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5A UBEC brown out

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Old 09-14-2014, 04:16 PM
  #1  
Peter_OZ
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Default 5A UBEC brown out

Folks,
my first venture into electric flight and having a few issues I need some informed advice on.

I have a EDF jet, runs a 8S Lipo pack, 100A ESC & 5A UBEC.

all onboard flight system servos, retracts etc work fin if run off a 6v NiMh flight pack and can spin up the fan fine running off the ESC/Lipo.

However if I try and power the onboarsd system servos off the UBEC and stor all the pots at once with flaps down the Rx browns out.

The jet runs small Turnigy nano type servos, 11 in total. I would think that a 5A UBEC could handle this but seems not.


thoughts?
thanks
Peter
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Old 10-01-2014, 01:37 PM
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chuckk2
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The problem may be the 8S Lipo voltage. Some UBECs don't have full current capability with the higher voltage batteries.
Another issue might be that the 5A UBEC isn't really 5A continuous.
Finally, I don't know exactly how things are wired as to wire size, length, connection scheme etc.
I have a 40 size P51 with electric retracts. The ESC has an internal switching BEC and an external 5A SBEC
is also used. The internal one is sufficient for "core" control surfaces, and the external one is used for flaps and the electric retracts.
This prevent the high momentary current draw of the electric retracts from having any impact on the critical flight controls.
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Old 10-02-2014, 12:39 AM
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jofro
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With that sort of load you should always power RX with separate battery, J.
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