CC BEC ,design flaw.

You can increase the power handling of a zener by adding a power transistor. I think this is what what'snitro was saying except with a transistor. The transistor should be able to dissipate the power, but if you are afraid of melting wires, you could add a fuse. The nice thing about the zener shunt is that it is completely passive until needed.

[BrianG]

Originally Posted by kona

You can increase the power handling of a zener by adding a power transistor. I think this is what what'snitro was saying except with a transistor. The transistor should be able to dissipate the power, but if you are afraid of melting wires, you could add a fuse. The nice thing about the zener shunt is that it is completely passive until needed.

Yup, that should work. Once the output voltage exceeds the zener voltage, there will be enough current flow through the resistor to bias the transistor, which will dump the voltage to ground, which will then blow the fuse.

[What's_nitro?]

Originally Posted by kona

I think this is what what'snitro was saying except with a transistor. The transistor should be able to dissipate the power, but if you are afraid of melting wires, you could add a fuse. The nice thing about the zener shunt is that it is completely passive until needed.

Yeah that was what I meant. Sorry, I was too lazy to draw up a schematic, upload it to photobucket, and post it here. One small difference is that I would put the circuit across the power leads, but have it triggered from the output. Although you see full voltage either way, attaching it straight across the batteries (input) instead of the output of the BEC would allow for faster current rise and the fuse would blow sooner...