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THend
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Riddle me this Batman

Post by THend »

[:p]

I have the Athena 28 ESC. It has dual BEC, but I don't understand the statement where it handles more cells with less servos..?

states:
Handles 5-8 cells with five micro servos
Handles up to 10 cells with four micro servos
Handles up to 12 cells with two micro servos

It would seem to me that as the available voltage goes up, it could handle more servos. OR, is this because of the higher voltage it will draw more current...thus lowering the available voltage for the RX while the battery/esc is under load??
TheKid
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Post by TheKid »

Its not so much that it has to handle more current because of the increase in voltage. Your ESC likely has a "linear BEC", which means that it has to drop the voltage from the pack (3s lipo fresh off the charger is 12.6V) down to a useable level for the Rx and servos (something around 5.1V). So the more voltage you have, the more it has to drop the voltage, and thus the more heat is created...

I did once run my CC25 esc with a full size rx and 5 servos on a 3s lipo, and it recieved no ill effects. That was an awesome plane, though heavy. It had the standard 4 channels, plus flaperons and tailivators (i think thats what they are called). Rolled about 1 million times per second!
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Dane McGee
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Post by Dane McGee »

Terry, from the Castle website:



1. Why is it the more batteries I use, the less servos the BEC can handle?

The BEC converts the excess voltage from the power battery down to 5 volts by turning the excess voltage into heat. The higher the power battery voltage is, the more heat the BEC needs to dissipate. Making sure there is airflow over the BEC, which is on the LED side of the controller, helps with BEC heat dissipation and is important to BEC operation. The BEC is thermally protected and will shut down, then immediately come back on without being damaged, if the servo load is too much.
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