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Mar 19, 2003, 06:02 PM
Tragic case
davidleitch's Avatar

Overload controller and ultimate bec?


Lets say you have a 40 amp controller and are using the UBEC.

Now for some reason (you run 80 amps through it) the controller shuts down, will the UBEC continue to function?

I am actually only running 60-70 amps according to Motocalc (hacker b407L 15x10 and 8x1700). Since it will only be on for 10-15 seconds it should be allright, but sure don't want to lose any more planes due to equipment failure.

txs
dave
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Mar 19, 2003, 08:11 PM
Registered User
Yes, the UBEC will continue. It has nothing to do with the controller and is actually a bypass circuit that is a direct feed, stepped down to Rx voltage, directly from the battery pack to the Rx.

Dave
Mar 19, 2003, 09:24 PM
Registered User
"Now for some reason (you run 80 amps through it) the controller shuts down, will the UBEC continue to function? "

It depends on why the controller shut down. Thermal protection or a short ?

I have used an "old rule of thumb" that anything over 40 amps (was 20, then 30, now 40 amps) should use a rec battery, not BEC. Even a UBEC may be applicable.

My concern, is that as the amps increase, failures are more likely for the batt pack, esc, or motor. A dead batt pack will still cause the UBEC to quit.

I have had a brake FET short in a brushed ESC that dumped the battery really fast, but this happened on the bench and not in the air. So as I watched the batt smoke I realized there was a problem.

If you use a BEC or UBEC and the motor seems low on power, shut the throttle off and land.

It is a tough call,
Dave