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04-26-2011 02:58 AM  10 years ago
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Newbe Guy

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Phoenix, AZ

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What is a BEC?....
AND exactly what does it do? thanks I'm sure this is an easy one for most on here!
Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 02:59 AM  10 years ago
Rogman88

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West Monroe, LA

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Battery
Eliminator
Circuit

Eliminates the need for a receiver battery as you run power off your main battery to the electronics.

Basically it turns the voltage down to acceptable levels for your receiver. I run a 44.4 volt system. My BEC takes the 44.4 volts off my main battery system and drops it to my specified 6 volts to run my electronics.
High Voltage just works better
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04-26-2011 03:03 AM  10 years ago
dkshema

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Cedar Rapids, IA

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It is a voltage regulator. Since most electric helis already have a pretty darn big, healthy battery on board to run the motor, the BEC also gets its input power from that battery, then regulates the raw battery voltage down to a range usable by the radio, servos, and gyro.

And, as already noted, it eliminates the need to carry an additional, separate battery to power the radio and rest of the electronics.
-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz
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04-26-2011 03:06 AM  10 years ago
Newbe Guy

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Phoenix, AZ

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okay. slowly Im remembering now. 6V electronics is standard? thats prolly what my 450 is running on? HELL I prolly have a BEC! is this optional?Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 03:07 AM  10 years ago
Newbe Guy

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Phoenix, AZ

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ok. thank you....

I THINK/THOUGHT my batt plugged into esc? lettme check...
Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 03:11 AM  10 years ago
Newbe Guy

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Phoenix, AZ

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ok... Batt --> esc --> rec./servos
.............(splits)--> motor

This is what I have. BEC is seperate unit from esc... physically?
Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 03:12 AM  10 years ago
Rogman88

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West Monroe, LA

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If it's a 450 sized heli, then your ESC may have a BEC on it that send power to your receiver through the throttle lead. Some only run at 4.8v and not 6V.
This is what I have. BEC is seperate unit from esc... physically?
I may have already answered your question but, BEC's can be run both internally on the ESC or externally like on my big heli that's running 44.4 volts.
High Voltage just works better
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04-26-2011 03:14 AM  10 years ago
Newbe Guy

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Phoenix, AZ

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ok...built in.

Because my stuffs not running @ 11.1v that makes sense.
Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 03:14 AM  10 years ago
Newbe Guy

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ok. either way. thanks alot all!Blade mSR / Trex 450se V2 - AMA#965156
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04-26-2011 03:48 AM  10 years ago
dkshema

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Cedar Rapids, IA

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If you're using a stock Align ESC on your 450, the ESC HAS a built-in regulator (BEC) for your radio power.

Many ESCs have a built-in regulator for the radio. The biggest problem with regulators built into the ESC is their maximum power rating. Many 35/45 amp speed controls with built-in regulators will state that the regulator is good to 3 amps. But that's usually not a continuous rating, it's a peak rating. For 450 sized and smaller helis, that's usually sufficient to do the job. If you start adding in some higher torque/speed servos, and go with a flybarless system, then that built-in 3 amp rated regulator may become marginal.

Some of the larger ESCs have regulators that are good up to maybe 5 or 6 amps, so there is some additional power for somewhat larger birds -- 500s, 550s.

But as you move up in heli size, you most likely will end up using an ESC that only powers the motor, and doesn't HAVE an internal regulator for the radio. In that case, you need an external BEC (Align has a 6-amp regulator that runs on a couple of LiPos, Castle Creations has their BEC [good up to 5 amps, with short duration 10 amp peaks], and their CC PRO BEC with even higher continuous rated current operation, and there are many more external regulators with a healthy power handling capability on the market).

Back to your 450 ESC.

Most likely your ESC connects to your receiver through the receiver's Throttle channel (so you can control the motor speed, the wire will be either orange or white in most cases, as that is the throttle signal wire). That same connector also probably has two more wires, most likely red or orange (+5V) and brown or black (ground).

The Red/Orange wire is the output of the ESC's internal 5V regulator, and provides power to your on-board electronics through the receiver -- the power pins on the connector blocks are usually all bussed together. The brown/black wire is ground and provides the ground return path for the current supplied by the ESC's regulator. Again, the ground signal is usually bussed to all other ground pins on the RX connector block.

If it's an Align ESC, you may have the option of programming the regulator output to 5 V, 5.5V, or 6V (or somewhere in-between if you have a voltmeter and patience). (Other brands of ESCs with built-in regulators may or may not have programmable voltage outputs).

Battery plugs into ESC, ESC provides high current, unregulated juice to the motor, and the ESC's built-in regulator provides lower current, regulated voltage to the electronics.

If you want to use an external BEC in conjunction with your ESC that has a built-in regulator, simply remove the red/orange wire from the connector block that plugs into your throttle channel. This disconnects the regulator's output voltage from the ESC, but continues to allow the throttle signal and the ground reference to remain intact. Then plug the output of your external BEC into either the RX battery port, or into any unused servo port of the RX and you're in business.

You disconnect the voltage regulator output of the ESC when using an external BEC for the simple reason that you don't want to have two different voltage regulators trying to drive the same input. This is because unless the two separate voltage regulators were designed to operate in parallel with each other, you'll most likely end up with a situation where the output of one or both regulators begins to oscillate, and that will do really bad things to BOTH outputs, and your radio will be VERY unhappy. So just make sure to disconnect the output lead of your ESC if you decide to go the external BEC route.

Many radio components were not originally designed for 6V power (especially high-speed tail-rotor servos), as they share their lineage with the "old" days when Nicad and NiMh 4-cell battery packs ruled. Those were 4.8 volt nominal systems, with fully charged packs maybe sitting at 6 volts briefly after a full charge, but that peak drops off real soon when you put a load on them. Most high-speed tail rotor servos will not tolerate being run above about 5.8 V for any length of time.

That's why the "5V step down" regulator is a popular item (nothing more than a 3 amp rated silicon diode placed in series with the power signal lead going to the servo, as a silicon diode, when forward biased, has a typical voltage drop of about 0.7 volts across its junction). Put 6 volts in, you'll get somewhere in the range of 5.3 volts out...safe enough for that TR servo.

So if you're going to set the output voltage on that ESC to 6V -- you best make sure the radio components will be happy with 6V, otherwise you'll let the smoke out, and typically it will be in the air and you'll bend your heli in the process.
-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz
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04-28-2011 03:30 PM  10 years ago
Newbe Guy

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Phoenix, AZ

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WOW! dkshema! What a great breakdown. Thank you for your time and info! IF anything... for now I guess Id look into the programability of the stock align 35A esc w/ bec. That IS what Ive got. Ill try to research on that. Thanks so much!
Happy flying.
Blade mSR / Trex 450se V2 - AMA#965156
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