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View Full Version : How to eliminate BEC on SeaKing 180



KartRacer
11-08-2012, 09:28 PM
My understanding is that to use a receiver battery on my SeaKing 180 instead of BEC I have to disconnect a wire on the connector to the esc.
Which one?
Red /hot?
Black/ ground?
White / signal?
So should I disconnect the red?
Thanks for your info?

dana
11-08-2012, 09:32 PM
Red

Chilli
11-08-2012, 10:38 PM
If you don't want to mess with the actual wires on the esc, you can add a servo extention cable and just clip/disconnect the red wire on that.

KartRacer
11-08-2012, 10:57 PM
Thanks wanted to be sure. I'll pull the red terminal out of plug.

iamandrew
11-09-2012, 12:55 AM
the MIDDLE ONEE!!!

SpeedFreak_86
11-09-2012, 01:00 AM
But does disconnecting the red wire actually disable the bec in the esc? Or does it not having that draw give the same affect as disabling it?

kevinpratt823
11-09-2012, 06:37 AM
But does disconnecting the red wire actually disable the bec in the esc? Or does it not having that draw give the same affect as disabling it?
It eliminates he draw, like you said.

siberianhusky
11-09-2012, 06:57 AM
I believe it's what's known as a switching regulator, it only "does what's required" in terms of load, no load - no amp draw, or very little.
A regulator like a 7805 just keeps cranking out the juice with the "excess" dissipating as heat.

JonD
11-12-2012, 04:42 AM
I believe it's what's known as a switching regulator, it only "does what's required" in terms of load, no load - no amp draw, or very little.
A regulator like a 7805 just keeps cranking out the juice with the "excess" dissipating as heat.

Sort of right, but not quite.

Yes a switching regulator "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, and does so with minimal losses (minimal heat). A linear regulator like the 7805 also "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, but it does so by the dissipating excess voltage (i.e. the difference between the LiPo cell voltage and the 5V - 5.5V required by the servos/receiver), in heat within the regulator.

And therein lies the problem with linear regulators. As the number of LiPo cells increases, the heat in the regulator increases even though the actual power required by the servo and receiver stays the same.

Example: Say the servo/receiver needs 0.5A at 5V. If the main Lipo battery is 7.4V then the power dissipated in the linear regulator is 0.5A x (7.4-5.0V) = 1.2 watts.
But if the battery is 22V then the heat dissipated in the regulator is 0.5A x (22.0-5.0V) = 8.5 watts! That is some serious heat!
Of course, if the linear regulator is not connected to anything at it's output (no load) , then that's fine, no power/heat at all dissipated in the regulator regardless of LiPo voltage 0.0A x (22.0-5.0V) = 0 watts

With "switching" style regulators (as per later version T180 ESC's) the losses (heat) in the regulator is pretty much a constant, regardless of LiPo voltage and load, typically about 20% loss in the regulator i.e 5.0V x 0.5A x 20% = 0.5W

So switching style BEC regulators are the only way to go. And I think pretty much that's how they all are today, including the internal BEC in the T180.

Cheers,

Jon

Mike Caruso
11-12-2012, 06:44 AM
Sort of right, but not quite.

Yes a switching regulator "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, and does so with minimal losses (minimal heat). A linear regulator like the 7805 also "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, but it does so by the dissipating excess voltage (i.e. the difference between the LiPo cell voltage and the 5V - 5.5V required by the servos/receiver), in heat within the regulator.

And therein lies the problem with linear regulators. As the number of LiPo cells increases, the heat in the regulator increases even though the actual power required by the servo and receiver stays the same.

Example: Say the servo/receiver needs 0.5A at 5V. If the main Lipo battery is 7.4V then the power dissipated in the linear regulator is 0.5A x (7.4-5.0V) = 1.2 watts.
But if the battery is 22V then the heat dissipated in the regulator is 0.5A x (22.0-5.0V) = 8.5 watts! That is some serious heat!
Of course, if the linear regulator is not connected to anything at it's output (no load) , then that's fine, no power/heat at all dissipated in the regulator regardless of LiPo voltage 0.0A x (22.0-5.0V) = 0 watts

With "switching" style regulators (as per later version T180 ESC's) the losses (heat) in the regulator is pretty much a constant, regardless of LiPo voltage and load, typically about 20% loss in the regulator i.e 5.0V x 0.5A x 20% = 0.5W

So switching style BEC regulators are the only way to go. And I think pretty much that's how they all are today, including the internal BEC in the T180.

Cheers,

Jon

Thank Jon,

Great info and it explains plenty to me!
I am new to Electric power and just could not understand why all of the ESC failures happening. Not saying BEC was always the cause but it sure looks like it is #1 reason.
I was just talking about these failures yesterday and said I wonder if it could be the use of Hi power draw servo's?

Mike

siberianhusky
11-12-2012, 07:57 AM
Cool! Always happy to lean more about something!
The only electronics I really know is how to make old hand wired guitar tube amps work again, they are simple!

dana
11-12-2012, 08:47 AM
Sort of right, but not quite.

Yes a switching regulator "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, and does so with minimal losses (minimal heat). A linear regulator like the 7805 also "does what's required" in terms of delivering the correct voltage to the load (servos and receiver) at whatever current the load requires, but it does so by the dissipating excess voltage (i.e. the difference between the LiPo cell voltage and the 5V - 5.5V required by the servos/receiver), in heat within the regulator.

And therein lies the problem with linear regulators. As the number of LiPo cells increases, the heat in the regulator increases even though the actual power required by the servo and receiver stays the same.

Example: Say the servo/receiver needs 0.5A at 5V. If the main Lipo battery is 7.4V then the power dissipated in the linear regulator is 0.5A x (7.4-5.0V) = 1.2 watts.
But if the battery is 22V then the heat dissipated in the regulator is 0.5A x (22.0-5.0V) = 8.5 watts! That is some serious heat!
Of course, if the linear regulator is not connected to anything at it's output (no load) , then that's fine, no power/heat at all dissipated in the regulator regardless of LiPo voltage 0.0A x (22.0-5.0V) = 0 watts

With "switching" style regulators (as per later version T180 ESC's) the losses (heat) in the regulator is pretty much a constant, regardless of LiPo voltage and load, typically about 20% loss in the regulator i.e 5.0V x 0.5A x 20% = 0.5W

So switching style BEC regulators are the only way to go. And I think pretty much that's how they all are today, including the internal BEC in the T180.

Cheers,

Jon
Uhm....huh? Yeah, uhhhhh.... Just unplug the red wire

JonD
11-13-2012, 05:39 AM
The only electronics I really know is how to make old hand wired guitar tube amps work again, they are simple!

Now that's a skill in it's own right! Nothing like the sound of a good classic valve guitar amp. I have a Vox AC30 myself and wouldn't change it for anything!