.4V to 8.4V range)

• HBECHV was laboratory tested with ventilation in excess of 3.5A output current with 58.8V input voltage, but does not state the output voltage (5V or 6V)

The test information for the HBECHV is not too bad because the range for the missing datum is one Volt. However, the ranges for the missing data of the other two products are significant.

The manual for the WRL-HBECS states that it "...MUST BE used cautiously with forced cooled air ventilation directed at the Hercules" for 10A continuous operation. Even though WRL provides a link to the manual, this information would be helpful on the website.

[Andy W]

Some people are never satisfied..

(further thoughts on this deleted..)
..a

[Mike66]

Originally Posted by Andy W

Some people are never satisfied..

(further thoughts on this deleted..)
..a

I do not know to whom that was directed, but just in case...

It is not a matter of being satisfied because I am going to buy a CC BEC PRO when I find a stocking dealer. However, I prefer specifications to be relevant and in context, not ambiguous with key information buried in manuals.

I can afford to test a $40 regulator. I prefer not to experiment with a $100 regulator.

[Andy W]

I was referring to this:

Originally Posted by Vinger

Looked at the press release and thought WAHOOO 20A for helis on 12S, untill I read the specs only 8A and the max continuous ever can only be 15A on 6S.

Come on guys/girls give us the truth instead of some sales hype. Pretty Pleeeeeezzzeee

They do need to clarify on the main page @ CC. They show the limits for the regular BEC, but have left them off for the Pro. I bet that changes on Monday!

Thankfully, their main distributor has it listed (from http://www3.towerhobbies.com/cgi-bin...?&I=LXYCA6&P=7 ):

SPECS:    Max Input: 12S LiPo (50.4V)
          Max Output Current: 20 amps peak
          Max Continuous Current: Input Voltage  Max Continuous Output Current
                                     16V                    15A
                                     24V                    13A
                                     32V                    11A
                                     40V                     9A
                                     48V                     8A

[Mike66]

Originally Posted by Andy W

They do need to clarify on the main page @ CC. They show the limits for the regular BEC, but have left them off for the Pro. I bet that changes on Monday!

Thankfully, their main distributor has it listed (from http://www3.towerhobbies.com/cgi-bin...?&I=LXYCA6&P=7 ):

SPECS:    Max Input: 12S LiPo (50.4V)
          Max Output Current: 20 amps peak
          Max Continuous Current: Input Voltage  Max Continuous Output Current
                                     16V                    15A
                                     24V                    13A
                                     32V                    11A
                                     40V                     9A
                                     48V                     8A

Thanks for the Tower Hobby link! This is the first vendor I have seen with a placeholder for the BEC Pro.

These are the same specs in the first post below. I did not go to the CC website until now so I did not realize that CC did not have the information there.

Still, it would be nice to have that third parameter (the output voltage) that corresponds to the table, unless the current is constant over the 4.8V to 12.5V output.

[RC Man]

The next think that they need is to make a helicopter version with dual outputs. One high current adjustable output for most of the helicopter and a 5v 2A output especially for the rudder servo.

I have tried the step down circuits be they are not regulators so I don’t like them that much. Some of my helicopters I use two BEC’s so I can get both 6v and 5v regulated.

Two BEC Pro’s would do the trick but it would be good to have it all in one package.


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CC,

BEC Pro Heli – Put it on the to-do list.

[lestingoy]

re specs. These aren't engineering spec sheets. Our ratings are for hobby use. Stock/default output for those ratings. 5.1 volts I believe.

Re dual output. That would be 2 becs in the same package. Not much advantage in that, just use 2 becs. Could event use a BEC and BEC PRO.

Lee